Effect of High Energy and High Protein Diets on Zinc and Copper Metabolism in Goats

Abstract

The effect of different levels of energy and protein on the utilization of zinc and copper were evaluated in four metabolic experiments. A total of nine growing castrated male balady kids having nearly the same age (8-9 months) and body weight (15-18kg) were experimented on. Kids were housed individually in metabolism cages in order to collect feces and urine. Four experiments, 3 trials per each were done on the same animals, with about 10 days as a rest period between one experiment and another, in which the animals were fed on control ration during the interval. The nine kids were randomly divided into 3 groups (A, B and C), 3 kids per each. The first group (A) was fed the control ration and used as control, while the other two groups (B and C) were fed the tested rations which furnished 15% more or less DE and CP than the control. Feeding the high energy ration increased the apparent absorption and retention of copper and decreased the apparent retention of zinc, while feeding low energy ration decreased the apparent absorption and retention of zinc and copper. Feeding the high protein ration decreased the apparent absorption and retention of copper, while low protein ration increased the absorption and retention of zinc and copper. Feeding the high energy-high protein ration increased the apparent absorption of zinc but decreased the apparent absorption of copper. On the other hand, low energy-low protein ration decreased the absorption and retention of zinc but increased the absorption and retention of copper.