LIBRARY, 'A 8: M COLLEGE, CAMPUS. A66-740-7M-L180 TEXAS AGRICULTURAL EXPERIMENT STATION A. B. CONNER, DIRECTOR COLLEGE STATION, BRAZOS COUNTY, TEXAS BULLETIN NO. 589 , AUGUST 1940 DIVISION OF CHEMISTRY Metabolizable Energy of Some Chicken Feeds / AGRICULTURAL AND MECHANICAL COLLEGE OF TEXAS T. O. WALTON, President [Blank Page in Original Bulletin] SYNOPSIS This publication is one of a series dealing with the utilization of the energy of animal feeds and of human foods. The metabolizable energy is the energy in the feed eaten less that excreted and is the maximum amount of energy that can be utilized by the animals. No allowances are made for the work of digestion and other losses involved in the utilization of the digested nutrients. Comparison of the heats of combustion found by analysis with the heats of combustion calculated by the usual methods, showed an average percentage difference of 2.1 per cent for 48 samples of feeds, 0.9 per cent for 62 rations, and 2.1 per cent for 136 samples of excrements, with standard deviations of 2.1 per cent, 1.8 per cent and 2.8 per cent, respectively. The values used in the calculations for feeds were 5.7 Calories per gram of protein, 9.47 Calories per gram of fat, and 4.2 Calories per gram of nitrogen-free extract and of crude fiber. The same values were used for excrements with the additional values of 2.735 Calories per gram of uric acid and 5.8 Calories per gram of ammonia. \ When correction was made for the protein retained, the metabolizable energy calculated from the digestible nutrients agreed well with the value found in 128 tests with growing chickens. The average difference was 2.0 per cent and the standard deviation of the differences was 2.8 per cent. The metabolizable energy (on maintenance basis) of ordinary chicken feeds can be calculated by using the value of 4.4 Calories per gram of digestible protein, 9.47 Calories per gram of digestible ether extract (fat), and 4.2 Calories per gram of digestible nitrogen-free extract and crude fiber. When lactose is present in appreciable quantities, (as in dried whey, dried skim milk, and to a less extent, in dried buttermilk), greater accuracy can be secured by allowing for the fact that its heat of combustion is 3.7 Calories per gram instead of the 4.2 Calories per gram used for nitrogen-free extract in ordinary feeds. .. 4n ‘B’: PH‘ 1i 15,5; .-= l1 v I . CONTENTS Page Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Method of procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Comparison of heats of combustion of feeds as found by analysis and as calculated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 6 Relation of heat of combustion of excrements as found by combustion and as calculated from the chemical composition . . . . . . . . . . . . . . . . 1O Metabolizable energy of the mixtures . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 17 Metabolizable energy of individual feeds . . . . . . . . . . . . . . . . . . . . . . . . . .. 20 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 R€ferences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 BULLETIN NO. 589 - AUGUST 1940 METABOLIZABLE ENERGY OF SOME CHICKEN FEEDS G- S- FY3115, Chief, E- C. Carlyle and J. F. Fudge, Chemists, Division 0f Chemistry \ The work here presented is a part of a comprehensive investigation of the utilization of the energy of feeds by animals. Previous publica- tions have discussed the digestibility of some chicken feeds (5), the utilization of energy of feeds by growing chickens (6), the utilization of the energy of wheat products by chickens (7), and the energy values of corn bran, rice bran, and rye flour (8). Other work is in progress. This publication deals with the metabolizable energy of chicken feeds. The values of feeds have been judged by consideration of the quantities of the various digestible nutrients, of the metabolizable energy, or by measuring the utilization of the food by animals. The metabolizable energy is defined as the total energy less the energy in the solid excrement, in the liquid excrement, and in case of ruminants, the gases produced by fermentation in the process of digestion. The metabolizable energy is, therefore, the maximum quantity of the energy of the food which may possibly be used by the animal. The energy cost of utilization is not in- eluded in the metabolizable energy. Mitchell and associates have reported that for chickens metabolizable energy of corn is 331.6 Kg. Calories per 100 gm. or 82.6% (14), 85% (11), and 83% (12) of the gross energy, that of Wheat as 80.5% of the gross energy (12), and that of soybean oil meal 52 to 65% of the gross energy (13). Axelson (2) reported the metabo- lizable energy of some chicken feeds, but the values given were secured by multiplying the digestible nutrients by assumed factors: for protein, 4.7, for fat, 8.3, for nitrogen-free extract, 3.8, and for crude fiber, 3.8. Daikow (3) reported the metabolizable energy of whole barley as being 71.2, 71.8, 71.5, and 72.3%, of whole oats as 62.3%, and of millet as 75.8% of the gross energy. Metabolizable energy used in Texas Bulletin 571 (6) was calculated on the assumption that the metabolizable energy of the effective digestible constituents of the feeds was 4.1 Calories per gram. A number of digestion experiments have been made at the Texas Agri- cultural Experiment Station on chicken feeds, with use of chickens from 2 to 10 weeks of age, in connection with studies of the productive energy values of feeds already reported in part (6, 7, 8). The metabolizable energy was determined in connection with a number of these experiments. 6 BULLETIN NO. 589, TEXAS AGRICULTURAL EXPERIMENT STATION Method of Procedure The chicks were kept in electrically heated brooders in groups of 7 t0 l 10 chickens. The ration being tested was fed for a preliminary period of A 3 days followed by a test period of 4 days, during which the excrement was collected. A little less feed was given daily in the collection period than in the preliminary period, so that little feed would remain uneaten. Any scattered feed was collected and Weighed. The excrements were col- lected twice a day and dried in an electric oven at 85°C. The feeds and excrements were analyzed for protein, fat, crude fiber, water, and ash by A.O.A.C. methods. The heat of combustion was determined in an Emerson bomb calorimeter with adiabatic jacket. Uric acid in the excrement was determined by the following method: Weigh 1.4 grams into a 150 cc beaker, add 25 cc of ice-cold alcohol and allow to stand for thirty minutes in ice water. Trans- fer quantitatively to a 50 cc centrifuge tube and centrifuge until clear. Decant the liquid and wash twice with 25 cc ice cold 95% alcohol. Transfer the residue with 25 cc ether to a hardened filter paper and wash twice with 15 cc ether. Transfer to a beaker and add 25 cc 0.2 hydrochloric acid and allow to stand over night in a refrigerator. Transfer to a centrifuge tube, centrifuge and wash twice with ice cold water. Transfer the residue to a 150 cc beaker with 25 cc water, add 15 cc 0.2 N sodium hydroxide and heat on the water bath until the white particles of uric acid have all dis- solved. Centrifuge, pour the supernatant liquid into a 250 cc beaker and wash the residue three times with 50 cc hot water. Evaporate the solution to about 50 cc, transfer to a 150 cc beaker, and continue the evaporation to about 30 cc. Add 5 cc concen- trated hydrochloric acid, evaporate to about 25 cc, and allow to stand 24 hours in the refrigerator. Centrifuge and wash twice with ice-cold water. Transfer residue