The Influence of Chlortetracycline Supplementation of the Ration on Distribution, Quantity and Quality of Fat Deposited in Swine. I. Metabolic Effects in Relation to Carcass Composition2

Abstract

Data have been obtained on the effect of chlortetracycline (crystal-line Aureomycin) supplementation in practical rations of pigs from weaning to 85, 125, 165, and 205-lb. at which time they were slaughtered and the blood and carcass data collected. At a 15% protein level the supplementation of the ration with chlortetracycline gave an increase in the average daily gain of the barrows which was highly significant (1%). The weight at which the barrows were removed also had a highly significant effect on average daily gains. In the gilts, treatment with chlortetracycline did not affect the average daily gains. The weight at which the gilts were removed had a significant (5%) effect upon the average daily gains. The blood fat levels for the chlortetracycline supplemented lots were lower (not significantly) than the blood fat levels of the controls. The absorptive blood fat levels of the 165 and 205-lb. groups were significantly higher than the levels of the 85-lb. groups. The iodine number of the leaf and back fat from barrows was lower (near 5% and 1%, respectively) due to chlortetracycline supplementation. There was no significant difference in percentage of moisture, ether extract, or protein of the carcass, shoulder or ham composites and all physical carcass measurements except back fat thickness as a result of chlortetracycline supplementation. The average back fat thickness of the males was significantly (5%) increased as a result of chlortetracycline supplementation. This finding is in agreement with the trend toward greater carcass fatness as expressed in other physical and chemical measurements. Copyright © . .