| Low fishmeal diet is one of the important factors affecting the sustainable development of shrimp culture.How to maintain the growth performance and stress resistance of shrimp culture under low fish meal diet conditions is a hot topic in shrimp nutritional feed research.In this study,0%(A),2.5%(B),3.5%(C),4.5%(D),5.5%(E)of proteolytic soybean meal were added to the basic diet containing 10% fish meal.0%(a),3.5%(b),4.5%(c),5.5%(d),6.5%(e)of proteolytic soybean meal were added to the basic diet containing 5% fish meal.The juveniles of Litopenaeus vannamei with an initial body weight of(0.450±0.002)g were fed to each group for 8 weeks to explore the growth and resistance of the proteolytic soybean meal in the low-fish meal diet to freshwater culture conditions.The impact of coercive capacity.The results show:After 8 weeks of the culture experiment,the final weight of the shrimps in the test group containing 10% fish meal was 14.65-15.38g/tail,and there was no significant difference in the weight gain rate,survival rate and feed coefficient index between the groups(P<0.05),the final weight of the shrimps in the test group containing 5% fish meal was 13.65-14.93g/tail,and the proteolytic soybean meal significantly affected the growth performance of Litopenaeus vannamei.Group a(0% PSM)shrimp terminal The weight and specific growth rate were significantly lower than those of group c(4.5% PSM),group d(5.5% PSM)and group e(6.5% PSM)(P<0.05).The bait coefficient of group a(0% PSM)was significantly higher than that.Other test groups(P<0.05).The muscle composition of the shrimp in each treatment group of 10% fish meal was analyzed.The crude protein content of the muscle of group D(4.5% PSM)was significantly higher than that of group A(0% PSM)(P<0.05).The crude protein and total fat between the other groups were There was no significant difference in ash and water(P>0.05).The conventional muscle composition of 5% fish meal treatment group was analyzed.The crude protein content of group d(5.5% PSM)and group e(6.5% PSM)was significantly higher than that of group a(0% PSM)(P<0.05),there was no significant difference in crude protein,total lipid,ash and water between the other groups(P>0.05).The detection of digestive enzyme activity in hepatopancreas of 10% fish meal shrimp showed that the activity of hepatopancreas was the highest in group E(5.5% PSM),and the amylase activity and lipase activity of shrimp liver and pancreas were significantly higher than that of control.Group A(0% PSM)(P<0.05),5% fishmeal control group a(0% PSM)showed the lowest hepatopancreatic protease and amylase activity in shrimp(P<0.05),and the lipase activity of shrimp and hepatopancreas showed The highest amount of proteolytic soybean meal was 3.5%(P<0.05).After 8 weeks of the culture experiment,Antioxidant activity of immune enzyme in 10% fish meal group showed that the lysozyme activity was significantly increased when the amount of proteolytic soybean meal reached 4.5% or more(P<0.05),and the T-SOD activity showed that the control group A(0)% PSM)was the lowest(P<0.05),and the malondialdehyde content was the highest in group A(0% PSM),the lowest in group 4.5%(P<0.05),5% in fish meal group,lysozyme and T-SOD.The activity showed that the control group a(0% PSM)was the lowest and significantly lower than the other groups(P<0.05).When the dosage was 6.5%,the malondialdehyde content was significantly lower than that of the control group(P<0.05).In the stress test of artificially infected high-dose Vibrio Parahaemolyticus,the cumulative mortality of group A(0% PSM)shrimp in the 10% fishmeal group at 48 h and 60 h was significantly higher than that in group D.(4.5% PSM)cumulative mortality of shrimp(P<0.05),cumulative mortality of group d(5.5% PSM)in 5% fishmeal group was significantly higher than that of group c(4.5% PSM)(P<0.05)),but the difference with group a(0% PSM)was not significant(P>0.05).At 72 hours of infection,the cumulative mortality of group e(6.5% PSM)was significantly lower than that of group a(0% PSM).P < 0.05).After artificial acute infection of Vibrio Parahaemolyticus,the expression levels of Toll receptor,IMD and lysozyme were detected in the tissue of the shrimp,and the results of the 10% fishmeal group showed that the shrimp Toll receptor The maximum peak of mRNA expression appeared in group C(3.5% PSM),and the peak appeared at 24 hours after infection.Group B(2.5% PSM)and E group(5.5% PSM)peaked at 12 h after infection,and group D(4.5% PSM)and group A(0% PSM)peaked at 36 h and 42 h,respectively.Peaks of group B(2.5% PSM),group C(3.5% PSM),and group E(5.5% PSM)were greater than group A(0% PSM).The maximum peak of IMD mRNA expression in shrimp was in group B(2.5% PSM),and the peak appeared in 42 h after infection.Group A(0% PSM),Group D(4.5% PSM),and Group E(5.5% PSM)peaked at 24 h after infection,and group C(3.5% PSM)peaked at 42 h after infection.The peak of the test group in which the proteolytic soybean meal was added to the feed was larger than that in the test group which was not added.The maximum peak value of lysozyme mRNA expression in shrimp was in group D(4.5% PSM),and the peak appeared in 24 hours after infection.Group A(0% PSM),Group B(2.5% PSM),Group C(3.5% PSM),and Group E(5.5% PSM)peaked at 6h,36 h,42h,and 24 h,respectively.The peaks of group D(4.5% PSM)and group E(5.5% PSM)were greater than group A(0% PSM).The results of the 5% fishmeal group showed that the maximum peak of Toll receptor mRNA expression in the shrimp group appeared in the e group(6.5% PSM),and the peak appeared at 18 h after infection.Group a(0% PSM)and group c(4.5% PSM)peaked at 30 h of infection,and group b(3.5% PSM)and group d(5.5% PSM)peaked at 36 h and 18 h,respectively.The peak of the test group in which the proteolytic soybean meal was added to the feed was larger than that in the test group which was not added.The maximum peak of IMD mRNA expression in shrimp was observed in group e(6.5% PSM),and the peak appeared at 18 hours after infection.Groups a(0% PSM)and b(3.5% PSM)peaked at 6 h and 42 h,respectively,and c(4.5% PSM)and d(5.5% PSM)peaked at 18 h of infection.The peak of the test group in which the proteolytic soybean meal was added to the feed was larger than that in the test group which was not added.The maximum peak of lysozyme mRNA expression in shrimp was observed in group c(4.5% PSM),and the peak appeared at 42 hours after infection.Group a(0% PSM)and group e(6.5% PSM)peaked at 42 h of infection,and group b(3.5% PSM)and group d(5.5% PSM)peaked at 12 h and 30 h,respectively.The peak of the test group in which the proteolytic soybean meal was added to the feed was larger than that in the test group which was not added.The above results showed that the proteolytic soybean meal with less than 5.5% in the feed containing 10% fish meal had no significant effect on the growth performance of L.vannamei,and the proteolytic soybean meal in the feed containing 5% fish meal reached 4.5% or more.The growth performance of L.vannamei has a significant effect.Adding proper amount of proteolytic soybean meal will increase the serum lysozyme and T-SOD activity of L.vannamei and reduce the serum malondialdehyde content of L.vannamei.Under the experimental conditions,the addition of enzymatic hydrolyzed soybean meal significantly changed the arc of L.vannamei.The resistance of bacteria and the spatiotemporal expression of immune-related genes.The use of 4.5% and 5.5% of proteolytic soybean meal in feeds containing 10% fishmeal and 5% fishmeal,respectively,gave the cultured shrimp the best anti-vibration ability. |
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