to a Kjeldahl flask and determine nitrogen. The nitrogen multiplied by 3 is uric acid. Ammonia in the excrement was determined as follows: Weigh 1.4 grams excrement into a Kjeldahl flask and add 200 cc water, a drop of lubricating oil, some pieces of sharp glass or broken alundum and about 2.0 grams magnesium hydroxide. Dis- till into 15 cc 0.2 N hydrochloric acid. Calculate nitrogen as ammonia. Comparison of Heats of Combustion of Feeds as Found by Analysis and as Calculated The heat of combustion waf- ingredients of foods and feeds have been determined by a number of workers. Armsby (Nutrition of Farm Ani- mals) (1) gives the following values in Calories per kilogram: Animal protein . . . . . . . . . . .5700 Animal fats . . . . . . . . . . . . . .9500 Vegetable protein . . . . . . . . .5636 Vegetable fats . . . . . . . . . . .9470 Carbohydrates . . . . . . . . . . .4185 Ether extract of seeds. . . . .9467 Sucrose . . . . . . . . . . . . . . . . . .3955 Ether extract of roughages.7962 METABOLIZABLE ENERGY OF SOME CHICKEN FEEDS 7 The heats of combustion (Calories per kilogram) of digested nutrients as digested by ruminants are calculated by Armsby as follows: Protein (wheat gluten) . . . . . . . . . . . . . . . . . . . . . . . . .. 5975 Protein (assumed average) . . . . . . . . . . . . . . . . . . . . .. 5700 Crude fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4254 Nitrogen-free extract of hay . . . . . . . . . . . . . . . . . . . . . . 4232 Nitrogen-free extract (starch) . . . . . . . . . . . . . . . . . . . . 4185 Ether extract of hay. ..' . . . . . . . . . . . . . . . . . . . . . . . . . . 8322 Peanut oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8821 Total organic matter of roughage . . . . . . . . . . . . . . . . 4472 The heats of combustion of the feeds here discussed were determined directly with a bomb calorimeter. They were also calculated (1) from the chemical analysis with use of 5.7 Calories per gram for protein, 9.47 Calories for ether extract (fat), 4.2 Calories for nitrogen-free extract, and 4.2 Calories for crude fiber. In the determination of heat of combustion, the heat evolved was meas- ured by a thermometer calibrated by the U. S. Bureau of Standards, which was graduated at intervals of 0.02°C. and which could be read to an accuracy of about .002 degrees C. The change in temperature during the combustion was usually from 1.6 to 2.0°C. The error of reading could therefore be .004 degrees or about 0.2 per cent. The actual error may be less than this, since the heat of combustion used was the average of 2 or more independent analyses. Other factors could, however, affect the accu- racy of the work. A difference of 1 per cent could be ascribed to the error of analysis. The composition and heats of combustion of 48 samples of feeds as found by direct combustion and as calculated are given in Table 1 together with the ratio between them, expressed as percentage of the calculated value. The average difference between the value found and the value calcu- lated is 2.1 per cent. The standard deviation is 2.8 per cent with the 48 samples, 2.3 per cent if lactose is excluded. On an average, the calculated heat of combustion (4.792 Calories per gram) is practically the same as the heat of combustion found by use of a bomb calorimeter (4.777). The heats of combustion found were higher than those calculated for alfalfa leaf meal (2.9%), casein (4.1%), oat hulls (4.0%), and yeast (1.6%), and lower than those calculated for corn meal (1.9%), low grade flour (1.9%), patent flour (2.3%), lactose (10.7%), rice bran (1.2%), rice polish (1.6%) and starch (2.9%). The difierences are small, except for lactose. The calculated value of lactose is too high compared with the value found, which latter, however, (3.717 Calories per gm.) is close to the value of 3.731 given by Emery and Benedict (4) or in the International Critical Tables (10) for lactose containing 1 molecule of water. For feeds high in lactose, such as dried buttermilk, dried skimmed milk, and dried whey, it is probably desirable to use 3.7 calories per gram of nitrogen-free extract in place of 4.2 calories. Other special feeds may also require different values. Table 1. Percentage composition and heat of combustion of feeds as found and as calculated Heat 0f comb istion Found Cal. per gm. Calmlated C3]. per gm. Nitrogen Lab. Ether Crude ree Water N0. extract fiber extract 45210 Alfalfa leaf meal . . . . . . . . . . . . . . . . . 2.75 23.34 35.78 7.80 48263 Alfalfa leaf meal . . . . . . . . . . . . . . . . . 2.88 17.04 38.19 7.83 Average (2) . . . . . . . . . . . . . . . 2.82 20.19 36.99 7.82 47987 Casein . . . . . . . . . . . . . . . . . . . . . . . . . .13 .23 4.76 9.41 48261 Casein . . . . . . . . . . . . . . . . . . . . . . . . . .27 .29 4.67 8.23 48544 Casein . . . . . . . . . . . . . . . . . . . . . . . . . .37 .23 3.67 7.71 52124 Casein . . . . . . . . . . . . . . . . . . . . . . . .. .43 .17 3.28 9.01 Average (4) . . . . . . . . . . . . . . .. .30 .23 4.10 8.59 50740 Corn bran . . . . . . . . . . . . . . . . . . . . . . 6.57 12.54 62.06 7.21 50742 Corn bran . . . . . . . . . . . . . . . . . . . . .. 8.16 10.20 61.70 6.92 50786 Corn bran . . . . . . . . . . . . . . . . . . . . . . 3.95 14.79 65 70 7.73 Average (3) . . . . . . . . . . . . . . . 6.23 12.51 63 15 7.29 48280 Corn meal (white) . . . . . . . . . . . .. 2.84 1.48 72.33 10.51 47955 Corn mrai (uh te) . . . . . . . . . . . . . .. 3.00 1.39 73.15 9.93 48260 Corn mcal (vs hite) . . . . . . . . . . . . . .. 4.11 1.35 72.78 10.84 48440 C rn meal (v hi-te) . . . . . . . . . . . . . .. 4.96 1.58 69.63 10.27 50868 Cfin meal (v hi e) . . . . . . . . . . . . . . . 2.67 1.01 74.3.5 10.04 51556 C nmeal (vhte) . . . . . . . . . . 3.23 1.12 73.97 9.74 51960 Corn meal (vshzte) . . . . . . . . . . . . . .. 2.81 1.06 74.35 9.79 51824 Corn meal (V1116) . . . . . . . . . . . . . .. 2.85 1.04 73.87 .32 . Average (8) . . . . . . . . . . . . . . . . 3.31 1.26 73.05 18 48437 Corn meal (yellow) . . . . . . . . . . . . . . 4.41 2.27 71.06 .01 47762 Flour, low grade . . . . . . . . . . . . . . . . . 2 .24 .43 71 .67 .52 48244 Flour, low grade . . . . . . . . . . . . . . . . . 1.94 .50 70.18 .46 48436 Flour, 10w grade . . . . . . . . . . . . . . . . . 2.08 .50 64. 8.! .74 Average (3) . . . . . . . . . . . . . .. 2.09 .43 68.91 .91 47761 Flour, patent . . . . . . . . . . . . . . . . . . . .91 .25 73.25 .55 48243 Flour, patent . . . . . . . . . . . . . . . . . . . . 84 .24 73 .43 . 17 48435 Flour, patent . . . . . . . . . . . . . . . . . . . .01 .40 70.83 .22 Average (3) . . . . . . . . . . . . . .. .92 .30 72 52 ‘ .65 51581 Kafir (blackhull) . . . . . . . . . . . . . . . . 3.45 70.96 _81 51582 Kahr (waxy cndosperm) . . . . . . . . . . 4.06 2.43 70.52 Average (2) . . . . . . . . . . . . . .. 3.70 2.38 70.74 .16, .49. , 971 vkhik 0500 0003 CAJCDQJCAJ all wwooe-wamww JR>§IPIP UTOTUTCDUI 000000 O0 \l n5 .911 .750 .831 .856 902 .006 890 905 886 894 087 .132 .110 ~l>$>~rl> 0309 0000 >§$|POJ r5 PPIP>§>P>§DQH>1PH> >I>>§J>>J> vhrPLM-brk 000007 c .. hi (D R NOLLVLS LNEINIHEIJXEI TVHIILTIIOIHDV SVXELL ‘689 "ON NLLEITIIlH 51568 Lactose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .24 .00 .17 98.58 .97 .04 3.717 4.161 89.3 50787 Hydrogenated oil . . . . . . . . . . . . . . . . 276 . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.559 9.470 100.9 50788 Hydrogenated oil . . . . . . . . . . . . . . . . 277 . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.427 9.470 99.6 Average (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.493 9.470 100.3 51609 Oat hulls . . . . . . . . . . . . . . . . . . . . . .. 