LIBRARY,_ A 8: M COLLEGE. CAMPUS. = soon-use TEXAS AGRICULTURAL A V A. B. “CONNER, DIRECTOR . - BULLETIN NO. 477 JULY, 1933 DIVISION OF CHEMISTRY Vitamin A Content of Foods and Feeds AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. O. WALTON, President STATION STAFFT Administration : A. B. Conner, M. S., Director R. E. Karper, M. S., Vice-Director Clarice Mixson. B. A., Secretary M. P. Holleman, Chief Clerk J. K. Francklow, Asst. Chief Clerk Chester Higgs, Executive Assistant Howard Berry, B. S., Technical Asst. Chemistry: Veterinary Science : ‘M. Francis, D. V. M., Chief H. Schmidt. D. V. M., Veterinarian "F. P. Mathews, D.V.M., M.S., Veterinarian J. B. Mims, D. V. M., Asst. Veterinarian Plant Pathology and Physiology: J. J. Taubenhaus, Ph. D., Chief W. N. Ezekiel, Ph. D., Plant Pathologist Farm and Ranch Economics: G. S. Fraps, Ph. D., Chief; State Chemist L, P, Gabbard, M, S., Chief S- E- Aebllry. M- S» Chemist W. E. Paulson, Ph. D., Marketing J- F- Fudge. Ph- D» Chemist C. A. Bonnen. M. S., Farm Management E- C- Carlyle. M- 5-. Aest- Chemist 1“W. R. Nisbet, B. S., Ranch Management T- L- Cgiel‘. B- S" ASBt- Chemiet A. C. Magee, M. S., Farm Management A. J._ Sterges, M. S., Asst. Chemist Rum] Home Research: Ray Treichler, M. S., Asst. Chemist Jessie Whitacl-e, P11, D., Chief V W- H- Wfllkel‘. ASBt- Chemist Mary Anna Grimes, M. S., Textiles Velma Graham, Asst. Chemist Jeanne F. DeMottier, Asst. Chemist R. L. Schwartz, B. S., Asst. Chemist C. M. Pounders, B. S., Asst. Chemist Horticulture : S. H. Yarnell. Sc. D., Chief Range Animal Husbandry: J. M. Jones, A. M., Chief B. L. Warwick, Ph. D., Breeding Investiga. S. P. Davis, Wool Grader 1"J. H. Jones, B. S., Agent in Animal Husb. Entomology: F. L. Thomas, Ph. D., Chief; State Entomologist H. J. Reinhard, B. S., Entomologist K. Fletcher, Ph. D., Entomologist . L. Owen, Jr., M. S., Entomologist N. Roney, M. S., Entomologist C. Gaines, Jr., M. S., Entomologist E. Jones, M. S., Entomologist F. Bibby, B. S., Entomologist W. Dunnam, Ph. D., Entomologist . W. Moreland, B. S., Asst. Entomologi . E. Heard, B. S., Chief Inspector .......................................... .., Foulbrood Inspector S. E. McGregor, B. S., Foulbrood Inspector Agronomy: E. B. Reynolds, Ph. D., Chief R. E. Karper, M. S., Agronomist P. C. Mangelsdorf, Sc. D., Agronomist D. T. Killough, M. S., Agronomist Publications : A. D. Jackson, Chief st II l-i QWSTQFHPE-‘QP No. 1, Beeville, Bee County: R. A. Hall, B. S., Superintendent No. 2, Lindale, Smith County: P. R. Johnson, M. S., Superintendent “B. H. Hendrickson, B. S., Sci. in Soil Erosion "R. W. Baird, M. S., Assoc. Agr. Engineer No. 8, Angleton, Brazoria County: R. H. Stansel, M. S., Superintendent H. M. Reed, M. S., Horticulturist No. 4, Beaumont, Jefferson County: R. H. Wyche, B. S., Superintendent "H. M. Beachell, B. S., Junior Agronomist No. 5, Temple, Bell County: Henry Dunlavy, M. S., Superintendent C. H. Rogers, Ph. D., Plant Pathologist H. E. Rea, B. S., Agronomist S. E. Wolff, M. S., Botanist "H. V. Geib, M. S., Sci. in Soil Erosion "H. O. Hill, B. S., Junior Civil Engineer No. 6, Denton, Denton County: P. B. Dunkle, B. S., Superintendent "I. M. Atkins, B. S., Junior Agronomlst No. 7, Spur, Dickens County: R. E. Dickson, B. S., Superintendent B. C. Langley, M. S., Agronomist No. 8, Lubbock, Lubbock County: D. L. Jones, Superintendent Frank Gaines, Irrig. and Forest Nurs. Teachers in the School of Agriculture G. W. Adriance. Ph. D., Horticulture S. W. Bilsing, Ph. D., Entomology V. P. Lee, Ph. D., Marketing and Finance D. Scoates, A. E., Agricultural Engineering A. K. Mackey, M. S., Animal Husbandry Car ‘Dean, School of Veterinary Medicine. "In cooperation with U. S. Depar iln cooperation with Texas , Nutrition Soil Survey: "W. T. Carter, B. S., Chief E. H. Templin, B. S., Soil Surveyor A. H. Bean, B. S., Soil Surveyor R. M. Marshall, B. S., Soil Surveyor Botany: V. L. Cory, M. S., Acting Chief Swine Husbandry : Fred Hale, M. S., Chief Dairy Husbandry: O. C. Copeland, M. S., Dairy Husbandman Chief Poultry Husbandman Poultry Husbandry : R. M. Sherwood, M. S., J. R. Couch, B.S., Asst. Agricultural Engineering: H. P. Smith, M. S., Chief Main Station Farm: G. T. McNess, Superintendent Apiculture (San Antonio): H. B. Parks, B. S., Chief A. H. Alex, B. S., Queen Breeder Feed Control Service: F. D. Fuller, M. S., Chief James Sullivan, Asst. Chief S. D. Pearce, Secretary J. H. Rogers, Feed Inspector K. L. Kirkland, B. S., Feed Inspector S. D. Reynolds, Jr., Feed Inspector P. A. Moore, Feed Inspector E. J. Wilson, B. S., Feed Inspector H. G. Wickes, D. V. M., Feed Inspector SUBSTATIONS No. 9, Balmorhea, Reeves County: J. Bayles, B. S., Superintendent No. 10, College Station, Brazos County: R. M. Sherwood, M. S., In Charge L. J. McCall, Farm Superintendent o. 11, Nacogdoches, Nacogdoches County: . F. Morris, M. S., Superintendent "No. 12, Chillicothe, Hardeman County: "J. R. Quinby, B. S., Superintendent "J. C. Stephens, M. A., Asst. Agronomist No. 14, Sonora, Sutton-Edwards Counties: W. H. Dameron, B. S., Superintendent I. B. Boughton, D. V. M., Veterinarian W. T. Hardy, D. V. M., Veterinarian 0. L. Carpenter, Shepherd "'0. G. Babcock, B. S., Asst. Entomologist No. 15, Weslaco, Hidalgo County: W. H. Friend, B. S., Superintendent S. W. Clark, B. S., Entomologist W. J. Bach, M. S., Plant Pathologist J. F. Wood, B. S., Horticulturist No. 16, Iowa Park, Wichita County: C. H. McDowell, B. S., Superintendent L. E. Brooks, B. S., Horticulturist No. 19, Winterhaven, Dlmmit County: E. Mortensen, B. S., Superintendent “L. R. Hawthorn, M. S., Horticulturist F‘ rying Cooperative Projects on the Station: J. S. Mogford, M. S., Agronomy F. R. Brison, B. S., Horticulture W. R. Horlacher, Ph. D., Genetics J. H. Knox, M. S., Animal Husbandry A. L. Darnell, M. A., Dairy Husbandry TAs of July 1, 1933. tment of Agriculture. Extension Service. Vitamin A is one of the most important of the vitamins which must be present in the food of man and animal in optimum amounts for health 0r growth or good production. The units of vitamin A activity estimated in 107 samples of foods and feeds are tabulated together with all other determinations found in the literature or calculated from the data given. Vitamin A activity de- creases with the time of storage of dried milk, alfalfa hay, yellow corn, and other feeds. The vitamin A in crosses of yellow and white corn was found to be in proportion to the number of genes for yellow present. The storage of vitamin A in the grains of corn dur- ing growth was found to be fairly regular excepting during the fourth week, when it was high, and after the eighth week, when there was none because the process had been completed. The effects of other factors are mentioned briefly. The amount of vitamin A in butter and eggs depends upon the quantity in the feed. If an inadequate supply of vitamin A is fed to the hen, the quantity in the eggs laid decreases during the period of production. Human beings are provisionally estimated to require 1000 units of vitamin A per day. Bananas, carrots, yellow corn, cod liver oil, collard greens, liver, mustard:- greens, spinach, sweet potatoes, and turnip greens are low-priced sources of vitamin A and supply 1000 units for one-half cent or less. Other sources of vitamin A are discussed and a table gives the relative cosh of vitamin A in a number of feeds at the specified prices. Green pasture plants are the best sources for enabling animals to pro- duce milk or eggs high in vitamin A, or to store a reserve of vitamin A to tide them over periods of scarcity. CONTENTS Page Introduction A 5 Vitamins and their importance ..... _- __ 6 Method of estimating vitamin A activity _____ __ 8 Details of method of estimating vitamin A __________________________________________ _- 8 Tabulation of vitamin A activity of foods and feeds _________________________________ __14 Some factors which affect the vitamin A activity of foods ______________________ __19 Effect of time of storing of foods" v 19 Effect of drying or curing .20 Effect of canning 20 Relation to hereditary factors in corn 20 Relation to stage of growth of corn seeds -21 Effect of locality on vitamin A in corn.- 22 Effect of vitamin A in the food on vitamin A activity in A milk, butter, and eggs - 23 Vitamin A in some human foodsm 24 Cost of vitamin A in human food -. 26 Quantities of vitamin A required by animals and man __________________________________ __28 Vitamin A in some feeds for animals 29 Summary 30 References 31 BULLETIN NO. 477 July, 193s VITAMIN A CONTENT OF FOODS AND FEEDS By G. S. FRAPS AND RAY TREICHLER The importance of small amounts of various ingredients in the rations of man and animal has been recognized only in the last two decades. Before that time dietary standards were based almost entirely upon digestible protein and carbohydrates, even lime and phosphoric acid, though recognized as essential, not being given much attention. Since 1910 it has Table 1. Classification, functions, and sources of vitamins Vitamin Descriptive name Functions in body Excellent sources A Anti-ophthalmic Anti-infective Promotes growth, long life, health, vigor, appetite, and di- gestion. Prevents infections, and essential to reproduction. Cod liver oil, spinach, m u s t a r d greens, turnip greens, tomatoes, butter, milk, cheese, eggs, liver, carrots. B Anti-neuritic Anti-beri-beri Promotes appetite, digestion and growth._ Protects from certain nerve diseases, essential to re- production. Whole wheat, corn, rice, oats, peas, eggs, yeast, car- rots, spinach. C Anti-scorbutic Required for proper metabolism of bones, formation and main- tenance of teeth, and protects Cabbage, 1 e t t u c e, onion, spinach, tomatoes, lemons, oranges, celery, pineapple, from scurvy. strawberries. Sunlight, cod liver oil, other fish oils, eggs, salmon, milk, and viosterol. Required for formation and maintenance of bones and teeth and for protection of young against rickets. D Anti-rachitic Whole wheat, lettuce, vege- table oils, alfalfa, beans, corn, oats, rice, meat. E Anti-sterility Essential for reproduction. lean meat, turnip salmon, Liver, kidney, spinach, potatoes, greens, eggs, milk, tomatoes. Required for growth and for functions which prevent pellagra. G Anti-pellagric been recognized that deficiency in growth or production as Well as various disorders from which man and animals suffer may be due to deficiencies of various substances. Very small amounts of some of these substances are required, but their presence in adequate amounts is a necessity for health or normal growth and development. These substances include iron, copper, iodine, manganese, and vitamins. Deficiencies of one or more.