Effect of Sodium Nitrate on the Vitamin A Nutrition of Sheep

Abstract

Rations containing 2.5 and 3.0% of added sodium nitrate were used in separate experiments to determine their effect on tissue vitamin A levels of sheep. Only small amounts of methemoglobin were found at regular bleeding periods in sheep receiving either level of nitrate, although seven sheep were lost from suspected acute nitrate poisoning while being fed 3% of sodium nitrate. Vitamin A offered no protection from nitrate poisoning. A transient increase in plasma vitamin A levels occurred about the middle of the first trial in sheep fed 2.5% of sodium nitrate and 2.5% of sodium nitrate plus 3000 I.U. of vitamin A. By the end of the trial, however, the values for these lots of sheep approximated the values obtained in sheep receiving corresponding non-nitrate treatments. No effect of nitrate on plasma vitamin A levels was observed in the second trial. However, lower liver vitamin A stores were found in the nitrate-fed sheep. After 56 days on experiment, sheep fed 3% of sodium nitrate had liver vitamin A concentrations that were 46.0% lower than those fed the control ration. Similarly, sheep fed 3% of sodium nitrate plus 4100 I.U. of vitamin A daily had liver vitamin A values 45.1% lower than those fed 4100 I.U. of vitamin A without nitrate. Copyright © 1964. American Society of Animal Science . Copyright 1964 by American Society of Animal Science