The Study Of Alkalinity Regulation On The Formation Of Biolflocs And Treatment Of Aquaculture Water Efficiency

Bioflocs is mainly composed of aerobic micro-organism,and their extracellular polymeric,combined with various organic matter,inorganic matter,microalgae and zooplankton and phytoplankton in the aquaculture water,the residual,feces and other organic debris attached to the bioflocs,suspended in the flow of water.Biofloc technology（BFT）promotes residual bait,fecal absorption and transformation into bioflocs in the aquaculture system by adjusting the carbon-nitrogen ratio,mixing intensity,dissolved oxygen,temperature,alkalinity,p H and organic matters.reduce the inorganic nitrogen in water,and its conversion into its own microbial protein for feeding animals,so that the second use of fish bait,to improve feed utilization.In the biological system,inorganic nitrogen is transformed into the biomass of heterotrophic bacteria and nitrification needs alkalinity,so the need for timely adjustment alkalinity.In this paper,Studied the effects of alkalinity regulation on the formation of bioflocs,using bioflocs treatment different alkalinity recirculating water,Based on the above research,farmed animals,cost and ecological benefits were taken into account,take the best alkalinity,Studied the effects of different concentration of biolflocs regulation on the water quality and bioflocs nutrition,growth traits of Penaeus vannamei.The test content is divided into the following three parts:1.Alkalinity effect of nitrogen conversion and biological characteriztion of bioflcs on aquatic bioflocculation processAlkalonity control in non-situ mode reactor,add feces of Anguilla marmorata and solid waste cultivate bioflocs,the experiment consisted of three treatements,with three replicates each:A≥250 mg（CaCO₃）/L、B 150²00 mg（CaCO₃）/L、C 75¹00 mg（CaCO₃）/L.To evaluate the three nitrogen changes and bioflocs’ s conversion rate of nitrogen、crude protein、crude fat、extracelluar polymeric,to detect bioflocs the diversity of microbial communities by Illumina Miseq sequencing technology.The results showed that the group B,Nitrogen conversion rate（70.8±7.7）%、crude protein content（36.7±0.6）%,and the ratio of protein and polysaccharide in LB-EPS、TB-EPS、Prokaryotic and eukaryotic microbial community Shannon diversity index is better than that of group A and C（P<0.05）.The alkalinity increased to above 150 mg（CaCO₃）/L,and can promote nitrification occurs.Three groups of flocs procaryote microbes,at phyla level,dominant bacteria with significant differences were Proteobacteria and Saccharibacteria,and the percentage of Proteobacteria in group A、B、C was 45.96%、27.81%、80.07% respectively;Eucaryotic microbes dominant bacteria with significant differences were Ascomycota and Ciliophora,and the percentage of Ciliophora in group A、B、C was 7.24%、0.43%、14.85%,respectively。In conclusion,The bioflocculation precess alkalinity should be controlled in more than 150 mg（CaCO₃）/L,can increase the bioflocs microbial diversity,thereby improving the efficiency of nitrogen conversion.2.Alkalinity effected biofloc technology treating recycling aquaculture water and the structure of biofloc microbial in the sequencing batch reactorAdding feces of Anguilla marmorata and solid waste cultivate bioflocs,the content is 4000mg/L in the sequencing batch reactor,studied the influence of alkalinity on treating recycling aquaculture water and the structure of microbial biofloc,the alkalinity of the experiment was 75 mg（CaCO₃）/L,150 mg（CaCO₃）/L,250 mg（CaCO₃）/L,350 mg（CaCO₃）/L,450 mg（CaCO₃）/L and 600 mg（CaCO₃）/L。The results showed that the removal rate of ammonium nitrogen and nitrate nitrogen reached more than 90%,and the higher the alkalinity was,when the alkalinity was 350⁶00 mg（CaCO₃）/L,the removal rate was higher than 99%.After the end of the experiment,the crude protein and crude fat of the high alkalinity group were higher than those of the solid waste.Community structure of microbial biofloc under different alkalinity by the 16 S r DNA gene amplification technique of Illumina Miseq sequencing.The diversity of community structure was quite different in the seven samples,but the 600 mg（CaCO₃）/L was the highest,Proteobacteria has an absolute advantage in all samples,Pseudoxanthomonas accounted for 31.52% in the newly cultured bioflocs,which take effect in the formation of bioflocs,Zoogloea、Saccharibacteria_n orank、Bdellovibrio content of in each group of test bioflocs reaches more than 40%.3.Alkalinity-regulating effect of biolfloc technology culture of Litopenaeus vannameiIn this experiment which is under the control of alkalinity,the effects of different concentration of biolflocs regulation on the water quality and bioflocs nutrition,growth traits of Litopenaeus vannamei during the 20 day culture were studied.Providing for reference of BFT.The concentration of alkalinity was 100 mg（CaCO₃）/L,Total suspended particulates in the four groups was A: 100 mg / L,B: 150 mg / L,C: 200 mg / L,D: 250 mg / L,The results showed that physical and chemical parameters of the aquaculture water in the D treatment group were better than those in the A,B and C groups.The ammonia nitrogen and nitrite in the treatment group fluctuated greatly during the breeding period,but they were at a low level.The nitrate in water of all treatment showed increase before 14 days,then decreased and the concentration of high TSS group was lower,the highest in group A was 45.75 mg / L,and the highest in group D was 37.38 mg / L.with the time,but the high TSS treatment group had a lower concentration.There was no significant difference in the crude protein content of the bioflocs in the four groups,and the content varied from 32.4% to 42.2%,which was lower than that of the shrimp fed 49.5%.Shrimp fed and bioflocs had 17 kind of amino acids,The total amino acids in shrimp fed was 33.37 mg/100 mg,and in group D was 28.43 mg/100 mg,which was higher than that of other treatments bioflocs.The Methionine content in bioflocs is higher than that of feed shrimp.The final length and weight of shrimp,D group>C group>B group>A group,The survival rate of shrimp was significantly different（P<0.05）,group D was highest at 50.2%.