Effect of single or combined supplementation of zinc and probiotics on muscle and bone characteristics and haematobiochemical profile in broilers

Abstract

The study was conducted to elucidate the effect of a single or combined supplementation of zinc sulphate monohydrate (ZnSO₄.H₂O) and a probiotic (Protexin^®) on the pectoral muscle, tibial bone and serum biochemistry in broilers. Day-old chicks (n = 192) were divided into: Control (basal diet), Zn30 (basal diet + ZnSO₄.H₂O 30 mg/kg feed), Zn60 (basal diet + ZnSO₄.H₂O 60 mg/kg feed), Pro (basal diet + Protexin^® 0.1 g/kg feed), Com30 (basal diet + ZnSO₄.H₂O 30 mg/kg feed + Protexin^® 0.1 g/kg feed) and Com60 (basal diet + ZnSO₄.H₂O 60 mg/kg feed + Protexin^® 0.1 g/kg feed). The birds were slaughtered on the 42^nd day and blood was collected to determine the cortisol, cholesterol and zinc concentrations. The pectoral muscle was selected for the assessment of the pH and water holding capacity (WHC) along with the histological sections. After defleshing, tibial bone measurements were also taken. Statistical analysis revealed a significant (P < 0.05) increase in the ultimate pH (pHu), WHC and muscle fascicle diameter in the Zn30, Zn60, Pro, Com30 and Com60 groups compared to the control group. Myofibre area showed a significant increase (P > 0.05) in the Com30 and Com60 groups against the control group. The medullary canal diameter of the tibia was smaller (P > 0.05) in the Zn60, Pro, Com30 and Com60 groups than in the control group. The tibiotarsal index was greater (P > 0.05) in the Zn60, Pro, Com30 and Com60 groups. The serum cholesterol was decreased (P > 0.05) in the Pro and Com30 groups when compared to the control group. It is concluded that zinc sulfate monohydrate and probiotic supplementation individually or in combination positively affected the histological characteristics of the muscle, tibial bone strength and haematobiochemical indicators.