Effect of Vitamin a Deficiency on the Content of Three Forms of Vitamin a in Hen's Eggs.

In the ripe eggs of all species of marine teleost fish so far examined, retinal (vitamin A aldehyde) is the predominant form of vitamin A, and in some species it represents 90% of the total vitamin A-active material in the eggs (Plack, Kon & Thompson, 1959; Plack & Kon, 1961). Hen’s eggs also contain retinal and, for forty-one eggs from six hens on a diet of breeder’s mash, a value of 21.7 pg/egg was obtained, representing 13 % of the total vitamin A (Plack, 1963). The predominance of retinal in fish eggs suggests that it may be of importance in the development of the embryo. With hens, an increased intake of vitamin A results in increases in the retinal, retinol esters and retinol contents of eggs (Plack, 1963) and we show here that vitamin A-depleted birds lay eggs containing reduced amounts of the three forms of vitamin A. The retinal content did not become predominant under conditions of vitamin A deficiency, as might have been expected if it were of particular significance for the development of the embryo.