[ht/Zelda 87/ xfi§t‘*\? \ t... "a . " v,‘ x“. . A~__ L éafiy-“ a . xaw “ “Wk ' ‘ M U~u " Antilriotics and Arscnictz/s in E Poultry Nutrition fluyuu‘ 1957 TEXAS AGRICULTURAL EXPERIMENT STATION R. D. LEWIS. DIRECTOR. COLLEGE STATION. TEXAS 5»; f; CQNTENTS Summary . . . . . . . . . . . . . . . . . Introduction . . . . . . . . . . . . . . . Broiler Studies . . . . . . . . . . . . Turkey Studies . . . . . . . . . . . . Laying Hen Studies . . . . . . . References . . . . . . . . . . . . . _ . . z . . . . . . ts . _ . . . . ¢\3 . . . . . .. 1 . . . . . .fs . . . . . . v~11 SUMMARY Experimental work conducted by the Texas Agricultural Expo ment Station with poultry showed that the addition of antibiotics the diet of all ages of chickens and turkeys stimulated the gro rate and improved the feed efficiency. _ ' The use of high levels of antibiotics during periods of stress ' disease outbreak, at this Station and elsewhere, reduced mort and morbidity losses. Early mortality in turkeypoults was redu markedly through the use of pre-starter rations containing high lev _ of antibiotics and other nutrients. Egg production should increase 3 to l0 percent through the use antibiotics in the laying ration. HE RECENT DISCOVERY of the groWth-pro- moting action of antibiotics in poultry _ diets opened up a new field of re- Vitamin B12 was isolated in 1948 and fpreparations of the vitamin appeared soon e in feeds. Striking differences which ex- between some of these products (ferment- residues) led workers at the Lederle Lab- i. ies to investigate the possibility of residual 'otic activity. Significant amounts of aure- _'n Were found in certain of the fermenta- products. orkers in poultry nutrition at the Texas jultural Experiment Station were among the to obtain results indicative of accessory h promoting effects of fermentation resi- a (E. L. R. Stokstad, 1953). ' Investigations een concerned for some time with the dis- _ve properties of animal proteins and the X (animal protein factor) concentrates, which “ow known to contain vitamin B12, anti- ~ in some cases and other growth factors l be identified. Some of the work con- u on the effect of such products and anti- j in poultry rations are reported in this 1n. .. BROII.ER STUDIES _ e original study of Couch and Reed was ed in Poultry Science in 1950, using the shown in Table 1. Diet R-1 was deficient 'tamin B12, while diet R-2 contained both -meal and fish solubles which are good . es of the vitamin. Two APF concentrates fed in these studies. One was designated 9-B (Lederle’s APF concentrate) and the ctively, assistant professor and formerly research as- » t, Department of Poultry Science; superintendent, Sub- gn No. 21; head, Department of Poultry Science; and sor, Departments of Poultry Science and Biochemistry Nutrition. TABLE 1. COMPOSITION OF DIETS ‘ents R-I R-2 — Percent —» yellow corn 30.0 30.0 d sorghum grain 28.5 30.0 an oil meal (41%) 35.0 24.5 ¢ meal 6.0 nsed fish solubles 3.0 o leaf meal if, =..- 3.0 3.0 I d bone meal "v 2.0 2.0 ne flour 1.5 1.5 Supplements added. gm. per 100 lb. i-~- sulphate _ 5 5 tivated animal sterol 18 18 (riboflavin supplement) 30 30 Antibiotics and Arsonioa/s in Poultry Nutrition B. l. Reid, B. G. Crmh, A. A. Camp. l. H. Ouisenberrg and l. R. Couch* other as No. 3 (Merck’s APF concentrate). The 199-B concentrate contained 3.6 to 4.00 mg. of aureomycin per gm. in addition to vitamin B12, While concentrate No. 3 contained only vitamin 12- When supplemented with the 199-B concen- trate, the basalydiet (R-1) produced more rapid growth than the basal control. There also were marked improvements in feed efficiency and mortality. The growth of the birds fed the diet adequate in vitamin B12 (R-2), although better than for the birds fed the R-1 diet, was not as good as the birds fed APF 199-B. These data were additional proof that the feeding of aureomycin would stimulate the growth of chicks and improve feed efficiency. The results obtained with APF concentrate No. 3 also demonstrated the difference between the two supplements, and indicated no antibiotic effect when this supplement was fed (Table 3). In an effort to determine the mode of action of antibiotics in stimulating the growth of chicks, Elam, Gee and Couch reported in 1951 on the function and metabolic significance of penicillin and bacitracin. The experimental design of this study is shown in Table 4. Penicillin was injected at levels calculated to be equivalent to the amounts supplied in the feed. Autoclaved penicillin, which failed to show any antibacterial activity against test organisms, also was supplied orally and by injection. The injection of penicillin in a sesame oil suspension to delay diffusion through the body and thus maintain a constant blood level of the antibiotic also was included in the