| By adding bagasse to factory-farming pond, this paper analysis the physical andchemical factors of water, physiological indicators of farmed shrimp(digestion andimmunization)changes. The variability of bacterial community composition with theculturing and special distribution in the culture pond were investigated using aculture-independent method of16S rDNA PCR-DGGE fingerprinting and BiologEOC, which overcome the cultivation-based limitations and it was carried out bytraditional cultivation methods.The main results are detailed as follows:1. The effect of adding different bagasse(0,0.5kg/m2,1kg/m2) on LitopenaeusvannameiThe levels of dissolved oxygen(DO) and pH fell down as the culture daysprolonged; Adding bagasse was conducive to the propagation of bacteria and thebioflocs in water, the number of bacteria in farming: adding1kg/m2bagasse group>adding of0.5kg/m2bagasse group> control group; In reducing47%water-changecondition, ammonia and nitrite content in water was control. Ammonia and nitrite inwater was first up and then fell down,and the content of bagasse group was in generallower than the control group, while the bagasse group was higher than the controlgroup on the content of nitrate and COD; Due to the disease in later farming phaseof the control group, Ua and UI of shrimp: adding1kg/m2bagasse group <adding0.5kg/m2bagasse group <control group, but PO, SOD and POD: adding1kg/m2bagasse group>adding0.5kg/m2bagasse group>control group; the production ofadding1kg/m2bagasse group and adding0.5kg/m2bagasse group were8.7%and14.9%higher than the control group. In result, adding1kg/m2bagasse is best.2. The effect of adding bagasse(1kg/m2) on the physiological indicators and growth ofLitopenaeus vannamei:The activity of hepatopancreas amylase, hepatopancreas trypsin and intestinaltrypsin in the bagasse group was significantly higher than the control group(P<0.05), while the activity of intestinal amylase in the control group wassignificantly higher than bagasse group (P<0.05); the UI activity and PO activity ofbagasse group was significantly higher than the control group (P<0.05), POD andUI activity of bagasse group was slightly lower than the control group, and thedifference was not significant (P>0.05);the production of bagasse group was6%higher than the control group, the results show that adding bagasse improve Litopenaeus vannamei digestion and andimmunity, and promote the growth of shrimp.3. The effect of adding bagasse on the bacteria quantity fluctuation and bacteriacommunity functional diversity in shrimp farming system:The levels of heterotrophic bacteria and total bacteria rise as the culture daysprolonged, and the bagasse group was significantly higher than the control group,while Vibrio of the bagasse group was lower than the control group. Biologexamination showed the AWCD levels of attached bacteria on bagasse and waterbacteria rise as the culture days prolonged, this proved that adding bagasse cansignificantly increase the carbon-source utilization and microbial activity of waterbacteria and attached bacteria on bagasse, water bacteria of Shannon-wiener’sdiversity index in the bagasse group was lower than the control group, thisphenomenon was verified by the DGGE‘s result.The authors think that some bacteriadeveloped the dominant species in the later culture phase, so the diversity of thepopulation decline. The results of the DGGE profiles showed that the water bacteriawas mainly composed of Actinobacteria, Firmicutes, Proteobacteria and Bacteroidetesin which Proteobacteria and Bacteroides was the dominant bacteria. As the culturedays prolonged,the community structure of bacterial was different, the bacteria ofActinomycetes was gradual decline, the bacteria of α-Proteobacteria,Rhodobacteraceae in the later culture phase developed into the dominant bacteria,especially in the bagasse group,it proved that adding the bagasse can effectivelypromote the breeding of such bacteria, which make the culture environment have astronger self-purification capacity, and provide a good environment forthe growth ofshrimp.4. The effect of adding bagasse(1kg/m2) on disease resistance of Litopenaeusvannamei:The shrimp was injected with infective tissue homogenate supernatant whichcontained white spot syndrome virus (WSSV). According to the semi-lethal time, thebagasse group’s semilethal time was102h after injected infection, the control groupfor96h; the result of real-time quantitative PCR showed that the virus absolutecontent of gill tissue is1.78×108copy/mg-tissue in died shrimp of bagasse group, incontrol group it was8.45×107copy/mg-tissue,the result means that the shrimp ofbagasse group can be live at a higher virus content and prove that adding bagasse inthe shrimp’s pond improve shrimp’s disease resistance... |
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