| As one of the highest yield of shrimps all over the word, Penaeus vannamei is attracting more and more attentions from people. In our country the breeding scale of Penaeus vannamei is also expanded with the developing aquatic product market. However, we still need pay more efforts to improve our products' harvest and quality because of difference in seedshrimp and the complexity of raising environment. Facing the fierce competition of the aquaculture industry it is a big problem to us about how to construct green, high-yield and efficient culture mode in order to make our Penaeus vannamei more competitive.In our experiment water samples were collected from different fish ponds in an aquatic product factory which is located in Jinshan District of Shanghai in2011from June to October. There were three ponds in our experiment including one soiled pond, one canopy pond with green plants (we call it grass pond) and one canopy pond with microbubble aerator (we call it microbubble pond). Also we got the water from the open ditch. The samples'microbial diversity were compared and analyzed by denaturing gradient gel electrophoresis (DGGE) technique. In addition the microbe quantity and the physical and chemical characters of all the samples also had been detected. From the NCBI we found the main advantages of species in different months were discrepant. But generally speaking all the main species belonged to Actinobacteria, Cyanophyta, proteobacteria and Firmicutes with Poteobacteria wildly existing in all monthes. The large amount of organic matters in the later culture period was one of the reasons that made Cyanophyta present in October.In all samples the quantity of bacterium had the same trend of changing on the whole. It reduced in the first and then rose obviously later. The quantity of the inorganic phosphate-solubilizing bacteria increase gradually with the time passing. The numbers of yeast and lactic acid bacteria were decreased in grass pond while they were steady in soiled pond and open ditch. From this result we can indicate that the open environment may go against with the growth of yeast. The quantity of mould changed sharply in the soiled pond. And it could be the highest number of8×102CFU/mL in September. The open ditch had the similar changing trend with soiled pond in mould. So the mould could grow well in the open environment. The plants could make the water clear because the quantity of the mould in the grass pond was lower and more steady than the samples from other ponds.The results showed that microbe similarity of all samples in different months was above 39%and the number could be44%in August. There was a higher similarity in the same pond while the number of microbe similarity reached89.3%in grass pond and88.2%in microbubble pond. The samples from different ponds had a low similarity with the number of25.8%between grass pond and open ditch. On the while the grass pond was similar with microbubble pond. And the soiled pond had a higher similarity with open ditch. The two phenomenons might be caused by the difference between indoor and outdoor environment.According to the results the grass pond had the lowest DO of4.47mg/L in July while has the highest Of6.37mg/L in September. And the average value of DO in the grass pond was5.57mg/L, lower than the number in microbubble pond and soiled pond. The numbers of pH, T and DO were more stable than the other physical and chemical character in the mode with green plants. The grass pond also had lowest values of suspended particulates, COD and total phosphorus among all the ponds with the numbers were67mg/L,65mg/L and0.35mg/L. The results indicated that green plants could make the water environment more stable and clear. But they did not have an obvious effect on oxygenation. From our result we found there was some relation between different indicators, for example DO had an antidependence relationship with NH4+, NO2+, and total phosphorus. It might imply that beside green plant DO also can improve the quality of aquaculture water. |
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