‘ of these substances in the diet may cause diseases such as anemia, pellagra, scurvy, eczema, rickets, or goiter, as well as susceptibility to other diseases, retardation in growth of young animals, and deficient production of milk or eggs. 6 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Vitamins are organic substances which are present in very small amounts in foods and are known to be essential to the health of animals (55). VITAMINS AND THEIR IMPORTANCE The exact number of the vitamins and their nature has not yet been ascertained. Vitamins are studied by means of feeding experiments on animals and the complete or partial lack of them in the food is recognized by the failure of the animal body to grow or perform some of its functions. An outline of the classification, functions, and occurrence of vitamins is given in Table 1. Following are brief descriptions of the vitamins known at present (55, 64): Vitamin A: This is also called the fat soluble A, anti-ophthalmic, or anti-infective vitamin. Its presence in sufficient amounts promotes ap- petite, digestion, growth and long life, maintains health and vigor, prevents infections, especially of the eyes and lungs, and is essential for normal re- production, lactation, and rearing of the young. When deficient or absent from the diet the animal may, if young, have a retardation of growth and development. Animals receiving insufficient vitamin A may suffer a loss of appetite and are susceptible to infections of the glands at the base of the tongue, of_ the sinuses in the ears, and of the lymph glands, lungs, nose, and skin. The animals may also suffer from night blindness and infections of the eyes, and infections of the kidney, bladder, and ali- mentary canals. Excellent sources of vitamin A are green feeds such as spinach, mustard, or grass. Carrots, tomatoes, and cod liver oil are also good sources of vitamin A. Vitamin A is closely related to carotene, a yellow coloring matter found in carrots, yellow corn, green vegetables. and other foods. Carotene is converted into vitamin A in the body. Vitamin A survives ordinary processes of cooking but is partly destroyed by long boiling, as in making certain stews. Vitamin B: This is also called the anti-neuritic or anti-beri-beri vitamin. Its presence in sufficient amounts promotes appetite, digestion, and growth. It protects the body from such nervous diseases as beri-beri and poly- neuritis. It is required by the mother for normal reproduction and lactation. When insufficient amounts are in the food eaten, there occurs a decrease of appetite and impairment of digestive processes, loss of weight and vigor, and impaired growth of the young. Beri-beri or polyneuritis may also occur. Vitamin B is found inwhole cereals such as wheat, corn, rice, oats, barley and in peas, wheat‘ bran, egg yolk, yeast, rice polish, and rice bran. Smaller amounts are found in other foods. Vitamin B is partly destroyed by long-continued cooking, especially if the water is alkaline, but only a part is destroyed by ordinary processes o_f cooking. Vitamin C: This is also termed the anti-scorbutic vitamin. When present in sufficient amounts it protects the body from scurvy, and promotes the VITAMIN A CONTENT OF FOODS AND FEEDS 7 proper metabolism 0f the bones and the normal formation and maintenance of the teeth. When present in insufficient amounts in the diet, the disease known as scurvy will occur, which is manifested by spongy and bleeding gums, pains and swelling in the joints and limbs, or hemorrhages of the mucus membranes or skin. The bones may also lose so much lime and phosphoric acid asto become fragile. The teeth may decay or become loose or even be shed. There may be a loss of weight or appetite and a sallow complexion. Vitamin C is found in oranges, lemons, and in vege- tables such as spinach, tomatoes, lettuce, onions, and cabbage. Smaller amounts are found in a number of other vegetables. Vitamin C is partly destroyed by cooking, especially if it is long continued. Ordinary cook- ing is not highly destructive. Vitamin D: This is known as the anti-rachitic vitamin. When present in sufficient amounts it regulates the absorption and metabolism of the lime and phosphoric acid in the bones and teeth. It is, therefore, required for the proper formation and maintenance of bones. When an insufficient amount is in the diet, a bone disease known as rickets may occur, especially vzith children and young animals. This is manifested in soft and fragile bones, enlargements of the wrist, elbow and junctions of the ribs, softening of the bones of the head, or bow-legs or knock-knees. A general muscular weakness and instability of the nervous system may occur together with a low content of lime and phosphoric acid in the blood and bones, and defects in the teeth such as decay or soft teeth. Vitamin D is most abundant in cod liver oil and some other fish oils. It is also supplied by sunlight or ultraviolet light or by foods irradiated by ultraviolet light. Vitamin D prepared by irradiating ergosterol is effective for rats but not for chickens (61). It occurs in eggs and salmon in good amounts, while small amounts are found in butter and milk. A few minutes of bright Texas sunshine is sufficient to supply a rat with all the vitamin D it needs for 24 hours, and is probably sufficient for other animals also. Vitamin D is quite stable and not destroyed by ordinary processes of cooking. Vitamin E: This is known as the anti-sterility vitamin. Although other vitamins are also required for reproduction, it is necesary for the normal reproductive functions of both males and females. If a sufficient amount is not present in the food, the animals become sterile. It is found in good quantities in lettuce, wheat, Wheat germ, and in a number of ordinary feeds, such as alfalfa, barley, beans, corn, peas, rice, and oats. Vitamin E is not destroyed by ordinary processes of cooking. It is remarkably stable. Vitamin G: This is also known as the anti-pellagric vitamin. When present in sufficient amounts it aids in preventing pellagra, although other factors are probably concerned in the prevention or cure of pellagra. When an insufficient amount is present in the food the animal may suffer from pellagra, which manifests itself in disturbances of the digestive tract. darkening and thickening of the spleen, soreness and inflammation of the 8 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION tongue and mouth, and nervousness and mental disorders. It is found in good quantities in yeast, liver, kidneys, spleen, and lean meat, as well as beet leaves, potatoes, spinach, turnip greens, eggs, milk, and salmon. Vitamin G is not destroyed by ordinary processes of cooking, but is relatively stable to heat. Other vitamins: It appears that vitamin D in cod liver oil is different from that in irradiated ergosterol, since the former will prevent bone- weakness in chickens but the latter will not (61). Evans (13) applies the term vitamin F to unsaturated fatty acids which appear to act as vitamins. It’ also seems possible that the vitamin B complex may be split into three other vitamins (29) in addition to vitamin B and vitamin G already accepted. METHOD OF ESTIMATING VITAMIN A ACTIVITY There ls no chemical method for estimating the vitamin A content of the various foods and feeding stuffs; so the estimation must be made by a biological method. The method consists in measuring the growth of rats fed upon a ration complete except for vitamin A, and to which a weighed amount of the material to be tested is added. The estimation measures the vitamin A activity, since the results may be due to carotene or other precursor of vitamin A, as well as to the vitamin A itself. For the sake of brevity, vitamin A is frequently used in place of vitamin A activity in this Bulletin.. The animals used must have previously been fed upon a ration free of vitamin A until the vitamin A stored up in the body of the animal has been almost removed (60). This is manifested by the animals begining to decline in weight. The determinations made by the method given above are expressed as rat units, a rat unit being a gain of 24 grams in eight weeks. An in- ternational unit has recently been adopted (27) which is .001 milligrams of a certain preparation of carotin. Direct comparisons of the international unit and of the rat unit have not yet been published, but according to a private communication (1) it has been found in one laboratory that the rat unit and international unit are practically the same. It is desirable to standardize the rat units of the various laboratories in terms of inter- national units. They may not be exactly the same in different laboratories on account of differences in procedure. ' Details of Methods of Estimating Vitamin Activity In accordance with the established procedure in this laboratory all quantitative vitamin A determinations were made by using a modified Sherman and Munsell procedure commonly known as the unit method (14). ' All experimental animals originated from our own stock colony composed ‘of Albino rats, descendants of breeding rats received from the Wistar Institute and the Albino Supply Company, Philadelphia, Pennsylvania (14). The breeding animals were selected for uniformity of growth. VITAMIN A CONTENT OF ‘IFOODS AND FEEDS 9 The breeding stock has access to fresh water and a stock ration consist- ing of the following: Corn meal .................... _. .1200 grams Cottonseed meal _____________________________________________________ __ 200 grams Powdered whole milk __________________________________________ _- 600 grams Alfalfa meal _________ -_ 40 grams Sodium chloride 10 grams Calcium carbonate 10 grams Ferric citrate __ 1 gram Copper sulphate ______ __ .5 gram The ferric citrate and copper sulphate were added after April 15, 1931. Fresh cooked bones are fed once a month and canned spinach is given once a week. At parturition the females are removed to individual cages provided with suitable material for making a nest and continued on the stock ration, fresh water, and canned spinach once a week. At the end of 21 to 28 days the young weigh between 35 and 45 grams. _At this point they are weaned and placed in individual cages with raised wire bottoms so as to prevent their eating the excrement, which may contain vitamin A. The experimental animals are provided with fresh water and an irradiated basal ration deficient in vitamin A. This ration consists of the following: Corn starch (purified) ______ ____________________________ -_ 130 grams Casein (purified) . . _ _ _ . . . _ . _ __ 40 grams Powdered yeast 71 _____ 1 20 grams Salt mixture __________________________________________________________ __ 8 grams Sodium chloride 2 grams To purify the casein, it was spread on trays in an electric oven to a depth of one-fourth inch, heated at a temperature of 100° C. for 24 hours, and stirred thoroughly twice at equal intervals of time (14). The corn starch was treated in the same manner. Destruction of vitamin A was found to be completed in both casein and corn starch after having been treated in the above-mentioned manner. The palatability was not affected by the heat and oxidation treatment. The salt mixture used was a modification of the salt mixture of Osborne and Mendel and has already been described (14). A supply of vitamin D was furnished by irradiating the basal ration by means of a quartz mercury vapor arc lamp at a distance of 18 inches for 30 minutes. The basal ration was spread in a thin layer directly under the lamp and stirred thoroughly at the end of 15 minutes. The rats were weighed when placed upon the basal ration deficient in vitamin A. After 28 days the rats were weighed every other day until their weights remained constant for 6V days or until a loss in weight occurred. Weighed quantities of the feed to be tested were then fed daily for eight weeks. If test feed was rich in vitamin A it was in some cases fed every other day or twice a week. The rats were weighed once a week on the same day. Records were kept of the amounts of the basal ration eaten. 