study. Bacitracin was supplied in the feed and through intramuscular injection. The administration of oral or injected peni- _ cillin increased the growth rate of the chicks (Figure 1). TABLE 2. EFFECT OF DIFFERENT LEVELS OF APF CON- CENTRATE l99-B ON THE AVERAGE WEIGHT, FEED EFFICIENCY AND MORTALITY OF NEW HAMPSHIRE CHICKS AT l0 WEEKS OF AGE . Av. " Gm. of t d , sultoflglfifinéaflon weight. required ezer Al. ' gm. gm. live weight mom! “Y 0 689.9 4.3 36.0 0.15% APF 199-B 973.7 3.3 1.5 0.25% APF 199-B 1,065.2 2.9 2.5 0.50% APF 199-B 1,055.8 2.9 2.5 100% APF 199-B 1,137.4 2.9 5.0 Diet R-2‘ 961.6 3.3 2.5 16% fish meal and 3% fish solubles. TABLE 3. EFFECTS OF DIFFERENT LEVELS OF APF CON- CENTRATE NO. 3 ON THE AVERAGE WEIGHT. FEED EFFICIENCY AND MORTALITY OF NEW HAMPSHIRE CHICKS AT 10 WEEKS OF AGE . Av. Gm. of Feed a s“‘i’§"§?;f“§i‘i‘°“ weight- "qvired w m...{:;1... gm. gm. live weight 0 949.99 9.29 7.92 0.019% APP N5 .9 799.29 9.52 9.54 0.095% APF N5. 9 915.95 9.40 9.29 0.0547, APP No. 9 019.72 _ 9.94 $.79 0.072% APP No. 9 795.42 ' 9.42 12.14 Diet 11-21 909.24 9.47 0.07 ‘6% fish meal and 3% fish solubles. A somewhat greater growth increase was apparent on the injection of either autoclaved penicillin or the sesame oil suspension. The fact that the feeding of autoclaved penicillin failed to stimulate the growth of the birds, while in- jection was effective, was highly significant. These data led to the postulation that a frag- ment of the penicillin molecule might serve as a metabolite in the bird or that the chick was capable of resynthesis of the antibiotic. The results were not altered in the presence of vita- min B12 (Figure 1). Bacitracin administered orally or by injection produced an increase in growth over that of the birds fed the basal diet. The birds fed the unsupplemented basal diet Weighed 765 gm. at 10 weeks, while the oral and injected bacitracin groups weighed 930 and 900 gm., respectively. In the presence of vitamin B12, these same supplements produced growth increases of 100 and 50 gm., respectively. A study of the effect of the treatments used in this study on the fecal microflora showed that the oral administration of penicillin produced an increase in the number of penicillin-resistant or- ganisms present in the feces as well an an in- crease in the number of aureomycin-resistant organisms and yeasts (Table 5). TABLE 4. SUPPLEMENTATION TO BASAL DIET uoo 1000 — . 90o ‘q __ T aoo _ __ 10o 1 k5. g eoo 3%, m‘ a l? - i 50o ,_ o — g 5 u .2‘. 8 u , - § i i’ i 9 I 400 3 1, 1, v. q t 2 v. ._ ~ -> <> ~ u g 1: g 5 g + g i 30° O ,_ '1 U T; 2 g g 2 E 3L. ' 2 2 - 2 g 5 9‘, é <1 i i‘ 9. é 20° .5 s .5 .2 s é s -§ ‘o0 E I72 37:» 17:» § I72 1g Z73 1g ' C c C c l: C < 3 a a a a a 5-‘ a a a _ o enoups Figure 1. Effect of oral and parenteral administr penicillin. autoclaved penicillin and inie ‘ vitamin B14 on growth of New Hampshire‘ - There was no significant change in th number of organisms found, or in the J ococci, lactics or coliforms when penicilli fed in the diet. The injection of penici water solution failed to produce a sign‘! change in the fecal microflora. The inj, of penicillin in sesame oil, containing alui monostearate, produced an increase in j penicillin-resistant organisms and yeasts ‘ feces. These data indicated that the v assimilation of the sesame oil suspension a, the maintenance of a higher level of pe _ in the animal over a prolonged period. The autoclaved penicillin, when inject not alter the microfloral counts to an v able extent, but did stimulate the growth l‘ birds. These data led to the postulation‘: metabolic function of a portion of the pe v molecule. “i Penicillin Bacitracin Group (gal, Injected. A§ti§jifgid Affiffed Oral. Injected. g‘ mg‘ mg. mg. units mg‘ mg‘ I 0 2 3 33’ 4 1.2" 5 1.2‘ 5 33 7 15.0005 8 33 9 1.2 l0 1.2 11 33 l2 15.000 13 33 I4 1.2 l5 33 15 1.2 ‘Injected per bird per week. “ Per kg. of diet. “Injected per bird per week. 4 ‘Autoclaved 15 min. at 15 lb. ‘Injected per bird on alternate days. 5. SUMMARY OF STATISTICAL ANALYSIS OF ENUMERATIVE DATA FROM FECAL DROPPINGS OF cmcxsms 2 ro 10 wrzsxs or AGE Penicillin Basal Oral Injected Afltjoeilgaed Augrlzfved Moiggrreigrcfile F Value‘ LSD” '11“ 4.61‘ 6.66 5.15 6.06 6.26 6.61 3.66“ 1.22 '__ ycin” 2.33 4.06 2.62 3.21 2.12 3.03 3.656 .65 4621.656 (yeast) 2.0a 3.24 2.24 2.31 2.04 2.36 5.515 .56 g Penicillin + B1, = '6“ 6.03 1.60 5.64 6.16 5.15 1.61 3.665 1.22 ycin” a 2.43 3.64 3.31 3.21 - 3.03 3.25 3.656 .65 316211666 (yeast) 2.21 3.42 2.32 2.32 2.44 - 2.66 5.515 .56 calculated for all 1f.