PSIII-19 Growth Performance, Carcass Traits, and Meat Quality of Pigs from Divergent Groups for Pork Loin Tenderness

Genetic selection for improved feed efficiency and lean growth in pigs has resulted in reduced intramuscular fat content. The aim of this study was to evaluate growth performance, carcass traits, and meat quality in genetically lean immunocastrated pigs grouped based on divergent Warner-Bratzler Shear Force (WBSF) values. The WBSF values of the longissimus lumborum (LL) muscle were obtained from a previous trial evaluating 4 diets, 6 replicates per diet, and 3 pigs per pen, summing up to 72 Large White immunocastrated male pigs. Pigs (initial BW = 28.44 ± 2.95 kg) were fed diets containing either 1.5% soybean oil (CON) or 3% soybean oil (SO), canola oil (CO), or fish oil (FO) in a 98-d study. The original dataset was used to segregate pigs into 2 treatments: high (5.4 to 4.3 kg) and low (3.8 to 2.8 kg) WBSF. The SO diet did not show extreme values for WBSF and was not included in the resulting dataset, which comprised 2 treatments (high- and low-WBSF), 3 blocks (CON, CO, and FO), and 6 replicates per treatment (12 experimental units). No significant differences were observed for growth performance between WBSF groups. When compared with low-WBSF pigs, high-WBSF pigs tended to have decreased (P = 0.07) backfat thickness and intramuscular fat content in the LL and greater (P = 0.09) carcass lean percentage and cooking losses. Oleic acid concentration was less (P = 0.05) in the LL intramuscular fat of high- than low-WBSF pigs. There were statistical tendencies for decreased (P = 0.06) total monounsaturated fatty acids and increased (P = 0.09) total polyunsaturated fatty acids concentrations in the LL intramuscular fat of high- than low-WBSF pigs. In conclusion, immunocastrated male pigs with tender meat had improved nutritional attributes of pork, with no effects on feed efficiency and carcass traits.