Effects of Excess Thiamine and Pyridoxine on Growth and Reproduction in Rats

Abstract
An experiment was conducted to determine whether excess thiamine or pyridoxine or both affect growth and reproduction in rats receiving an otherwise adequate diet. Groups of female weanling rats were fed a basal diet containing 150 µg of thiamine and of pyridoxine per 100 gm of diet, alone or supplemented with 50 times this level of thiamine or pyridoxine or both. After a 12-week growth period, the animals were mated to stock males for study of reproductive performance. The mothers were sacrificed after the young were weaned, and liver vitamin levels were determined. The young were given a pyridoxine-deficient diet for 5 weeks, and growth and liver thiamine and pyridoxine levels were measured at intervals. The results showed that excess thiamine or pyridoxine or both had no effect on weight gain, reproductive performance or the levels of solids, total lipid, riboflavin, pyridoxine, pantothenate and vitamin B12 in the livers of the animals after parturition and lactation. Liver thiamine levels in these animals, and in their young at weaning, were markedly increased by excess thiamine. Liver pyridoxine levels in the mothers were not increased by excess dietary pyridoxine, although pyridoxine stores in the livers of the young at weaning were greatly increased by excess pyridoxine intake of the mothers. During 5 weeks on a pyridoxine-deficient diet, the young of mothers which had received excess pyridoxine gained significantly more weight than did those of mothers which had received the basal diet.