Effect of Diet and Breed on Fatty Acid Composition of Porcine Adipose Tissue

Abstract

Two feeding trials involving 64 pigs from four breeds were conducted to compare the fatty acid composition of the three layers of backfat and perirenal fat as influenced by diets containing whole roasted soybeans versus extracted soybean meal. The initial weight of the pigs at the beginning of the experiments was approximately 31 kilograms. All pigs were slaughtered at a live weight of approximately 102 kilograms. Adipose tissue samples were excised from the right 10th to 12th rib area over the longissimus muscle of the carcass, separated into layers at the visible septum and rendered. Myristic, palmitic, palmitoleic, stearic, oleic, linoleic and linolenic acids were identified by comparing their retention times with those of pure methyl ester standards. Backfat and perirenal fat from pigs that received whole roasted soybeans in their diet contained more (P<.05) unsaturated fatty acids than fat from pigs that received soybean meal in their diet. The degree of unsaturation increased as the level of whole roasted soybeans in the diet was increased. The total unsaturated fatty acid content was greater (P<.05) in the first layer of backfat than in the second or third layers. There was a preferential deposition of more unsaturated fatty acids in the first layer of backfat compared to second and third layers, and linoleic acid was the most responsive to diet. Perirenal fat contained a higher proportion of saturated fatty acids than the individual layers of backfat. The fatty acid composition of perirenal fat was affected less than backfat by the whole roasted soybean diet. Backfat from barrows contained less (P<.05) linoleic acid than gilts. Backfat and perirenal fat from Hampshire pigs contained more (P<.05) unsaturated fatty acids than Duroc pigs. The levels of total unsaturated fatty acids for Yorkshire and Crossbred pigs were intermediate between those of Hampshire and Duroc pigs. Copyright © 1973. American Society of Animal Science . Copyright 1973 by American Society of Animal Science