Abstract
It has been repeatedly suggested that congenital blindness in animals may be caused by a maternal nutritional deficiency. Blindness in cattle associated with a constriction of the optic nerve of probable nutritional origin was reported by Moore et al. 1 who also reviewed the literature concerning this subject. Hale 2 reported the occurrence of anophthalmos and microphthalmos in pigs whose mothers had been fed a diet deficient in vitamin A. No corresponding findings have been reported in rats. Mason 3 who studied reproduction of vitamin A deficient rats described foetal death, prolonged gestation and difficult parturition but not congenital malformations of the offspring. Cannon 4 also reported failure to produce congenital anomalies in the young of rats whose mothers were depleted of vitamin A.
We have recently observed congenital defects of the eyes in the offspring of rats raised on a diet containing very small amounts of carotene and bred on a diet entirely free of carotene and vitamin A. The preparatory diet (Diet U) fed for approximately 3 months after weaning had the following percentage composition: Ground whole wheat, 74; crude casein (Borden), 15; brewer's yeast (Mead Johnson), 10; sodium chloride C.P., 1. This diet was supplemented by 60 I.U. of vitamin D (Drisdol, Winthrop) and 25 μg of carotene (SMACO) in cottonseed oil every tenth day. This small amount of carotene made possible slow growth and maturation but no storage of the vitamin. If the growth curves of the rats became flat during this preparatory period, which happened about 3 or 4 times, each rat was given 5 g of horse muscle.
The purified diet (Diet W) which was completely free of vitamin A had the following percentage composition: Sucrose, 68; vitamin test casein, 18; vegetable oil, 10; salt mixture, 5 4.
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