‘ groups. t significant difference-calculated for all 12 groups. illin resistant. acitracin administration did not affect the f cocci, lactics, yeasts, coliforms, penicillin- ; nt or bacitracin-resistant organisms; how- , the growth rate of the birds was increased. Z provided further evidence that the anti- i s tested might serve as metabolites in the and thus exert a beneficial growth effect is manner. Later studies will show that ugh there is no significant alteration in the *1 organisms, the anaerobic (Clostridia) t is altered in antibiotic feeding and may ‘nother explanation of the growth responses ined. ‘ ter work of Elam et all. (1953) further nstrated the growth effects of oral and in- W‘ penicillin as well as the effect of the in- ated antibiotic (Table 6). he oral or injected penicillin, injected in- ated penicillin or combinations of penicillin ‘ aureomycin or bacitracin produced highly 'ficant decreases in the fecal Clostridia ts. The oral feeding of inactivated peni- .1 failed to stimulate the growth of the birds, ugh it did produce a slight decrease in the tridia count per gm. of feces. n vitro studies with Clostridiat isolates that 1 mcg. of either penicillin, aureo- ‘n or bacitracin would inhibit growth com- ly, While 1,000 mcg. of the inactivated peni- 4. did not inhibit the growth of such isolates. g data obtained with the Clostridia counts v in agreement with the work of Sieburth i. (1951), where the inhibition of Clostridium ringens was given as an explanation for the h-promoting effects of penicillin and terra- Kiser 6t al. (1952) also reported that mber of Clqslfridia were destroyed by the tion of aureomycin, penicillin or terramycin 1 e medium. n a second experiment in the same report, .1 et al. (1953), showed that, although the f~ h rate of the birds was retarded by the * Average number of microorganisms in logarithms. “Significant at the 1% level. " Aureomycin resistant. onset of summer, the feeding of penicillin, aureo- mycm, bac1trac1n, terramycin, arsanilic acid or sodium arsanllate produced an increase in growth rate. duced a growth response. cillin decomposition products failed to exert a stimulating effect on growth (Table 7). Inactivated penicillin, when injected, pro- The injection of peni- As in the previous study, the feeding of anti- biotics again produced a significant reduction TABLE 6. EFFECT OF FEEDING ANTIBIOTICS WITH AND WITHOUT 3% DRIED WHEY (50% LACTOSE) ON THE WEIGHTS AND THE ANAEROBIC MICRO- FLORA (CLOSTRIDIUM) OF NEW HAMPSHIRE CHICKS‘ With whey Without whey Total Total number of number of Group 135219‘? Clostridium evvelailgigle Clostridium isolates isolates gm. gm. per gm. of per gm. of feces feces Control 1252 12.450 1153 45.580 Penicillin (Oral) 1392 138 1295 275 Penicillin (Injected) 1338 850 1242 300 Inactivated penicillin (oral) 1256 1.250 1179 1.100 Inactivated penicillin (injected) 1242 563 1257 100 Aureomycin 1270 100 1278 125 Bacitracin 1284 a 2.812 1286 100 Penicillin + aureomycin 1371 100 1335 100 Bacitracin + penicillin 1391 100 1263 150 ‘ Amount of antibiotic administered: penicillin. 2 mg. per 1b.: aureomycin. 5 mg. per 1b.: bacitracin. 5 mg. per lb..- inacti- vated penicillin. 2 mg. per lb. The iniected antibiotics were administered ‘at a level of 1.2 ‘mg. per bird per week. 5 TABLE 7. EFFECT OF ANTIBIOTICS, COMBINATIONS OF ANTIBIOTICS. DERIVATIVES OF PENICILLIN. ARSENICALS AND COMBINATIONS OF ARSEN- ICALS AND PENICILLIN ON THE WEIGHTS AND ANAEROBIC MICROFLORA (CLOSTRIDIUM) OF NEW HAMPSHIRE CHICKS AT 10 WEEKS OF AGE Total Average number oi Group weight. Clostridium gm. isolates per gm. oi leces Control 907 1 1.930 Penicillin (2 mg. per lb.) 1056 233 Aureomycin (5 mg. per lb.) 1064 392 Bacitracin (5 mg. per lb.) 1011 423 Terramycin (5 mg. per lb.) 1143 83 Arsanilic acid (45 mg. per lb.) 1097 72 Sodium arsanilate (45 mg. per lb.) 1029 1.402 Arsanilic acid (22.5 mg. per lb.) + penicillin (1 mg. per lb.) 1064 146 Sodium arsanilate (22.5 mg. per lb.) + penicillin (1 mg. per lb.) 1044 366 Inactivated penicillin (1.2 mg.)‘ 1007 164 Sodium potassium benzylpenilloate (1.5 mg.)‘ 902 5.750 Sodium benzylpenicilloate (1.2 mg.)1 (38% mortality) 7.004 Beta-diethvlaminoethanol (0.4 mg.)1 (1007, mortality) Penicillin (1 mg. per lb.) + aureomycin (2.5 mg. per lb.) 1032 360 Penicillin (1 mg. per lb.) + bacitracin (2.5 mg. per lb.) 1026 102 Penicillin (1 mg. per lb.) + terramycin (2.5 mg. per lb.) 1081 153 Aureomycin (2.5 mg. per lb.) + bacitracin (2.5 mg. per lb.) 1051 277 Aureomycin (2.5 mg. per lb.) + terramycin (2.5 mg. per lb.) 1054 95 Bacitracin (2.5 mg. per lb.) + terramycin (2.5 mg. per lb.) 1066 288 Penicillin (0.67 mg. per lb.) - + aureomycin (1.67 mg. per lb.) + bacitracin (1.67 mg. per lb.) 1077 391 Penicillin (0.67 mg. per lb.) + aureomycin ( 1.67 mg. per lb.) + terramycin (1.67 mg. per lb.) 1071 21 Penicillin (0.67 mg. per lb.) + bacitracin (1.67 mg. per lb.) + terramycin (1.67 mg. per lb.) 1114 138 Aureomycin (1.67 mg. per lb.) + bacitracin (1.67 mg. per lb.) + terramycin (1.67 mg. per 1b.) 1109 84 Penicillin (0.5 mg. per lb.) + bacitracin (1.25 mg. per lb.) + aureomycin (1.25 mg. per lb.) and terramycin (1.25 mg. per lb.) 1084 55 ‘Injected intramuscularly into each bird weekly. 