10 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Six rats were usually placed on each quantity of feed being tested. An attempt was made to feed such a quantity of the material that the rats would make an average gain of 3 grams per week for the test period of 8 weeks. Considerable difficulty was encountered in finding the right amount t0 produce exactly this ‘gain. Usually the estimate is made from the average gain in weight of two lots of rats, the gain of one lot being slightly less than 24 grams gain in 8 weeks, the gain of the other lot being somewhat more than 24 grams in 8 weeks. With some samples so low in vitamin A that it is impossible for the rat to ingest daily a sufficient quantity of vitamin A to bring about the necessary gain in weight, a mixture was used that contained, in addition Table 2. Estimation of vitamin A in feeds and foods I 9.. M 0 < -° ° Description =44 °° 5 “.5 $3 “l ‘PM °"°"" i ° s‘? _ is ~=z:5;m*s;a§s§§_§=§g“ 26282 Alfalfa, leafy hay ......................... 3 4 1 31 .3 3.3 26312 Alfalfa stemmy hay . . . . _ . _ . . . . . . . . _ . ..1 3 2 1 18 .35 3 32789 Alfalfa leaf meal, original .................... _. 1 12 6 23 .1 10 .15 6 2 34 Stored 11 months .......................... ..l .2 6 1 16 .25 4 .3 6 4 44 24427 Alfalfa leaf meal .................................. _. 1 | 4 1 13 .15 7 2 6 6 39 33973 Alfalfa leaf meal __________________________________ __ .1 6 6 73 .05 20 .033 6 2 —7 34860 Alfalfa leaf meal, machine cured .... .. .02 6 5 63 .03 6 5 56 .015 66.6 36169 Alfalfa meal ............................................ __ .066 6 2 24 .066 15 35120 Alfalfa meal, machine-cured .026 6 4 44 .02 50 35121 Alfalfa meal, sun-cured ______________________ 1 .053 6 3 5 .1 6 4 41 .08 12.5 .133 6 6 58 34885 Alfalfa stem meal ___________________________________ _, .4 6 4 44 .36 2,4 35107 Banana, raw ____________________________________________ 1 .33 6 4 14 .5 6 4 32 .45 2.0 .66 6 5 59 36314 Bermuda grass, dried in vacuum ...... .. .01 6 5 35 .008 120 .016 6 4 51 36294 Burr clover, dried in vacuum ______________ 1 .003 6 1 23 _()05 200 .01 6 6 88 34182 Carrots, yellow, dried in air ______________ __ .02 6 2 -15 .1 6 6 91 .04 25.0 36027 Carrots, yellow, dried in vacuum ....... .. .006 6 2 —-1 .03 6 4 62 .013 77.0 35108 Carrots, raw. yellow .............................. .. .02 6 5 67 .015 66.6 .08 6 6 68 35974 Carrots, raw, yellow _______________________________ .02 8 6 11 | .026 6 6 49 .023 43.0 35672 Carrot juice, sterilized __________________________ _, .24 6 _ 0 0 0 1.00 6 0 34183 Carrot tops, dried in air ______________________ __ ,1 6 5 63 _()6 16 30275 Corn, Bloody Butcher, Beeville __________ __ .3 4 1 19 . .4 4 4 48 .3 3.3 30311 Corn, Bloody Butcher, Temple, orig. .15 4 1 11 .2 6 3 34 .2 5 Ditto, stored 11 months ____________ __ .3 4 1 -_2() Ditto, stored 18 months _____________ 1 .7 5 4 16 _8 L2 28635 Corn, Fentress Strawberry, Angleton .8 2 2 1 .9 6 3 26 .9 1.1 1.0 4 4 50 28647 Corn, Fentress strawberry, Troup ..... .. .9 4 2 28 .9 1.1 1.0 2 2 48 VITAMIN A CONTENT OF FOODS AND FEEDS 11 Table 2. Estimation of vitamin A in feeds and foods—Continued. | N Q < < 24E 2.2 "as-E "avg 26% 2365555., 0:28 D . . “mg ‘mg ‘FQHQQQ pS-nalb-‘oo .58; escrlptlon (SW58 243g 2g“ gag h§.awsdha 4-7 ~= = w “MwU-H-‘s w 28978 I Corn, Fentress strawberry I Nacogdoches .... __ . ................................ 1 .7 6 3 16 ~ .9 2 2 52 1.0 2 2 35 .9 1 1 29033 Corn, Fentress strawberry, Lubbock, .8 2 2 31 .8 1 2 .9 4 2 41 Ditto, stored 15 months ............ 1 .9 4 3 ———5 1. 1 29037 Corn, Fentress strawberry, Beeville original .................................................. 1 .9 2 2 67 .5 2 1.0 2 2 102 Stored 15 months ......................... 1 .7 4 3 24 .7 1.4 29134 Corn, Fentress strawberry, » College Station ____________________________________ 1 .4 4 3 25 .4 2.5 30213 Corn, Fentress strawberry, Troup ...... .. .5 4 4 34 .4 2.5 .6 2 1 67 30384 Corn, Fentress strawberry, Denton .3 4 2 15 .4 6 1 25 .5 2 2 39 .4 2 5 30274 Corn, Fentress strawberry, Beeville .4 4 3 13 .6 4 3 37 .5 2 30495 Corn, Fentress strawberry, Weslaco .2 2 2 24 .2 5 33316 Corn, Ferguson yellow dent, Beaumont .15 6 4 9 .2 6 5 30 .18 5.5 33317 Corn, Ferguson yellow dent, I Nacogdoches ......................................... _. .15 6 1 ——8 .2 6 5 25 .2 5 33318 Corn, Ferguson yellow dent, College Station .................................... 1 .15 6 4 8 .2 6 4 22 .2 5 34980 Corn, Ferguson yellow dent, 14 days after pollination .................................. 1 .6 6 6 31* 5 2 .8 6 6 46* 34984 Corn, Ferguson yellow dent, 21 days after pollination ................................. __ .4 6 6 28 4 2.5 .8 6 6 75 35119 Corn, Ferguson yellow dent, 28 days after pollination .................................. 1 .2 6 6 37 .18 5.5 .4 6 5 53 35122 Corn, Ferguson yellow dent, 35 days | after pollination ................................ 1 .2 6 5 56 .15 6.6 .4 6 6 50 35128 Corn, Ferguson yellow dent, 45 days after pollination ................................ 1 .15 6 6 32 .14 7.1 .2 6 5 53, .3 6 6 51 35126 Corn, Ferguson yellow dent, 50 days I after pollination ................................ .. .2 6 3 42 .15 6,6 .2 6 5 54 . 35165 Corn, Ferguson yellow dent, 57 days ' after pollination ................................ _. .15 6 4 29 .15 6,6 .2 6 6 36 33309 Corn, red pericarp, yellow endosperm .2 6 5 6 ’ .3 6 3 16 .4 8 7 20 .4 2.5 36375 Corn, yellow ............................................. .. .15 6 2 28 .2 5 .2 6 2 20 ' .25 6 4 87 33918 Corn feed meal, original ...................... 1 .15 7 2 12 - .25 6 4 19 .3 3 3 .3 6 4 26 Ditto, stored 7 months .............. .. .3 6 2 —4 .4 6 3 25 4 2.5 34884 Corn feed meal ....................................... 1 .4 6 6 3 3 3,3 *6 Weeks. 12 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Table 2. Estimation of vitamin A in feeds and foods—Continued. i feed | h b0 q’ w h < gig _ _ 28g sag 2E2 2:53 ‘gafgsgag p35 Description flqflg 5E5 0'2: ‘$3.5: g-g-Eg cg!» 3 Q c: 223,112 “émoowgflggpfird .0 > i> p‘ 30995 Corn meal, yellow original ................ .. .3 4 I 2 62 2 5 Ditto, stored s months. .3 4 4 as 3 3.3 36170 Hegari stover ...................................... .2 6 I 3 9 I .3 6 3 29 .3 33 | .4 6 5 85 I 32304 Kafir, black ____________________________________________ .. 2.0 I 6 1 —31 32305 Kafir, red . .. 2.0 I 6 2 11 29722 Kafir, white ................ .. 2.0 l 4 1 37 29415 Loco weed, air dried ............................ .. I 4 4 55 .1 2 2 48 .06 I 16 33249 Milk, whole dried, original ________________ ._ .08 6 2 ——18 .1 6 3 22 1 10.0 .15 6 4 33 Ditto, stored 12 months ............ .. .2 6 4 17 .3 6 6 22 .3 30 .5 6 6 61 35030 Milk, whole dried .................................. _. .1 6 3 —1 .15 6 3 23 .15 6.6 35125 Milk, whole dried .................................. .. .24 6 6 57 .3 I 6 6 52 .12 6 4 10 .15 6.6 33258 Okra pods, dried in air ......................... .. .05 6 1 1 .2 6 1 28 .4 6 6 39 .3 3 32928 Orange peel and pulp, dried .............. .. .2 10 4 32 .2 5.0 .3 6 4 60 25058 Orange peel and pulp, dried ........... .. .2 2 0 .3 8 6 21* .3 30 .4 10 4 40 30212 Orange peel and pulp, dried ............. .. .25 4 3 24 .25 4 .3 4 4 36 30490 Peanut meal ........................................... .. 2.0 4 2. 46 32224 Peanut meal .......................................... .. 1.5 4 0 2.0 4 0 32041 Peas, blackeyed, green, dried in air .2 4 1 11 .3 6 3 14 .4 2 .45 5 2 16 .5 2.0 Ditto, stored 9 months ................ .. .7 4 1 38 30186 Peas, green, dried in air ..................... .. .08 4 4 30 .08 12.5 .1 2 2 42 35746 Pecan meats, Burkett variety, original .6 6 6 25 .6 1 6 1.0 6 6 59 .8 6 4 53 Ditto, stored 8 months .............. .. .6 6 3 19 1.0 6 1 44 35747 Pecan meats, Texas prolific ................ .. .6 6 4 39 .5 20 .8 6 5 59 34977 Pepper, green dried in air .................. .. .02 6 2 17 .05 6 5 26 .05 20.0 32060 Pepper, green dried in air .................. ._ .02 4 3 21 .025 40.0 , .02 6 0 Ditto, stored 18 months .......... _.I .05 6 2 ——1 25918 Potatoes, yellow sweet, porto Rico I variety, dried in air, Nacogdochesm. .5 2 1 39 5 2.0 1.0 4 3 67 I 25958 Potatoes, yellow sweet, Porto Rico variety dried in air, Marion county .5 3 3 22 I 5 2.0 33783 Potatoes, yellow sweet, dried in air, Bryan .................................................... .. .3 6 1 21 .4 6 4 14 .5 6 5 64' 3 3.0 .8 6 6 76 *6 Weeks VITAMIN A CONTENT OF FOODS AND FEEDS 13 Table 2. Estimation of vitamin A in feeds and foods—Continued. I g‘ mi i) u; 7-1 4 gig _ _ E”;- “as-gflsg"; 3E6 §3"<3.E§.Eg'8 £85 Description Egg 5,333 523 5.5g gg-‘gggggbfi h; i: U 21.592 fl > 37082 Potatoes, yellow sweet, Porto Rico variety, dried in vacuum ................. .. .01 6 1 5 .02 6 4 27 .02 50 .03 6 6 44 36942 Potatoes, yellow sweet, Porto Rico I variety _________________________________________________ -1 .02 | 6 | 0 | 0 | i .04 6 3 8 .06 6 5 45 .05 20 33784 Potatoes, yellow sweet, peelings, dried in air ......................................... ., .8 6 4 41 .5 2 1.0 6 5 43 35742 Potatoes, yellow sweet, Porto Rico variety, raw _______________________________________ 1 .033 6 6 56 .02 50 .066 6 6 75 .0066 6 2 —15 .016 6 3 19 35831 | Sorghum silage ..................................... _. .1 6 0 .2 6 3 40 .18 5.5 .4 6 5 55 37106 ] Sorghum silage ........................................ 1 .1 6 3 39 .1 10 .2 6 5 62 .3 6 1 19 36241 Spinach, canned (moist solids) .......... _. .01 6 5 30 .01 100.0 .02 6 6 79 37086 Spinach, canned (moist solids) .......... ._ .008 6 3 57 .007 140 01 g 4 39 | 012 6 5 60 ' 37110 Spinach, canned, dried in vacuum ..... _. .0026 6 2 20 .003 333 .003 6 4 30 .005 6 4 61 | 36338 Sudan grass, dried in vacuum ............ 