The Niacin Requirement of Young Chickens

DANN and Handler (1941) stated that the hatched chick contained ten times as much niacin as the unincubated egg. This led the authors to suggest that the hatched chick is able to synthesize niacin and is therefore independent of a dietary supply of this vitamin. Snell and Quarles (1941) observed that niacin is synthesized by the chick embryo to the extent that the final amount present is twenty times that originally present in the unincubated egg. They presumed that the synthesizing powers of the embryo are retained by the chick and, if so, it would indicate that niacin is not required in the diet of the chick. Briggs et al. (1942) reported that niacin is essential in the diet of chicks for optimal growth and to prevent “chick blacktongue.” They found niacinamide equally effective in stimulating growth and preventing blacktongue. Studies by Briggs et al. (1943) indicated that a dietary . . .