6 in the number of Clostridia in the feces. number of Clostridia per gm. of feces q creased in all instances in which antibiotics fed singly or in combination (Table 7). ‘f feeding of the arsenicals (arsanilic acid an ium arsanilate) likewise produced a sign‘ decrease in the total number of fecal Clos i The injection of inactivated pencillin also‘: duced a significant reduction in Czloiéstridia,“ seems to indicate that there was “an exc of active penicillin into the gut in this gro Another facet of antibiotic feeding ist versus clean environment studies which ' been conducted. These studies may explal variable results which have been reported; antibiotic feeding. "f Coates et al. (1951, 1952), working in f land, reported that chicks reared from 1 y 3 weeks of age in quarters not previously for poultry failed to show a growth respo antibiotic feeding, whereas such respon curred in old quarters. The chicks fed no‘. biotics in the new quarters grew more r than those fed the antibiotic diet in the o_ vironment. These authors concluded th reason for the antibiotic response in th, quarters was the presence of an ‘infection’; made the birds sensitive to the antibiotic. et al. (1953) reported that the weight of i fed no antibiotic in new quarters was’ :- than that of chicks given 10 mg. aureo per kg. of diet in old quarters. Hill et al. ( f reported that growth responses to penicillin-c greater in old quarters than in new ones. TABLE 8. EFFECT OF FEEDING PENlCILI.1N AND I CLOSTRIDIA ON WEIGHTS AND l" CLOSTRIDIA IN OLD AND CLEAN QU Average weight Total n ‘ Supplements to at m weeks oi Clostn _ basal diet gm ' isolator. per gm. of FIRST EXPERIMENT Old Quarters 15.57"‘ i None 969 Penicillin 1085‘ 265‘ 1 Clean Quarters y. None 1167 1.215 ‘a Penicillin 1210 615 = Fecal Clostridia 1042‘ 10.260‘ 1 Fecal Clostridia + ; penicillin 1180 450 ‘f Heat inactivated * fecal Clostridia 1150 v 1.110 i SECOND EXPERIMENT Old Quarters ‘t; None 1134 12.450 . Penicillin 1262‘ 640' < Fecal Clostridia 1170 16.710 t Fecal Clostridia + ' » penicillin 1310‘ 740' ' Clean Quarters None _ 1324 940 I» Penicillin 1343 650 Fecal Clostridia 12101 _ 9.440‘; Fecal Clostridia + . penicillin 1339 625 ‘ Significant at the 1% level. ers reported further that bacteriological ination of cecal microflora of representative »= revealed striking differences between the “animal houses. imilar studies by Elam et al. (1954) at the Agricultural Experiment Station demon- y ed that the feeding of penicillin to birds in f: quarters failed to produce asignificant ease in fecal Clostridia or an increase in h, while the same diets fed to birds in quarters resulted in a significant decrease in tridia and a significant improvement in the - h of the birds (Table 8). here also was a significant difference be- pn the two control groups. The birds reared he clean environment weighed more at the of the 10-week experimental period than 5 fed the basal diet in the old quarters. _ he addition of fecal Clostridia isolated from birds fed the basal diet in the old quarters irds in the clean environment resulted in a ificant decrease in the growth of these birds. combined feeding of the Clostridia with peni- I returned the growth to that of the control __ p (Table 8). Heat inactivated Clostridia ‘- without effect on the growth of the birds n the microflora counts. ‘n a second experiment of this report, the ition of penicillin increased growth and de- ed the total Clostridia count in the old quar- , but failed to affect the growth rate in the n environment. The total Clostridia count 1 low in both studies conducted with birds ed under the clean conditions. Fecal Clos- i’, when fed under the “old” conditions, did ‘affect the growth rate of the birds; but, in clean environment it produced significant ctions in the growth rate with a concurrent ase in fecal Clostridia. Penicillin, when fed I the Clostridia culture in the clean environ- t, reversed the detrimental effects of the tridia (Table 8). ' Further evidence of the effect of antibiotics ld and clean environments was obtained with opening of the new poultry facilities at the was A. and M. College in 1951. Results of the t experiment conducted at the new quarters shown in Table 9. At the end of 9 weeks, the s in this study weighed around 2.75 pounds, rdless of the supplement fed. There were arked differences in feed efficiency which d be attributed to the supplements tested no difference in mortality. The weights 1 l birds were good at that time. - he next study conducted in the same house ed different results (Table 10). The basal p weighed only» 966 gm. at 10 weeks, while previous basal group weighed 1,238 gm. at leeks. Antibiotic