XI II. KKQUIREMENTS 509 



hatched from eggs hiid l)y hens on various supplements were placed on the 

 basal corn-soybean meal diet, it was evident that a growth-promoting factor 

 in fish products was transmitted from the hen through the egg to the chick. 

 These results are illustrated in Table XIX. 



The necessity for a dietarj'^ supply of the factor for the production of 

 hatchable eggs provided a i-lue to the reason for a seasonal variation in 

 hatchability which was described by the Beltsville group.'' • " The factor was 

 shown to be present not only in cow manure but also in chicken manure/- 



TABLE XIX 



Effects of Fish Meal in the Diets of Hens and Chicks 

 UPON the Growth of Chicks'" 



Soybean oil Soybean oil 1 50 42.7 115.6 401.8 0.0 



meal plus 2% meal 2 50 39.9 110.6 413.0 0.0 



fish solubles 

 or fish meal 



and in the latter case bacterial production of the factor took place after 

 the feces had been voided. Furthermore, in cold weather the fermentation 

 which led to the biogenesis of the factor was evidently slowed markedly so 

 that insufficient quantities were ingested by the hens during their alimen- 

 tary explorations of the litter on the floor of their houses. With the advent 

 of warmer weather, fennentation in the litter was accelerated and the hens 

 then obtained enough of the factor from their excreta to enable hatchable 

 eggs to be produced. The fecal matter was also shown to be capable of 

 producing a growth response in chicks on the all-vegetable diet.^-"^^ 



" D. Whitson, H. W. Titus, ami 11. R. Bird, Poultry Sci. 25, 143 (1946). 

 '2 M. Rubin, H. R. Bird, and I. Rothchild, Poultry Sci. 25, 526 (1946). 

 '3 J. McGinnis, J. M. Stevens, and K. Groves, Poultry Sci. 26, 432 (1947). 

 '* A. C. Groschke, M. Rubin, and H. R. Bird, Po7iltry Sci. 27, 302 (1948). 



