Growth Efficiency and Trace Mineral Status of Growing Awassi Lambs Fed Two Levels of Zinc Methionine

Eighteen growing Awassi lambs were used in this study to determine the effect of supplementing two levels of protected Zinc-methionine (Zn-met) on their growth rate, trace minerals concentrations and growth performance. The lambs were divided to three groups, the dietary treatments were the control diet (C), the control diet plus 400 mg Zn-met/ kg feed (T1), the control diet plus 800 mg Zn-met/ kg feed (T2). The lambs received 200 mg/ lamb/ day and 400 mg/ lamb/ day for T1 and T2, consequently. Lambs general performance were recorded and mineral concentrations in blood, liver, kidney, bone and meat were analyzed using Atomic Absorption Spectrophotometery (AAS). Results show a significant higher (P 0.05) total gain, average daily gain and lower feed conversion ratio in lambs from T1 compared with lambs from the control and T2 groups. No significant effect (P 0.05) of Zn-met supplementation on total feed intake and dressing percentage. Significant effects (P 0.05) of treatment and treatment×time interaction on Cu, Co and Mn concentrations in blood serum were detected, but no effect on Zn concentrations. Moreover, lambs received 200-mg/ day Zn-met showed a significantly higher (P 0.05) Cu, Zn and Co concentrations in liver and only Zn in kidney when compared with the control and T2. Zinc, Cu and Co concentration in meat of lambs from T2 (400 mg/ lamb/ day Zn- met) were significantly higher (P 0.05) when compared with lambs from the control and T1. In conclusion, feeding growing Awassi lambs methionine in a form of Zn-met, with a low level of 200 mg/ lamb/ day, improved growth and utilization of dietary Cu, Zn and Co by growing lambs and consequently increased profit