Abstract: 【Objective】This experiment was conducted to investigate the effects of different compatibility enzymes on growth performance and nutrient digestibility of Dorper × Small Tail Han sheep crossbred male lambs fed with corn straw-based diets.【Method】Lambs were assigned to one of four groups of 100 animals per group with five replicates in a randomized complete block design being:control (basal diet without any supplementation), treatment groups (TG): TGⅠ (basal diet with enzymes preparation of Cellulase + β-glucanase + Xylanase), TGⅡ (basal diet with enzymes preparation of Cellulase + β-glucanase + Xylanase + Pectase), or TGⅢ (basal diet with enzymes preparation of Cellulase + β-glucanase + Xylanase + Pectase + Laccase) in a 76-day experiment including a 10-day preliminary test period and a 66-day formal trial period. The basal diets as TMR was fulfilled the growth requirements of lambs according to NRC (2007) with a concentrate: forage ratio of 4:6(at first phase) and 5:5(at second phase) (DM basis). The compound enzyme preparation for treatment diets was dissolved in water to form a 4% solution containing a mix of carrier and enzymes, which was sprayed directly onto the corn straw at a rate of 1.0 kg/t of TMR (Air dry basis), just prior to feeding.【Result】The results showed as follows: different compatibility enzymes had significant effects on ADG and ratio of feed to gain (F/G) (P＜0.05), but no significant differences were found in dry matter intake (P=0.107). ADG of TGⅢand TGⅡwas significantly higher than those in Control and TGⅠ(P＜0.05), and F/G of TG Ⅲ was significantly lower than that in Control (P＜0.05), but there was no difference between TGⅢ and TGⅡ or Control and TGⅠ(P＞0.05), respectively. Addition of enzymes preparation also increased (P＞0.05) apparent digestibility of all nutrients, except for CP(P=0.166). TGⅢ was the highest in nutrient digestibility. Apparent digestibility of DM, OM, GE, NDF, ADF in TGⅢ was significantly higher than that in Control (P＜0.05), but there was no difference between TGⅢ and TGⅡ or Control and TGⅠ(P＞0.05). The magnitude of improvement in digestibility varied among nutrients, with the highest improvement occurred in digestibility of DM and ADF (about 11% and 19%, respectively). The addition of enzyme preparation in TGⅢ also achieved good economic benefits. 【Conclusion】It was concluded that there are positive responses to growth performance and nutrient digestibility of fattening sheep for corn stalk diet treated with different compatibility enzymes. The effect of TGⅢ was significantly better than that of TGⅡ, although the effects of TG III and TG II were both significantly. Compared with the control, average daily gain of TG III was increased by 23.51%, nutrient digestibility was increased by 11%, feed conversion ratio was increased by 26.36%, and diet cost for 1kg weight gain was reduced by 18.42%.

Key words: fattening sheep, different compatibility enzymes, corn straw, live-weight gain, digestibility