Protected methionine and dry fat for improving performance of growing Awassi lambs

摘要

This study was carried out to evaluate the effect of high dietary energy as dry fat and protected methionine on growth efficacy, feed intake and efficiency and carcass parameters of Awassi lambs during finishing stage. Twenty four Awassi lambs (3-4 months old) were distributed equally into four treatments groups as follow: Control (NRC requirements); T1 (High energy 3.0 Mcal ME/kg); T2 (high energy 3.0 Mcal ME/kg and 2.5 g protected methionine/head/day) and T3 (high energy 3.0 Mcal ME/kg and 5 g protected methionine/head/day methionine). Feeding Awassi lambs with high energy alone or with protected methionine caused a significant (P<0.05) increase in weight gain during second, third and overall gain when compared with the control group. Treatments did not cause any significant effect on feed intake, feed conversion, average and relative growth rate, dressing and tissues percentages except for spleen, heart and lungs. Moreover, back fat thickness, omental fat percentage and blood serum cholesterol significantly decreased (P<0.05) with feeding protected methionine (T2 and T3) when compared with lambs fed dry fat (T1). In conclusion, increasing dietary energy by using dry fat with or without protected methionine of Awassi lambs during the finishing period improved the total weight gain. This indicated that the requirements of energy by growing Awassi lambs might be higher than reported by NRC.