supplementation produced h responses of 10 and 18 percent, respec- y, for bacitracin and penicillin fed singly. binations of bacitracin and penicillin pro- TABLE 9. EFFECT OF SUPPLEMENTING AN ALL-VEGE- TABLE PROTEIN RATION WITH DRIED WHEY, FISH MEAL AND ANTIBIOTICS ON THE GROWTH. FEED EFFICIENCY AND MORTALITY OF NEW HAMPSHIRE CHICKS AT 9 WEEKS OF AGE KEPT UNDER A “LOW-DISEASE LEVEL" Average - Feed Supplement 1x21321159 efficiieilcyé 7t, I 0 gm. o ee mor a - basal diet (males 8‘ suppLeml-Int’ er m. it females), fl, p l; _ Y gm_ gain None 1238 — 2.81 3.4 3% dried whey product 1267 2.34 2.84 3.4 3% fish (meal 1246 0.65 2.87 0.0 Aureomycin (5 mg. per lb.) 1263 2.01 2.95 6.7 Bacitracin I (5 mg. per lb.) 1257 1.53 2.63 3.4 Penicillin (2 mg. per lb.) 1284 3.72 2.70 0.0 duced 24 to 26 percent more growth to 10 weeks of age. The weights of the birds, however, failed to approach that obtained under the “low-disease level conditions” observed in the previous study (Table 9). If higher levels of the antibiotics had been used, growth comparable with that of the previous study may have been obtained. TURKEY STUDIES Concurrent investigations with turkeys also were made to determine the effect of antibiotics on the growth and feed efficiency of the turkey poult. Atkinson and Couch reported in 1951 that the feeding of either aureomycin or strep- tomycin would stimulate the growth of turkey poults (Tables 11, 12, 13). The results of the first experiment (Table 11) indicated that the feeding of streptomycin TABLE 10. EFFECT OF SUPPLEMENTING AN ALL VEGE- TABLE PROTEIN RATION WITH ANTIBIOTICS AND FISH SOLUBLES ON THE GROWTH. FEED EFFICIENCY AND MORTALITY OF NEW HAMP- SHIRE CHICKS AT 10 WEEKS OF AGE UNDER A “HIGH-DISEASE LEVEL" wzilghgte Increase Feed Supplement at m weeks due to efficiency. ‘X, to males a ‘ supple- gm. of feed mortal- basal diet females ment. per gm. ity gm_ ‘ ‘Y, gain None 966 — 3.35 24.1 Bacitracin (5 mg. per lb.) 1064 10.14 3.30 10.2 Penicillin (2 mg. per lb.) 1142 18.22 2.90 3.5 Fish solubles (3%) 1048 8.49 3.50 27.6 Bactracin (5 mg. per lb.) + penicillin (1 mg. per lb.) 1202 24.43 3.02 6.9 Bacitracin (5 mg. per lb.) + penicillin (2 mg. per lb.) .1220 26.29 2.80 0.0 TABLE 11. EFFECT OF FEEDING STREPTOMYCIN. APF 4. FISH MEAL AND FISH SOLUBLES. AND LIVER “L" AND INIECTING VITAMIN B11 ON THE WEIGHTS OF BROAD BREASTED‘ BRONZE POULTS AT 8 WEEKS OF AGE WHEN KEPT ON LITTER Feed / Average efficiency. °° Group sggggjnfiggo weight. gm. of feed mortal- gm. per gm lty gain None l 1139 _ 2.6 2 §III Vitamin B11 iniected (2 mcg. per bird per week) 1177 2.5 2 3 MK-23 (66 mg. streptomycin + 13 mcg. vitamin B12 per kg.) 1547 2.2 10 4. 2% APF 4 (12 mcg. B12 p91‘ ICQZ) 5 5 Fish meal (6%) ‘l- fish solubles (3%)‘ 1255 2.7 16 Liver “L" (4%) mcg. B12 per kg.) 1392 2.3 2 1 Supplied 25.8 mcg. B11 per kg. of diet. produced a marked improvement in growth and feed efficiency. The APF 4 used in th1s study also supplied significant quantities of aureomy- cin and produced improvements 1n both feed efficiency and growth over the group rece1v1ng the vitamin B12 supplementation or the group fed the fish meal and fish solubles diet. TABLE 12. EFFECT OF FEEDING STREPTOMYCIN. AUREO- MYCIN. APF 4. LIVER “L." FISH MEAL AND FISH SOLUBLES. AND INIECTING VITAMIN B11 ON THE WEIGHTS OF BROAD BREASTED BRONZE TURKEY POULTS AT 8 WEEKS OF AGE l Feed Supplement Average efficiency, °,, Group to weight. gm. of feed mortal- basal ration gm. per gm. llY gain 1 None 1391 "2.s a 2 MK-23 (66 mg. streptomycin + 13 mcg. B11 per kg. of diet) 1498 2.6 7 3 Vitamin B11 iniec- ted (2 mcg. per bird per week) ' 1313 2.4 _ 5 4 Aureomycin (100 mg. per kg.) 1585 2.2 2 5 Aureomycin (44 mg. per lb.) + vitamin B12 iniec- ted (2 mcg. per . bird per week) 1740 2.0 6 6 Fish meal (6%) + fish solubles (3%)‘ 1652 2.3 3 7 2% APF 4 (12 mcg. B12 per kg.) 1644 2.0 9 8 Liver “L" (4%) (49.6 mcg. B11 per kg.) 1539 2.3 5 TABLE l3.__ EFFECT OF FEEDING AUREOMYCIN A L ER Y‘L" AND INIECTING VITAMIN B11 OI‘. WEIGHTS OF BROAD BREASTED BR TURKEY POULTS AT 14 WEEKS OF AGE ~ TAINED ON LITTER ' ‘Supplied 25.8 mcg. B11 per kg. of diet. 8 Feed Supplement Average efficiency. Group to weight. lbs. of feed -- basal ration lb. perlb. of 1+ “W511 3 None 7.0 3.3 5 Aureomycin (44 mg. per lb.) 8.8 2.8 8 Liver "L" (4%) (49.6 mcg. B11 per kg.) 8.1 3.0 The use of crystalline aureomycin in§ next study made it possible to evaluate ‘ clearly the benefits of feeding the anti (Table 12). The addition of aureomycin ‘ diet resulted in an increase in growth of app ' mately 400 gm. over the group fed vitamin‘ Ina third experiment (Table 13), a. mycin produced an increase in weight of pounds over the control group at 14 w» age. Feed efficiency likewise was imp (Table 13). a LAYING HEN STUDIES Nutrition studies with mature hens also f conducted