Effect Of Exogenous Fibrolytic Enzymes On Ruminal Fermentation And Gas Production By Rusitec,in Vitro Abomasum And Ileum Digestibility

Three studieswere conductedto investigatethe effect ofan exogenous fibrolytic enzymes?EFE?on ruminal fermentation and gas production using the RUSITEC,in vitro abomasum and ileum digestibility.The total mixed ration contained 55%concentrates,22.5%corn silage and 22.5%alfalfa hay.The first study was conducted over 2 independent fifteenday incubation times,with the last eight days utilizedfor data collection.Exogenous fibrolytic enzymecreatedfrom Ruminococcus flav was used in this experiment.It was assayed for numerousenzymeactivity to include?units/g of enzyme preparation?17500 units of?-glucanase,2000 units of xylanase and 3500 units of cellulase activity.Four levels of the EFE?0.0,0.4,0.8,and 1.2 g?were used as E0,E2,E4,and E6,respectively,these levels of EFE were added directly into 20 g of diet in nylon bags and incubated in the RUSITEC for forty-eight hour.In the second experiment,the in vitro abomasum digestibility,undigested RUSITEC residue was weighed?2.40 g±0.05 g?and replicated four times for eachtreatment.In the third experiment,in vitro ileum digestibility was carried out,the undigested abomasum residue was weighed?0.56g±0.05 g?into 100-mL bottles in triplicate,and 10 mL of abomasum fluid and 30 mL of artificial saliva and small intestinal fluid?0.45g?were added,and for each treatment replicated four times.Results of the RUSITEC experiment showed no effect?P>0.05?on pH-values,dry matter,organic matterdigestibility,crude protein digestibility,gas production,CH₄ productionand total volatile fatty acids among all treatments in RUSITEC by using different EFE levels.Thedigestibility's of dry matter,organic matter neutral detergent fiber,acid detergent fiber,and NH₃-N concentrations were increased?P<0.05?with increasing EFE levels.The in vitro abomasum and in vitro ileum experiment,the dry matter,organic matter digestibility and total volatile fatty acidswere unchanged?P>0.05?.NH₃-N concentrations were also increased?P<0.05?with increasing EFE levels.Moreover,in the in vitro abomasum experiment,the neutral detergent fibre digestibility and acid detergent fiber digestibilitywas increased?P<0.05?with increasing EFE levels.The results indicate that using high doses of EFE?VTR^??containing Ruminococcus flavefaciens in TMR?45:55?could improve the neutral detergent fibre digestibility and acid detergent fiber digestibilityin rumen and small intestine.