Abstract
While observations on vitamin A deficiency in the dog have been reported by several investigators, 1 - 4 no attempt to determine the dog's minimum requirement of vitamin A has appeared in the literature. This report deals with such a study.
The synthetic vitamin A-free milk previously described 5 was used in these experiments. In that report 5 illustrations are given of xerophthalmia produced with this synthetic milk and cured by the addition of Carotene to this diet.
In this group of puppies herein reported, the curative method was used. All the puppies used were started on the vitamin A-free ration at weaning, or at most, 1 or 2 weeks later. It has been found highly important to rid the animals of any intestinal parasites at the beginning of the experiment. All the animals were devocalized under deep anesthesia. The total number of puppies used was 31.
The first curative levels used were based on the curative dose per 100 gm. of body weight of the albino rat. The negative results obtained with these levels resulted in the loss of a large number of the puppies. With considerably higher levels, a growth response and improvement in the condition of the animals were obtained.
The results of various levels in the largest litter are given in the chart. The minimum curative dose which effected definite increase of weight was 20 U.S.P. units per 100 gm. of body weight per day. The weight used for these figures is the weight at the beginning of the curative dose. The maximum curative dose used in these experiments was 70 U.S.P. units per 100 gm. of body weight per day.
While the daily minimum curative dose seems high in comparison with the rat, no blue units were found in any of the livers of the test animals killed at the end of the experiment.
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