The Discovery Of MiRNA For The Disease Of Hybrid Snakehead (Channa Maculata? × Channa Argus?) And Construction Of Tilapia Microecological Non-resistant Culture System

Non-resistant breeding is a new concept of aquaculture produced under the background of aquatic product quality and safety.The aim is to reduce the use of antibiotics in aquaculture and to protect human safety.In the context of the frequent occurrence of food safety incidents and the concept of aquatic product quality and safety,it has become a development trend and research hotspot in the field of aquaculture.In this paper,the research on the development of the anti-disease microRNA(miRNA)and the micro-ecological non-resistant breeding system of the economic freshwater fish is concerned,and the quality and safety of aquatic products are concerned,so as to provide new ideas for the realization of non-resistant breeding.The thesis is divided into two parts:First part:The discovery of miRNA for the disease of hybrid snakehead(Channa maculata?×Channa argus).With hybrid Li as the research object,by examining the aquatic common pathogenic bacteria infection hybrid Li spleen miRNA expression changes before and after the screening of differentially expressed micrornas,looking for hybrid Li play an important role in the process of resistance to bacterial infection control factor,for fish immune mechanism research and development of disease-resistant germplasm resources.Experiment to choose the average weight of 30±0.75 g hybrid Li 40 tail,randomly divided into two groups,respectively,the abdominal cavity injection and four kinds of common aquatic pathogenic bacteria PBS solution(Aeromonas hydrophila,?Vibrio anguillarum?Vibrio parahaemolyticus?Streptococcosis)mixture(10~7cfu/mL)0.1 mL/stern,spleen samples after 24h.For hybrid Li spleen samples miRNA expression spectrum sequencing and bioinformatics analysis,and found that differentially expressed micrornas 828(including new predicted micrornas 23),raised 546,down 274,raised the miRNA to cut micrornas 1.99 times;The other eight sequencing Numbers were different,and the overall difference was small.The expression of mirnas in the spleen,mir-30d,mir-489,mir-216b,mir-216b and mir-103,etc.,were significantly up-regulated after the infection of four pathogenic bacteria,and the expression of mirnas in mir-196a,mir-125b,mir-15a,mir-216b and mir-205 were down-regulated.Micrornas candidate target genes of known differentially expressed the GO and KEGG enrichment analysis shows that the candidate target genes involved in infectious diseases(viruses,bacteria and parasites)target genes related to total 274,involved in the immune system and signal transduction system respectively in 112 and 103 genes,to participate in the digestive system 161 genes.The present study showed that miRNA was an important regulatory role in the immune disease process of spleen and spleen before and after infection.Second part:Construction of tilapia microecological non-resistant culture system.To explore the feasibility of the application of microecological circulation culture in the non-resistant culture through the construction of the GIFT,Oreochromis niloticus and the micro-ecological compound aquaculture system.Test is divided into control group and experimental group,each group set three repeat,choose one individual robust,posture uniform tilapia fry 360(average weight 30.7±0.37 g),randomly assigned to six sets of fish food symbiotic cultivation system,each system range 60 tail,the experimental group cultivation water convolvulus,control group is not a garden,test the entire feeding feed,test process is not to change water drainage operation,adding only due to the evaporative loss of water,breeding cycle for 42d.Test in the process of collecting water samples,tilapia,and water spinach samples,every week for aquaculture water quality index,tilapia fish growth performance,body composition,oxidation resistance and ACP and AKP,determination of water spinach growth performance,no resistance breeding system of comprehensive evaluation of the ecological effect in practical application.The results show that:1.The micro-ecological aquaculture system can purify the water body,and the content of ammonia nitrogen,nitrite and phosphate in the water is decreasing first and then the water quality is obvious.2.The breeding system is conducive to the cultivation of tilapia,and the survival rate of tilapia in the experimental group is above 96%,while the control group has a large number of deaths due to the second week of water quality.The production systems to improve tilapia antioxidant and immune capacity,including tilapia SOD in serum and liver,T-AOC,ACP and AKP as time increases with the increased significantly,serum MDA content gradually reduced.3.In the breeding system,the water cabbage branches are strong,the leaves are flourishing,the survival rate is as high as 98.35%,the average weight of the single plant is 77.14g,and the growth condition is good,which is conducive to the cultivation of water spinach.