| The current worldwide growth rate of the aquaculture business is needed in orderto copewith the problem of shortage in protein food supplies since the1970s, which isparticularly situated in the developing countries. With the rapid development of theaquaculture industry, the proportion of factory farming of high-density rapid increased,but the aquaculture water environment pollution has been worsening,which is aserious impediment to the development of aquaculture. The aquaculture system basedon the bio-floc and biosafety zero-exchange can solved these problems. Bio-floc isaggregates formed of organic matter’s flocculation in the culture water which ismainly composed of heterotrophic microorganism, which can improve water quality,save feed and promote animal immunity.The first part was to explore the optimum carbon dosage for bio-floc technologywhich was used in vannamei farming process，investigating the effectiveness ofbio-floc technology for water quality control, feed conversion and disease resistance.The experiment was progressed with6groups differentiated by control group A0,20％sucrose addition group A1,50％sucrose addition group A2,70％sucrose additiongroup A3,90％sucrose addition group A4and120％sucrose addition group A5in18indoor concrete ponds separately. After97days of breeding experiments show that theoptimal most economical carbon dosage is70%of the amount of the feed. Themonitoring indicated that ammonia-N, nitrite-N and COD concentrations of water in70％sucrose addition group A3were significantly lower than the control group(P<0.05). Comparing with the control group A, the SOD,AKP, POD and LZMactivity in shrimp serum of70％sucrose addition group A3were significantlyimproved (P<0.05). Comparing with the control group A, the feed conversion rate,shrimp survival rate and special growth rate of70％sucrose addition group A3weresignificantly improved (P<0.05).The second part was that A91-day experiment was conducted to investigate the effectiveness of bio-floc technology for water quality control, feed conversion anddisease resistance in high-intensive, zero exchange farming systems of Litopenaeusvannamei. The experiment was progressed with4groups differentiated by controlgroup A, probiotic addition group B, sucrose addition group C, sucrose and probioticaddition group D in12indoor concrete ponds separately. The monitoring indicatedthat ammonia-N, nitrite-N and COD concentrations of water in sucrose and probioticaddition group D were significantly lower than the rest three groups (P<0.05);Comparing with the control group A, the sucrose and probiotic addition group Dresulted in80.9%higher SOD activity,75%higher POD activity,106.35%higherAKP activity,109.09%higher LZM activity,75%PO higher activity and87.02%higher total protein concentration; After WSSV challenge test, the relative percentagesurvival (RPS) of the sucrose and probiotic addition group D was as high as40.86%;The sucrose and probiotic addition group D had higher special growth rate of12.28%,higher feed conversion rate of20.14%, and higher shrimp survival rate of103.24%than the control group A; The production of L. vannamei reached to (3.40±0.26)kg·m-2after91-day farming in the probiotic addition group D. All of above concludedthat bio-floc conformed by sucrose and probiotic addition not only maintained goodwater quality and increased feed conversion rate, but also raised immunity andanti-infectivity of L. vannamei.The third part was using bio-floc technology in the factory farming of vannameiwith different densities. The experiment was progressed with3traditional farminggroups and3bio-floc technology farming groups in different densities of200,400and600shrimps per square meter. After97days of breeding experiments show thatbio-floc technology achieved remarkable results in400/㎡vannamei culture（P<0.05）,with the per unit of production as high as (3.54±0.29) kg/m. |
PDF Full Text Request