A Study On The In Vitro Enzyme Method To Evaluate The Quality Of Non-starch Polysaccharides Enzymes

This study was aimed to evaluate the quality of non-starch polysaccharide(NSP)enzymes by using in vitro simulated animal digestion methods and also,to establish a rapid and practical method for evaluating the quality of NSP enzymes in vitro.An animal experiment was used to verify the in vitro results.During the in vitro study,wheat was used as the substrate,and different types of NSP enzymes were used as the variate.The rate of dry matter’s digestibility in vitro and the effect of NSP enzymes on NSP content of digestion residue were measured to test the quality of NSP enzymes.Five NSP compound enzymes(A-E)and three NSP single enzymes(F-H)were detected and screened.The results of in vitro experiments showed that the addition of NSP enzymes in wheat significantly affected the rate of dry matter digestibility(P<0.05)and the NSP content of digestion residue(P<0.05).There were significant differences among different NSP enzymes(P<0.05),especially among compound enzymes.Compared to other compound enzymes,the effect of compound enzyme D was poor,while the effect of enzyme E was better.Among single enzymes,the effect of enzyme G was better,while enzyme H was poor.The selected NSP enzymes according to the evaluation results of the in vitro test were used for the preparation of the in vivo experiment wheat diet.One-day-old 720 broilers with similar body weight were selected and divided into 6 groups randomly.Each group had 8 replicates and each replicate had 15 broilers.Broilers were fed with wheat-based diet(Control group),or fed with wheat-based diet+NSP enzyme D,wheat-based diet+NSP enzyme E,wheat-based diet+NSP enzyme G,and wheat-based diet+NSP enzyme H(Experimental group),or fed with a corn-soybean diet(Positive control group).The results of the in vivo experiment showed that enzyme G increased the body weight of broilers in 21-day and 42-day(P<0.05)and the effect of enzyme G was better than enzyme H.There was no significant effect of NSP enzymes on the performance of broiler at the early growth stage(P>0.05).However,the average daily gain was significantly different between groups(P<0.05)for broilers at the late growth stage and enzyme G was better than enzyme H.Two NSP compound enzymes D and E reduced the feed/gain ratio(P<0.05)significantly at the late growth stage of broilers.During the whole 42 days,the feed/gain ratio of the NSP enzyme E group was significantly lower than that of the control group(P<0.05)and the effect of enzyme E was better than enzyme D which was in accord with the results of in vitro digestion.The effect of NSP enzymes on apparent metabolizable energy was not significant(P>0.05).NSP enzyme E and G increased the digestibility of NSP in 42-day-old broilers(P<0.05).And the effect of enzyme E was better than the enzyme D,the effect of enzyme G was better than the enzyme H which was in accord with the result of in vitro digestion.NSP enzymes had no significant effect on the chyme viscosity of broiler ileum(P>0.05).The cecal chyme viscosity of the wheat-based diet group was higher significantly than the corn-soybean diet group at 21-day of age.The cecal chyme viscosity of the enzyme H group was lower significantly than the control group(P<0.05)and the effect of enzyme H was better than enzyme G.Two Single enzymes G and H had a significant effect on the viscosity of manure(P<0.05).Enzyme H reduced significantly the manure viscosity of 21-day-old broilers(P<0.05)and the effect of enzyme H was better than enzyme G.Enzyme G reduced the manure viscosity of broilers significantly in 42 days(P<0.05)and the effect of enzyme G was better than enzyme H.NSP enzymes had no significant effect on the proportion of liver,abdominal fat,pancreatic,breast muscle and intestinal tract(P>0.05).The thigh proportion of broiler chickens fed with the wheat-based diet was lower than the corn-soybean diet group significantly(P<0.05)at 21-day of age.The NSP enzymes increased the concentration of blood glucose(P<0.05).NSP enzymes affected the morphology of the ileum and cecum(P<0.05),but not jejunum.Enzyme G increased significantly the villus length/crypt depth of the ileum of 21-day-old broilers and the effect of enzyme G was better than enzyme H,in accord with the result of in vitro digestion.NSP enzyme E increased the villus length and villus length/crypt depth of 42-day-old broilers(P<0.05).And the effect of enzyme E was better than the enzyme D which was in accord with the result of in vitro digestion.In summary,a method for the quality assessment of NSP enzyme products by using in vitro enzyme digestion was established in this study.Product testing and production verification were conducted as well.The results in vitro and in vivo were relatively consistent.This study established an in vitro quality assessment method of the NSP enzymes products,which had certain feasibility.