296 6.60 1.92 26 10 52.48 7.08 5.82 4.025 3.871 104.0 52971 Corn oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.444 9.470 99.7 52972 Peanut cil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.394 9.470 99 ._2 52970 Soybcan cil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.497 9.470 100.3 52973 Wesaon oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100.00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.391 9.470 99.2 Average oils (4) . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.432 9.470 99.6 51682 Rice bran . . . . . . . . . . . . . . . . . . . . .. 298 13.10 11 17 .78 50.77 8.98 9.20 4.176 4.225 98.8 51681 Rice- polish . . . . . . . . . . . . . . . . . . . .. 297 13.17 15.31 .10 52.11 9.53 7.78 4.409 4.479 98.4 51683 Rye flour . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12.61 1.90 .16 69.77 11.75 1.81 3.903 3.921 99.5 47956 Starch . . . . . . . . . . . . . . . . . . . . . . . . . 196 .49 .09 .26 88.10 10.91 .15 3.660 3.748 97.7 51567 Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .64 .07 .16 87.90 11.15 .08 3.666 3.742 98.0 51955 Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .63 0 .15 87.83 11.27 .12 3.613 3.731 96.8 52123 Starch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .58 .23 17 88.46 10.45 .11 3.624 3.777 96.0 Average (4) . . . . . . . . . . . . . . . . . . . . . .. .59 10 19 88.07 10.95 .12 3.641 3.750 97.1 47763 Wheat bran . . . . . . . . . . . . . . . . . . . .. 170 17.87 4.18 10.13 52.47 8.93 6.42 4.035 4.050 99.6 48264 Wheat bran . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19.24 4.05 9.41 50.64 10.33 6.33 4.078 4.008 101.8 52122 Wheat bran . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 18.48 4.05 9.93 52.04 8.80 6.70 4.101 4.045 101.4 Average (3) . . . . . . . . . . . . . . . . . . . . . .. 18.53 4.09 9.82 51 72 9.35 6.48 4.071 4.034 100.9 47764 Wheat gray shorts . . . . . . . . . . . . . . . . . . . . . .. 19.03 4.24 6.43 54.81 10.51 4.98 4.002 4.062 98.5 48265 Wheat gray shorts . . . . . . . . . . . . . .. 171 19.50 4.62 6.47 54.94 9.57 4.90 4.119 4.132 99.7 Average (2) . . . . . . . . . . . . . .: . . . . . . .. 19.27 4.43 6.45 54.88 10.04 4.94 4.061 4.097 99.1 48262 Yeast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.42 .99 6.26 33.20 5.53 8.60 4.405 4.343 101.4 51954 Yeast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 47.25 1.19 1.08 34.97 7.57 7.94 4.399 4.321 101.8 Average (2) . . . . . . . . . . . . . . . . . . . . . . . . 46.34 1.09 3.67 34.09 6.55 8.27 4.402 4.332 101.6 Average (48 samples) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.777 4.792 99.6 Average cf difierences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1 Standard deviations 0f difTerences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 Standard deviations of difierences, lactose excluded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 SCIEIEIJ NEDIOIHO EIWOS .10 LDHEINEI EITHVZITOHVLEIW 10 BULLETIN NO. 589, TEXAS AGRICULTURAL EXPERIMENT STATION The corn meal was fed in balanced rations A, B or C given in Table 2. The other feeds were fed in similar rations, in which they replaced the corn meal to the extent of 50% with most of the feeds, 15% with oils, and 40% with casein. The chemical composition and the heats of combustion of the rations as calculated and as found are given in Table 3 with the ratio of the values found divided by the values calculated expressed in per cent. The average difference for the rations is 0.9 per cent, much less than the 2.1 per cent for the unmixed feeds. The standard deviation is 1.8, less than 2.3 per cent found for the unmixed feeds, lactose excluded. These data show that on an average of 62 samples the heat of combustion found is 99.8% of the calculated value. The heat of combustion can therefore be calculated for the feeds in question from the chemical analyses with an excellent degree of accuracy. Table 2. Percentage constituents of rations 47990 48841 49205 52133 corn meal Basal corn meal corn _meal ration ration ration ration (Basal A) (Basal A) (Basal B) (Basal C) Corn meal . . . . . . . . . . . . . . . . . . . . . . .. 6.0 12.0 6.8 . . . . . . . . . . .. Alfalfa leaf meal . . . . . . . . . . . . . . . . .. 6.0 12.0 6.0 4.0 Casein . . . . . . . . . . . . . . . . . . . . . . . . . .. 12.0 24.0 12.0 . . . . . . . . . . .. Yeast . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2.0 4.0 2.0 6.0 Wheat gray shorts . . . . . . . . . . . . . . .. 20.0 40.0 20.0 16.3 Calcium carbonate . . . . . . . . . . . . . . . . 1.0 2.0 1.0 1.5 Salt . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.0 2.0 1.0 1.0 Tri-calcium phosphate . . . . . . . . . . . . . 1.0 2.0 1.0 1.0 Sardilene oil . . . . . . . . . . . . . . . . . . . . . . 1.0 2.0 . . . . . . . . . . . . . . . . . . . . . . . . Cod liver oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0.2 0.2 Skimrned milk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 Cottonseed meal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.0 Corn meal . . . . . . . . . . . . . . . . . . . . . . .. 50.0 . . . . . . . . . . .. 50.0 50.0 Relation of Heat of Combustion of Excrements as Found by Combustion and as Calculated from the Chemical Composition The heats of combustion of the dried excrements were measured directly in the bomb calorimeter. They were calculated from the analyses by use of the same values as those used for the feeds, with the addition that the uric acid was considered to have the value of 2.735 Calories per gram (9) and the ammonia that of 5.8 Calories per gram. The numbers of the digestion experiments in which each was used are given in Table 3 and those for the corresponding excrement in Table 4. .Analyses of the excre- ments and comparisons of the heats of combustion as calculated and as found are given in Table 4. The ratio between the calculated heats of combustion and those found by means of the bomb calorimeter are given in Table 4, expressed as per cent. The average of the differences is 2.1 per cent and the standard deviation is 2.8 per cent. These data show that Table 3. Percentage composition and heat of combustion of rations as found and as calculated Heat of combustion Nitrogen Ratio Lab. D. E. Protein Ether Crude free Water Ash Found Calculated in No. N0. extract fiber extract Cal. Cal. per cent per gm per gm. 48266 Basal ration . . . . . . . . . . . . . . . . . . . . 166 32.79 .68 5.04 39.42 8.20 9 .87 4.203 4.182 100.5 48841 Basal ration . . . . . . . . . . . . . . . . . . .. 197 34.28 4.99 4.43 36.97 8.71 10.62 4.140 4.168 99.3 51766 Basal ration . . . . . . . . . . . . . . . . . . .. 291 33.51 .70 4.71 40.65 8.48 9.95 4.125 4.073 101.3 Average (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.156 4.141 100.4 49206 Casein ration . . . . . . . . . . . . . . . . . . . 228,232 49.23 2.11 2.63 30.35 9.70 5.98 4.393 4.393 100.0 49479 Casein ration . . . . . . . . . . . . . . . . . . . 240,244 49.35 1.83 2.66 30.81 9.42 5.93 4.345 4.393 98.9 Average (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.369 4.393 99.5 48792 Corn bran ration . . . . . . . . . . . . . . . . 199,204 22.10 6.22 9.31 48.49 8.09 5.79 4.301 4.282 100.4 49026 Corn bran ration . . . . . . . . . . . . . . .. 215,221 22.00 7.77 8.09 46.16 8.70 7.28 4.291 4.273 100.4 50870 Corn bran ration . . . . . . . . . . . . . . .. 236,251 21.01 4.61 8.70 50.64 9.37 5.67 4.107 4.132 99.4 50871 Corn bran ration . . . . . . . . . . . . . . .. 237,252 21.30 5.01 7.80 51.03 8.89 5.97 4.156 4.163 99.8 50872 Corn bran ration . . . . . . . . . . . . . . . . 