Simple Fermentation Of Functional Probiotics And The Application Of Probiotics In Litopenaeus Vannamei Biofloc Culture System

Shrimp aquaculture, as one of the main components of the aquaculture industry, had produced enormous economic benefits and social benefits. But the sustainable development of the shrimp farming industry had been affected and restricted by the discharge of the waste and the frequent occurrence of diseases and so on. Biofloc technology by taking to breed pool add sugar, molasses and other carbon source to promote heterotrophic microbial growth and reproduction to control the water pollution of bio floc technology, showed great prospects for development in shrimp.In this article,the biological flocculation technology was explored from the following contents.1. The study on the simple fermentation of a functional probiotics and the application in prawn bio-floc breedingThe simple fermentation used a strain of Bacillus megaterium with the activity of denitrification. And we used prawn feed and brown sugar as the medium.It was showed that the best ratio of medium was prawn feed 3 g/L,brown sugar 6 g/L and inoculation volume 1×108 CFU·m L-1 through the orthogonal experiment.And the other conditions were optimized by single experiment.We got the fermentation products with the viable cell number was 1.16×1010CFU·m L-1 that fermented with 31 ℃,40%liquid volume and 24 hours.Then we fed the Penaeus vannamei through the bio-floc technology by using the fermentation products.The result showed that the volume of biofloc was formed more quickly in bacterium group(added bacillus and sugar) than sucrose group(just added sugar)and control group(traditional culture pattern)(P<0.05), and the concentration of nitrite-N in bacterium group was much lower than the other groups(P<0.05).At the end of the culture, the highest of the average body length and weight in prawns was bacterium group,and sucrose group and control group were significantly lower(P < 0.05).This study established a simple and feasible method for thefermentation of probiotic bacteria.And the results showed the effectiveness of the bio-floc technology in prawn culture is verified by the additiong of probiotics.2. Influence of functional probiotic on the culture of Litopenaeus vannamei and the structure of bacteriaUsed of simple fermentation conditions of functional probiotic,it was optimizated and fit to culturing farm,to ferment Debaryomyces nepalensis、Pichia kudriavzevii and Bacillus megaterium. Then got the culture broth that can adpot to strengthen bio-floc(NO.). Cultural of Litopenaeus vannamei by use bio-floc and comparison of each group of stracture of Bacterial Community in water, the groups including single-bacteria group, compound group bacteria and carbon source group. The result showed that :the complex probiotic had many benefits, firstly it was beneficial to control cultural-water and could significantly increased survival and growth rate of shrimp; secondly the complex probiotic could change stracture of Bacterial Community and increase the proportion of bacterial that could improve water;finally it could decrease rate of vibrio in water.3. Application of biofloc technology to strengthen the function of probiotics in Litopenaeus vannamei in factory productionUsing of Debaryomyces nepalensis,Pichia kudriavzevii,Bacillus firmus and Bacillus megaterium Under farm conditions, using the optimized simple fermentation conditions for a certain scale fermentation, getting enough can be for Litopenaeus vannamei shrimp bio flocculation group farming production of fermentation broth. Used 4 strains of fermentation broth of bio floc technology compound probiotic enhanced, and was applied in Litopenaeus vannamei factory production. By comparing only added carbon source floc delegations and added complex probiotics can effectively control water ammonia nitrogen content, and remained at a low level in the breeding process. After strengthened the complex probiotics, the average weight of shrimp, survival rate, growth rate, per unit of output than the traditional flocculation delegations were increased by 24.8%, 4.0%, 25.5% and 31.0%. After 55 D breeding of Litopenaeus vannamei per unit area yield enhanced floc group can reach 1.66 kg/ square meters. It is shown by experiments in the scale of production, by adding compound probiotics on bio floc were strengthened to effectively improve the effect of bio floc technology inLitopenaeus vannamei aquaculture plant.