Applied Research Of Probiotics In Pond Culture

80:20polyculture pond is considered as a promising modern aquaculture technology because of the advantages in the sustainability, safety, environment protecting and water-saving. And veterinary drugs and chemicals are prohibited to use in this aquaculture to make sure that the fishes are no pollution and safety to eat. But the intensive and high-density aquaculture can cause ecological damage, so the chances to get cross infection of pathogens between aquatic animal are increased. Using drugs to control the occurrence of disease goes against the original intention. And because of the extensive using of antibiotics, bacterial resistance is increased, microbial flora of the aquaculture environment is destroyed and interfered, the antibiotics residue and enrich in fishes eventually lead to the body harm. There are many characteristics of probiotics, such as environmentally friendly, nontoxic, no side effects, without residual contaminants, no drug resistance, low cost, efficient, safe and reliable. Ecological environment of aquaculture and animal immunity are effectively improved and diseases are reduced by using probiotics. The aim of the research is to clear the using method and effect of probiotics in80:20polyculture pond, to explore the mechanism of them, to explore and demonstrate the use of the pollution-free and healthy mode by using them. Finally, providing theoretical support and reference to theory of probiotics and the green Cyprinus carpio breeding mode. Probiotics were used in treatment group1and treatment group2, and the forage fed to group2were mixed with probiotics, group3planed as a control group. The results are:1. Application of probiotics in80:20polyculture pond and economic benefit analysisThe pH value in group1, group2and the control group is between6.8～8.2. Ammonia nitrogen in group1and group2is lower than the control group. There is no significant difference in nitrites among the three groups.24h water quality testing was carried out the third day after probiotics were used in pond. And the DO in group1and group2is higher than the control group. Weight gain rate, multiples of weight gain and growth rate of group2are the highest, group1is lower, the control group is the lowest. Feed conversion ratio and breakeven point of the control group are higher than group1, and group2is the lowest. Output input ratio of ponds from high to low is group2, group1and the control group.2. The influence of probiotics to the health status, digestive enzymes and intestinal flora (1) Relative fatness and visceral index of group2are the highest. Group1is lower than group2. The control group is the lowest. But there is no significant differences between the three groups (P>0.05). Spleen index of group2is slightly higher than the group1and the control group. Hepatopancreas index of group1and group2is slightly higher than the control group (P>0.05).(2) Water, crude fat and ash content in muscle do not have significantly differences between the three groups (P<0.05). Crude fat of the hepatopancreas is significantly lower in group1and group2when compared to the control group (P<0.05). Crude protein of the hepatopancreas in group1is significantly lower than that in group2and the control group (P<0.05). And crude protein of the hepatopancreas in group2is lower than that in the control group, but there is no significantly differences (P>0.05).(3) ALT of group1and group2is lower than the control group, and there is a significantly difference between group1and the control group (P<0.05). TP of group1and group2is higher than the control group, TP of group1is significantly higher than the control group (P<0.05). There is no significantly difference on AST, ALB, GLO, GLU, CHOL, TG of the three groups (P<0.05).(4) Amylase and lipase of group1and group2is significantly higher than the control group (P<0.05). Alkaline protease of group2is significantly higher than the control group (P<0.05). No significantly differences are found between acid protease of the three groups (P>0.05).(5) There are14amplified bands in group1,16bands in group2,11bands in the control group. It is found that similarity of the structure of intestinal microflora between group1and group2is0.62by cluster analysis. And it is0.57between control group and treatment groups. Thirteen sequences of16SrDNA V3area separated by DGGE belongs to Bacilli, Gammaproteobacteria, Spirochaetes, Fusobacteria, Betaproteobacteria. The7th,8th and11th band of group1and group2belongs to Gammaproteobacteria, Bacilli, Fusobacteria, relatively. Band11is uncultured bacteria and significantly abundance than the control group. Band4and band18are unique in group2. They are both uncultured bacteria and belong to Betaproteobacteria and Bacilli.Conclusion:(1) The quality of pond is improved by using probiotics.(2) Activities of digestive enzymes in intestinal of Cyprinus carpio are enhanced, structure of intestinal microflora is ameliorated by using probiotics. And Feed conversion ratio is reduced, growth performance is improved, the health of the Cyprinus carpio is promoted.(3) Feed costs are reduced, output input ratio is increased, breakeven point is decreased by using probiotics. And then economic benefits and ability to resist market risks are improved.(4) Probiotics have a positive effect under80:20pond fish culture.