Can copper amino acid chelates reduce the physiological strain of growing rabbits under summer conditions?

This study was conducted at the Poultry Research Centre, Faculty of Agriculture, Alexandria University, Egypt, during the summer season (July and August months) 2018. For five weeks, until 63 d of age, a total number of 140 weaned V line rabbits were randomly distributed into seven groups of 20 rabbits each. Rabbits of groups 2 and 3 were fed basal diet plus copper sulphate (100 and 200 mg Cu-Sul/kg, respectively). Groups 4 and 5 were fed basal diet plus copper methionine (100 and 200 mg Cu-Meth/kg, respectively) and groups 6 and 7 were fed basal diet plus copper glycine (100 and 200 mg Cu-Gly/kg, respectively), while the first group was fed basal diet only as control. Rabbits fed diet supplemented with higher level (200 mg/kg) of Cu-Meth or Cu-Gly chelates had significantly higher body weight and daily body weight gain (P<0.05) compared to those fed diets supplemented with both levels of Cu-Sul. Rabbits fed diets supplemented with Cu-Meth or Cu-Gly chelates had significantly increased (P<0.05) red blood cells, lymphocyte, high-density lipoprotein and Cu values in blood. Within the studied Cu sources, serum total lipids values of rabbits were significantly lower than in the control group. However, serum total antioxidant capacity, glutathione peroxidase and superoxide dismutase were higher by both organic chelates studied than other groups. In general, copper supplementation improves productive performance and physiological status under summer conditions. 