Influence of dietary inorganic and organic form of copper salt on performance, plasma lipids and nutrient utilization of Black Bengal ( Capra hircus) goat kids

Abstract

Twenty 3–4-month-old castrated male Black Bengal goat kids ( Capra hircus) were used to determine the effects of inorganic and organic forms of supplemental copper (Cu) with different dose on performance, plasma lipids and nutrient utilization. These kids were randomly assigned to one of five treatments in a {(2×2) + 1} factorial arrangement. Factors were two source of Cu-salt (Cu-sulfate versus Cu-proteinate) fed at two dietary levels (20 and 40 mg/kg dietary DM) and the control (no supplemental Cu). Kids were fed a basal diet containing maize (195 g/kg), soybean (170 g/kg), wheat bran (225 g/kg), deoiled rice bran (340 g/kg), molasses (30 g/kg), di-calcium phosphate and salt (20 g/kg each), salt (10 g/kg) and mineral and vitamin mixture (5 g/kg) supplements at 35 g/kg live weight to meet NRC requirements for protein, energy, macro and micro minerals, excluding Cu. The basal diet (DM basis) contained 9.54 mg Cu/kg, 494 mg Fe/kg, 178 mg Zn/kg 171 mg Mn/Kg and 0.28 mg Mo/kg. Kids were housed in a well-ventilated shed with facilities for individual feeding in a plastic trough in an open-sided barn. Blood samples were collected on days 0, 28, 56 and 84 to determine blood hematology and blood metabolites and plasma lipids concentration. A metabolism trial of 5 days was conducted during the last week of experimental feeding. BW of the experimental kids was increased during the supplementation period. It was observed that body weight gain (BWG) and average daily gain (ADG) increased (P<0.01) linearly with the dose of supplemental Cu. Effect of Cu-salt was also found for BWG and ADG. There was a negative linear (P<0.01) effect of dose of Cu on plasma cholesterol and low density lipoprotein (LDL-C) concentrations. Concentration of plasma glucose, proteins and enzymes were similar among the treatments throughout the experimental period. Concentration of haemoglobin, packed cell volume, total erythrocyte count and total leukocyte count were not affected by dose and source of Cu-salt. Cu-P supplementation showed increased digestibility of DM and OM (P<0.10) compared to CuSO 4. A linear and quadratic response to Cu dose was noted for DM and OM (P<0.05) digestibility and a linear effect on N retention (P<0.01) was also seen. In conclusion, Cu-P supplemented kids showed higher BW gain and a reduction of plasma cholesterol, compared to CuSO 4 supplementation. An added level of 40 mg Cu/kg DM was not toxic to the kids during the 84-day feeding trail. Dose of Cu had an important role in the growth performance, plasma lipids and nutrient utilization in castrated Black Bengal kids.