238,253 19.25 3.17 9.95 52.92 9.32 5.39 4.099 4.043 101.4 Average (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.191 4.179 100.3 47990 Corn meal ration . . . . . . . . . . . . . . .. 162 21.80 3.67 3.59 56.33 9.19 5.42 4.110 4.110 100.0 48274 Corn meal ration . . . . . . . . . . . . . . .. 172,176 21.55 4.42 3.20 55.44 9.65 5.74 4.158 4.111 101.1 48466 Corn meal ration . . . . . . . . . . . . . . .. 184,188 22.71 5.22 3.26 54.13 8.85 5.83 4.184 4.200 99.6 48791 Corn meal ration . . . . . . . . . . . . . . .. 198,203 22.81 5.06 3.18 53.80 9.38 5.77 4.211 4.174 100.9 49023 Corn meal ration . . . . . . . . . . . . . . .. 212,218 22.81 4.72 3.13 53.53 10.02 5.79 4.144 4.128 100.4 49205 Corn meal ration . . . . . . . . . . . . . . . . 227,231 22.75 3.77 3.00 53.80 10.81 5.87 4.075 4.032 101.1 49478 Corn meal ration . . . . . . . . . . . . . . . . 239,243 22.08 2.84 3.03 55.90 10.53 5.62 3.923 4.005 98.0 50869 Corn meal ration . . . . . . . . . . . . . . . . 235,250 2.1.40 2.73 2.86 57.81 9.79 5.41 4.022 4.029 99.8 51359 Corn meal ration . . . . . . . . . . . . . . .. 255,263 21.91 3.22 2.65 57.17 9.58 5.47 4.197 4.068 103.2 51570 Corn meal ration . . . . . . . . . . . . . . .. 272,278 21.92 3.02 2.77 57.51 9.57 5.21 4.061 4.068 99.8 51684 Corn meal ration . . . . . . . . . . . . . . .. 283,287 21.94 3.01 2.90 57.18 9 .77 5.20 4.036 4.061 99.4 51833 Corn meal ration . . . . . . . . . . . . . . . . 292,299 22.09 2.86 2.82 57.49 9.52 5.22 4.040 4.065 99.4 51956 Corn meal ration . . . . . . . . . . . . . . . . 303,308 22.25 2.73 2.73 57.71 9 .37 5.21 3.986 4.067 98.0 52133 Corn meal ration . . . . . . . . . . . . . . .. 312,320 20.10 3.38 3.43 58.19 8.15 6.75 3.961 4.056 97.7 Average (14) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4.079 4.084 99.9 52332 Corn oil ration . . . . . . . . . . . . . . . . . . 325,329 18.35 16.89 3.48 47 58 6.84 6.86 4.838 4.791 101.0 49025 Clear flour ration . . . . . . . . . . . . . . . . 214,220 25.53 2.86 2.70 53.71 9.74 5.46 4.053 4.097 98.9 47992 Low grade flour ration . . . . . . . . . . . 164 23.49 3.20 3.01 55.78 9.25 5.27 4.088 4.113 99.4 48276 Low grade flour ration . . . . . . . . . . . 174,178 24.03 3.14 2.74 54.66 10.00 5.43 4.088 4.079 100.2 48468 Low grade flour ration . . . . . . . . . .. 1 6,19 25.75 3.48 3.04 52.02 10.29 5.42 4.059 4.112 98.7 Average (3) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.078 4.101 99.4 1T SCIEIELI NEDIDIHO EIIAIOS e10 LDHEINH EITHVZYIOHVLEIWI Table 3. Percentage composition and heat of combustion of rations as found and calculated—(continued) D. E Protein Ether N0. extract Patent flour ration . . . . . . . . . . . . . . . 63 22 .74 Patent flour ration . . . . . . . . . . . . . . . 173, 177 23 .76 Patent flour ration . . . . . . . . . . . . . . . 185,189 24 .92 Patent flour ration . . . . . . . . . . . . . . . 213 ,219 24 .74 Average (4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Kafir ration . . . . . . . . . . . . . . . . . . . . . 294,301 22 .97 Kafir ration . . . . . . . . . . . . . . . . . . . . . 295,302 22 .26 Average (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Lactose ration . . . . . . . . . . . . . . . . . . 274,280 16. .44 Oat hull ration . . . . . . . . . . . . . . . . . . 293 ,300 19. .34 Peanut oil ration . . . . . . . . . . . . . . . . 326, 330,332 18. .26 Rice bran ration . . . . . . . . . . . . . . . . . 285,289 23. 7 .48 Rice polish ration . . . . . . . . . . . . . . . 284,288 22. .12 Rye flour ration . . . . . . . . . . . . . . . . . 286,290 22. .29 Soybean oil ration . . . . . . . . . . . . . . . 327, 331,333 18. .85 Starch ration . . . . . . . . . . . . . . . . . . . . 229,233 17. .35 Starch ration . . . . . . . . . . . . . . . . . . . 241,245 16. .05 Starch ration . . . . . . . . . . . . . . . . . . . . 273,279 16. .43 Starch ration . . . . . . . . . . . . . . . . . . . 304,307 17. .33 Average (4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Starch and casein ration . . . . . . . . . . 313,321 19. .87 Starch and yeast ration . . . . . . . . . . 305,310 19. .47 Starch, yeast and corn oil ration. .. 306,311 19. .61 Iiydrogenatcdtnlrafion . . . . . . . . .. 257.265 20.. .66 Hydrogenated oil ration . . . . . . . . . . 258,266 20. .45 Heat of combustion Nitrogen Crude free Water fiber extract .93 56.89 .52 .15 .67 57.14 .05 .25 .76 56.17 .75 .3€ .59 55 .36 . 87 .21 .43 56.63 .70 . 48 .46 56.87 .31 .52 .35 69 .71 .68 .95 .64 46.88 . 70 .56 .53 47.46 6.75 .60 .56 45.93 8.69 .28 .37 47.47 8.73 .60 .48 55.76 .01 .68 .27 47.80 .97 .69 .41 62.86 .73 .02 .32 63.79 .95 .99 .50 64.15 .92 .01 .39 64.73 12 .81 .06 60.05 .73 . 39 .40 62.11 34 18 .53 61.69 .99 .11 .04 45.99 .45 .30 .69 47.43 .93 .33 Ratio lIl per cent 99. 99. 100. 99 99 99 98 99. 94 104. m k wbd Qdmqw 99. 99. 99. 99. QOMWQ 101. CD CO [OUT 2O F‘ \1 OOGNJQ \I ZI E i NOLLVLS LNEINIHEIJXEI TVHIIJ/IIIOIHDV SVXELL ‘689 ‘ON NIJLEUYIHH Wesson oil ration . . . . . . . . . . . . . . . . Wesson oil ration . . . . . . . . . . . . . . . . Wesson oi] ration . . . . . . . . . . . . . . . . Wesson oil ration . . . . . . . . . . . . . . . . Wesson oil ration . . . . . . . . . . . . . . . . Average (5) . . . . . . . . . . . . . .. Wheat bran ration . . . . . . . . . . . . . . . Wheat bran ration . . . . . . . . . . . . . . . Wheat. bran ration . . . . . . . . . . . . . . . Wheat bran ration . . . . . . . . . . . . . . . Average (4) . . . . . . . . . . . . . .. Wheat gray shorts . . . . . . . . . . . . . . . Wheat gray shorts . . . . . . . . . . . . . . . Average (2) . . . . . . . . . . . . . .. Average (62) . . . . . . . . . . . . . . . . . .. Average of differences. ._ . . . . . . . . . . Standard deviation of difierences. . 230 ,234 242 ,246 256 ,264 315 ,323 324,328 187,191 200,205 O5G5U1U1U\ U3 N) vP nkbrirbfi HiMPI-Bv-Ikflik r-l i.»- C? 1P Qfiii sl>§>~>¥>d>>> viiviinivPn-Pzb >- O n» boiobc Allah: iobbbol- steps-nap £1 SCIEIEIJ NEDIOIHO EIWOS JO LDHEINEI EPIHVZITOHVLEIW Table 4. Percentage composition of excrements and heat of combustion as calculated and as found Nitrogen - Heat of combustion Laboratory Number D. E. N0. Protein Ether Crude free Uric N as in Cal. per gm. Ratio extract fiber extract acid Ammonia per cent Found Calculated 48133 . . . . . . . . . . . . . . . .. 162 15.75 1.53 11.49 41.48 11.46 .26 3.510 3.601 97.5 48134 . . . . . . . . . . . . . . . .. 163 16.75 1.23 9.61 44.10 11.04 .33 3.605 3.652 98.7 48135 . . . . . . . . . . . . . . . .. 164 16.75 1.48 8.88 44.91 10.65 .32 3.569 3.668 97.3 48136 . . . . . . . . . . . . . . . .. 165 13.20 1.12 13.82 47.52 7.14 .21 3.741 3.648 102.3 48286 . . . . . . . . . . . . . . . .. 166 14.56 1.36 10.37 35.81 13.74 .51 3.241 3.310 97.9 48287 . . . . . . . . . . . . . . . .. 166 14.06 1.27 10.04 34.87 13.59 .46 3.163 3.212 98.5 48305 . . . . . . . . . . . . . . . .. 172 14.00 1.50 10.80 41.70 10.68 .41 3.458 3.466 99.8 48306 . . . . . . . . . . . . . . . .. 173 15.50 1.33 8.92 46.46 10.59 .43 3.617 3.655 99.0 48307 . . . . . . . . . . . . . . . .. 174 16.69 1.43 8.71 44.93 10.92 .41 3.529 3.666 96.3 48308 . . . . . . . . . . . . . . . .. 175 14.13 1.11 12.64 47.47 .89 .38 3.755 3.679 102.1 48313 . . . . . . . . . . . . . . . .. 176 13.19 1.54 11.11 42.34 10.98 .39 3.439 3.471 99.1 48314 . . . . . . . . . . . . . . . .. 177 17.28 1.39 8.70 41.85 11.43 .45 3.521 3.584 98.2 48315 . . . . . . . . . . . . . . . .. 178 16.50 1.35 8.25 43.59 11.52 .43 3.459 3.591 96.3 48316 . . . . . . . . . . . . . . . .. 179 12.63 1.08 13.19 46.56 8.22 .43 3.709 3.589 103.3 48540 . . . . . . . . . . . . . . . .. 184 15.81 2.20 10.88 43.00 9.54 .30 3.574 3.655 97.8 48541 . . . . . . . . . . . . . . . .. 