Effect of supplemental exogenous enzymes on performance of finishing Awassi lambs fed olive cake-containing diets

Twenty-four Awassi lambs (initial body weight; BW ± SD; of 19.3 ± 2.1 kg) were utilized to study the effects of supplemental exogenous enzymes (EE) on growth performance, nutrient digestibilities, and nitrogen balance of male finishing lambs fed diets containing olive cake. Lambs were individually housed in shaded pens and randomly assigned to one of two treatments: where 0 (Control, n = 12) or 3 g/d/lamb of EE (Enzyme, n = 12) were supplemented to the basal diet just before feeding. At the end of the study (lasted for 59 days), six lambs from each treatment were randomly housed in metabolism crates to measure nutrient digestibilities and nitrogen balance. Supplemental EE had no effects (P ≥ 0.55) on nutrient intakes or growth performance of lambs in terms of growth rate, final BW, and total gain. As a result, feed conversion ratio was not affected (P = 0.94) by EE supplementation. Additionally, supplemental EE did not affect (P ≥ 0.47) nutrient (dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber) digestibilities or retained nitrogen. Finishing diets containing olive cake supported acceptable performance of Awassi lambs. However, supplemental EE failed to improve lambs performance. Further studies are needed to determine the appropriate method of enzyme supplementation (i.e., composition, level, etc.) or other methods to improve the nutritive value of olive cake as a feedstuff for finishing lambs.