THE EFFECT OF ADDING COPPER AND VARIOUS FAT SOURCES TO THE DIETS OF WEANLING SWINE ON GROWTH-PERFORMANCE AND SERUM FATTY-ACID PROFILES

An experiment involving 540 weanling pigs was conducted to determine t he effect of the addition of Cu (5, 125, or 250 ppm) on the growth per formance and serum fatty acid profiles of pigs fed diets that containe d no added fat (NO FAT), 5% added soybean oil (SBO), 5% added animal f at (ANI), or 5% added medium-chain triglycerides (MCT). Pigs had ad li bitum access to corn-soybean meal-based diets that contained 10% whey and 5% fish meal during the 28-d trial. Pigs were weighed and pen feed intakes were recorded weekly. Blood samples were collected for serum fatty acid analysis on d 1, 14, and 28 of the trial. The addition of a ll sources of fat to the diet increased (P < .001) ADG and gain:feed r atios during the 28-d trial. Increasing levels of dietary Cu linearly increased (P < .001) ADG and quadratically increased (P < .05) ADFI du ring the 28-d experiment. A Cu x fat source interaction was observed d 14 to 28 for ADG. The ADG of pigs fed NO FAT or SBO linearly increase d with increasing levels of Cu, and pigs fed MCT or ANI had quadratic increases in ADG as Cu levels increased. Compared with the NO FAT diet , d-28 serum saturated fatty acid concentrations were decreased (P < . 01) by the addition of SBO or ANI, monounsaturated fatty acid concentr ations were decreased (P < .001) by the addition of SBO, and polyunsat urated fatty acid concentrations were increased by the addition of SBO (P < .001). These data indicate that the performance of nursery pigs can be improved by the addition of growth-promoting levels of Cu and b y the addition of 5% fat from various fat sources.