185 18.38 1.52 9.14 42.60 11.52 .41 3.615 3.708 97.5 48542 . . . . . . . . . . . . . . . .. 186 18.94 1.59 8.58 44.22 10.77 .44 3.583 3.774 94.9 48543 . . . . . . . . . . . . . . . .. 187 15.13 1.47 12.14 47.40 7.89 .32 3.755 3.743 100.3 48592 . . . . . . . . . . . . . . . .. 188 17.38 2.42 10.40 39.47 9.66 .32 3.542 3.603 98.3 48593 . . . . . . . . . . . . . . . .. 189 18.63 1.45 8.83 41.26 10.47 .40 3.515 3.616 97.2 48594 . . . . . . . . . . . . . . . .. 190 17.13 1.67 8.04 43.88 11.10 .47 3.640 3.650 99.7 48595 . . . . . . . . . . . . . . . .. 191 13.00 1.47 11.59 46.48 9.15 .38 3.642 3.597 101.3 48831 . . . . . . . . . . . . . . . .. 198 14.00 1.91 10.34 42.63 10.50 .38 3.611 3.517 102.7 48832 . . . . . . . . . . . . . . . .. 199 10.69 1.48 15.41 53.02 5.37 .30 3.860 3.795 101.7 48833 . . . . . . . . . . . . . . . .. 200 12.94 1.76 11.05 47.71 8.88 .40 3.726 3.645 102.2 48834 . . . . . . . . . . . . . . . .. 201 14.19 2.05 12.03 44.61 9.06 .40 3.674 3.659 100.4 48867 . . . . . . . . . . . . . . . .. 203 12.94 1.99 10.52 42.70 10.89 .39 3.511 3.487 100.7 48868 . . . . . . . . . . . . . . . .. 204 10.19 1.22 15.19 52.52 6.18 .36 3.823 3.739 102.3 48869 . . . . . . . . . . . . . . . .. 205 14.31 1.44 11.35 45.69 9.03 .46 3.678 3.627 101.4 48870 . . . . . . . . . . . . . . . .. 206 14.00 1.22 13.01 44.83 7.83 .51 3.585 3.594 99.8 48969 . . . . . . . . . . . . . . . .. 197 18.69 1.63 10.34 32.04 12.60 .66 3.340 3.387 98.6 48970 . . . . . . . . . . . . . . . .. 197 17.25 1.72 10.33 31.35 14.76 .80 3.313 3.352 98.8 48971 . . . . . . . . . . . . . . . .. 197 15.38 1.65 10.01 34.00 14.85 .74 3.305 3.335 99.1 48972 . . . . . . . . . . . . . . . .. 197 15.44 1.73 11.61 31.33 15.00 .81 3.302 3.310 99.8 48303 . . . . . . . . . . . . . . . .. 167 16.63 2.10 8.02 42.71 14.19 .74 3.564 3.713 96.0 48304 . . . . . . . . . . . . . . . .. 167 17.13 2.02 7.94 45.52 13.02 .72 3.441 3.813 90.2 48334 . . . . . . . . . . . . . . . .. 168 10.56 .95 2.65 68.15 8.25 .47 3.732 3.920 95.2 48335 . . . . . . . . . . . . . . . .. 169 13.69 1.18 3.32 58.90 10.86 .63 3.696 3.841 96.2 48377 . . . . . . . . . . . . . . . .. 170 12.56 1.17 13.79 52.72 4.95 .40 3.846 3.785 101.1 48378 . . . . . . . . . . . . . . . .. 171 13.75 1.25 10.99 51.41 7.20 .49 3.819 3.753 101.8 48420 . . . . . . . . . . . . . . . .. 180 14.69 2.43 18.06 39.46 6.06 .21 3.834 3.670 104.5 48421 . . . . . . . . . . . . . . . .. 181 16.31 1.08 9.31 50.37 6.96 .28 3.727 3.750 99.4 48504 . . . . . . . . . . . . . . . .. 182 17.75 2.57 12.30 47.03 6.87 .41 3.887 3.965 98.0 48505 . . . . . . . . . . . . . . . .. 182 17.88 2.46 11.29 48.58 7.62 .40 3.923 4.003 98.0 VI NOLLVLS SLNSIIAIIHEIJXH "IVHILLTQOIHDV SVXEIL ‘689 ‘ON NLLEITIHH 1b loan-Mm» r-n- Hv-nwmwr-lwbibar-d r-u-nd b-lb-lb-lflaflt-l vigor-n h-gm-u-mqwg [Qv-nwwlqmwr-nmp-N: l0 b! p-A pa» gdhud l-lp-Ap-l p-lpi 0-1 OOLQQQQOQIYI-‘WUTWP-‘OnikflM~UYHOO1O?OIF-HPUT>QQOOOOO c»:woowwwoawwwwwoopa»:wooAwwe»woocowwwwwwwwwwwwwwwwwwwwwwwwwwwooww L:L-bbolzokaL-lplobwbbobolowb=kalz>lobbolh~klékababo§lbrbbvLwlolcblsblhioboblolkbiobbbvihlnboflwbc QI SGEIEIJ NEDIOIHO EIIAIOS :10 XDHEINEI EFIHVZITOSIVLEIW Table 4. Percentage composition of excrements and heat of combustion as calculated and as found (Continued) 91 Average of diflcrcnccs. .. Standard deviation of differences . . . . . . . . . - _ Nitrogen Heat 0f combustion Laboratory Number D. E. No. Protein Ether Crude free Uric N as. in Cal. per gm. Ratio extract fiber extract acid Ammonia per cent Found Calculated 51751 . . . . . . . . . . . . . . . .. 289 13.94 1.97 13.79 37.37 6.96 .21 3.430 3.340 102.7 51752 . . . . . . . . . . . . . . . .. 290 16.25 1.73 9.08 46.12 8.79 .36 3.656 3.674 99.5 51852 . . . . . . . . . . . . . . . .. 291 12.63 1.17 10.46 36.78 13.59 .66 3.276 3.231 101.4 51853 . . . . . . . . . . . . . . . .. 291 15.50 1.07 11.20 34.80 12.39 .41 3.238 3.286 98.5 51871 . . . . . . . . . . . . . . . .. 292 13.88 1.73 10.55 41.95 12.12 .35 3.560 3.516 101.3 51872 . . . . . . . . . . . . . . . .. 293 8.44 .86 24.80 45.19 4.83 .19 3.825 3.784 101.1 51873 . . . . . . . . . . . . . . . .. 294 14.94 1.98 11.38 41.71 10.80 .35 3.609 3.591 100.5 51874 . . . . . . . . . . . . . . . .. 295 13.13 2.09 11.63 42.31 11.31 .36 3.696 3.547 104.2 51878 . . . . . . . . . . . . . . . .. 299 12.56 1.65 10.36 41.39 13.11 .39 3.532 3.432 102.9 51879 . . . . . . . . . . . . . . . .. 300 8.31 .82 24.44 45.06 5.16 .23 3.971 3.638 109.2 51880 . . . . . . . . . . . . . . . .. 301 14.75 1.90 11.26 40.24 11.76 .40 3.594 3.635 101.7 51881 . . . . . . . . . . . . . . . .. 302 15.56 1.92 11.17 40.86 10.17 .38 3.620 3.560 101 7 51998 . . . . . . . . . . . . . . . .. 303~ 15.06 1.47 10.26 39.88 12.09 .34 3.532 3.459 102.1 51999 . . . . . . . . . . . . . . . .. 304 12.13 .91 9.73 44.07 11.19 .33 3.494 3.367 103.8 52000 . . . . . . . . . . . . . . . .. 305 15.69 1.11 10.27 40.15 10.92 .32 3.446 3.439 100.2 52001 . . . . . . . . . . . . . . . .. 306 15.69 1.55 9.57 40.86 10.50 .30 3.453 3.468 99.6 52045 . . . . . . . . . . . . . . . .. 308 15.31 1.41 10.05 38.72 11.64 .34 3 398 3.398 100.0 52046 . . . . . . . . . . . . . . . .. 309 12.00 1.12 9.52 43.05 10.92 .29 3.339 3.321 100.5 52047 . . . . . . . . . . . . . . . .. 310 16.75 1.24 8.98 37.65 11.67 .36 3.405 3.375 100.9 52048 . . . . . . . . . . . . . . . .. 311 17.00 1.49 9.41 38.91 9.72 .32 3.476 3.429 101.4 52163 . . . . . . . . . . . . . . . .. 312 13.38 1.30 10.38 45.55 6.39 .16 3.507 3.424 102.4 52164 . . . . . . . . . . . . . . . .. 313 13.88 .74 9.55 47.09 6.81 .22 3.486 3.444 101.2 52165 . . . . . . . . . . . . . . . .. 314 14.25 1.12 10.72 47.53 6.42 .38 3.621 3.568 101.5 52166 . . . . . . . . . . . . . . . .. 315 13.56 6.48 9.80 41.72 5.94 .16 3.774 3.727 101.3 52175 . . . . . . . . . . . . . . . .. 320 14.19 1.48 10.16 44.28 7.23 .16 3.473 3.448 100.7 52176 . . . . . . . . . . . . . . . .. 321 14.06 .90 9.27 46.58 7.35 .22 3.509 3.450 101 7 52177 . . . . . . . . . . . . . . . .. 322 14.69 1.45 12.22 45.98 5.55 .32 3.645 3.595 101.4 52178 . . . . . . . . . . . . . . . .. 323 13.31 4.41 9.70 43.63 6.36 .23 3.645 3.608 101.0 52555 . . . . . . . . . . . . . . . .. 324 15.81 4.96 9.23 39.62 5.49 .11 3.636 3.583 101.5 52556 . . . . . . . . . . . . . . . .. 325 14.75 7.12 9.79 37.63 5.55 .11 3.712 3.669 101.2 52557 . . . . . . . . . . . . . . . .. 326 14.06 10.79 8.77 36.59 5.85 .13 3.951 3.901 101.0 52558 . . . . . . . . . . . . . . . .. 327 14.94_ 6.65 9.92 38.14 5.67 .13 3.741 3.669 102.0 52675 . . . . . . . . . . . . . . . .. 328 13.63 3.72 10.40 40.59 6.78 .17 3.569 3.471 102.8 52676 . . . . . . . . . . . . . . . .. 329 14.06 4.50 9.68 40.71 5.70 .18 3.613 3.514 102.8 52677 . . . . . . . . . . . . . . . .. 330 14.44 5.89 9.60 40.10 5.64 .19 3.776 3.638 103.8 52678 . . . . . . . . . . . . . . . .. 331 14.13 3.87 9.80 40.95 5.79 .21 3.535 3.478 101.6 52679 . . . . . . . . . . . . . . . .. 332 13.44 4.88 9.35 42.64 5.76 .18 3.670 3.584 102.4 52680 . . . . . . . . . . . . . . . .. 333 14.00 3.04 8.95 43 38 5.82 .19 3.437 3.458 99.4 Average (136) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .8 NOLLVLS LNIEIHIHEIJXH "IVHHJTIHOIHDV SVXELL ‘689 'ON NLLEITIIIH . 1.. 1.....