1 .01 6 6 107 I .02 6 5 57 .03 6 6 64 .0016 6 0 .003 I 6 0 I | .006 6 1 1 29455 I Mustard tops, dried in air, original... .02 4 3 7 .03 2 2 21 .03 33 .03 2 0 I Ditto, stored 11 months ............. H .05 4 0 | I to the test feed, a known amount of yellow corn oi; which the vitamin A content was known. Additional gains in weight above that caused by the vitamin A in the yellow corn in the test ration was attributed to the g vitamin A in the feed being tested (14). In some cases it was found necessary to mix the feed being tested with casein or other material used in the basal mixture in order to make it more palatable. Only enough of such mixture to last less than two weeks was prepared; in this way any loss of vitamin A due to oxida- ' a tion was reduced to a minimum. Some samples too moist for preservation were dried at about 65° C. Other samples were fed in the fresh moist condition, new supplies being secured from time to time. Still others were dried in a vacuum oven at a temperature of 95 to 100° C. for 5, 7 or 12 hours. Butter was melted at a temperature of 60° C. and the Water and curd allowed to settle. V“ The clear butterfat was then decanted off and filtered through ordinary 14 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION filter paper into brown glass bottles tightly stoppered and kept in an electric refrigerator at a temperature of about 6° C. Whole eggs were weighed, and boiled for 10 minutes; the yolks were then removed and Weighed. The yolk was cut up and kept in glass bottles in the refrigerator. Fresh samples o_f yolk were prepared each week. TABULATION OF VITAMIN A ACTIVITY OF FOODS AND FEEDS Quantitative estimations of the vitamin A activity in foods and feeds re- ported in the literature are comparatively small in number. The most exten- sive report is that of Rice and Munsell (52), who list 59 foods. Fraps (14) reported on a number of samples of corn. Quantitative measure- ments have been made by other Workers, or their results reported in such a Way that an estimate of the quantity could be made. The details of some of our quantitative tests are given in Table 2. Other details have been published elsewhere (5, 14, 16). The vitamin A activity in terms of Sherman-Munsell rat units of a number of foods and animal feeds, as found in the work presented in this Bulletin, and elsewhere in the literature, or calculated from data in the literature is given in Table 3. The numbers in the last column of the table refer to the source of the data as given in the references cited at the end of this Bulletin. If these are marked T, the work was done at the Texas Station. There is considerable variation in the vitamin A content of a particular food or feed, dependent on conditions of growth, storage, or other factors. These are discussed below. The units. of vitamin A are rat units, estimated by the method described, and based upon the edible portion of the feed. Since the vitamin A was not separately estimated, and since vitamin A can be made from carotene in the animal body, the units here used really represent the vitamin A activity of the food, and not the vitamin A alone. The method for estimating vitamin A is not highly accurate. Ordinarily an error of ten per cent may be expected. For this reason the results in Table 3 are rounded off. In some cases, where the number of units Table 3. Approximate number of units of vitamin A in foods and feeds ' Litera- Units Units Units ture per per per refer- gram ounce pound ence . number Alfalfa, machine-dried .................................... a . ....... 100 i 2,835 45,360 54 Alfalfa, sun-cured ................................................... .. 20 567 9,072 54 Alfalfa, field-cured and exposed to rain." 12 340 5,440 54 Alfalfa, field-cured and exposed to rain ....................... .. 14 396 6,336 54 Alfalfa leafy hay ............................................................. .. 3.3 93 1,488 T17 Alfalfa stemmy hay .......................................................... .. 3 85 1,360 T17 Alfalfa meal ........................................................................ _. 12.5 354 5,664 T 17 Alfalfa meal ........................................................................ .. '15 425 6,800 T 17 Alfalfa leaf meal ................................................................ __ 20 567 9,072 T17 Alfalfa leaf meal ................................................................ ._ 10 283 I 4,528 T17 Alfalfa leaf meal ................................................................ .. 7 198 3,168 T17 Alfalfa leaf meal 20 567 i 9,072 T17 VITAMIN A CONTENT OF FOODS AND FEEDS 15 Table 3. Approximate number of units of vitamin A in foods and feeds—Continued ‘ Litera- Units Units Units ture per per per refer- gram ounce pound ence number Alfalfa leaf meal, machine-dried ____________________________________ .. 66.6 1,888 30,208 T17 Alfalfa leaf meal, machine-dried __________________________________ .. 5O 1,417 22,672 T17 Alfalfa stem meal 2.4 68 1,088 T17 Apples . .5 15 240 52 Apples .5 15 240 2 Apricots, fresh 50 1,417 22,672 45 Apricots, fresh frozen 7 198 3,168 46 Apricots, sundried, sulphured ................. .'. ..................... .. 12 340 5,440 45 Apricots, sundried, unsulphured .................................... .. 8 220 3,620 45 Artichokes ............ __ 3 85 1,360 52 Asparagus 1.2 35 560 52 Bacon .2 5 80 52 Banana ,,,,,,, __ 2 56 896 2 Banana I 2 56 896 T 17 Banana 3.5 100 1,600 52 Banana 2 56 896 T 17 Barley, less than .... .. 1 28 448 55 Beans 3.6 102 1,632 3 Beans, canned navy 0.5 15 240 52 Beans, dried lima ' 0 0 0 52 Beans, string 5.2 150 ' 2,400 52 Beets . _______ _. . 0.2 5 80 52 Bermuda grass, dried in vacuum .................................. ..| 120 3,402 I 54,432 T 17 Bread, commercial, less than........_. 1 28 I 448 52 Bread, commercial, mixed ............................................... 0.1 3 50 55 Broccoli __________ .. 3.3 95 1,520 52 Brussels sprouts ...... _. ‘ 3.3 95 1,520 52 Bur clover, dried in vacuum ........................................... -. 200 5,670 90,720 55 Butter .. 30 849 13.584 55 Butter 50 1,415 22,640 55 Butter 50 1,515 22,640 2 Butter .. 49 1,400 22,400 52 Butter fat, creamery. ......... .. 17 481 7,696 T15 Butter fat, cows on pasture .. _____________________________ .. 50 1,417 22,400 T 15 Butter fat, creamery, average ........................ .. 28 792 12,672 T 15 Butter fat, cows on pasture ...................... .. 40 1,132 18,112 T 15 Butter fat, cow on silage (no pasture)... 3.6 102 1,632 T 15 Butter fat, feed low in vitamin ........................... ._ 2.5 71 1,136 T 15 Castor Oil ......... .. . . _ . . .. 0 0 0 7 Cabbage, new, average of green and white ........... .. 0.4 10 160 52 Cabbage, Chinese (estimated) .......................................... _. 50 1,415 42 Cantaloupe ..... .. 3.3 93 1,488 48 Cantaloupe ________ .. 3.2 90 1,440 52 Carrot 25 708 11,328 2 Carrot ________ ._ 33 940 15,040‘ 52 Carrot 25 708 11,328 3 Carrot ........... .. 43 1,219 19,504 T 17 Carrot, yellow raw .... .. 67 1,888 30,208 T17 Carrot, yellow, dried ........................................................ .. 25 708 11,328 T17 Carrot, yellow, dried in vacuum .................................. .. 77 2,182 35,376 T 17 Carrot juice, sterilized l 0 0 0 T17 Carrot tops, dried (estimated) .................................... .. 16 453 7,248 T17 Cauliflower .. 0.5 15 240 52 Celery, bleached .......... __ 0 0 0 52 Cereals .......... .. 0 0 0 52 Cheese, American .. 24.5 700 11,200 52 Cheese, cottage ............ .. 1.1 30 480 52 Cheese, cream 49 1,400 22,400 52 Cheese, Parmesan 24.5 700 11,200 52 Cherries, frozen, (Montmorency, Royal Ann, Late Duke) ................................................................ .. 0.3 8 128 51 Cherries, frozen, (Bing, Deacon, Lambert).... 0.4 I 10 160 51 Clover, bur, dried in vacuum ......................................... .. 200 5,670 90,720 T17 Cod liver oil ...... .. 250 7,075 113,200 65 Cod liver oil ............. .. 500 14,150 226,400 65 Cod liver oil ....... .. 1,000 28,300 452,800 65 Cod liver oil ......... .................. .................................... .. 1 250 35,375 556,000 65 16 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Table 3. Approximate number of units of vitamin A in foods and feeds——Continued Litera- Units Units Units ture per per per refer- gram ounce pound ence number ' I Collards, green, raw or boiled 45 min. , ________________________ 5O 1,417 I 22,672 48 Corn, Bloody Butcher __________________________ __ 2.5 70 I 1,120 T17 Corn, Bloody Butcher . . . . . _ . . . . _ _ _ ,_ 5 141 2,256 T17 Corn, Fentress Strawberry _ _ _ _ _ _ _ _ . _ . _ _ . . _ _ _ _ . _ . . _ 1.1 31 496 T 17 Corn, Fentress Strawberry-.. ______________________________ .. I 5 I 141 2,256 T17 Corn, Ferguson yellow dent __ 5 141 2,256 T 17 Corn, Ferguson yellow dent ____ .. 6.6 187 2,992 T 17 Corn, red _______________________________ __ 0.9 25 400 T 14 Corn, red _____________________ ._ __ 5 141 2,256 14 Corn, white _____________________________ __ "I 0 0 0 T 14 Corn, white . . _ . . . _ . _ . . _ _ _ . . _ . _ _ _ _ . . _ _ . _ _ _ _ . _ ._ .5 14 224 T 14 Corn, yellow __ ___________ ._ _.__ 2.5 70 1,120 T 14 Corn, yellow _______________________________________________________ _, . 8 226 3,616 T14 Corn, Ferguson yellow dent, Beeville, Texas 6.6 187 2,992 T 17 Corn, Ferguson yellow dent, Troup, Texas ........ .. 6.2 175 2,800 T 17 Corn, Ferguson yellow dent, Angleton, Texas. 6.6 187 2,992 T 17 Corn, Ferguson yellow dent, Beaumont, Texas“. 5.5 155 2,480 T 17 Corn, Ferguson yellow dent, Nacogdoches, Texas ..... .. 5 141 2,256 T 17 Corn, Ferguson yellow dent, College Station, Texas 5 ' 141 2,256 T 17 Corn, Ferguson yellow dent, Nacogdoches, Texas 5 141 2,256 T 17 Corn, yellow 6.6 187 2,992 T17 Corn, yellow 6.6 187 2,992 T17 Corn, yellow 5 141 2,256 T17 Corn germ meal ..................................................... .. 0 0 0 40 Corn meal, white (estimated)_. .......... _. 0 0 0 T17 Corn meal, golden ..................... .. ....I 3 85 1,360 T17 Corn meal, yellow, granulated 3 85 1,360 T17 Corn meal, feed .............................. ._ 3.3 93 1,488 T17 Corn meal, feed .............................. ._ 3.3 93 1,488 T 17 Corn meal, yellow... ................................... 5 141 2,256 T 17 Corn meal, yellow . _ . . . . . . . . . . . . . . _ . . . . _ . . . . _ . . . . . . . _ . . . . ..I 5 141 2,256 T 17 Cottonseed meal, less than“. ....I 1.0 28 448 18-55 Cottonseed meal (estimated) ............ .. ._..I 0.1 2.8 45 T 17 Cottonseed meal and cake, less than- 1 28 448 52 Cottonseed oil, less than ...................... .. 1 28 448 55 Cucumber ............................................................ .. .4 10 160 52 Dates . . . . _ . . . . . . . . . . . _ . . . . . . . . _ . . _ . _ . . . . . . . . . . ._ 3 85 1,360 52 Dates, Deglet noor ........ .. .8 22 352 58 Dates, Maktum variety... 1 28 448 58 Dates, Thoory ..................................... .. 1 3 36 576 58 Eggs, June laid, Rhode Island Red. 28 792 12,672 23 Eggs, June laid, White Leghorn ............ .. 28 792 12,672 23 Eggs (edible part) . . . . . . . . . . . . . . . . . . . . . . . . . . . _ . . _ . . . . . .. 19 550 8,800 52 Egg yolk ............................................................. .. 50 2 Egg yolk, beginning of laying season- 30 850 13,600 T56 Egg yolk, end of laying season . . . . . . . . . . . . . . . . .. 6 170 2,720 T56 Egg plant .................................... .. .7 20 320 52 Escarole .................................................... .. 210 6,000 96,000 52 Figs, cooking ......................................... .. .4 10 160 52 Fish, fat . _ _ . _ . . . . _ _ . . _ . _ _ . . _ _ . _ . . . . . . .. .4 10 160 52 Fish, lean . . . . . . _ . . . . . . . . . . . . _ . . . . .. 0 0 0 52 Fish “opihi”, Hawaiian . . _ . _ . . . _. 