Effect of Zn deficiency on serum vitamin A level, tissue enzymes and histological alterations in goats

Abstract

An experiment was conducted to elucidate the effect of dietary zinc on serum vitamin A levels and its influence on certain enzyme activities in ovaries using 16 female kids, divided into four groups. The animals in group 1 and 2 were fed a basal diet (15 p.p.m. zinc) whereas those in groups 3 and 4 were supplemented with 65 p.p.m. zinc. Groups 2 and 4 were supplemented with 1800 i.u. of vitamin A kg diet. The development of deficiency symptoms in a few animals after a period of 46–177 days was taken as an index to kill the animals periodically for collection of tissues. The mean zinc levels were significantly ( P < 0.01) higher in zinc-supplemented groups compared to controls. The zinc supplementation resulted in significantly higher levels of serum vitamin A in group 4 compared to those in other groups ( P < 0.01). The alcohol dehydrogenase activity in liver, intestine and retina was significantly greater ( P < 0.01) in groups 3 and 4 than in zinc-deficient groups. In liver ( P < 0.01) and ovaries ( P < 0.05) of zinc-supplemented animals, the superoxide dismutase activity was higher. The microsections of ovary from the animals of groups 1 and 2 showed deformed ateretic follicles, whereas in group 3 some deformed ova were seen. However, the animals in group 4 did not show any such abnormality, indicating that zinc and vitamin A were both necessary for the normal functioning of the germinal epithelium of the ovary.