- . METABOLIZABLE ENERGY OF SOME CHICKEN FEEDS 17 on an average of the 136 samples of excrement, the calculated heat of combustion is the same as the heat of combustion measured in a bomb calorimeter, the ratio being 100.14 to 100.0. The results show that by means of the factors used the heat of com- bustion of the excrements can be calculated with an excellent degree of accuracy. Metabolizable Energy of the Mixtures The metabolizable energy per gram of the mixtures was ascertained from each of the digestion experiments by subtracting the calories of heat of combustion in the grams of excrement, from the calories in the grams of the feed mixture eaten, and then dividing the difference by the grams of the feed mixture eaten. The metabolizable energy of the mixtures was also calculated from the digested nutrients, as found in each digestion experiment, with the same factors used in calculating the heat of combustion, namely, 4.2 for nitrogen-free extract and crude fiber and 9.47 for ether extract (fat). However, the value of 4.0 previously used by other workers (15) was used for protein. The metabolizable energy so calculated was found to be too low as compared with the values found by experiment. This discrepancy is due to retention of protein by the growing chicks. Previous work (6) has shown that growing chicks, similar to these used in this work, retained on an average 56.6 per cent of the digested protein. The value of 4 calories per gram of protein used in the calculation, how- ever, was based on the assumption that all the protein digested was utilized by the animal and excreted in the form of uric acid. This assumption is entirely correct only for animals on maintenance, that is, for those not retaining any of the digested protein. If all the protein eaten (5.7 calories per gram) is excreted as uric acid (2.785 Calories per gram of uric acid (9), equal to 1.3 Calories per gram of protein) the metabolizable energy of the protein would be 4.4 Calories per gram, which is greater than the 4.0 Calories assumed in the preliminary calculation. In the pre- vious work cited the chickens on an average retained 56.6% of the protein digested. The factor (4.4 Calories per gram) for calculating metab- olizable energy derived from protein was therefore corrected by adding 56.6% of the value of the uric acid produced from 1 gram of protein, (.73 Calories) which gave 5.13 Calories per gram for protein instead of 5.7 Calories per gram, for the growing chickens. The apparent metabolizable energy was recalculated with use of the revised factor 5.13 Calories for protein and the calculated results are com- pared in Table 5 with those found in the 128 metabolizable energy experi- ments on the rations. The average value found was 2.97 Calories per gram compared with 3.00 calculated, which is 99.1% of the calculated value. The average difference is 2.0 per cent and the standard deviation 18 BULLETIN NO. 5S9, TEXAS AGRICULTURAL EXPERIMENT STATION Table 5. Metabcllzable energy of rations as calculated and as found Metab. Metab. Lab. Basal energy energy Ratio No. ration found calculated per cent Cal. per gm. Cal. per gm. 48266 Basal ration . . . . . . . . . . . . . . . . . . A 2.775 2 764 100.4 48266 Basal ration . . . . . . . . . . . . . . . . . . A 2.753 2 755 99,94 48841 Basal ration . . . . . . . . . . . . . . . . . . A 2.648 2 696 98.2 48841 Basal ration . . . . . . . . . . . . . . . . . . A 2.744 2 802 97.9 48841 Basal ration . . . . . . . . . . . . . . . . . . A 2.675 2 783 96.1 48841 Basal ration . . . . . . . . . . . . . . . . . . A 2 .814 2.884 97.6 51766 Basal ration . . . . . . . . . . . . . . . . . . B 2.726 2.715 100.4 51766 Basal ration . . . . . . . . . . . . . . . . . . B 2.722 2.675 101.8 49206 Casein ration . . . . . . . . . . . . . . . . . Sp (B) 3.198 3.191 100.2 49206 Casein ration . . . . . . . . . . . . . . . . . Sp (B) 3.153 3.178 99.2 49479 Casein ration . . . . . . . . . . . . . . . . . p (B) 3.220 3.455 93.2 49479 Casein ration . . . . . . . . . . . . . . . . . Sp (B) 3.181 3.253 97.8 48792 Corn bran ration . . . . . . . . . . . . . . A 2.130 2.155 98.8 48792 Corn bran ration . . . . . . . . . . . . . . A 2.277 2.317 98.3 49026 Corn bran ration . . . . . . . . . . . . . . A 2.276 2.267 100.4 49026 Corn bran ration . . . . . . . . . . . . . . A 2.153 2.131 101.0 50870 Corn bran ration . . . . . . . . . . . . . . B 2.127 2.059 103.3‘ 50870 Corn bran ration . . . . . . . . . . . . . . B 2.037 2.152 94.6 50871 Corn bran ration . . . . . . . . . . . . . . B 2.294 2.278 100.7 50871 Corn bran ration . . . . . . . . . . . . . . B 2.282 2.324 98.2 50872 Corn bran ration . . . . . . . . . . . . . . B 1.887 1.773 106.4 50872 Corn bran ration . . . . . . . . . . . . . . B 1.818 1.848 98.4 47990 Corn meal ration . . . . . . . . . . . . . . A 3.193 3.175 100.6 48274 Corn meal ration . . . . . . . . . . . . . . A 3.254 2.964 109.8 48274 Corn meal ration . . . . . . . . . . . . . . A 3.191 3.148 101.4 48466 Corn meal ration . . . . . . . . . . . . . . A 3.239 3.223 100.5 48466 Corn meal raticn . . . . . . . . . . . . . . A 3.170 3.171 99.9 48791 Corn meal ration . . . . . . . . . . . . . . A 3.213 3.201 100.4 48791 Corn meal ration . . . . . . . . . . . . . . A 3.233 3 .203 100.9 49023 Corn meal ration . . . . . . . . . . . . . . A 3.059 3.057 100.1 49023 Corn meal ration . . . . . . . . . . . . . . A 3.192 3.167 100.8 49205 Corn meal ration . . . . . . . . . . . . . . A 3.082 3.022 102.0 49205 Corn meal ration . . . . . . . . . . . . . . A 3.095 3.038 101.9 49478 Corn meal ration . . . . . . . . . . . . . . B 2.962 3.035 97.6 49478 Corn meal ration . . . . . . . . . . . . . . B 2.999 3.093 97.0 50869 Corn meal ration . . . . . . . . . . . . . . B 3.072 3.062 100.3 50869 Corn meal ration . . . . . . . . . . . . . . B 3.053 3.091 98.6 51359 Corn meal ration . . . . . . . . . . . . . . B 3.332 3.168 105.2. 51359 Corn meal ration . . . . . . . . . . . . .. B 3.311 3.213 103.1 51570 Corn meal ration . . . . . . . . . . . . . . B 3.123 3 . 186 98.0 51570 Corn meal ration . . . . . . . . . . . . .. B 3.145 3.165 99.4 51684 Corn meal ration . . . . . . . . . . . . .. B 3.137 3.103 101.1 51684 Corn meal ration . . . . . . . . . . . . .. B 3.100 3.196 97.0 51833 Corn meal ration . . . . . . . . . . . . . . B 3.132 3.161 99.1 51833 Corn meal ration . . . . . . . . . . . . .. B 3.124 3.197 97.7 51956 Corn meal ration . . . . . . . . . . . . . . B 3.033 3.187 95.2. 51956 Corn meal ration . . . . . . . . . . . . . . B 3.055 3.134 97.5 52133 Corn meal ration . . . . . . . . . . . . . . C 2.729 2.860 95.4 52133 Corn meal ration . . . . . . . . . . . . .. C 2.916 3.012 96. 8 52332 Corn oil ration . . . . . . . . . . . . . . . . C 3.541 3.521 100.6 52332 Corn oil ration . . . . . . . . . . . . . . . C 3.618 3.601 100.5 49025 Clear flour ration. .. . . . .. . . . .. A 3.076 3.081 99.8 49025 Clear flour rati0n........ A 3.151 3.186 98.9 47992 Low grade flour ration. . . . . . . . A 2.999 3.004 99.8» 48276 Low grade flour ration . . . . . . . . . A 3.112 3.068 101.4 48276 Low grade flour ration . . . . . . . . . A 3.149 3.110 101.2 48468 Low grade flour ration . . . . . . . . . A 3.035 3.029 100.2. 48468 Low grade flour ration . . . . . . . . . A 2.829 2.896 97. 7 47991 Patent flour ration..... . . . . . . .. A 3.070 3.085 99.5 48275 Patent flour ration. . . A 3.050 3.059 99.7 48275 Patent flour ration.. A 3.184 3.188 99.9 48467 Patent flour ration.. A 3.210 3.175 101.1 48467 Patent flour ration.. A 3.172 3.133 101.2. 49024 Patent flour ration . . A 2 .862 2 .860 100. 