500 14,175 226,800 43 Flour, wheat (estimated) I 0 I 0 I 0 T17 Grapes, Concord, Tokay, Malaga.._. .7 _.20 320 52 Grapes, Sultanina and Malaga .................................... .2 5 80 6 Grapefruit peel and pulp, dried, less than .................. 5 —--—_ T 17 Grapefruit juice (estimated) ......................... .. I 0.1 I 2.8 I 45 44 Grape juice, commercial ................................................. ..I I O 0 6 Halibut liver oil I37500 I1063000 I 12 Halibut liver oil . 62300 1779000 12 l-Iegari stover ...................................................................... _. 3.3 93 1,488 T 17 Hegari, grain .. _-.| 0.3 8.5 136 57 Hominy, yellow ................................................................... -.I 8.3 235 3,760 T 17 Hominy feed, yellow ............ .. ...| 1.5 42 6'72 T 17 Hominy, white (estimated) ...I 0 0 0 T17 Kafir grain, black ............................................... ._ 0.3 9 144 T17 Kafir grain, red ___________ ..I 0.4 11 176 T17 VITAMIN A CONTENT OF FOODS AND FEEDS 17 Table 3. Approximate number of units of vitamin A in foods and feeds——Continued Litera- Units Units Units ture per per per refer- gram ounce pound ence number Kafir grain, white ........... ................................................. 0.5 I 14 I 224 T 17 Kidney I 8 I 230 I 3,680 52 Lard (estimated) . | 0 0 0 Lemons ____ .. I 0 I 0 0 52 Lettuce I 1.5 I 42 6'72 2 Lettuce, head ,,,,,, ..I 1.8 50 800 52 Lettuce, head I 1.7 45 720 3 Lettuce, head, inside leaves ............................................ _. 3.3 93 1,438 9 Lettuce, Iceberg, from center of head 1.7 45 720 33 Lettuce, Iceberg, outside green leaves _..- 67 I 1,888 30,208 33 Lettuce, Iceberg, outside green leaves ._.| 50 1,417 22,672 33 Lettuce, Romaine ............................................................. _.I 5.3 I 150 2,400 52 Liver ____ __ I 98 I 2,800 44,800 52 Liver fat I 5000 I 141,500 I2,264,000 53 Loco weed, air dried ......................................................... ..| 16 53 7,248 T17 Meal, corn, white (estimated) ...................................... _. 0 0 0 T 17 Meat, average, muscle 0.2 5 80 52 Meat, pork (estimated) ____________________________________________________ 0 0 0 T 17 Milk, condensed ,, 4.9 140 2,240 52 Milk, dried, whole I 17.5 500 8,000 52 Milk, dried, whole ..... ._ I 6.6 187 2,992 T 17 Milk, dried, whole __ ________________________________________________ 10 283 4,528 T 17 Milk, evaporated ............................................................... _. 4.9 140 2,240 52 Milk, whole . . 2.3 65 1,040 52 Milk, whole . . . . _ . . _ _ . . . . . . . . . _ .. 1.3 36 576 3 Milk, Whole 2 56 896 37 Milo grain, yellow 0.5 14 224 57 Milo, white, chop ...... .. 0 0 0 T 17 Milo grain, dwarf yellow ............................................... 4* 0.5 14 224 T 17 Milo grain, yellow 0.4 11 176 T 17 Milo, dwarf yellow, less than ........................................ .. 0.5 14 224 T17 Milo,‘ dwarf yellow, less than... 0.3 8 128 T17 Milo, dwarf yellow, less than ........................................... .. 0.5 14 224 T 17 Milo, yellow, less than... 0.5 14 224 T17 Milo, yellow, less than 0.5 14 224 T17 Mushrooms 0 0 0 52 Oats, less than 0.2 5 80 41 Oat meal (estimated) ......................................................... 1 0 0 0 T 17 Oat oil, less than 0.6 17 272 41 Oil, cottonseed 0 0 0 Oil, raisin 0 0 0 Oil, sesame . . 0 0 0 Okra, ends, dried, less than .......................................... 2 56 896 T 17 Okra, ends, dried, less than ................... _. 2 56 896 T 17 Okra, pods and seed, dried .................................... ._ 3 75 1,200 T 17 Onions . 0 0 0 52 Orange juice (estimated) .......... .............................. __ 0.5 141 2,256 49 Oranges _ 0.7 20 320 52 Orange peel and pulp, dried ................................ __ 3 85 1,360 T17 Orange peel and pulp, dried ________________________ .. 4 113 1,803 T17 Orange peel and pulp, dried ......................... .. 6.6 186 2,976 T17 Orange peel and pulp, dried _________________________________________ _. 5 141 2,256 T17 Oysters, raw frozen 0.5 14 224 26 Oysters, raw frozer .......................................................... __ 1 28 443 26 Peaches . 0 0 () 52 Peaches, Elberta, fresh 20 566 9,072 45 Peaches, Muir, fresh ........................................................ .. 12 340 5,443 45 Peaches, canned _ 2 56 896 30 Peaches, frozen Elberta ............................................ ._ 0.5 14 224 43 Peaches, frozen Hiley, less than.. 0.5 14 224 48 Peanut meal, less than ................................................. __ 0.5 14 224 T 17 Peanut meal, less than 0.5 14 224 T17 Pears, Bartlett, less than 0.1 4 64 34 Peas, cooked green . ' 2 56 896 2 Peas, dried green ____ __ 3 85 1,360 52 Peas, dried green . 12.5 354 5,664 Peas, raw and canned _ I 6.1 175 2,800 52 18 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Table 3. Approximate number of units of vitamin A in foods and feeds-Continued Litera- Units Units Units ture per per per refer- gram ounce pound ence number Peas, raw and cooked ...................................................... 1 2 56 896 3 Peas, raw 0r cooked, 10 min.11 11} 67 1,888 30,208 11 Peas, canned ............................ _. 67 1,888 30,208 11 Peas, blackeyed, dried _. 2 56 896 17 Pecan meats ______________________________________ 1 3.6 102 1,632 35 Pecan meats, Burkett variety ____________ .. 1.6 45 720 T17 Pecan meats, Texas Prolific variety .............................. 1 2 56 896 T 17 Pecan meats, stored 14 months, less than 1 28 448 T17 Peppers ____ 1 1 I 6 175 2,800 52 Peppers, sweet green, dried .......................................... 1 40 1,134 18,144 T17 Peppers, sweet green, dried .............. 1 20 567 9,072 T17 Pineapple, canned, including syrup ............................ 1 0.3 9 144 50 Potatoes, sweet 3 85 1,360 52 Potatoes, white, or Irish ................................................ 1 0.4 10 160 52 Potatoes, sweet, Nancy Hall ........................... ._ 30 849 13,584 52 Potatoes, Sweet, Porto Rico . ............... 1 50 1,417 22,672 T17 Potatoes, yellow, sweet, raw _ . . _ . _ . . _ 1 . 1 1 _ _ . . .. 20 567 9,072 T17 Potatoes, yellow, sweet, dried in air 2 56 896 T 17 Potatoes, yellow, sweet, dried in air...11111.. .... 1 2.5 70 1,120 T17 Potatoes, yellow, sweet, dried in vacuum1 50 1,417 22,672 T17 Potatoes, yellow, sweet, dried ............................ 1 2 56 896 T17 Potatoes, yellow, sweet, dried . . . . . _ . . _ ._ 2 56 896 T17 Potatoes, yellow, sweet, dried ............................. .. 3 85 1,360 T17 Potatoes, yellow, sweet, peeling, dried .......................... 1 2 56 896 T 17 Prunes 1 1| 10.5 300 4,800 52 Prunes, French, fresh ...................................................... 20 567 9,072 45 Pumpkin, dehydrated 1 50 1,417 22,672 44 Raisins 0 0 0 52 Raisins, Thompson seedless and Malaga ...................... 1 0 0 0 41 Sorghum silage 5.5 156 2,496 T 17 Sorghum silage 1 10 283 4,528 T17 Sourkraut .. 0.2 5 80 52 Spinach, canned, juice poured off ................................. 1 100 2,835 45,360 T 17 Spinach, canned, juice poured off-.. 140 3,920 62,720 T 17 Spinach, dried in vacuum, canned ................................. 1 333 9,324 149,184 T17 Spinach, New Zealand 11 314 5,024 39 Spinach, ordinary garden ................................................ 1 14 402 6,432 39 Spinach, raw I 63 1,771 28,336 8 Spinach, raw and canned .................................................. 1 49 1,400 22,400 52 Spinach, raw, Virginia Savoy, Princess Juliana. and Viroflay 83 2,361 37,776 28 Strawberries ....................................................................... 1 0.2 5 80 31 Strawberries 1 0.16 45 720 31 Sudan grass, dried in vacuum (estimated) __________________ 1| 150 4,245 67,920 T 17 Tomatoes, green, raw or canned ................. ._ 1 7 187 2,992 32 Tomatoes. raw and canned ___________ 1 1 6 170 2,720 62 Tomatoes, ripe, raw or canned _________________________________________ 1 13 374 5,934 32 Tomato soup, canned 6 170 2,720 52 Turnips ‘ _ 0,2 5 30 52 Turnip greens. raw or boiled ......................................... 1 50 1,417 22,672 4s Turnip greens, dried 33 935 14,960 T17 Watermelon pulp 1 1 23 443 47 YVheat, whole, less than 0.3 7.8 125 T17 Wheat (estimated) 1 0.2 5.6 89 T17 Wheat bran, less than 11| 1 >28 448 55 Wheat gray shorts | 0.3 9 144 T17 Wheat gray shorts 0.05- 1.4 22 T17 was given by the worker in terms of ounces or pounds, they were calcu- lated by us to units per gram, and then rounded off to 0.1 unit or whole units. If the units per ounce or pound are then calculated from the units per gram, the results will not check exactly with those given in the table, but they will be within the limit of error. VITAMIN A CONTENT OF FOODS AND FEEDS 19 SOME FACTORS WHICH AFFECT THE VITAMIN A ACTIVITY OF FOODS It is known that a number of factors affect the vitamin activity of foods or feeds (8). Definite measurements are, however, limited in number. There seems to be a definite relation between greenness and vitamin A content. The green outer leaves of cabbage and lettuce con- tain much more vitamin A than the white inside leaves (9). Chlorotic spinach contains less vitamin A than normal green spinach. There are indications that the vitamin A content of carrots and of alfalfa is at its maximum during the early stages of growth. - Effect of Time of Storing of Foods The effect of storage of the vitamin A content is shown in Table 4. We (16) have shown that the vitamin A content of dried foods decreases meal 50 per cent in 5 months, yellow corn 3O per cent in 5 months, and Table 4. Effect of storage on vitamin A in dried feeds during storage. Dried whole milk lost 60 per cent in 9 months, alfalfa leaf . Labora- , Um,“ Per cent tory Description Vvfamln A loss of number m one vitamin A gram feed 32789 Alfalfa leaf meal, original 1() Stored 8 months 8 20 Stored 11 months"... 5 50 32041 Blackeyed peas, dried, original ................................................ __ 3 Stored 7 months 2 30 Stored 9 months 1,5 50 Stored 14 months ................................................................... __ 0.7 75 32060 Green sweet pepper, dried, original ..................................... ._ 50 Stored 19 months 10 80 33249 Powdered whole milk, original .............................................. ._ 10 ___ Stored 9 months a 3 60 30997 Yellow corn, whole, original 7 Stored, whole, 7 months ....................................................... __ 5 30 Stored, unground, 30 months 1- 35 Stored, ground, 30 months 1_- 35 33313 Ferguson yellow dent corn, original ___________________________________ _, 7 Stored, ground, 5 months 3 50 Stored, unground, 5 months _________________________________________________ ,_ 2,5 65 33314 Ferguson yellow dent corn, original _____________________________________ _, 7 Stored, ground, 6 months _ 3 50 33315 Ferguson yellow dent corn, original ______________________________________ __ 7 ____ Stored, ground, 6 months 3 50 35746 Pecans meats , 1_6 ___ Stored in shell 8 months (estimated) ______________________________ __ 3 50 l’ ;_ dried green pepper 80 per cent in 19 months. It follows that the quantity of vitamin A present in the dried food at a given time will depend upon . how old the particular material is at the time of the determination. Thus 4.