Comparative Effect on Vitamin A Metabolism in Sheep of Urea, Soybean Oil Meal and Cottonseed Meal as Sources of Protein

Abstract

Comparable groups of sheep which had been partially depleted in their stores of vit. A were fed low-carotene rations containing soybean oil-meal, cottonseed meal and urea as the principle N sources. They were given supplements of high-potency cod liver oil, prairie hay and a carotene concentrate. Vit. A was detd. periodically in the blood. Its storage in the liver was detd. at the beginning and end of the supplement feeding period. The marked efficiency of fish liver oil as compared to carotene supplements in promoting storage of vit. A in the liver was demonstrated. There were insignificant differences in blood and liver vit. A values related to differences in the N source. The trend of results indicated greater vit. A storage when cottonseed meal was fed than when soybean oil-meal was the protein supplement. Urea was without effect on carotene and vit. A metabolism as measured by the plasma and liver values.