Effects of Feeding Restaurant Grease With or Without Conjugated Linoleic Acid or Phase-Integrated Beef Tallow on Finishing Pig Growth Characteristics and Carcass Fat Quality

The objective of this study was to determine the effect of conjugated linoleic acid (CLA) and tallow on belly firmness in 120 gilt finishing pigs. Pigs were assigned to 1 of 5 treatment combinations and fed 30 d prior to slaughter. Treatments were as follows: control, a 5% restaurant grease for 30 d (RG30); 5% restaurant grease for 0 to 20 d and switched to CLA (0.83%) and restaurant grease (4.17%) combination for 20 to 30 d (RGCLA); 5% restaurant grease for 0 to 20 d and switched to a 5% tallow for 20 to 30 d (Tallow10); 5% restaurant grease for 0 to 10 d and switched to a 5% tallow for final 20 d (Tallow20); and 5% tallow for 0 to 30 d (Tallow30). No changes occurred in drip loss, pH, loin eye color, or size, and no difference occurred in growth parameters, except for ADG between 20 to 29 d, where pigs allotted to Tallow20 and Tallow30 had greater (P < 0.05) ADG when compared with pigs fed RGCLA. In Tallow30, belly firmness was greatest, and consequently iodine value (IV) was lowest, when compared with RG30. A lower IV and trend for greater belly firmness was observed in RGCLA when compared with RG30. These data suggest that supplemented tallow at 5% improves belly firmness and lowers IV when compared with a 5% restaurant grease diet. Adding 0.83% CLA to a restaurant grease diet improves firmness and lowers IV, but not to the same magnitude as tallow alone.