Study On The Culture Effect Of The Marbled Eel Based On Biofloc Technology

At present,the research on biofloc is mainly environmental factors,carbon source,the impact on the culturing of objects,etc.,among which C / N has been studied in the field of biofloc technology.Different carbon sources and C / N have different effects on biofloc technology,which puts forward higher requirements for the stability and controllability of biofloc technology system.The main research objects of biofloc technology is the filter aquatic animals.As an eutrophic fish with high nutritional value and high economic value,the marbled eel has high research significance.In order to solve this problem,this paper proposed the application of biofloc technology in the culture of the marbled eel,studied the effect of zero carbon source on the culture of marbled eel,and the effect of biofloc technology on the feeding of the marbledeel Impact.The test content is divided into the following three parts:1.The effect of biofloc technology on the culture of the marbled eelThe effects of biofloc technology on the growth performance,body composition,digestive enzymes and blood parameters of marbledeel were studied.The test period was 60 days.In this experiment,the recirculating aquaculture model was set as the control group and the biofloc technology model was taken as the treatment.Each set has three parallel cylinders.The culture density per cylinder is 10 kg/m3.The initial weight of the marbled eel was 393.59 ± 11.83 g.The results showed that the contents of total nitrogen(TAN),nitrite(NO2--N)and NO3--N in the treatment were significantly higher than those in the control group,1.12 ± 0.2 mg / L,0.16 ± 0.05 mg / L and 228.44 ± 28.48 mg / L,respectively,in which nitrate nitrogen continued to increase during the experiment.There was no significant difference in the final density(FD),weight gain rate(WGR),specific growth rate(SCR)and feed coefficient tate(FCR)between the treatment and the control group at the end of the experiment(P> 0.05).The superoxide dismutase(T-SOD)of the liver of the treatment on the 60 th day was significantly higher than that on the 30 th day,which was not significantly different from the control group.The levels of serum alkaline phosphatase(ALP),alanine aminotransferase(ALT),triglyceride(TG),blood glucose(GLU)and total protein(TP)in the treatment were not significantly different from those in the control group.During the experiment,the pepsin was decreased in the treatment and the control group,and the control group decreased significantly.There was no significant difference in intestinal protease activity between the treatment and the control group2.Effects of adding biological flocs in the feed on the culture of the marbled eelThe effects of biofloc technology on the growth performance,body composition,digestive enzymes and blood parameters of eel were studied.The test period is 60 days.The test group was divided into the compound feed group(control group)and the biological floc mixed feed group(experimental group).Each set has three parallel cylinders.The initial density of each cylinder is 12.03 ± 0.23 kg / m3.The initial weight of the eel is 400.96 ± 6.84 g.The results showed that the weight of the marbled eel was significantly lower than that of the control group(P <0.05).At the beginning of the experiment,the weight gain rate of the treatment was 2.19 ± 1.06%,which was lower than that of the control group(P <0.05)(P> 0.005).There was no significant difference between the treatment and the control group,and the intestinal protease was 1723.51 ± 255.35 U / gprot,which was significantly lower than that of the control group(P <0.05),and there was no significant difference between the treatment and the control group.The content of ash in the treatment was 1.06 ± 0.03%,and the crude fat was 17.63 ± 1.17%,which was significantly higher than that of the control group.3.Study on Water Treatment Effect of Biofilter and Circulating Water CultureSystem under Different C / N ConditionsThe effects of different flocculation free flora and flocculation flora under different C / N conditions were studied,and the water treatment effect of free flora and filter flora of circulating water culture system was studied.The results showed that when the C / N was 8,12 and 16,the ammonia flocculation of the flocculant free flora and the flocculant were effectively removed within 12 h,and the ammonia nitrogen of the free bacteria group gradually increased after 12 h,When the C / N was 0,4,the maximum removal rate of ammonia nitrogen in the free bacteria group was 37.75±7.10%、53.07±2.35% respectively.During the experiment,the ammonia nitrogen of the flax was gradually decreased.When the C / N was the same,The removal rate of ammonia nitrogen was significantly higher than that of free bacteria.