1 49024 Patent flour ration. . A 2.984 2.989 99.8 51835 Kafir ration. . . .. . .. . . . . . . . . B 3.067 3.052 100.5 51835 Kafir ration . . . . . . . . . . . . . . . . . . . B 3 .044 3.115 97.7 51836 Kafir ration . . . . . . . . . . . . . . . . . . . B 3.022 3 .065 98.6 51836 Kafir ration . . . . . . . . . . . . . . . . . . . B 2.987 3.095 96.5 51572 Lactose ration . . . . . . . . . . . . . . . . B 2.021 2.132 94 .9 METABOLIZABLE ENERGY OF SOME CHICKEN FEEDS 19 Table 5. Metabolizable energy of rations as calculated and as found——(continued) Metab. Metab. Lab. Basal energy energy Ratio No. ration found calculated per cent Cal. per gm. Cal. per gm. 51572 Lactose ration . . . . . . . . . . . . . . . . B 1 989 2.210 0.0 51834 Oat hull ration . . . . . . . . . . . . . . . B 1 759 1.687 104.3 51834 Oat hull ration . . . . . . . . . . . . . . B 1 751 1.796 97 .5 52331 Peanut oil ration . . . . . . . . . . . . . . C 3 417 3 .449 99.1 52331 Peanut oil ration . . . . . . . . . . . . . C 3.566 3.621 98.5 52331 Peanut oil ration . . . . . . . . . . . . . C 3 590 3 .628 98.9 51686 Rice branration............... B 2 810 2.676 105.0 51686 Ricebranration............... B 2 684 2.863 93.7 51685 Rice polish ration. . . . .. . . . . . . .. B 3 091 3.178 97.3- 51685 Rice polish ration . . . . . . . . . . . . . B 3 118 3.153 98.9 51687 Rye tlour ration . . . . . . . . . . . . . . . B 2 697 2.630 102.5 51687 Rye flour ration . . . . . . . . . . . . . . . B 2 642 2.710 97.5 52333 Soybean oil ration . . . . . . . . . . . . . C 3 741 3.716 100.7 52333 Soybean oil ration . . . . . . . . . . . . . C 3 748 3.722 100.7 52333 Soybean oil ration . . . . . . . . . . . . . C 3.772 3.723 101 .3 49207 Starch ration . . . . . . . . . . . . . . . . . B 3 048 3 .084 98.8 49207 Starch ration . . . . . . . . . . . . . . . . . B 3 124 3.154 99 .1 49480 Starch ration . . . . . . . . . . . . . . . . . B 2 981 3.059 97.5 49480 Starch ration . . . . . . . . . . . . . . . . . B 2 967 3.076 96.5 51571 Starch ration . . . . . . . . . . . . . . . . . B 3 098 3.060 101.3 51571 Starch ration . . . . . . . . . . . . . . . . . B 3 039 3.147 96.6 51957 Starch ration . . . . . . . . . . . . . . . .. B 3 016 3.201 94.2 51957 Starch ration . . . . . . . . . . . . . . . . . B 3 045 3.127 97.4 52134 Starch and casein ration. . .. . . . . C 2 809 2.872 97.8 52134 Starch and casein ration. . .. . . .. C 2 941 3 .001 98.0 51958 Starch and yeast ration . . . . . . . . B 3 075 3.188 96.5 51958 Starch and yeast ration . . . . . . . . B 5.108 3.143 98.9 51959 Starch, yeast and corn oil ration. B 3.172 3 .376 94.0 51959 Starch, yeast and corn oil ration. B 3.252 3 .248 100.1 51361 Hydrogenated oil ration . . . . . . . . B 2 876 2.942 97 .8 51361 Hydrogenated oil ration . . . . . . . . B 2 809 3.040 92.4 51362 Hydrogenated oil ration . . . . . . . . B 3 960 3.948 100.3 51362 Hydrogenated oil ration . . . . . . . . B 3 974 3.938 100.9 49208 Wesson oil ration . . . . . . . . . . . . Sp B 3 680 3.657 100.6 49208 Wesson oil ration . . . . . . . . . . . . . . Sp B 3 707 3.702 100.1 49481 Wesson oil ration . . . . . . . . . . . . . . B 3 940 3.910 100.8 49481 Wesson oil ration . . . . . . . . . . . . . . B 3 863 3.848 100.4 51360 Wesson oil ration . . . . . . . . . . . . . . B 3 843 3.866 99.4 51360 Wesson oil ration . . . . . . . . . . . . . . B 3 849 3.886 99.0 52136 Wesson oil ration . . . . . . . . . . . . . . C 3.611 3.614 99 .9 52136 Wesson oil ration . . . . . . . . . . . . . . C 3 908 3.892 100.4 52330 Wesson oil ration . . . . . . . . . . . . . . C 3 640 3.639 100.0 52330 Wesson oil ration . . . . . . . . . . . . . . C 3 675 3.695 99.5 47993 Wheat bran ration............. A 2 131 2.197 96.9 48277 Wheat bran ration. . .. . . . . . . . .. A 2 003 2.039 98.2 48277 Wheat bran ration . . . . . . . . . . . . . A 2 163 2.214 97.7 48794 Wheat bran ration . . . . . . . . . . . . . A 2 168 2.223 97.5 48794 Wheat bran ration.... . . . . . . . .. A 2 296 2.317 99.1 52135 Wheat bran ration . . . . . . . . . . . .. C 1 615 1.712 94.3 52135 Wheat bran ration............. C 1 744 1.811 96.3 48469 Wheat gray shorts ration . . . . . . . A 2.405 2.724 99 .2 48469 Wheat gray shorts ration . . . . . . . A 2.431 2 .479 98 .1 48793 Wheat gray shorts ration . . . . . . . A 2 .487 2.489 99.9 48793 Wheat gray shorts ration . . . . . . . A 2.537 2.529 100.3 Average (128) . . . . . . . . . . . . . . . . . . . . . . . . .. 2.970 3.000 99.1 Average of differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 Standard deviation of differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8 of the differences is 2.8. These values are very close to those found for the feeds and for the excrements, the differences being 2.1 and 2.1 per cent respectively and the standard deviations being 2.3 and 2.8, but greater than for the rations, which were 0.9 for the differences and 1.8 for the standard deviation. The agreement between the calculated analyses and those found is therefore excellent, when a factor for protein is used which corrects for the protein retained by the growing animal. 20 BULLETIN NO. 589, TEXAS AGRICULTURAL EXPERIMENT STATION The data presented show that the metabolizable energy of the feed» a growing chicken is appreciably less than that of an animal on a tenance diet. The amount of the difference would depend upon the i centage of the protein retained by the growing animals. In order to culate the metabolizable energy on a maintenance basis, the value of ., Calories per gram should be used instead of the value of 5.13 Calo found necessary in this work. The data show that such a calcula should be very nearly correct. The actual metabolizable energy is calculated to a maintenance basis, since the energy retained by a groi animal is part of the metabolizable energy. " Metabolizable Energy of Individual Feeds The metabolizable energy of the individual chicken feeds fed in rations was calculated from the experiments here described, with g results given in Table 6. The metabolizable energy can also be calcula? from the digestion experiments for a maintenance basis by means of factors here given, namely, 4.4 Calories per gram of digestible prot 9.47 Calories for digestible ether extract, and 4.2 Calories per grami digestible nitrogen-free extract and digestible crude fiber. Since a la_ number of unpublished digestion experiments with chickens are avai r’ and since the metabolizable energy can be calculated from the results? such experiments, the calculation of the metabolizable energy of n. vidual feeds can Well await publication of more data on digestibility. f Table 6. Metabolizable energy of feeds fed growing chicks, not corrected to maintena“ Totalfheat Metabolizable ener Q __________ Labi ' ' D. E. N0. combustion N0. found Cal. Cal. per gm. per gram 48706 Corn bran . . . . . . . . . . . . . . . . . . 199 4.421 1.519 204 1 .812 50740 Corn bran . . . . . . . . . . . . . . . . . . 236 4.346 1.169 251 1 . 532 50742 Corn bran . . . . . . . . . . . . . . . . . . 237 4.429 1.819 252 1.864 50786 Corn bran . . . . . . . . . . . . . . . . . . 238 4.091 .775 253 1.050 48800 Corn bran . . . . . . . . . . . . . . . . . . 215 4.421 1.810 221 1.565 Average (5) . . . . . . . . . . . . . . . . . . . .. 4.342 48280 Corn meal (white) . . . . . . . . . . . 167 3.952 47955 Corn meal (white) . . . . . . . . . . . 162 3.947 3.646 172 3.769 176 3.640 48260 Corn meal (white) . . . . . . . . . . . 180 4.012 3.555 48440 Corn meal (white) . . . . . . . . . . . 184 4.104 3.737 _ 188 3.599 198 3.685 203 3.560 50868 Corn meal (white) . . . . . . . . . . . 235 3 .874 3.345 250 3.421 51556 Corn meal (white) . . . . . . . . . . . 283 4 .061 3.403 287 3.552 METABOLIZABLE ENERGY OF‘ SOME CIHCKEN FEEDS 21 Table 6. Metabolizable energy of feeds fed growing chicks. not corrected to maintenance ——(continued) Totalfheat Metabolizable energy 0 Lab. D. E. N0. combustion In N0. found Cal. per cent Cal. per gm. per gram of energy 51824 Corn meal (white) . . . . . . . . . . . 303 3.982 3.432 88.26 308 . . . . . . . . . . .. 3.389 87.17 51824 Corn meal (white) . . . . . . . . . . . 292 3 888 3.511 90.30 299 3.544 91.15 48986 Corn meal (white) . . . . . . . . . . . 