Study On The Ecological Breeding Technology Of The National Variety Litopenaeus Vannamei "Gui Hai 1"

The ecological breeding technique of Litopenaeus vannamei refers to the selection of natural bio-bait for prawns on the bait.The bio-physical methods such as microbial regulation and physical adsorption are used in the water treatment.The compound Chinese herbal preparations are used for disease prevention and control at each stage of the nursery.High-health ecological seedlings with uniform specifications,high vigor,high anti-stress,no specific pathogens,and no antibiotics are grown without any antibiotics.Single-cell algae is the core of ecological breeding.The specific species of unicellular algae is not only a suitable open bait for shrimp larvae,but also can purify water quality and maintain a benign breeding ecological environment.However,there are few papers on ecological breeding technology at present.In this paper,the growth of Chaetoceros muelleri and the ecological nursery technology of Litopenaeus vannamei were studied:?1?To explore the effects of inoculation density,environmental factors and nutritional factors on the growth of Chaetomium murense;?2?To explore the effects of environmental factors and diets on ecological breeding of Litopenaeus vannamei"Gui Hai 1";?3?To develop and establish the technical specification for high health ecological nursery of Litopenaeus vannamei"Gui Hai 1".1.The effects of salinity,temperature and light on the growth of Salmonella Merinos were studied by single factor method.Different environmental factors had significant effects on the growth of Chaetoceros muelleri.?P<0.05?.Chaetoceros muelleri could grow under 5?40‰salinity.The medium salinity group?20-30‰?was the optimum growth condition.The low salinity group?5‰,10‰?was better than the high salinity group?35,40‰?.Under the condition of 0‰,the algae cells gradually increased after environmental adaptation.The maximum cell concentration of Chaetomium moussuriensis was reached at 31?.The lower the temperature,the slower the growth rate,the longer the stable period.The higher the temperature,the faster the growth rate and the shorter the stable period.4000Lx is the most suitable light intensity for the growth of Chaetoceros muelleri.The higher the light intensity,the longer the stability period.The optimum growth conditions were salinity 20‰,temperature 31?,light intensity 4000Lx,in which the growth rate and algal cell density were the highest.Excessive or low salinity,temperature and light could inhibit the growth of Chaetoceros muelleri.2.Effects of inoculation density and five nutrient salts such as nitrogen source etc.on the growth of Chaetoceros muelleri were studied by single variable method.Inoculation density and five nutrient salts had significant effects on the growth of Chaetoceros Mueller.?P<0.05?,and the best inoculation density was 0.7×10⁶cell/mL;and suitable nitrogen sources were NaNO₃>CO?NH₂?₂>NH₄HCO₃,yet CO?NH₂?₂ and NH₄HCO₃ had significant inhibitory effects on the growth of Chaetoceros muelleri at high concentrations?>75mg/L?;and the suitable phosphorus source is KH₂PO_4,its optimum concentration was 2.5mg/L;and the organic carbon source(C₆H₁₂O₆)had a better growth promoting effect than the inorganic carbon source?NaHCO₃?,and its optimum concentration was 20mg/L;and the optimum concentration of the silicon source?Na₂SiO₃?was 30mg/L;and the combination of vitamin B₁ and B₁₂ was significantly better than the separate addition?P<0.05?.The inoculation density and the five nutrients obtained by screening could significantly promote the growth of Chaetoceros muelleri at the appropriate concentration,thereby increasing the yield and stability of large-scale culture.But high concentration has obvious inhibitory effect on the growth rate and algal cell concentration of Chaetoceros muelleri.3.The effects of temperature,salinity,density and diet on survival rate and metamorphosis time of Litopenaeus vannamei seedlings were studied by single factor variable method,and the optimal environmental conditions and diet combination for Litopenaeus vannamei seedlings were explored.The results showed that temperature,salinity,density and diet had significant effects on the survival rate of Litopenaeus vannamei under the ecological nursery mode,and temperature and density had significant effects on the metamorphosis time of Litopenaeus vannamei,while salinity and diet had no significant effects on the metamorphosis time of Litopenaeus vannamei.The optimum temperature,salinity and density of ecological seedling were 28-30?,30‰and 100tails/L,respectively.In the bait experiment,the emergence rate of CM+SC was the highest,and that of SP+FD group was the lowest.The effect of CM seedling was significantly better than that of SC,and the effect of adding SC was obviously better than that of adding SP.Under the ecological seedling cultivation mode,the survival rate can be significantly increased by controlling temperature 28-30?,salinity 30‰,density 100tails/L.The results showed that Chaetoceros muelleri could be used as the best opening bait.Adding Chaetoceros muelleri could significantly improve the survival rate of Litopenaeus vannamei,and the effect is more significant with the Skeletonema costatum,and the emergence rate was better than using artificial diet.