The Animal Protein Factor in the Nutrition of Chickens

The use of the chicken for the study of the animal protein factor (APF) has brought to light several properties of vitamin B,, and related substances, and has contributed largely to the recognition of their significance in animal nutrition, apart from their function as anti-pernicious-anaemia factor(s).In particular, their importance in reproduction and growth has been studied with poultry. Properties of the animal protein factorEfiect in reproduction.Many workers in the past have postulated the existence of a 'hatchability factor' essential for the successful hatching of fertile eggs from hens on all-vegetable diets.Among others, Bird, Rubin, Whitson & Haynes [ 1946) reported improvement in hatchability with supplements of fish meals, dried milk, fermentation products and dried cow manure; Lindstrom, Moore, Petersen, & Wiese (1949) obtained similar improvements with fish meal and a concentrate from cow manure, and Black, Getty, Coates, Harrison & Kon (1950) with a vitamin B,, concentrate (Examen, Glaxo Laboratories Ltd.).That the active material was in fact vitamin B,, was shown by Lillie, Olsen & Bird (1949), who injected solutions of the crystalline vitamin into eggs from hens on vegetable diets during incubation and obtained a marked increase in the number hatched.Carver & McGinnis (1950) confirmed their observation by injecting 2 pg vitamin B,, into deficient eggs before incubation with a consequent increase in hatchability from 35 to 90 %.Olcese, Couch, Quisenberry & Pearson (1950) have described signs of vitamin B,, deficiency in the developing embryo, including atrophy of the leg muscles, multiple haemorrhages and perosis.These authors also confirmed our own experience that embryos die most frequently about the 17th day of incubation.As yet there is no evidence that APF deficiency has adverse effects on fertility of either male or female.E'ect on growth.It is now generally accepted that a source of the APF is essential in the diet of the growing chick.The literature on the subject is too extensive to be quoted in detail; early work has been revieqed by Schweigert (1949).It is our own experience, and that of many other workers, that hens given normal diets pass on to their progeny sufficient reserves of the APF to last through the initial growing stages.It is probably this transference of reserves from mother to offspring that has delayed for SO long the discovery of the animal protein factor; its existence was only recognized when plant sources of proteins came into extensive use in American poultry rations, resulting in poorer hatchability and viability of the young chicks.The chick, being a rapidly growing animal, very soon shows signs of a lack of essential growth factors and although, in contrast to man, no anaemia is evidenced, a severe deficiency of the APF results in very poor growth, poor feathering and usually death in 3-4 weeks.