Growth Performance and Serum Metabolites of Awassi Lambs Fed Wheat Straw Treated with Urea and Supplemented with Fibrolytic Enzymes

Abstract

The aim of this study was to evaluate the effect of treating wheat straw with urea, supplementing with fibrolytic enzymes (Safaziyme®, cocktail enzymes contained: β-glucanase, xylanase and cellulase) to untreated wheat straw and urea treated wheat straw on growth performance, feed intake and some serum metabolites of growing lambs. Sixteen Awassi male lambs with an average weight 19.0±0.24 kg and 3-4 months old were used at ruminant farm belong to the Faculty of Agriculture, University of Kufa, Najaf, Iraq. Lambs were distributed randomly to four treatment groups four lambs per treatment and fed: T1: Concentrate diet plus untreated wheat straw (control); T2: Concentrate diet plus wheat straw treated with 3% urea solution; T3: Concentrate diet supplemented with fibrolytic enzymes (2g/head/day) plus untreated wheat straw; T4: Concentrate diet supplemented with fibrolytic enzymes (2g/head/day) plus wheat straw treated with 3% urea solution. Lambs were individually fed concentrate diet at 3% of their live body weight while wheat straw treated with urea or untreated was offered ad libitum for 63 days. Results revealed that total weight gain (TWG) and average daily gain (ADG) were significantly increased (P≤0.01) with lambs fed a combination of urea treatment and enzyme supplementation (T4) as compared to those fed urea treated what straw (T2), supplementation with fibrolytic enzymes(T3) and untreated wheat straw (T1). There were no significant differences in total dry matter intakes among treatments. The feed conversion ratio (FCR) was improved (P≤0.05) for lambs in T2 and T4, the superiority with lambs in T4. Results were also revealed no significant differences (P≥0.05) on lamb serum metabolites, with numerical decrease in serum urea nitrogen in lambs of T4. These results indicate that supplementation of fibrolytic enzymes alone did not improve the growth performance of lambs. However, combination of urea treatment and enzyme supplementation efficient for lambs growth without adverse effects on animal health.