during this period. The studies determined that vitamin B12 was an ess nutrient for both egg production and hatc ity. However, after 9 to 11 weeks, the '-, of vitamin B12 was no longer apparent and? sumably the birds were being depleted second hatchability factor which could be l plied by liver or fish solubles. .. A continuation of these studies involv determination of the effects of antibiotics i diet of mature hens. Halick and Couch rep_ in 1951 the results of studies using a pu 1' diet composed of 63 percent sucrose, 5 peé‘ dried whey, 22 percent soybean protein, 3; cent soybean oil, 2 percent fortified fis (3,000 A-400 D) and 5 percent Salts IV. , diet was supplemented adequately with vita and with methionine and glycine. “ The data of this study pointed out tha injection of vitamin B12 increased hatcha slightly, but there existed another facto, quired for hatchability, which could be sud by liver fraction “L.” The feeding of c I. line aureomycin and penicillin apparently w, in the depletion of the birds of both vi B12 and the second factor required for f ability (Table 14). Antibiotics produced, parent increase in hatchability. The stud w of too short duration to allow a significant. uation of the effect of antibiotics on egg‘; duction. _. ncurrently with the previous study, the i of penicillin on the growth and fecal micro- ‘ of the chick also was investigated. Elam, and Couch (1951) obtained an increase in "growth of chicks by feeding vitamin B12 penicillin either alone or in combination in l-vegetable protein diet (Table 15). g e pullet chicks were reared to maturity i1 same diets and the effect of penicillin on ‘production and hatchability was determined Ale 15). An improvement in egg produc- § was obtained by the injection of crystalline 1| in B12. Penicillin alone failed to affect the of egg production. However, the combina- ‘of both vitamin B12 and penicillin stimu- (egg production 12 percent over the group ted with vitamin B12. Thus, an antibiotic, l illin, was found to exert an effect on egg uction as well as on the growth in the en. A slight stimulation in hatchability also f: observed, but it was not considered sig- ‘ nt. acteriological examinations of the fecal pings showed that the feeding of penicillin ted an alteration in the intestinal micro- y. The feeding of penicillin increased the l4. EFFECT OF VITAMIN B12. LIVER EXTRACT, AN- TIBIOTICS. LEDERLE APF AND LIVER “L" ON HATCHABILITY AND VITAMIN B12 CONTENT OF EGG YOLKS Average vitamin Supplement Average percent B12 content to ; i hatchability of egg yolks. basal diet mcg. per gm. 2-4 wk. 5-8 wk. 2-4 wk. 5-8 wk. None 25 0 1.4 0.9 2 mcg. B12 iniected‘ 38.4 14.2 7.5 5.2 0.5 ml. liver ex- tract injected‘ 50 33.3 7.2 4.1 Aureomycin HCl (66 mg. per kg. . of diet) 0 0 2.6 1.1 Aureomycin HC1 (66 mg. per kg. of diet) + 2 mcg. B12‘ 26.6 l0 5.8 5.7 Streptomycin dihydrochloride (66 mg. per kg. of diet) 52.9 4.3 3.0 1.4 Streptomycin dihydrochloride (66 mg. per kg. of diet + 2 mcg. vitamin B12 50 6.6 7.8 4.0 Procaine penicil- lin (G) (33 mg. per kg. of diet) 5 0 2.3 1.3 Procaine penicil- lin (G) (33 m . per kg. of diet ‘i’ ‘--" + 2 mcg. B121 T‘ 62.9 10 3.6 4.5 2% APF 4 (24 mcg. B12) 71.4 26.6 7.1 6.1 4% liver “L" (49.6 mcg. B12) 95.4 - 78.3 7.8 6.8 Practical 96.2 90.4 2.7 1.2 , hen per week. TABLE 15. EFFECT OF PARENTERAL ADMINISTRATION OF VITAMIN B12 AND PENICILLIN ON THE GROWTH OF CHICKS TO l0 WEEKS OF AGE AND SUBSEQUENT EGG PRODUCTION AND HATCHABILITY Average weight of Egg Supplement to males and produc- Iiaifihm basal diet females tion. 19y‘ at l0 wks., ‘X, ° gm. - None 565 29 0 1 mcg. B12 injected per bird per week 800 38 72 Penicillin ( 33 mg. per kg. of diet) 725 22 39 Penicillin (33 mg. per kg. of diet) + 1 mcg. B12 per . bird per week 1030 ' 50 80 total number of organisms present, increased the enterococci and also increased the number of penicillin-resistant organisms present. It was concluded that the beneficial effect of penicillin was due to a change in the microflora of the intestinal tract. The basal group in this study had received penicillin intravenously after the fourteenth Week of the test. There was a stim- ulation in growth of the birds injected with,_. penicillin and a shift in the microflora of the gastrointestinal tract. These data on the “shift” in microfloral population in the bird are in agreement with the work of Kratzer et al. (1951) and Williams et a-Z. (1951). Results of several studies with laying hens in cages and on the floor have shown an increase in egg production from the use of aureomycin, penicillin, bacitracin, terramycin, streptomycin, 3-nitro-Al-hydroxphenylarsonic acid and arsanilic TABLE 16. EFFECT OF AUREOMYCIN ON EGG PRODUC- TION AND FEED EFFICIENCY Pre-experi- o ' . A _ Supple mental fl, egg production erg‘: men‘ 0-4 5-8 