In Vitro Degradation of Vitamin A and Carotene by Rumen Liquor

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Abstract
Rumen liquor from 12 steers which were on a 2×2 factorial feeding trial involving ethoxyquin and nitrate was used to determine the in vitro destruction of vitamin A acetate and beta-carotene. The ration ethoxyquin maintained the levels of vitamin A in both roughage and grain rations. The addition of 1% KNO3 to the ration had little effect on the in vitro destruction of vitamin A. In addition, six fistulated and four normal steers were used as a source of rumen liquor from high- roughage and high-grain rations. Ethoxyquin, added in vitro to rumen liquor collected from steers fed all-roughage rations, positively influenced the retention of vitamin A. The in vitro addition of high levels of nitrate to the rumen liquor adversely affected the retention of vitamin A with concentrate rations only. Nitrite additions adversely affected the retention with both high- and low-roughage rations. Beta-carotene levels appeared to be little affected other than by nitrite additions to rumen liquor obtained after feeding a low-roughage ration. In this instance, the nitrite additions reduced significantly the retention of carotene. Destruction of vitamin A by rumen liquor from steers on a high-roughage ration was significantly greater than with rumen liquor obtained from steers receiving a high-grain ration. Copyright © 1964. American Society of Animal Science . Copyright 1964 by American Society of Animal Science