Effect of Feeding Conjugated Linoleic Acid over Different Periods of Weight Gain on Swine Performance and Body Composition

Materials and Methods Ninety-two pigs were fed diets containing 1.25% CLA oil (oil contained 60% CLA) for the last 0, 29, 58, and 87 kg of body weight gain. Pigs were marketed at a body weight of 115 kg. Diets were made isocaloric by substituting CLA oil for soybean oil. Diet formulas and calculated analyses of diets are presented in Table 1. The experiment was designed as a randomized complete block with four treatments and five blocks. Each block contained four contiguous pens, with littermates in each of the four pens. Pens contained four or five pigs and all pens within a block contained the same number of pigs. Body weight and feed intake data were recorded every other week. Real time ultrasound was used to determine backfat thickness and loin muscle area at approximately 28, 57, 86, and 115 kg of body weight. At market, backfat thickness and loin muscle area were measured. A five point subjective measure was used to evaluate marbling, firmness, and color of the loin muscle. Table 1. Diet composition and calculated analysis. Body weight range, kg Ingredient 28 to 57 57 to 86 86 to 115 Corn 68.76 83.47 85.01 Soybean meal 27.38 12.99 11.76 Dicalcium phosphate 1.24 .82 .57 Calcium carbonate .82 .77 .77 Salt .25 .25 .25 Vitamin premix .20 .20 .20 Trace mineral premix .05 .05 .05 Tylan 40 .05 .05 .05 Lysine·HCl .00 .15 .09 Oil 1.25 1.25 1.25