‘, freshly prepared or freshly harvested foods or feeds will contain more i vitamin A than those which have been in storage for several months. f This fact may account for some of the differences in vitamin A found ' between different lots of the same kind of material. It is therefore 20 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION important to record the period of storage, if possible, in connection with the estimation of vitamin A. In a period of several months there may be a decline in the quantity of vitamin A in the‘ food being used. Effect of Drying or Curing It is known that there is a. loss of vitamin] A in the drying 0r curing of alfalfa and similar feeds. Sun-dried alfalfa contains much less vitamin A than heat-dried alfalfa (54). The extent of the loss seems to depend upon the procedure adopted in the drying. Hauge and Aitkenhead (20) conclude that much of the loss in the drying of hays and fodder is due to changes caused by enzymes in slow drying in the feed. If the material is dried rapidly the loss on drying is much less than if the drying took place slowly. Poorly cured hays or fodders may be low in vitamin A (4, 35). The following results were secured in testing the effect of drying upon carrots, spinach and sweet potatoes. Raw yellow carrots contained approximately 43 units per gram of fresh material containing 11.4 per cent dry matter, or 337 units per gram of dry matter. Dried carrots contained 77 units of vitamin A per gram. The carrots lost approximately 80 per cent of their vitamin A when dried. Canned spinach contained 140 units of vitamin A in the pressed solids containing 14.7 per cent dry matter, or 952 units per gram of dry matter. Vacuum dried spinach contained about 333 units vitamin A per gram. The spinach lost 65 per cent of its vitamin. A in drying. Yellow Porto Rico sweet potatoes contained 20 units vitamin A per gram, with 28.7 per cent dry matter or 69 units per gram of dry matter. The vacuum-dried sweet potatoes contained 50 units per gram. The sweet potatoes lost 29 per cent of its vitamin A in drying. Effect of Canning Green peas or tomatoes canned by modern processes seem to contain as much vitamin A as similar fresh food purchased on the market, accord- ing to Eddy and his co-Workers (11, 32). No‘ direct estimation of the loss of vitamin A during the process of canning has yet been made, as it is difficult to preserve the fresh food without possible loss of vitamin for the period of eight weeks necessary for the test with the rats to compare it with the canned product. Com- parisons have been made between the canned food and the fresh food purchased on the market, but the samples compared were grown in different places and under different conditions. It is certain, however, that canned foods retain high percentages of their original vitamins. Relation to Hereditary Factors in Corn Hauge and Trost (21) state that vitamin A is always transmitted with the yellow endosperm of corn. With twenty per cent of corn in the rations fed the experimental rats, all three classes possessing yellow endosperm—- VITAMIN A CONTENT OF FOODS AND FEEDS 21 heterozygous F2, homozygous F2, and homozygous parent—were equally effective inpreventing ophthalmia. Hauge and Trost (22) also found that the vitamin A content of pure yellow corn of the genotype YYY is ap- proximately 3 times that of the crossed grains of the genotype Yyy. Manglesdorf and Fraps (36) showed that there is a direct quantative relationship between vitamin A in corn and the number of genes for yellow pigmentation. The vitamin A content of mixed white and yellow corn is related to the number of genes for yellow corn carried by the grain (see Table 5). They pointed out that the inheritance of vitamin A Table 5. Relation of vitamin A content to number of genes for yellow in corn I Units of vitamin A per gram No. of Factorial genes for composition yellow of endosperm 1928 I 1929 Average | I I 0 y y y I‘ 0.05 \ 0.05 0.05 1 I Y y Y I 2.50 I 2.00 2.25 I I 2 ] y Y Y | 5.00 5.00 5.00 I I 3 x Y Y Y 7.00 I 8.00 7.50 I I may be an indirect consequence of the inheritance of pigmentation in- volving the carotinoid pigments, as has also later been pointed out by Dutcher (8). In addition to the main genetic factors governing the forma- tion of pigment in the endosperm of corn, there are numerous modifying factors which affect the amount of pigment and hence also the amount of vitamin A. Russel (54A), for example, has found that white capping in yellow corn, which also has a hereditary basis, reduces the amount of vitamin A. Relation to Stage of Growth of Corn Seeds Samples of Ferguson yellow dent corn were examined fourteen days after pollination and thereafter at intervals of one week for a total period of six weeks, at which time the seeds had reached maturity. This work was done in cooperation with Dr. P. C. Manglesdorf of the Division of Agronomy, who also furnished the samples. Table 6 contains a summary of the results obtained. Examination of Table 6 shows that there was a gradual increase in the vitamin A content of the corn from approximately 2.0 units per gram fourteen days after pollination to a level of approximately 6.7 units per gram 43 days after pollination. It appears from these results that the maximum concentration of vitamin A in the corn kernel occurred roughly between the thirty-fifth and forty- fifth day after pollination, after which time it remained constant until maturity, though the total amount of vitamin continued to increase some- what with an increase in the weight of the seed. The total number of units of vitamin A gained by each grain of corn was fairly regular for each period, with the exception of the third period 22 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION (21 to 28 days), in which the gain was double that of any of the other periods, and the last period, in which there was no gain of vitamin A. It was also observed that the intensity of the yellow color in the samples increased in proportion to the length of time after pollination Table 6. Storage of vitamin A in relation to the stage of growth of the grain of yellow corn Days after Weight vittzlxliiiit: A , UniPS 10733233 pollination 100 to 1 gram vltamm A in the pre- seeds com to 100 seeds ceding period 14 5.2 2.0 10 .__. 21 14.3 2.5 36 26 28 18.6 5.5 103 67 35 25.0 5.5 139 36 43 27.0 6.7 180 41 50 31.2 6.7 208 28 57 30.4 6.7 203 —5 at which/ they were taken, until about the sixth week, after which time the color tended to remain constant up to the eighth week after pollination. Effect of Locality on Vitamin A in Corn Results of the experiments on the vitamin A content of Ferguson yellow dent corn as influenced by the localities are summarized in Table 7. Some of these results have already been presented (14). It is quite possible that any difference in the vitamin A content of the various samples might be due to factors, such as cross pollination, Table 7. Relation of season and locality to units of vitamin A in Ferguson Yellow Dent corn Where grown 1926 1927 1928 i 1930 Angleton _ . 1 1 . . . . 1 . . . . _ _ 1 2.5 2.9 4.0 6.6 Beaumont 3.0 ._ 1 1 ._ 5.5 Beeville 3.3 5.0 5.5 6.6 Lubbock 2.5 4.0 __ ._ __ __ Troup _____ 1 __ 1 6.0 7.1 6.2 Denton 5.0 ._ __ ,_ -_ Nacogdoches l 1 1 2.9 1 5.0 College Station ........................................................ 1 3.6 5.5 6.7 5.0 Temple .... 1 1 __ 3.6 6.7 1 1 Weslaco 1 ._ 1 1 6.7 __ _. Iowa Park .. -- 7.1 ._ _. other than those encountered during the growing season of the corn. Six samples grown in 1930 were examined for their vitamin A content. Three samples from Beeville, Troup, and Angleton, Texas, contained 6.6, 6.2, and 6.6 units of vitamin A per gram respectively, while three samples VITAMIN A CONTENT OF FOODS AND FEEDS 23 from Beaumont, Nacogdoches, and College Station, Texas, contained 5.5, 5.0, and 5.0 units of vitamin A per gram respectively. This variation is comparatively small and might easily fall within the experimental error. For this reason it is not considered significant. It might be due to cross pollination with White corn. A comparison of these and other results (14) leaves the question whether the locality has any effect somewhat doubtful. Three other samples of yellow corn examined contained ap- proximately the same amount of vitamin A as the Ferguson yellow dent corn. . Effect of Vitamin A in the Food on Vitamin A in Milk, Butter, and Eggs The vitamin A activity of milk, butter, and eggs depends upon the vitamin A content of the ration. The animal may contain a store of vitamin A, which at first will be used in the milk or eggs, but if the animal is fed a ration containing an insufficient amount of vitamin A, the vitamin A in the product will gradually decrease (5). Thus the eggs of pullets (56) fed on diets containing yellow corn as the only source of vitamin A gradually decreased in content of vitamin A (see Table 8), Table 8. Relation of units of vitamin A in yolks of eggs to the feed and to- the stage of laying period (no green feed) i Units of vitamin A per gram of egg yolk Date samples taken i Yellow corn Mixed- corn i White corn Dec. 3, 1931 ....... 20 12 i 13 Dec. 29, 1931 12 i 12 Jan. 29, 1932 i 14 10 10 Feb. 29, 1932 10 i i 14 Mar. 31, 1932 i i 6 i 5 May 2, 1932 .................................................................. 