Effects Of Rhizobium Larrymoorei On Growth,Non-specific Immune Factors And Water Environment Of Litopenaeus Vannamei

Recently,industrial farming of lilopemaeus vannamei has developed rapidly,which not only avoids the extreme weather(typhoon,cold wave)but also extends the breeding period.As a result,the breeding efficiency of shrimp out of season improves.However,disadvantages exist.Disease outbreaks(vibrio and virus)tend to bring about heavy lose in the high-density breeding.Also excessive ammonia nitrogen and nitrite which is common after a short period of time.Since the society has realized the drawbacks of antibiotic medicine,the microorganism preparation boomed.In this study,Rhizobium larrymoorei strain screened in the laboratory was added to the feed of lilopemaeus vannamei.The changes in growth performance,immune-related enzymes,vibrio in water and water quality indexes of lilopemaeus vannamei were measured.Effects of Rhizobium on Growth Performance,Immune-related Enzymes and Digestive Enzymes of Lilopemaeus vannamei.The results showed that the growth index and the serum activity of the experimental group was higher than that of the control group and the activities of phenol oxidase(PO),superoxide dismutase(SOD),peroxidase(POD)and alkaline phosphatase(AKP)were significantly enhanced.The hepatopancreas activity of the experimental group was higher than that of the control group.Rhizobium is added in the feed to the shore,shrimp hepatopancreas of amylase and hepatopancreas protease activity there was no significant difference,and for all who achieved liver pancreas lipase activity influence significantly(P < 0.05).It can be seen that the addition of rhizobium into the feed can promote the growth of Lilopemaeus vannamei,promote the digestion and absorption of fat,reduce the feed coefficient,improve the activity of non-specific immune-related enzymes,and enhance its disease resistance.Through the rhizobium experiment with different gradients in the feed,the optimal dose of rhizobium in the feed was finally determined to be 2 ml kg-1.Changes of Vibrio in Industrial Aquaculture Water by Adding Rhizobium to Feed and Test Results of Anti-Vibrio.The results showed that the effect on total vibrio and green vibrio in the test group was significantly higher than that in the control group(P < 0.05),while the effect on yellow vibrio was not significantly different,which showed that rhizobium could inhibit the proliferation of green vibrio.The cumulative death rate after vibrio parahaemolyticus infection showed that the ability of the experimental group to resist vibrio parahaemolyticus infection was significantly better than that of the control group(P < 0.05),further proving that the addition of rhizobium into the feed was conducive to enhancing the health of prawn and disease resistance.Effect of Rhizobium on Water Quality Indicators and Test Results of High Nitrogen Resistance in Feed.The results showed that the rising trend of ammonia nitrogen,nitrite and nitrate in the test group in the middle and late period is significantly lower than that in the control group(P < 0.05),and the change of p H value and total nitrogen is not significant compared with the control group.Between groups of water quality fluctuation of index are of the rising trend,but the control group in the range of the ammonia nitrogen,nitrite and nitrate rise significantly higher than experimental group(P < 0.05),especially in the breeding of later period,explain rhizobia is added to the feed can delay the rising velocity of water,ammonia nitrogen and nitrite.By adding rhizobium into the feed,not only can the specific growth rate of Lilopemaeus vannamei be improved,but also the body immunity and disease resistance be enhanced,the content of vibrio in the aquaculture pond be reduced,and the increase of ammonia nitrogen and nitrite in the middle and later period of aquaculture be delayed.The vibrio resistant and high ammonia nitrogen resistant experiments further demonstrated that the addition of rhizobium in the feed could enhance the body immunity and disease resistance of prawn.The addition of rhizobium into feed has the advantages of saving drug cost and high product utilization rate.