淀粉酶的补充方式对育肥牛生长性能、表观消化率和血液指标的影响OA

This study was conducted to investigate the effects of supplemental native amylase and double-coated amylase(DCA)on growth performance,nutrient digestibility and blood metabolites in fattening cattle.Sixty-three healthy Simmental cattle[body weight(517.3±7.5)kg,age(12.2±1.3)months]were ran-domly assigned to three groups of 21 head each:a control group received the basal diet only,while the amy-lase and DCA groups received the basal diet supplemented with 0.6 g amylase(10 000 U/g)per kg of dietary dry matter supplied as native amylase or DCA,respectively.The experiment consisted of a 10-day preliminary period followed by a 90-day formal trial.The results showed that dry-matter intake(DMI)and initial body weight(BW)did not differ among treatments during the experiment(P>0.05).On day 45,BW in the DCA group was already higher than that of the control(P<0.05);by day 90,the BW was highest in the DCA group,followed by the amylase group,lowest in the control group.From day 1 to 45,the average daily gain(ADG)of the DCA group was higher than that of the control group(P<0.05).During both day 46 to 90 and the over-all 90-day period,ADG was highest in the DCA group,followed by the amylase group,lowest in the control group.During 1 to 90 d,feed conversion ratio(FCR)in the DCA group was consistently lower than that of the control(P<0.05),but did not differ from the amylase group(P>0.05).Apparent digestibility of DM,OM,CP,ether extract(EE),and starch was highest in the DCA group,intermediate in the amylase group,and lowest in the control group.However,apparent digestibility of neutral-detergent fiber(NDF)and acid-detergent fiber(ADF)did not differ between the DCA and amylase groups(P>0.05),yet both were signifi-cantly higher than in the control group(P<0.05).Blood concentrations of glucose,total protein,and albumin were highest in the DCA group,followed by the amylase group,and lowest in the control group.Regardless of the supplemental form,no significant differences were observed in serum insulin,urea nitrogen,or lactate concentrations among treatments(P>0.05).In conclusion,supplementing 0.6 g/kg DM of amylase as DCA is superior to the native enzyme in improving nutrient digestibility and blood metabolites,thereby enhancing the growth performance of Simmental fattening cattle.