Influence of Dietary Vitamin A Level on Chicken Liver Glycogen

Abstract

T HERE are conflicting reports concerning the effect of a vitamin A deficiency on liver glycogen. Wolfe et al. (1957) reported that liver glycogen was essentially zero in vitamin A-deficient rats compared to a relatively high level in controls. Stoewsand and Scott (1964) found that liver glycogen formation during the first four hours of refeeding a high protein diet to chicks after a one-day fast was not impaired by a vitamin A deficiency. Their results indicated that vitamin A-deficient chicks fed a moderate protein level had a higher liver glycogen content per gram of feed consumed than the vitamin A adequate controls. Perek and Kendler (1969a) reported that fasted and nonfasted mildly vitamin A-deficient chicks were hyperglycemic and had liver glycogen concentrations reduced to less than half that of Contois. Singh et al. (1968) reported that nonfasted hypervitaminotic A rats were no different in liver glycogen levels than controls. However, the pair-fed hypervitaminosis rats had considerably more glycogen in their livers than controls after an 18-20 hour fast, and the authors suggested an impairment in glycogen breakdown in hypervitaminosis A. Preliminary results in this laboratory had indicated that nonfasted 4week-old chicks fed vitamin A deficient