Microbial Regulation Of Cherax Quadricarinatus' Aquaculture Water

The main problems brought by aquaculture are water pollution and disease outbreaks.The current solution is to directly change water and use chemicals such as antibiotics,but it will cause a series of environmental problems.Using bioaugmentation method to construct a water-based microbial stabilizer,study its ability to remove ammonia nitrogen,nitrate nitrogen and nitrite nitrogen and inhibit the common pathogenic bacteria,applied to Cherax quadricarinatus aquaculture system,analysis its water quality control ability and its impact on the microbial community structure of the culture environment.Two strains of Lactobacillus R1 and R2 with bacteriostatic effect,one heterotrophic nitrifying aerobic denitrifying bacteria H3 and one strain of Bacillus K4 were isolated from the river sediment.After 16 S rDNA identification,R1 is Lactobacillus chiayiensis,R2 is Lactobacillus zeae,H3 is Acinetobacter QETG_s,and K4 is Bacillus subtilis.The complex bacteria M5 was constructed by mixing in an equal amount of 1:1:1:1.In the degradation experiment of aquaculture wastewater,the removal rate of ammonia nitrogen by control group,H3,R1,R2,K4,M5 was 9.67 %,46.08 %,24.09 %,14.50 %,15.45 % and 29.20 %,respectively,the removal rates of nitrite nitrogen were 4.20 %,45.00 %,18.65 %,9.88 %,8.77 % and 33.13 %,respectively.The results showed that M5 had obvious inhibitory effect on Vibrio,Escherichia coli and Staphylococcus aureus,which R1 R2 and K4 had good inhibitory effect,while H3 had no inhibitory effect.The physiological toxicity test showed that M5 had no effect on the growth of zebrafish,which could be used in the pilot system of Cherax quadricarinatus aquacultureThe complex bacteria M5 was used in the Cherax quadricarinatus aquaculture system.The survival rate of the Cherax quadricarinatus in the experimental group was 73.80 % higher than that in the control group 58.82 %.In the experimental group,the concentration of ammonia nitrogen and COD was significantly lower than that in the control group;The removal rates of nitrite nitrogen and nitrate nitrogen were 46.46 % and 38.10 %,respectively,which were higher than the control group 24.83 % and 27.27 %.The pH of the experimental group was stable at 7.59,which was lower than the control group of 7.87,which was more suitable for microbial growth.It shows that the addition of compound bacteria M5 can not only improve the survival rate of Cherax quadricarinatus,but also stabilize the water quality in the aquaculture system.The results of the analysis on the microbial community of the system showed that the addition of M5 increased the diversity of the water community,the newly emerged Planctomycetes and Nitrospira were involved in the denitrification process,Vibrio was significantly reduced,and the abundance of Actinomycetes and Acidobacteria was increased.In the intestinal,pathogenic bacteria such as Vibrio,Chlamydia and Aeromonas veronii were significantly reduced,and the abundance of Bacteroidetes was increased.In the sediments,founded Desulfomicrobium and Thiobacillus,which can remove hydrogen sulfide,the organic removal Rhodocyclaceae and Rhodospirillaceae,the pathogens Actibacter,Mycoplasma and Rickettsiaceae are significantly reduced.With the addition of M5,the quantity of denitrifier in the system increased,the quantity of pathogenic bacteria was greatly reduced,the water quality was improved,and the survival rate of cultured species was increased,which had great application value.