0-4 4-8 8-12 for wk. wk. wk. wk. wk. period None 65.2 40.4 22.93 24.09 14.28 17.23 Aureomycin (5 mg. per lb.) 71.8 43.9 28.37 22.69 16.37 22.64 I Aureomycin (25 mg. per lb. 63.0 45.1 38.47 26.65 24.49 30.12 Aureomycin A (50 mg. per lb. 70.8 50.6 40.53 44.86 45.86 43.48 Feed efficiency. lb. of feed per dozen eggs None 3.93 5.47 I 9.66 12.66 15.25 11.65 Aureomycin (5 mg per lb.) 3.56 4.91 6.80 8.79 12.06 8.68 Aureomycin ( 25 mg. per lb.) 3.86 5.38 5.17 8.05 8.57 6.90 Aureomycin (50 mg. per lb.) 3.66 5.07 5.78 5.76 5.99 5.83 TABLE 17A. EFFECT OF PENICILLIN AND STREPTOMYCIN__ON EGG PRODUCTION, CAGE STUDY ‘y, egg production by period Grou ' p Dietary treatment p 1 2 3 4 5 6 P-1 Basal 74.56 70.18 58.11 50.07 ‘ 45.68 41.12 P-2 1.25 mg. penicillin + 3.75 mg streptomycin per lb. 73.22 70.01 61.83 55.87 51.73 44.64 P-3 6.25 mg. penicillin + 18.75 mg. streptomycin per lb. 69.11 65.92 62.79 59.59 50.78 .3. 42.06 P-4 12.5 mg. penicillin + 37.5 mg. -~- 3; streptomycin per lb. 77.28 69.27 58.99 54.66 53.80 40.18 TABLE 17B. EFFECT OF PENICILI.1N AND STREPTOMYCIN ON FEED EFFICIENCY. CAGE STUDY Group Dietary treatment Feed efficiency by period, lb. oi feed per dozen eggs 1 2 3 4 5 6 P-1 Basal 4.88 5.10 5.94 6.41 6.68 6.32 P-2 1.25 mg. penicillin + 3.75 mg. streptomycin per lb. 5.02 5.15 5.38 5.73 6.02 6.01 P-3 6.25 mg. penicillin + 18.75 mg. streptomycin per lb. 5.38 5.59 5.54 5.46 6.23 6.29 P-4 12.5 mg. penicillin + 37.5 mg. streptomycin per lb. 4.70 5.10 5.56 5.55 5.54 5.83 acid. Egg production may be increased 3 to 10 percent through the use of antibiotics in laying rations. The use of high levels of antibiotics (100 to 400 gm. per ton) during periods of stress, such as a respiratory disease outbreak, also helped maintain the level of egg production. A study conducted in 1955 illustrates the bene- ficial effect of antibiotics at higher levels (Table 16). A group of New Hampshire hens housed on litter had egg production rates as shown in the experimental columns of Table 16. After the initial high production, there was a rapid drop for the next month of the pre-experimental period; at this time the birds were fed levels of 0, 5, 25 and 50 mg. of aureomycin HCl per pound of diet. Production in the unsupplemented group continued to drop until after 12 weeks on the study it was only 14.3 percent, with an av- erage for the 3-month experimental period of 17.23 percent. The 5 mg. per pound level of aureomycin produced a slight stimulation in egg production, while the two higher levels used (25 and 50 mg. per pound) allowed the hens to main- tain egg production rates of 30.12 and 43.48 percent, respectively for the 3-month period. Feed efficiency also was improved highly under these conditions with the antibiotic feeding (Table 16) . TABLE 18. EFFECT OF ANTIBIOTICS ON EGG PRODUC- TION AND FEED EFFICIENCY TO 5 MONTHS. FLOOR STUDY O '7 average Supplement to Average feed effi- basal diet edgg Fm“ ciency. lb. of uc ‘on feed per doz. eggs None 45.7 5.39 25 mg. penicillin per lb. 53.2 4.63 50 mg. streptomycin per lb. 54.7 4.82 12.5 mg. penicillin + 25 mg. streptomycin per lb. 57.7 4.67 10 The use of a combination of penicillin’ streptomycin in cage-housed birds also was a ficial (Table 17A), especially during the I portion of the experimental period, which in study corresponded to the onset of hot wea The overall differences in egg production f0 6-months study were not too wide, but P were improvements in feed required to pr‘ a dozen eggs (Table 17B). When these biotics were fed at higher levels to birds y on litter, average egg production was incr with the addition of either penicillin or u» tomycin or a combination of these twoantibi Improvements in feed utilization amounti almost 1 pound per dozen eggs also Were f (Table 18). ' Two arsenicals, 3-nitro-4-hydroxyphen sonic acid and arsanilic acid, had a benew effect when supplemented to the rations of". ing hens. Studies using these compounds * been carried out on different strains of § Hampshire pullets maintained on litter. effect of 3-nitro-4-hydroxyphenylarsonic supplementation is shown in Table 19. Inc -- TABLE 19. EFFECT OF AN ARSONIC ACID ON EGG DUCTION. FLOOR STUDY + 22.5 mg. 3-Ni Strain Basal hydroxyphenyl it acid. Per lb. of g Percent production I 1 29.9 35.5 “ 2 29.5 33.4 ‘ X 3 35.7 42.2 Feed efficiency. lb. of teed per dozen eggs 1 8.44 7.78 2 9.57 8.04 3 7.55 6.30 . EFFECT OF ARSANILIC ACID ON EGG PRO- DUCTION AND FEED EFFICIENCY TO 5 MONTHS, FLOOR STUDY , 45 mg. arsanilic Basal diet I acid per lb. Average production. % 37.2 i 44.5 35.7 44.3 Feed efficiency 6.75 ‘ 5.83 7.58 7.66 I duction and marked improvements in feed ltion were noted When this arsenical was ‘to the control ration, regardless of the of birds used. Similar results were ob- With arsanilic acid in the same type of . (Table 20). An overall increase in egg tion in both strains was noted. Feed ef- y was improved greatly in one strain but I the other. REFERENCES on, R. L. and I. R. Couch, 1951. Vitamin B12, "APF concentrate, aureomycin, streptomycin, .» “L" and fish meal and fish solubles in the ition of the poult. I. Nutrition 44:249. x. M. E., C. D. Dickinson, G. F. Harrison, S. K. , S. H. Cummins and W. F. I. Cuthbertson, 3 Mode of action of antibiotics in stimulating th of chicks. Nature 168:332. , M. E., C. D. Dickinson, G. F. Harrison, S. K. , I. W. G. Porter, S. H. Cummins. and W. F. uthbertson, 1952. A mode of action of anti- 'cs in chick nutrition. I. Sc. Food Agric. 