THE EFFECT OF COPPER LEVEL ON NUTRIENT UTILIZATION OF WEANLING PIGS

The effect of addition of 15 or 250 ppm of Cu (as CuSO4.5H(2)O) and 0 or 5% added animal fat on the utilization of nutrients by weanling pig s was evaluated. Two trials were conducted with four groups of four li ttermate barrows (6.8 kg, 26 d) in each trial. Dietary treatments were arranged in a 2 x 2 factorial. Data were collected at the beginning o f the trial and at the end of each 3-d period. There were no treatment x period interactions (P > .15). There was a Cu level x fat level int eraction for ADG (P < .01), feed efficiency (P < .01), N intake (P < . 09), fat intake (P < .01), and ash intake (P < .09). Pigs fed 250 ppm of Cu and 5% fat had increased ADG and gain:feed, whereas pigs fed 5% fat and 15 ppm of Cu had decreased ADG and gain:feed compared to pigs fed the other treatments. Apparent digestibility of DM and ash and N r etention were increased (P < .05) by the addition of 250 ppm of Cu, wh ereas the addition of 5% fat decreased(P < .05) DM and ash digestibili ty. Fat digestibility increased from 28.3% to 75.6% when 5% fat was ad ded to the diet containing 15 ppm of Cu and from 60.8% to 85.1% when 5 % fat was added to the diet containing 250 ppm of Cu (Cu level x fat l evel, P < .01). Pigs fed diets containing 5% fat and 15 ppm of Cu had decreased (P < .06) Na, Cu, Fe, and Zn retention compared to pigs fed the other diets. Data from this study indicate that nutrient digestibi lity is influenced by Cu and fat level in the diet and that digestibil ity of dietary fat can be improved in weanling pigs by addition of Cu to the diet.