| This thesis was conducted to investigate the effects of different dietary levels of proteinase,lipase and non-starch polysaccharide enzymes(NSP enzymes)on growth performance,body composition,serum biochemical parameters,serum immune and antioxidant indexes,digestive enzymes activities,fore intestine structure of juvenile yellow catfish(Pelteobagrus fulvidraco).The contents and results are as follows: 1 Effects of different dietary levels of proteinase,lipase,NSP enzymes on growth performance,serum biochemical parameters,body composition of juvenile yellow catfish.A total of 840 yellow catfish with an initial average body weight of(1.23±0.07)g were randomly divided into 8 groups with 3 replicates of 35 fish and fed respectively with a basal diet and seven test diets supplemented with 200,400 mg/kg protease,150,300 mg/kg lipase and 50,100,300 mg/kg non-starch polysaccharide enzymes(NSP enzymes).The feeding trial was lasted for 56 days.The results showed that compared with the control,the weight gain rate in 200 mg/kg protease group was increased by 4.5 %(p>0.05),while in 150,300 mg/kg lipase groups the weight gain rate showed a downward trend and the final average weight was significantly lower than that in the control(p<0.05).Survival rate in supplemented groups performed better than in the control,and increased by 9.6% in 200 mg/kg protease group(p>0.05).Viscerosomatic index in 200 mg/kg protease,150 mg/kg lipase and 100,300 mg/kg NSP enzymes groups were significantly lower than the control(p<0.05).Dry matter,crude protein,crude lipid and ash contents showed no significant differences(p>0.05)among all groups.Serum cholesterol and triglyceride contents in 150,300 mg/kg lipase groups were significantly decreased(p<0.05)compared with the control group,while glucose,albumin,total protein,urea nitrogen contents and glutamic oxalacetic transaminase and glutamic oxalacetic transaminase activities showed no significant differences(p>0.05).In conclusion,supplementation of 200 mg/kg protease could improve growth performance of juvenile yellow catfish and the exogenous lipase showed an opposite trend.2 Effects of different dietary levels of proteinase,lipase,NSP enzymes on serum immune and antioxidant indexes of juvenile yellow catfish.After the feeding trail,15 fish from each replicate were randomly selected to collect serum for determination of serum immune antioxidant indexes.The results showed that the acid phosphatase(ACP)activity in each supplemented group was higher than that in the control group,with Lip300 being significantly higher than the control group(P<0.05).Alkaline phosphatase(AKP)activity in Pro200 was significantly higher than in the control(P<0.05).There was no significant difference in the activity of superoxide dismutase(SOD)among supplemented groups and control group(P>0.05).The catalase(CAT)activity in NSP50 was significantly lower than that in the control group(P<0.05).The CAT activity in Pro200,Lip150,Lip300,and NSP100 was significantly higher than that in the control(P<0.05).The total antioxidant capacity(T-AOC)in each supplemented group was higher than that in the control group,of which Pro200,Lip150,NSP100 were significantly higher than the control group(P<0.05).The malondialdehyde(MDA)content in each supplemented group was higher than that in the control group,with Pro400,Lip300,NSP50,and NSP100 reaching significant levels(P<0.05).In conclusion,supplementation of 200 mg/kg protease,150 mg/kg lipase,and 100 mg/kg NSP enzymes could increase the antioxidant capacity of the juvenile yellow catfish.3 Effects of different dietary levels of proteinase,lipase,NSP enzymes on digestive enzymes activities of juvenile yellow catfish.After the feeding experiment was completed,eight fish,which had been selected for blood collection,were randomly selected to prepare liver,stomach and intestine samples for determination of tissue digestive enzymes activities.The results showed that Pro200,Pro400,Lip150,NSP100,and NSP300 had higher protease activity in liver than the control group by 13.5%,1.6%,18.3%,14.2%,and 9.0%,respectively,but the difference was not significant(P>0.05).The intestinal lipase activity in each supplemented group was decreased compared with the control group,without significant difference(P>0.05).The gastric amylase activity in Pro400,Lip150,Lip300,NSP50,NSP100 and NSP300 groups was higher than those in the control group,but the differences did not reach significant level(P>0.05).In conclusion,the supplementation of protease,lipase and NSP enzymes could increase the activities of hepatic protease and gastric amylase of juvenile yellow catfish.4 Effects of different dietary levels of proteinase,lipase,NSP enzymes on fore intestine structure of juvenile yellow catfish.After the feeding trial was completed,four fish were randomly selected from the bloodcollecting fish to prepare paraffin sections from the foregut,and HE staining was used to observe and collect image information.The results showed that compared with the control group,the intestinal muscle thickness in Lip300 was significantly increased(P<0.05),and the increase rate was 59.6%.There was no significant difference in intestinal muscle thickness among the other groups(P>0.05).The intestinal fold height in NSP 50 and NSP 300 was significantly higher than that in the control group(P<0.05)and reached the maximum in NSP50.The folds in NSP50,NSP100,and NSP300 were more uniform and complete.In conclusion,the supplementation of NSP enzymes could increase the height of the foregut folds and improve the structure of the foregut to a certain extent. |
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