EFFECT OF DIETARY COPPER AND FAT ON NUTRIENT UTILIZATION, DIGESTIVE ENZYME-ACTIVITIES, AND TISSUE MINERAL LEVELS IN WEANLING PIGS

Two 15-d nutrient balance trials were conducted using a total of 32 we anling barrows (averaging 6.8 kg, 26 d). The effect of the addition of 15 or 250 ppm Cu (as CuSO4 . 5H(2)O) to diets containing 0 or 5% adde d animal fat on nutrient utilization, digestive enzyme activities, and tissue mineral levels in weanling pigs was investigated. In each tria l, four groups of four littermate barrows were randomly assigned to on e of four treatments in a 2 x 2 factorial arrangement. The addition of 250 ppm Cu improved apparent fat digestibility and apparent nitrogen retention (P < .02). The addition of 5% fat increased apparent fat dig estibility (P < .01). There were no Cu x fat interactions (P > .10) fo r any of the digestibility indices measured. The addition of 250 ppm o f Cu stimulated small intestinal lipase (P < .01) and phospholipase A( P < .05) activities but had no effect (P > .10) on pancreatic lipase o r phospholipase activities and no effect on trypsin, chymotrypsin, or amylase activities in the small intestine or the pancreas. The additio n of 250 ppm Cu to the diet increased Cu (P < .001) in plasma, liver, and kidney and decreased Fe in plasma (P < .05) and liver (P < .02). T he addition of 5% fat increased Fe in kidney (P < .05) and heart (P < .08). Copper x fat interactions were observed for spleen Ca (P < .01), Mg (P < .08), Na (P < .05), and K (P < .08) and spleen weight (P < .0 5). In additional in vitro assays, increased Cu concentrations tended to consistently stimulate-purified porcine pancreatic lipase activity (linear, P < .01) but not purified porcine pancreatic phospholipase A activity (P > .10). The results from this study indicate that 250 ppm Cu stimulated intestinal lipase and phospholipase A activities, leadin g to an improvement of dietary fat digestibility in weanling pigs.