Effect of Diets Devoid of One Essential Amino Acid on Pregnancy in Rats Maintained by Ovarian Steroids

Abstract

The effects of feeding diets each deficient in one essential amino acid on pregnant rats were investigated. The animals were given 0.5 µg of estrone and 4 mg of progesterone daily. Pregnancy was maintained with decrease in maternal body weight when each of the deficient diets was fed. In amino acid-deficient animals growth of the uterus, placenta and fetuses and the increase in the amount of amniotic fluid were less than in pair-fed controls. The difference was greatest in groups deficient in methionine, valine, isoleucine or leucine and least in those deficient in lysine or tryptophan. In general, rats receiving quantitatively or qualitatively inadequate diets produced small fetuses. In valine or methionine deficiency, the viable litter size also decreased due to partial resorption of fetuses in the third week of gestation. Changes in the fetal weight and litter size in relation to hormonal balances are discussed briefly.