The effect of dietary yeast and protected methionine on performance and trace minerals status of growing Awassi lambs

Eighteen growing Awassi lambs were used in this study to determine the effect of supplementing two levels of yeast and methionine (cyc-methionine) on the trace elements bioavailability, growth rate, and general performance. The lambs were divided to three groups. The dietary treatments were the control diet (C), control diet plus 2 g cyc-methionine/lamb/day (T(1)) and control diet plus 4 g cyc-methionine/lamb/day (T(2)). Lambs fed 2 g/day of cyc-methionine (T(1)) showed a significantly higher (P<0.05) copper, zinc, and cobalt concentrations in liver and meat tissues, but not the same trend in kidney. No significant (P>0.05) effect of time and time x treatment interaction on copper, zinc, cobalt, and manganese concentrations in blood serum, but cobalt and manganese concentration showed significant (P<0.05) change by time. Moreover, a significantly (P<0.05) higher total body gain, average daily gain, dressing percentage, and lower feed conversion were detected in lambs from T(1) compared with the control and T(2) groups. Feeding 2 g of cyc-methionine to growing lambs increased the net profit by $6.017/lamb and only $3.52/lamb fed 4 g cyc-methionine/day when compared with the control group. In conclusion, feeding growing Awassi lambs yeast and methionine in a form of cyc-methionine, with a low level of 2 g/day, improve the bioavailability, of copper, zinc, and cobalt by growing lambs and their growth performance. (C) 2007 Elsevier B.V. All rights reserved.