ABSTRACT
This experiment was designed to study the relationship of vitamin A with the immunocompetence of rats. On the base of a vitamin A-deficient diet, the rats were supplemented with a dose of vitamin A acetate that was two times the requirement of rats for vitamin A. Furthermore we had observed the effect of carbamate pesticide-sevin on the immune system of rats at different diets for nine weeks in all (group A: basic diet supplemented with 400 IU vitamin A per 100g diet; group B: basic diet only; group C: basic diet with 400 IU vitamin A and 100mg sevin per 100g diet; group D: hasic diet with 100mg sevin per 100g diet). On the end of feeding, the levels of serum vitamin A were significantly lower in rats fed on vitamin A-deficient diets than in that supplemented with vitamin A, but there were no obvious signs of vitamin A deficiency and toxic symptoms of sevin in any animals. Supplement of vitamin A to basic diet increased the levels of total serum complements, enhanced the antibody response of the animals to sheep RBC, and decreased the activity of serum lysozyme. Sevin could inhibit the antibody response to sheep RBC at vitamin A-deficiency state, but not at well-nourished state of vitamin A.