3:43. I. F., R. L. Iacobs, W. L. Tidwell, L. L. Gee - I. R. Couch, 1953. Possible mechanism in- ed in the growth-promoting responses ob- ed from antibiotics. I. Nutrition 49:307. Elam, I. F., R. L. Iacobs, Iean Fowler and I. R. Couch, 1954. Effect of dietary Clostridia upon growth-promoting responses of penicillin. Proc. Soc. Exp. Biol. Med. 85:645. Elam, I. F., L. L. Gee and I. R. Couch, 1951. Effect of feeding penicillin on the life cycle of the chick. Proc. Soc. Exp. Biol. Med. 77:209. Elam, I. F., L. L. Gee and I. R. Couch, 1951. Func- tion and metabolic significance of penicillin and bacitracin in the chick. Proc. Soc. Exp. Biol. Med. 78:832. Hill, D. G, H. D. Branion, S. I. Slinger and G. W. Anderson, 1953. Influence of environment on the growth response of chicks to penicillin. Poultry Sci. 32:462. : ' Kiser, I. S., G. C. de Mello, D. H. Reichard and I. H. Williams, 1952, Chemotherapy of experimental clostridial infections. I. Infect. Dis. 90:76. Kratzer, F. H., C. R. Grau, M. P. Starr and D. M. Reynolds, 1951. Growth-promoting activities of antibiotics and yeast cultures for chicks and tur- key poults. Fed. Proc. 10:386. Lillie, R. I., I. R. Sizemore and H. R. Bird, 1953. En- vironment and stimulation of growth of chicks by, antibiotics. Poultry Sci. 32:466. Reed, I. R. and I. R. Couch, 1950. The efficacy of different APF concentrates for chicks. Poultry Sci. 29:897. Sieburth, I. M., I. Gutierrez, I. McGinnis, I. R. Stern and B. H. Schneider, 1951. Effect of antibiotics on intestinal microflora and on growth of turkeys and pigs. Proc. Soc. Exp. Biol. Med. 76:15. Stokstad, E. L. R., 1953. Antibiotics in animal nu- trition. Antibiotics and Chemotherapy 3:434. Williams, W. L., R. R. Taylor, E. L. R. Stocktad and I. H. Iukes, 1951. Mechanism of the growth-pro- moting effect of aureomycin in chicks. Fed. Proc. 10:270. ll t mnismm Q ‘use suasmms I use mmueomronues 4 ooovaurrm srmous Location oi field research units oi the Texas Agricultural Experiment Station and cooperating agencies ORGANIZATICN OPERATION Research results are carried t0 Texas farmers, ranchmen and homema/cers by county agents and specialists of the Texas Agricultural Ex- tension Service jar/lay ,5 Qeziearcé ~95 jOIWlOPPOl/Ull POQPQIU State-wide Research ‘i v * t,’ The Texas Agricultural Experiment Stati is the public agricultural research agen oi the State oi Texas. and is one oi t parts oi the Texas A<§M College Syste? 1.5 h IN THE MAIN STATION, with headquarters at College Station, are 1§ f matter departments, 2 service departments, 3 regulatory services ' administrative staff. Located out in the major agricultural areas of Te ; 21 substations and 9 field laboratories. In addition, there are 14- coo h, stations owned by other agencies. Cooperating agencies include the? Forest Service, Game and Fish Commission of Texas, Texas Prison S U. S. Department of Agriculture, University of Texas, Texas Techno College, Texas College of Arts and Industries and the King Ranch. , experiments are conducted on farms and ranches and in rural ho’ THE TEXAS STATION is conducting about 400 active research projects, ; in 25 programs, which include all phases oi agriculture in Texas. these are: Conservation and improvement of soil Beef cattle Conservation and use of water Dairy cattle Grasses and legumes Sheep and goats Grain crops Swine Cotton and other fiber crops Chickens and turkeys Vegetable crops Animal diseases and parasit Citrus and other subtropical fruits Fish and game l Fruits and nuts Farm and ranch engineering Oil seed crops I Farm and ranch business g Ornamental plants Marketing agricultural prod l Brush and weeds Rural home economics v g Insects Rural agricultural economics i Plant diseases * Two additional programs are maintenance and upkeep, and central sell AGRICULTURAL RESEARCH seeks the WHATS. the l‘ WHYS. the WHENS, the WHERES and the HOWS oi ~ hundreds oi problems which coniront operators oi iarms I and ranches. and the many industries depending on I or serving agriculture. Workers oi the Main Station and the iield units oi the Texas Agricultural Experiment f Station seek diligently to iind solutions to these problems. i