| Two experiments were conducted to investigate the effect of combined α-galactosidase(40 U/g)and xylanase(860 U/g)supplementation on dietary nutrient digestibility,pH and viscosityof digesta,small intestinaldigestive enzyme activities,serum biochemical parameters,serum amino acid(AA),growth performance in growing pigs.In experiment 1,to assess the apparent ileal digestibility of nutrients,pH and viscosity of digesta,and digestive enzyme activities,a 2 × 2 Latin square design was conducted with 2 diets(basal vs.basal + α-Galactosidase(12 U/kg diet)+ Xylanase(258 U/kg diet)and 2 periods in each square using 8 barrows(45.03 ± 0.52 kg)installed with a simple T-cannula in the distal ileum.In experime nt 2,to assess the growth performance and serum biochemical parameters,a total of 432 growing pigs(Duroc × Landrace × Yorkshire;mean initial BW: 44.68 ± 0.66 kg)were allocated to one of four treatments with 6 replicates of 18 pigs as follows: 1)positive co ntrol [PC]: a corn-SBM basal diet containing 13.39 MJ/kg DE and 16.0% CP,2)negative control [NC]: DE andcrudeproteinwere reduced by 0.42 MJ/kg and 0.8% CP from the PC diet by replaced of corn and SBM with defatted rice bran.3)PC + α-galactosidase + xylanase.4)NC + α-galactosidase + xylanase.The results showed as fellow:Nurtrient digestibility : Pigs fed the α-galactosidase and xylanase supplementation diet had greater DE and DE/GE(P <0.05);higher AID of Arg,raffinose,stachyose,andxylan(P <0.05);tended to have greater ME,ATTD of P(P <0.1),and had not affect ATTD of DM,Ca,NDF,ADFcomparedwith those fed control diet.Characteristic of ileam digesta: Combined α-galactosidase and xylanase supplementation diet tended to increase the activity of trypsin(P <0.1)and not affected the activity of amylase(P >0.05)compared with the control group.Ileal digestaviscosity was much lower(P <0.05)and had no difference in pH when α-galactosidase and xylanasewas supplemented in the diet.Growth pe rformance:Compared with PC group,pigs from NC group had lower ADG(P <0.05).Pigs from PC and NC + α-galactosidase + xylanase groups had similar ADG(P >0.10),which indicates the decrease of ADG caused by nutrition-decreased diet could be counteracted by the dietary addition of α-galactosidase and xylanase.However,supplementation of α-galactosidase and xylanase to the PC group did not further improve growth performance of pigs(P >0.10).serum biochemical parameters: SUN of pigs was different among treatments.SUN had a tendency to increase when pigs fedlow-nutrientleveldietcomparedwith pigs fed normal-nutrient level diet(P <0.1).Extrasupplementation of α-galactosidase and xylanase had a tendency to decrease SUN in pigs,compared with those in non-supplemented groups(P <0.1).Compared with NC group,pigs in PC + α-galactosidase + xylanase group had significantly lower SUN(P <0.05).GLU and IGF-1 of growing pigs were unaffected by dietary nutrient levelsorα-galactosidase and xylanase supplementation in this trial(P >0.1).Serum amino acid concentrations: there were significant decreases in the serum concentrations of Ile,Val,Asp,Glu,Alaand total amino acidin pigs fed NCdietcomparedwith those fed PC diet(P <0.05).Dietary addition of α-galactosidase and xylanase increasedthe concentration of serum Lys,Arg and total AA in pigs,compared with those in non-supplemented groups(P <0.05).Serum concentrations of Phe,Thr,Ser,Tyr,His and Pro of growing pigs were unaffected by dietary nutrient levelsorα-galactosidase and xylanase supplementation in this trial(P >0.1).Collectively,supplementation of combined α-galactosidase(40 U/g)and xylanase(50 AXC/g)in diet could increase dietary DE,growth performance,serum total AA concentrations,and decrease SUN.The decrease of growth performance caused by nutrientlimited diet(0.42 MJ/kg and 0.8% CP decreased)could be counteracted by the dietary addition of combined α-galactosidase(40 U/g)and xylanase(860 U/g)in growing pigs. |
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