Physiological and Antioxidant Responses of Japanese Quail to Dietary Copper Supplementation

Abstract

Two experiments were conducted to elucidate the effect of dietary copper supplementation on performance, physiological, hematological and antioxidant responses of day-old unsexed Japanese quail chicks (Coturnix coturnix Japonica). In each experiment, a total number of 250 quails were summited to five experimental treatments (50 chicks in five replicates each. The first one (control) was fed the basal diet while the other groups were fed the same diet supplemented with copper as cupric sulfate pentahydrate at levels of 50, 100, 150 and 200 mg/kg diet. In experiment 1 (Exp.1), chicks were fed the Cu-supplemented diets until 6 weeks of age whereas the supplementation period in experiment 2 (Exp.2) was for the first five weeks of age followed by a final period of one week during which birds fed the control basal diet. Results demonstrated that supplementation of copper sulfate to diets either or 6 (Exp. 1) or 5 weeks (Exp. 2) had significantly improved live body weight, weight gain, feed conversion ratio and low mortality rate of quail chicks. Hematological indices in terms of RBCs count, hemoglobin concentration, hematocrit, mean corpuscular volume, WBCs count and H /L ratio were significantly improves in quails fed Cu-supplemented diets up to 100 mg/Kg in Exp.1 and up to 150 mg/Kg in Exp. 2. Birds fed Cu-supplemented diets for six weeks (Exp. 1) up to 100mg/Kg had significantly higher plasma total protein, globulin, Immunoglobulins (Y , M , A) and high density lipoprotein (HDL) but lower plasma total cholesterol, triglycerides and low density lipoprotein (LDL) than the control ones. A similar trend was recorded for Exp. 2 quails, but plasma protein fractions were not significantly affected. In both experiments, blood reduced glutathione (GSH), superoxide dismutase (SOD) activity and total antioxidant capacity (TAC) were significantly increased with Cu-supplemented diets, while malondialdehyde (MDA) was significantly decreased in the experimental groups compared with the control. The obtained results indicate that dietary supplementation with cupric sulfate pentahydrate at levels up to 100 mg/kg could improve growth performance, antioxidant defense system, immunity and lower cholesterol content of growing Japanese quail.