Effects of supra-nutritional Cu levels on growth, rumen fermentation and immune response of goat kids

摘要

Effects of supra-nutritional Cu levels (100 or 200 mg/day) (Cu sulfate) on growth, rumen fermentation and immune responses in 15 Boer x Spanish goat kids (BW = 21.3 ± 0.7 kg) were studied. Average daily gains were improved with 100 mg Cu intake. Protozoa counts tended to decrease with higher Cu intake, but VFA concentrations did not change. Blood leukocyte counts increased with higher neutrophils and lower lymphocytes at 100 mg Cu intake. There was no difference in ConA-induced lymphocyte proliferation, but PHA-induced lymphocyte proliferation was higher by day 72 in both Cu groups. Antibody tilers to chicken ovalbumin increased by day 98 due to Cu intake. The results indicate that Cu supplementation at 100 mg/day can improve weight gains in goat kids attributable to healthier animals with a stronger immune system. The requirements for Cu to optimize growth performance and the immune system may be greater than stated in NRC (1981). There was a delayed response in average daily gain by day 56 and the immune responses by day 72 for the humoral and by day 98 for the cell-mediated system with the intake of 100 mg Cu but not with 200 mg.