5 i 8 i showing these diets contained an insufficient amount of vitamin A. The butter fat from a cow fed on yellow corn but with no other source of vitamin A, decreased ‘in vitamin A. Sorghum silage did not supply enough vitamin A to a cow (15) to produce butter of high potency (Table 9). Table 9. Effect of feed of cows on vitamin A content of butter fat after a , feeding period of 15 to 16 months Units per Units per cow gram per day Cottonseed meal and hulls, average ______________________________________________ __ 2,5 340 Cottonseed meal, hulls and silage, average _____________________________ __ 3,8 1960 Cottonseed meal, hulls, silage and pasture, average _____________ __ 33 17239 24 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION Vitamin A in Some Human Foods Some of the foods listed in Table 3 are discussed briefly below. Eggs: The eggs examined for their vitamin A content were from White Leghorn pullets. The yolks averaged approximately fifteen grams in weight, while the whole eggs weighed about 50 grams, of which 10.9 per cent was shell. Thus the yolk was 30 per cent of the whole egg, or about one-third the edible part of the egg. There were nine eggs to the pound. The cost per pound of edible egg would be, for these White Leghorn eggs, the price per dozen multiplied by 0.84. Thus, with eggs at 3O cents a dozen, the edible part would cost 25.2 cents a pound. Assuming that eggs from pullets receiving green food in addition to a diet complete in minerals and other food elements can be called normal eggs, it was found that the normal vitamin A content of eggs from White Leghorn pullets is approximately 290 to 450 units per egg, which is 20 to 30 units to the gram of yolk, or 7 to 10 units to the gram of egg less the shell. From Work previously reported (56), it was found that a ration fed pullets when not supplemented with fresh green feed, which is rich in vitamin A, does not supply sufficient vitamin A to enable the pullet to put enough into theegg to keep the vitamin A content up to the normal. In those cases where the pullets are deprived of an optimum amount, after two or three months the vitamin A content of the egg may decrease to only 7 units per gram of yolk, 2 units per gram of whole egg (less shell), or 105 units per egg. Egg yolk from pullets fed liberal amounts of yellow corn in the mash and scratch feed contained approximately 20 to 3O units of vitamin A per gram at the beginning of the laying season. When the pullets were kept on a ration where the sole source of vitamin A was yellow corn there was a gradual decrease in the vitamin A content from 20.0 units per gram to 7 units per gram over a period of approximately five months (Table 8). Egg yolk from pullets fed a ration where the source of vitamin A was a mixture of yellow and‘ white corn contained approximately 12 units of vitamin A per gram at the beginning of the laying season with a gradual decrease in the vitamin A content in the eggs laid, to 6 to 8 units of vitamin A per gram, over a period of about five months. White corn contains a negligible amount of vitamin A; so the sole source of vitamin A could be said to be the yellow corn. Egg yolk from pullets fed white corn as the sole source of vitamin A contained approximately 12 units per gram at the end of the first month of feeding and there was a gradual decreasein vitamin A content to 6 units over a period of five months. The vitamin A in these eggs comes from that stored up in the body of the fowl. Dried Whole Milk: Three samples of dried whole milk contained from 6.6 units to 10 units of vitamin A per gram, all samples being relatively fresh when tested. After being stored for eleven months, approximately 66 per cent of the vitamin A had been lost (one sample). VITAMIN A CONTENT OF FOODS AND FEEDS V 25 Sweet Potatoes: Porto Rico (yellow) sweet potatoes were found to be excellent sources of vitamin A, as two samples examined contained 30 to 40 units per gram on the original wet basis. Since the sweet potatoes contained 70 per cent water, the dry matter would contain 100 to 133 units per gram. Rice and Munsell reported only 3 units per gram, while McLeod, Talbert, and Toale report Nancy Hall sweet potatoes to contain 30 units per gram (38). Sweet potatoes contained only two units per gram when dried under ordinary conditions, 50 units per gram when dried in a vacuum. Both the Porto Rico and Nancy Hall are yellow sweet potatoes. The vitamin A has not been established in white sweet potatoes, and it may be low in them. Possibly the sweet potatoes used by Rice and Munsell, which contained only 3 units of vitamin A to the gram, were white sweet potatoes. Carrots: Carrots, like sweet potatoes, are excellent sources of vitamin A, as the yellow carrots examined contained 43 to 67 units per gram on the original basis. As the carrots contained 87 per cent water, they would contain 330 to 500 units per gram of dry matter. Rice and Munsell (52) report 33 units to the gram, while Browning reports 25 units. These are somewhat lower values than those secured by us. Carrots when dried con- tained 25 to 67 units per gram, showing a decided loss in drying. Butter: Butter ordinarily contains 78 to 82 per cent butter fat, the remainder being salt, curd, and water. Average creamery butter seems to contain 3O to 40 units of vitamin A per gram, and must be considered to be a good source of vitamin A. The number of units per gram of butter fat depends upon the feed of the cow, as has already been pointed out. Pecan Meats and Peanut Meal: Three samples of pecan meats were examined for their vitamin A content. One sample consisted of low-grade pecan meats. The two remaining samples were the Texas Prolific variety, and the Burkett variety. The Burkett variety contained 1.6 units of vitamin A per gram of meats and the Texas Prolific variety contained 2.0 units of vitamin A per gram of meat. Peanut meal was found to be a poor source of vitamin A. One sample contained approximately .55 units per gram of material, while another sample examined would not allow growth when fed at a level of 2 grams daily. Spinach and Other Greens: Spinach, turnip greens, and mustard greens are excellent sources of vitamin A, as they contain 5O to 100 units per gram of the original material. As is shown elsewhere, vitamin A can be purchased in these materials at very low prices. Canned spinach in many cases cost more than the fresh spinach, but is still an excellent source of vitamin A. The canned spinach we examined was guaranteed to contain 1 pound 3 ounces. In one lot of cans, the juice weighed 316 grams and the pressed spinach 237 grams, and the pressed spinach con- tained 87.4 per cent water. In another lot the juice weighed 375 grams, 26 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION the pressed spinach 189 grams, and the pressed spinach contained 85.3 per cent water. For the two lots, the cans contained an average of 213 grams, or .47 of a pound of pressed spinach. To get the cost of the spinach per pound, it would be necessary to multiply the price of a can - (1 lb. and 3 oz.) by 0.47. Other Human Foods: The approximate vitamin A content of otherhuman foods is given in Table 3. COSTAOF VITAMIN A ACTIVITY IN HUMAN FOOD The costs of vitamin A in a number of foods are compared in Table 10. The costs here given are the cost per pound of the edible part of the food in question, calculated from the prices prevailing in Bryan, Texas, at the time they were collected, divided by the assumed number of units of vitamin A per pound in the edible part of the food, as given in the table. The cost of food of course varies from month to month and from locality to locality. This method of calculating the cost of the vitamin A is not exactly correct, because it does not allow for the value of the other ingredients in the food besides the vitamin A. As the other in- gredients have value and the values vary from one food to another the costs given for vitamin A are both too high, and relatively incorrect. A correct calculation would take all the factors of food value into account. This obviously cannot be done at the present time, on account of the absence of complete quantitative information regarding the food values of most foods. In spite of the defect, the calculations of the cost of vitamin A ought to serve some practical purposes. The units of vitamin A in Table 10 are assumed to be the average quantities present in the edible part of the food. It has already been pointed out that these quantities are likely to vary. There is usually a loss in preparing food for the table or in consuming it. The shells of eggs, the skins of bananas, the culls from greens, etc., are removed. Hence the food as purchased in many cases will contain somewhat less vitamin A than the quantities given in the table, which refer to the edible portion. The prices given are also for the edible part of the food, and therefore higher than the market price would be at the same time, as this price per pound applies to the unedible as well as the edible portion of the purchase. Bananas, carrots, yellow corn, cod liver oil, collard greens, liver, mustard greens, spinach, sweet potatoes, and turnip greens are the cheapest sources of vitamin A shown in the table. In these foods, 1000 units of vitamin A can be secured for half a cent or less. Sweet potatoes and yellow corn, in addition to supplying vitamin A at a low cost, also furnish energy and protein at a low cost per unit, and for this reason are especially important. The canned vegetables, including carrots, spinach, mustard and turnip greens, are somewhat more expensive than the fresh foods listed above but are still relatively low-priced sources of vitamin A. VITAMIN A CONTENT OF FOODS AND FEEDS 27 Butter, cantaloupe, cheese, and dried green peas are other low-priced sources of vitamin A, but the cost of vitamin A ranges from 1 to 2 cents per thousand units, which is much higher than in the mustard greens, etc., Table 10. Cost of 1000 units of vitamin A in food of the composition and at the prices .-given for the edible part <6 +1 m 5.55% a 6% 1: ., 3'5 a 5 u a3 ° "d w += 2 u _. a, s: n. w: g e5 H g3: g 2 g Q 2 o 0.5 ”‘ i} 9"“ :1 fir? s: t‘ w Qm "“ m "a V14» er: g "i, w t E 5'5 <6 g p, 4 i3. 5 Apples 240 2 8.0 Asparagus, canned 560 14 25.2 Banana _____ _. 896 4 0.4 Beans, navy 240 5 20.0 Beans, string, green . 2,400 10 4.2 Beets . . . _ . _ . . . . _ . . . . . . __ 80 7.5 93-8 Brussels sprouts 1,520 11 7.0 Butter _, ,_ 22,400 22 1.0 Cabbage ...... .. 160 5 31.0 Cantaloupe ____________________________________________________________________________ _. 1,488 2 0.9 Carrot 15,000 7.5 0.5 Carrot, yellow, raw ..... .. 7 .. 45,500 7.5 0.2 Cauliflower .. 240 12.5 52.0 Corn, yellow 3,616 1.5 0.4 Corn meal, yellow ............................................................ .. 2,480 4 1.6 Cheese, American 11,200 18 1.6 Cucumber ] 160 3 18.7 God liver oil ..| 226,500 200 0.4 Collards (greens) _. 22,672 5 0.2 Dates ..................................................................................... _. 500 26 52.0 Egg plant . 320 5 16.0 Eggs (30 cents a dozen) ................................................ __ 8,800 25 2.8 Grapes, Concord, Tokay, Malaga .......................... _____ _. 320 8 24.9 Kidney _. 3,680 10 2.7 Lettuce, head 800 7.5 9.0 Liver .......................... ._ 44,800 10 0.2 Milk, whole 1,040 6 6.0 Milk, evaporated 2,240 10 4.0 Milk, dried whole 4,000 85 21.0 Mustard greens . 40,000 5 0.1 Oranges . 320 5 15.0 Oysters . 400 25 62.5 Peaches, canned _______ _. . 896 25 26.7 Peas, dried green ____ _. 5,664 12 2.0 Peas, green 2,800 13 4.6 Peas, canned I 2,800 20 7.2 Peas, blackeyed, dried ......... _. 896 5 5.6 Peppers ____ .. _ 2,800 13 4.6 Pecan meats _ 720 50 69.0 Potato, white or Irish v 160 2.9 18.0 Potato, yellow, sweet .... .. 18,000 1 0.1 Prunes 4,800 5 1.0 Spinach, green 22,400 10 0.4 Spinach, canned (solids only) ......................................... .. 