Effect of cholecystokinin immunization, enhanced food intake and growth of swine on lean yield and carcass composition.

It was previously reported that cholecystokinin (CCK) immunization of swine increased food intake 8.2% and rate of growth 10.6%. This report compares carcass yields of lean, fat and bone tissues of CCK-immunized vs. human serum globulin (hSG) control animals. The experiment involved 24 castrated pigs, age 75 d, weight 25.6 kg, randomly assigned to the CCK-immunized or hSG control groups (2 pigs/pen, 6 pens/group). Food was offered for ad libitum access. Carcasses of CCK-immunized animals (vs. hSG controls) were 8.7% heavier (P less than 0.01) and 2.4% longer (P less than 0.01). Carcass yield and composition were analyzed by dissection to lean, fat and bone fractions and by proximate analysis of the resultant lean fraction. Carcasses from the CCK-immunized animals had 2.7 kg more lean (P = 0.09) and 1.8 kg more fat (P = 0.04). Proximate analysis indicated there were no significant differences in composition of the lean fraction. The 7.2% heavier lean fractions of the CCK-immunized animals contained 9.2% more protein (P = 0.09) and 5.1% more fat (P = 0.05). Lean:fat and protein:fat ratios were not significantly altered.