Influence of dietary fat source and feeding duration on pig growth performance, carcass composition, and fat quality

A total of 160 finishing pigs (PIC 327 × 1050; initially 100.5 lb) were used in an 84-d experiment to evaluate the effects of dietary fat source and feeding duration on growth performance, carcass characteristics, and fat quality. Dietary treatments included a corn-soybean meal control diet with no added fat or a 3 × 3 factorial with main effects of fat source (4% tallow, 4% soybean oil, or a blend of 2% tallow and 2% soybean oil) and feeding duration (d 0 to 42, 42 to 84, or 0 to 84). One pig was identified in each pen on d 0, and biopsy samples of the back, belly, and jowl fat were collected on d 0, 41, and 81. At the conclusion of the study, all pigs were harvested, carcass characteristics were measured, and back, belly, and jowl fat samples were collected. Overall (d 0 to 84), there were no differences between fat sources for growth and carcass characteristics; however, pigs fed diets with added fat from d 0 to 84 had improved (P \u3c 0.036) F/G compared with pigs fed a control diet without added fat. Pigs fed added fat throughout the entire study also had improved (P \u3c 0.042) ADG and F/G and heavier d-84 BW (P \u3c 0.006) compared with pigs fed additional fat for only period 1 or 2. Adding fat for the entire study increased (P \u3c 0.032) backfat and tended to reduce (P \u3c 0.083) fat-free lean index compared with pigs fed the control diet without added fat. Added fat also increased (P \u3c 0.05) iodine value (IV) compared with pigs fed the control diet. Increasing the feeding duration of soybean oil or a blend of soybean oil and tallow decreased monounsaturated and increased polyunsaturated fatty acids relative to feeding tallow (duration × fat source interaction, P \u3c 0.05), with the greatest changes in C18:1 and C18:2, respectively. In conclusion, feeding added fat improved ADG and F/G; however, feeding soybean oil for increasing duration, either alone or in a blend with tallow, negatively affected the fatty acid composition and IV of finishing pigs.; Swine Day, Manhattan, KS, November 20, 201