45,360 21 0.5 Sourkraut 80 10 125.0 Sweet potatoes, yellow 18,000 1 0.1 Tomatoes, raw 2,720 10 3.7 Tomatoes, canned ripe ______________________________________________________ 1 5,984 15 2,5 Tomato soup, canned 2,720 ' 12 4.4 Turnip tops I 22,672 5 0.2 listed in the first group. Eggs are a somewhat higher priced source of vitamin A but they also furnish protein, energy. minerals, and other vitamins and so must be considered as a good source of vitamin A. The same 28 BULLETIN NO. 4'77, TEXAS AGRICULTURAL EXPERIMENT STATION applies to milk. It is interesting to note that tomatoes, while a good source of vitamin A, cost more per unit of vitamin A than any of the foods mentioned above. Asparagus, cabbage, head lettuce, and canned peaches are classed as expensive sources of vitamin A. Additional data are needed both on other foods, and on the foods listed in the table, as there may be considerable variations in addition to those pointed out, and the data here presented are far from complete. QUANTITIES OF VITAMIN A REQUIRED BY ANIMALS AND MAN It is known that animals require more vitamin A for growth than for maintenance and more for production than for growth. The amount sufficient for bare maintenance is not sufficient for vigorous health and long life, as has been shown by Sherman. There is evidence that sup- plementary amounts of vitamins A and D added to the human foods ordinarily eaten may in some cases result in decreased sickness and better health (24). Information regarding the quantity of vitamin A required by animals is very meager. There are indications that 4 units per pound per day are required for maintenance of growing rats, 6 units per pound for proper growth of rats, and that White Leghorn pullets require 32 units per pound per day for maintenance while laying and 6.3 units for each unit of vitamin A in the eggs (56). Milk cows, like chickens, apparently require large quantities of vitamin A for maintenance, and still more to produce butter of high potency (5). Feeds such as sorghum silage, corn silage, and corn stover may not supply sufficient vitamin A to produce butter of high potency, and in fact may supply only enough to just about maintain the animal (5, 18). The vitamin A requirements for animals producing milk or eggs seem to be very high and the producing animal seems to have a higher requirement for maintenance than an animal not producing. Information regarding the number of units of vitamin A required by man and animals is much needed. As a tentative estimate of‘ the vitamin requirements of humans, we propose 5 units per pound for maintenance and 8 units per pound for growth, or a somewhat more liberal estimate of 1000 units per day per person—man, woman, or child. This may not be ample for the highest health and vigor, but should be sufficient for growth and maintenance. This requirement of 1000 units of vitamin A per person per day can be supplied at a cost of one-half cent or less at the prices given in Table 10 by using bananas, carrots, yellow corn, cod liver oil, collard greens, liver, turnip greens, mustard greens, spinach or sweet potatoes, and perhaps other foods. Other economical sources of vitamin A are butter, cheese, green peas, eggs, and milk; while the cost per unit of vitamin A is much higher in these foods than in those first mentioned, the vitamin A is associated with other food materials of high value, which renders them good sources. t vitamin A (5, 19, 56). A hays and fodder, and sometimes yellow corn. VITAMIN A CONTENT OF FOODS AND FEEDS 29 VITAMIN A IN SOME FEEDS FOR ANIMALS The most important sources of vitamin A for animals are green pasture grasses or legumes. These are high in vitamin A, being similar in that respect to spinach, and mustard greens, and probably contain 100 units or more to the gramof green material, when green and rapidly growing. Animals which have’ access to good pasture thus receive high amounts of vitamin A, and they can store liberal amounts to use when the supply in the food is more limited. Next to green pasture comes heat-cured alfalfa or other hays. Heat-cured alfalfa may contain 50 to 66 units of vitamin A to the gram. Ordinary dried hays and fodders contain some vitamin A, but not nearly so much as the fresh green material, as there seems to be considerable loss in curing (20). Alfalfa leaf meal (sun-cured) we found to contain 7 to 20 units per gram. Alfalfa meal contained 3 to 13 units per gram. Hays and fodders ordinarily furnish enough vitamin A for maintenance and growth, but hays of poor quality, or even of good quality fed in small amounts, may not furnish enough vitamin A, to maintain the milk cow over a long period of time (19). Leached or weathered prairie grass ‘is probably low in vitamin A. - Yellow corn is an important source of vitamin A, as it contains when fresh, about 5 units of vitamin A per gram. Cottonseed meal is low in Sorghum silage contains 5.5 to 10 units per gram (2 samples) but both corn silage (19) and sorghum silage (5) may not furnish enough vitamin A to cows to produce milk containing normal quantities of vitamin A. Orange peel and pulp contained 4 to 6 units of vitamin A per gram. For beef cattle and sheep, the chief sources of vitamin A are pasturage, Under ordinary conditions, l these will supply sufficient quantities of vitamin A. Prairie grasses, how- ever, dried and exposed to the weather are probably low in vitamin A. "It is possible that they do not supply enough vitamin A for maintenance, , so that towards the end of the winter with the exhaustion of the reserve stored in the animal, the animal may begin to suffer from a deficiency. " _ The same may happen with an animal sustained for several months on poorly-cured hay or with straw or fodder low in vitamin A. The amounts required for maintenance and growth are comparatively small and the deficiencies referred to here may occur only under exceptional conditions. The chief sources of vitamin A for milk cows are pasturage, hay or fodder, and yellow corn. Green pasturage furnishes an abundant supply a and the animal on good pasture is enabled not only to produce butter fat high in vitamin A but also to store large quantities as a reserve in the body. Well-cured hay contains fair amounts of vitamin A but it seems possible that insufficient amounts of well cured hay even supplemented , with yellow corn, may not furnish enough vitamin A to enable the cow to produce milk of high potency in vitamin A or to prevent the animal from depleting its reserve store. Dairy cows fed long periods of time with 30 BULLETIN NO. 477, TEXAS AGRICULTURAL EXPERIMENT STATION silage, straw, fodder, or other roughages containing moderate amounts of vitamin A may suffer from a deficiency in this vitamin (5, 19). The chief sources of vitamin A for pigs are pasturage, alfalfa meal, and yellow corn. Pigs raised on pasturage may store up sufficient vitamin A to last during the fattening period, even though fed on feeds 10w in this vitamin. If the pigs are raised on insufficient pasturage, thestore of vitamin A may not be sufficient and the pigs would then fail t0 make the good gains and might suffer in other respects from the deficiency. Yellow corn or alfalfa meal or other dried legume hay of good quality, would probably furnish sufficient vitamin A for the growing and fattening pigs. The chief sources of vitamin A for chickens are pasturage, yellow corn, and alfalfa meal or alfalfa leaf meal. The yellow corn or alfalfa meal would furnish enough vitamin A for maintenance or growth. If hens do not have access to pasture, it is doubtful if the yellow corn and ordinary alfalfa leaf meal together would furnish enough vitamin A to produce eggs of high potency in this vitamin (56) or to prevent the fowls from depleting their reserve store of this vitamin. SUMMARY A brief introductory description of the nature and characteristics of various vitamins is given. The units of vitamin A activity were estimated (in rat units) in over 107 samples of foods or feeds. These are tabulated together with all other estima- tions of vitamin A found in the literature or calculated from data given. The estimation of units of vitamin A was not highly accurate but they express the content of the material more accurately than the previous methods usually used for indicating the quantity present. The quantity of vitamin A decreases during the storage of alfalfa, dried whole milk, yellow corn, and other foods. There is a loss of vitamin A in drying moist foods. The effect of other factors is briefly discussed. As previously shown there is a direct quantitative relationship between vitamin A in corn and the number of genes for yellow pigmentation. There was a fairly constant gain of vitamin A in each grain during the period of growth of yellow corn, with the exception of the period of 21 to 28 days, when the gain was excessively rapid, and the last period, near maturity, when there was little gain. " Although some differences were found in yellow corn grown in different sections of Texas, it cannot be said definitely whether or not the locality in which the corn was grown affected its vitamin A content. As previously shown, the vitamin A content of butter and eggs depended upon the food eaten by the animal. The vitamin A content of butter and of eggs decreased during the period of feeding, when insufficient quantities of vitamin A were fed. VITAMIN A CONTENT OF FOODS AND FEEDS 31 The vitamin A content of eggs, dried whole milk, sweet potatoes, carrots, butter, pecan meats, spinach, and other foods and feeds are briefly discussed. Bananas, carrots, yellow corn, cod liver oil, collard greens, liver, mustard greens, spinach, yellow sweet potatoes, and turnip greens were the cheap- est sources of vitamin; A for human food at the prices used. In all of them 1000 units could be secured from one-half cent or less and in some of them 1000 units cost only one-tenth of a cent. Canned spinach, canned carrots, and canned mustard cost a little more than those mentioned above but are low-priced sources of vitamin A. Butter, eggs, cheese, dried green peas, and milk must be considered to be relatively economical sources of vitamin A. Asparagus, cabbage, head lettuce, and canned peaches are classed as expensive sources of vitamin A. As previously pointed out, growing rats required 4 units per pound per day for maintenance only and 6 units per pound per day for both growth and maintenance. White Leghorn pullets required 32 units per pound per day for maintenance and 6.3 units of vitamin A for each unit in the eggs. Milk cows have high requirements of vitamin A for maintenance and for production of butter of high potency. We estimated that a man, woman, or child requires 1000 units of vitamin A per day per person. Larger amounts may be required for higher vigor and better health. The 1000 units per person per day can be supplied at a low price by comparatively small quantities of collard greens, turnip greens, mustard greens, spinach, or by somewhat larger amounts of bananas, carrots, yellow corn‘ or sweet potatoes. Milk cows seem to require green pasture plants to produce milk of high potency and laying hens seem also to require green feed for the continued production of eggs of high potency. Orange peel and pulpcontained 4 to 6 units of vitamin A per gram. Cottonseed meal is very low in vitamin A. _ Hays and fodders may not supply enough vitamin A to maintain milk cows over a long period of time. Sorghum silage containing 5.5 to 10 units of vitamin A per gram does not furnish enough vitamin A for cows to produce milk containing normal amounts of vitamin A. REFERENCES Bills, C. E., of Mead Johnson & Co., Evansville, Indiana, 1932. Letter. lBIronson, 1930. Nutrition and Food Chemistry. John Wiley & Sons, . Y. Browning, E., 1931. The Vitamins. 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