Effect of Dietary Organic Zinc and Prebiotic on Productive Performance and Immune Response of Growing Quails

The aim of the present study was to investigate the possibility of improving productive performance and immunity of growing Japanese quail reared during summer in Egypt by supplementing the diets with or-ganic zinc (Bioplex zinc) and prebiotic (mannan oligosaccharides). Diets were a basal diet or the basal diet supplemented with 20 mg Bioplex zinc (3.0 mg Zn) (Zn1), 40 mg Bioplex zinc (6.0 mg Zn) (Zn2), 1.0 g prebiotic (P), P + Zn1 or P + Zn2. Ambient temperature and relative humidity ranged between 34 to 36 ?C and between 45 to 51%, respectively. No significant difference was observed in body weight, body weight gain, feed intake, feed conversion and mortality of the treated quails when compared to the control group. The effect of treatments on the carcass traits and relative weights of the lymphoid organs and thyroid gland was not significant. The primary and secondary immune responses were the highest in the treated quails. The results showed that plasma total protein of the (P) and (P+Zn2) treated quails increased significantly when compared to the control group. The level of plasma total lipids and cholesterol decreased significantly (P < 0.05) in quails fed the supplemented diets. No significant change was observed in the plasma AST and ALT enzyme activities and triiodothyronine concentration. It is concluded that, supplementing diets of growing Japanese quails reared during summer in Egypt with 20 or 40 mg Bioplex zinc/kg each alone or in combination with 1.0 g/kg prebiotic (mannan oligosaccharides) had no significant effect on productive per-formance but improved their immune response.