Synthesis of Nicotinic Acid by the Developing Turkey Embryo

Abstract

Chick embryos are known to synthesize nicotinic acid, since the newly hatched chick contains over 20 times as much of this vitamin as unincubated eggs (Snell and Quarles, 1941; Dann and Handler, 1941). Most of the increase occurs during the last half of the incubation period. Despite this synthetic capacity, which is at least partially retained by the chick (Dann and Handler, 1941; Briggs et al. 1943), growth on certain rations (Briggs et al. 1942, 1943), especially those low in tryptophane (Briggs, 1945) is markedly accelerated by addition of nicotinic acid. Under these conditions, the synthetic powers of the chick appear insufficient to furnish it with amounts of nicotinic acid required for optimal growth.Briggs (1946) recently reported that for optimal growth, turkey poults require 2 to 3 times as much dietary nicotinic acid as do chicks on a similar ration. To ascertain whether this increased requirement reflected inability of .