212 4.046 3.375 83.42 218 3.643 90.04 Average (9) . . . . . . . . . . . . . . . . . . . .. 3.985 48437 Corn meal (yellow) . . . . . . . . . . 182 4.148 3.498 84.32 3.495 84.26 48898 Flour, clear . . . . . . . . . . . . . . . . . 214 3.927 3.411 86.86 220 . 3. 561 90.67 47762 Flour, low grade. . .. . . . . . . .. 164 3.854 3.258 84.52 48244 Flour, low grade . . . . . . . . . . . . . 174 3.957 3.484 88.04 178 3.555 89.84 48436 Flour, low grade. . . .. . . . . . . .. 186 3.985 3.328 83.52 " 190 2.915 73.15 Average (3) . . . . . . . . . . . . . . . . . . . .. 3.932 47761 Flour, patent . . . . . . . . . . . . . . . 163 3.839 3.398 88.51 48243 Flour, patent . . . . . . . . . . . . . . . 173 3.753 3.359 89.51 177 3.626 96.61 48435 Flour, patent . . . . . . . . . . . . . . . 185 3.818 3.679 96.35 189 3.603 94.38 48897 Flour, patent . . . . . . . . . . . . . . . 213 3.861 2.983 77.26 219 3.226 83.55 Average (4) . . . . . . . . . . . . . . . . . . . .. 3.818 51568 Lactose . . . . . . . . . . . . . . . . . . .. 274 3.717 1.192 32.08 280 1 .320 35 .50 _ 51609 Oat hulls . . . . . . . . . . . . . . . . . . . 293 4.025 .760 18.93 300 .800 19.79 52973 Wesson oil . . . . . . . . . . . . . . . . . . 256 9.391‘ 8.564 91 .20 264 8.475 90.26 51682 Rice bran . . . . . . . . . . . . . . . . . . . 285 4.176 2.391 57.26 289 2.896 69.35 51681 Rice polish . . . . . . . . . . . . . . . . . 284 4.409 3.567 80.90 288 3.461 78.50 51683 Rye flour . . . . . . . . . . . . . . . . . . . 286 3.903 2.449 62.75 290 2.672 68.45 51567 Starch . . . . . . . . . . . . . . . . . . . . . 273 3.666 3.238 88.33 279 3.476 94.80 51955 Starch . . . . . . . . . . . . . . . . . . . . . 304 3.613 3.428 94.88 309 3.312 91 .66 Average (2) . . . . . . . . . . . . . . . . . . . . . 3. 640 47763 Wheatbran................. 165 4.035 1.520 37.68 48264 Wheat bran . . . . . . . . . . . . . . . . . 175 4.078 1.264 31.33 179 1 .586 39.31 48741 Wheat bran . . . . . . . . . . . . . . . . 201 4.063 1.595 39.26 206 1 .851 45.56 Average (3) . . . . . . . . . . . . . . . . . . . .. 4.059 47764 Wheat gray shorts . . . . . . . . . . . 200 4.002 2 .232 55.70 205 2.332 58.58 48265 Wheat gray ehorts . . . . . . . . . . . 187 4. 119 2 .069 50.23 191 2. 121 51 .49 Average (2) . . . . . . . . . . . . . . . . . . . .. 4.061 22 (l) (2) (3) (4) (5) (6) BULLETIN No. 589, TEXAS AGRICULTURAL EXPERIMENT STATION SUMMARY The heats of combustion of 48 samples of feeds were determined in a bomb calorimeter. The heats of combustion were calculated by use of the factors, 5.7 Calories per gram of protein, 9.47 Calories per gram of fat, and 4.2 Calories per gram of nitrogen-free extract and of crude fiber. The average difference between the values found and ‘the values calculated was 2.1 per cent and the standard deviation of the difference 2.8 per cent, 2.3 per cent if lactose is excluded. The heat of combustion of lactose found was 3.717 Calories per gram, which is close to 3.731_Calories previously reported by other workers. When the nitrogen-free extract is largely lactose, as is the case with dried whey and dried skim milk, the value 3.7 Calories per gram of nitrogen-free extract would be more accurate than the value 4.2 Cal- ories. However, in an ordinary mixed ration, the lactose content is too low to affect appreciably the value of the nitrogen-free extract. The heats of combustion of 62 rations, as found and as calculated by means of the same factors as used for the feeds, were in excellent agreement. The average percentage difference was 0.9 and the standard deviation was 1.8 per cent. The heats of combustion of chicken excrements from digestion experi- ments were calculated by means of the same values as used for feeds, with the addition of 2.7335 Calories per gram for uric acid and 5.8 Calories per gram of ammonia. With 136 samples, the average of the differences is 2.1 per cent and the standard deviation of the differences is 2.8 per cent. The metabolizable energy per gram of ration was calculated from the digestion experiments by subtracting the number of calories of heat of combustion in the excrement produced from the number of calories in the corresponding quantity of the ration eaten, and then dividing the difference by grams of ration eaten. The metabolizable energy was calculated by use of 4.0 Calories per gram for digested protein, 4.2 Calories per gram of digested nitrogen-free extract and crude fiber, and 9.47 Calories per gram of ether extract. The metabolizable energy calculated was too low. Since previous work showed that growing chickens retain, on an average, 56.6 per cent of the digested protein, correction was made for this retention by use of the value of 5.13 Calories per gram of digestible protein. The average difference be- tween the metabolizable energy for fattening as found by 128 ‘tests was 2.0 per cent and the standard deviation of this difference was 2.8 per cent. This agreement is excellent. The metabolizable energy for chickens on a maintenance basis of ordinary feeds or rations can be calculated with an excellent degree of accuracy from the digestible constituents by means of the values of (1) (2) (3) (4) (5) (6) (8) (9) (10) (11) (12) (13) (14) (15) METABOLIZABLE ENERGY OF SOME CHICKEN FEEDS 23 4.4 Calories per gram of protein, 4.2 Calories per gram of nitrogen- free extract and of crude fiber, and 9.47 Calories per gram of ether extract. If appreciable amounts of lactose are present, allowance should be made for the fact that its heat of combustion is 3.7 Calories per gram instead of 4.2 for the nitrogen-free extract in most feeds. There may be other ingredients in special feeds for which allowance must be made to secure increased accuracy of the calculations. REFERENCES The Nutrition of Farm Animals. 228, 229. Axelson, J. 1937. Der Allgemein Nahwert unserer gewohnlichsten Futtermittel der Huhner. Annalen der Landw. Hochschule, Swedens. Vol. 4. Daikow, M. J. 1931-2. Untersuchen uber verdaulichkeit, Stoff and Energieweschsel bei huhner als grundlagen fur die rationelle futterung des geflugels. Wiss. Arch. f. Landw. arch. f. Tiernahr u. Tierzucht. 7:571-637. Emery, A. G. and Benedict, F. G. 1912. The heat of combustion of compounds of physiological importance. Am. J. Physiol. 28:301-7. Fraps, G. S. 1928. Digestibility and production coefficients of poultry feeds. Tex. Ag. Exp. Sta. Bul. 372. Fraps, G. S. and Carlyle, E. C. 1939. The utilization of the energy of feeds by grow- ing chickens. Tex. Ag. Exp. Sta. Bul. 571 Armsby, H. P. 1917. Fraps, G. S. and Carlyle, E. C. 1939. Utilization of the energy of wheat products by chickens. Jour. Nut. 18:385-398. Fraps, G. S. and Carlyle, E. C. 1940. Energy values of corn bran, rice polish, rice bran and rye flour as measured by experiments on baby chicks. Proc. (1939) of the Amer. Soc. for Animal Nutrition. International Critical Tables. 5:167 (uric acid). International Critical Tables. 5:166 (lactose). Mitchell, H. H. 1926. Chickens are efficient energy users of corn. Report, Illinois Experiment Station, 78-79. Mitchell, H. H. 1927. Wheat found less valuable than corn for chickens. Report, Illinois Experiment Station, 138-139. Mitchell, H. H. 1930. Soy bean oil meal is poorly utilized feed for chickens. Annual Report, Illinois Experiment Station, 100-101. Mitchell, H. H. and Haines, W. T. 1927. The basal metabolism of mature chickens and net energy of corn. Jour. Ag. Res. 34:927-943. Morey, N. B. 1936. _An analysisand comparison of different methods of calculating the energy value of diets. Nutrition Abstracts and Reviews, 6:1-12. 39th Annual 40th Annual 43rd