| The yield of pond aquaculture was accounted for about45%of aquaculture production inChina, in which Litopenaeus vannamei and Ctenopharyngodon idellus were dominant species.Our research group has created the biofilm low-carbon aquaculture techniques in pond based onthe invention of the biofilm purification water bar, as the efficient biofilm carrier for pondculture. And the demonstration applications of the techniques for Litopenaeus vannamei culturein three kinds of ponds including freshwater, brackish water and sea water pond and for therearing of Ctenopharyngodon idellus fry in freshwater pond were carried out in this study toresearch the effects on pond water quality improvement and yields increasement. The mainresults were as follows:1. The effects on the application of the biofilm low-carbon aquaculture techniques forLitopenaeus vannamei in three kinds of ponds.The physical and chemical parameters of water quality: In the freshwater pond, theconcentration of total ammonia nitrogen in the treatment was significant lower than the controlby57.1%(P<0.05), and the concentrations of total nitrogen and nitrite nitrogen were verysignificant lower than the control by34.2%and77.7%respectively (P<0.01). In brackish waterpond, the concentrations of total nitrogen and nitrite nitrogen in the treatment were significantlower than the control by34.8%and32.6%respectively (P<0.05), and the concentration of totalammonia nitrogen was very significant lower than the control by67.1%(P<0.01). In seawaterpond, the concentrations of total nitrogen, nitrite nitrogen and total ammonia nitrogen in thetreatment were significant lower than the control by20.0%,58.5%and53.7%respectively(P<0.05). In freshwater and seawater pond, the concentrations of total phosphorus in thetreatment were significant lower than the control by42.3%and40.6%respectively (P<0.05), andvery significant lower than the control by38.9%(P<0.01) in the brackish water pond. In theseawater pond, the concentration of soluble reactive phosphorus in the treatment was significantlower than the control by45.2%(P<0.05), and very significant lower than the control by48.8%and44.8%respectively (P<0.01) in the freshwater and brackish water ponds. In freshwater,brackish water and seawater ponds, the concentrations of chemical oxygen demand and totalalkalinity were no significant difference between the treatment and the control (P>0.05). Biological parameters of water quality: The total bacteria in the treatment was significanthigher than the control by56.7%(P<0.05) in seawater pond, and very significant higher than thecontrol by134.7%and177.2%respectively (P<0.01) in freshwater and brackish water ponds.The quantitys of heterotrophic bacteria in the treatment were significant higher than the controlby78.8%and83.1%respectively (P<0.01) in freshwater and seawater ponds, and verysignificant higher than the control by285.8%(P<0.01) in brackish water pond. The quantity ofvibrio in the treatment was significant lower than the control by96.8%(P<0.05) in seawaterpond, and very significant lower than the control by64.1%and78.5%respectively (P<0.01) infreshwater and brackish water ponds. In the three kinds of ponds, the quantity of vibrio in thetreatment was less than100CFU/mL. The algae density in the treatment was significant lowerthan the control by65.3%(P<0.05) in brackish water pond, and very significant lower than thecontrol by76.9%and58.3%respectively (P<0.01) in freshwater and seawater ponds. Infreshwater, brackish and seawater ponds, blue algae relative density in the treatment weresignificant lower than the control by35.4%,45.5%and55.3%respectively (P<0.01). The diatomrelative density in the treatment was significant higher than the control by74.6%(P<0.05) infreshwater pond, and very significant higher than the control by61.1%and92.7%respectively(P<0.01) in brackish and seawater ponds. In three kinds of ponds cultrue for shramp, the algae intreatment were mainly composed of diatoms, green algae and blue algae, and the first and seconddominant species in control were blue algae. In the same time, the third dominant species wasdiatoms in fresh water pond, blue algae in brackish water pond, and green algae in seawaterpond.The microbial in the biofilm: The total bacteria and the quantity of heterotrophic bacteriacan reach109CFU/g in the biofilm, which were105times more than the quantity of totalbacteria in pond water. However, the quantity of vibrio was always0.Production results: In the brackish water pond, shrimp survival rate, harvest size and yieldin the treatment were very significant higher than the control by62.5%,53.9%and150.0%respectively (P<0.01), and feed conversion rate was very significant lower than the control by26.8%(P<0.01). In freshwater and seawater ponds, shrimp survival rate in the treatment wassignificant higher than the control by56.9%and24.8%respectively (P<0.05), the harvest sizewas higher than the control by7.07%and14.2%respectively (P<0.05), the yield was higher thanthe control by68.0%and45.2%respectively (P<0.05), and the feed conversion rate wassignificant lower than the control by16.9%and13.7%respectively (P<0.05).2. The effects on the application of the biofilm low-carbon aquaculture techniques forCtenopharyngodon idellus fry culture in freshwater pond. The concentrations of total ammonia nitrogen, total phosphorus, soluble reactivephosphorus and sulfide in the treatment were significant lower than the control by25.6%,41.6%,37.8%and27.9%respectively (P<0.05); pH and the concentrations of total nitrogen and nitritenitrogen were very significant lower than the control by3.7%,31.3%and38.7%respectively(P<0.01).In the treatment, the total bacteria and the quantity of heterotrophic bacteria were significanthigher than the control by50.8%and33.6%respectively (P<0.05), and the quantity of vibriowas very significant lower than the control by63.1%(P<0.01).In the treatment, blue algae relative density was significant lower than the control by16.6%(P<0.05), the algae density was very significant lower than the control by51.3%(P<0.01), andthe diatom relative density was very significant lower than the control by93.7%(P<0.01), whilethe algae biological diversity index and the algae species evenness index were no significantdifference between the treatment and the control (P>0.05).In the treatment the main dominant species of algae included green algae, green algae anddiatoms, which as good algal phase, while in the control included green algae, blue algae, andgreen algae, which as bad algal phase.Production results: In the treatment, survival rate was significant higher than the control by4.3%(P<0.05) and feed conversion rate was very significant lower than the control by15.6%(P<0.01).In conclusion, biofilm low-carbon aquaculture techniques whether applied in the freshwaterpond, brackish water pond, or seawater pond for Litopenaeus vannamei culture or in thefreshwater pond for Ctenopharyngodon idellus culture, had good effects on water qualityimprovement, diseases control, algal phase improvement, production increasement, feedconversion rate reduction and profit increasement. Therefore, there are wide prospect forextension of the techniques. |
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