| The current worldwide growth rate of the aquaculture business (8.9–9.1% per year since the 1970s) is needed in order to copewith the problem of shortage in protein food supplies, which is particularly situated in the developing countries. According to Food Agriculture Organization, aquaculture production increased more than 40 times during the last 50 years and is expected to rise another 5 times in the coming 50 years. With the rapid expansion and intensi?cation, there is, however, also a growing concern about the ecological sustainability of shrimp culture. Environmental and economical limitations can hamper this growth. Especially intensive aquaculture coincides with the pollution of the culture water by an excess of organic materials and nutrients that are likely to cause acute toxic effects and long term environmental risks. For long, the most common method for dealing with this pollution has been the use of continuous replacement of the pond water with external fresh water. However, the water volume needed for even small to medium aquaculture systems can reach up to several hundreds of cubic meters per day. For instance, penaeid shrimp require about 20m3 fresh water per kg shrimp produced. For a medium-sized trout raceway systemof 140m3, even a daily replacement of 100 times the water volume is applied. A second approach is the removal of the major part of the pollutants in the water as is performed in recirculating aquaculture systems (RAS) with different kinds of biologically based water treatment systems. The amount of water that needs to be replaced on a daily basis generally is reduced to about 10% of the total water volume. However, this technique is costly in terms of capital investment. Operation of RAS furthermore increases energy and labour costs, so that taking all costs into consideration (investment plus operation costs) it can be estimated that unsustainable pond production can be performed at two thirds of the costs of RAS.A relatively new alternative to previous approaches is the bio-?ocs technology (BFT) aquaculture. In these systems, a co-culture of heterotrophic bacteria and algae is grown in ?ocs under controlled conditions within the culture pond. The system is based on the knowledge of conventional domestic wastewater treatment systems and is applied in aquaculture environments. Microbial biomass is grown on ?sh excreta resulting in a removal of these unwanted components from the water. The major driving force is the intensive growth of heterotrophic bacteria. They consume organic carbon; 1.0 g of carbohydrate-C yields about 0.4 g of bacterial cell dry weight-C; and depending on the bacterial C/N-ratio thereby immobilize mineral nitrogen. As such, Avnimelech calculated a carbohydrate need of 20 g to immobilize 1.0 g of N, based on a microbial C/N-ratio of 4 and a 50% C in dry carbohydrate. In integrated aquaculture systems using bacteria as additional nutrient trapping stage, the increase in retention by the use of bacteria is rather small. Schneider et al. stated that hardly 7% of the feed nitrogen and 6% of the feed phosphorus were retained by conversion in microbial biomass. However, when carbon and nitrogen are well balanced in the water solution and microbial assimilation of the ammonium is ef?ciently engineered, a complete retention can be obtained.This paper firstly used agricultural by-products (straw, wheat bran, soybean meal, peanut meal, corn powder) to ferment Bacillus firmus, and the fermentation standard of proteomics for bioflocs aquaculture was established: Add 1.8% straw, 4%wheat bran and 0.6% peanut meal together in a vessel, control the initial pH 5.4-7.2, temperature 30-40℃, liquid filling rate of 50% of 37~ (-1)02h fermentation, then fermentation fluid can achieve the best results.On this basis, the carbon source and fermentation liquid was added in the sea water aquaculture system, then the bioflocs formation, growth and survival of the aquaculture animals and water quality parameters were observed, finally the bioflocs technology of different seawater aquaculture animals were established. According to carbon addition, the optimal bioflocs technology of Litopenaeus vannamei was estabilished: Sugar was added to the aquculture system of Litopenaeus vannamei with C/N=20 at the density of 150 PL/m2 without water exchanging. In this system, bio-floc was formed on the 4th day, the content of ammonia nitrogen and nitrite was kept below 0.1 mg/L and 0.3mg/L, respectively, the growth rate was reached to 1mm/d, the survival rate was more than 80%. The production of L. vannamei was reach to(2.14±0.08)kg/m2 after 98-day cultivation by the bioflocs technology. According to fermentation fluid addition, the optimal bioflocs technology of Apostichopus japonicus was established: Fermentation fluid was added to the aquculture system of Apostichopus japonicus with 100ppm everyday without water exchanging. In this system, bio-floc was formed on the 11th day, the content of ammonia nitrogen a was kept below 0.1 mg/L, the growth rate was higher, and the survival rate was reached for 68.7%. According to carbon and fermentation fluid addition, the optimal bioflocs technology of Marsupenaeus japonicus was established: Sugar was added to the aquculture system of Marsupenaeus japonicu with C/N=60 at the density of 200 PL/m2 without water exchanging. In this system, bio-floc was formed on the 4th day, the content of ammonia nitrogen and nitrite was kept below 0.1 mg/L and 0.1mg/L, respectively, the growth rate was higher and the survival rate was more than 75%.Finally, the optimal bioflocs technology of Marsupenaeus japonicus was applied to the high-intensive, zero exchange aquaculture system of Marsupenaeus japonicus, the concentrations of ammonia-N and nitrite-N were both reduced, moreover, the feed conversion ratio and protein efficiency ratio were both increased up to 167% and 142%, shrimp growth was significantly increased and shrimp survival rate was increased to 65.7%, and ultimately the net yield was reach for 1.3kg/m2. By comparing the microbial diversity of bioflocs in traditional control and bioflocs treatment, the breeding of Vibrio sp. and Pseudoalteromonas sp. were probably inhabited by Bacillus sp. On the basis of this result, microbial diversity of different functional bioflocs was determined. The results were shown that the predominant microbe of bioflocs in the function of water control may include Desulfobulbus japonicus andα-Proteobacterium; the predominant microbe of bioflocs in the function of shrimp growth may include Roseobacter sp. and Proteobacterium; the predominant microbe of bioflocs in the function of disease control may include Proteobacterium, Photobacterium, Bacteroidetes bacterium and Bacillus subtilis.In conclusion, the application of bioflocs technology in high-intensive M. japonicus culture systems performed equally well as observed in other shrimp species. Bioflocs technology offers the possibility to simultaneously maintain a good water quality within aquaculture systems and produce additional food for shrimp. However, the optimal bioflocs technology of different aquaculture animals was different, probably due to the different living habits. In addition, the different function of bioflocs technology in seawater aquaculture system may be resulted from the microbial diversity of bioflocs.
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