Effects of Nitrates and Nitrites in Feed on the Utilization of Carotene in Swine

Abstract
Experiments were conducted to determine the effects of adding nitrate (KNO3) and nitrite (KNO2) to the diets of pigs on the utilization of dietary carotene. Feeding of 3% NO3 (from KNO3) significantly (P<.01) depressed gains. However, a reduction in average daily feed consumption was only observed in pigs receiving 3% NO3 supplemented with beta-carotene. No adverse effects of the nitrate treatments were observed on liver vitamin A stores, serum vitamin A values or methemoglobin levels. Serum vitamin A values were significantly (P<.01) reduced when 0.3% NO2 was included in the diet, regardless of the source of supplemental vitamin A fed. Adding potassium nitrite to the diet gave measurable increases in methemoglobin at the higher levels of nitrite. A definite trend toward a decrease in liver vitamin A stores was observed when the nitrite level in the diet increased. However, none of the nitrite treatments significantly reduced liver vitamin A stores of the pigs. Hemoglobin and hematocrit values remained relatively constant throughout both experiments. Copyright © 1968. American Society of Animal Science . Copyright 1968 by American Society of Animal Science