| This paper mainly studys the Release rate of nitrogen and phosphorus byL.vannamei postlarvae under different conditions based on various setting parametersof temperature、salinity、pH and feeding state, to explore postlarve environmentaladaptive law, its own internal metabolic laws as well as metabolic intensity changesdesigned to provide a scientific basis for larval rearing and early farming; study theabsorption of Chlorella pyrenoidosa,Platymonas subcordiformis,Chaetocerosmuelleri,Chaetoceros gracilis, Bacillus subtilis and PSB in postlarvae metabolites andto provide reference for the amount of nursery in the algal species of the selection andthe appropriate launch; also further study and compare the impact of the four kinds ofalgae as well as two kinds of bacteria, respectively,in nursery water and nurserywastewater quaLlity, in order to provide a reference; still compare the water qualitychanges between ordinary breeding methods and using Chaetoceros gracilis seedling,to understand the effect of Chaetoceros gracilis in water quality control in the nurseryfor prawn breeding in the future.Results are as follows: temperature、salinity、pH value and feeding state influenceits metabolism.In15~30℃temperature range，the Release rate of phosphorus、nitrite、nitric nitrogen and ammonia nitrogen by L.vannamei juvenile increases with the risingtemperature and the Release rate of nitrogen and phosphorus by L.vannamei juvenilereaches to a maximum;in5~35salinity range，the Release rate of nitrogen andphosphorus by L.vannamei juvenile increases with the rising salinity.But in the30salinity, the Release rate of nitrogen and phosphorus by L.vannamei juvenile drops toa minimum,which reveals that it has significant effect（P<0.01） on the Release ofammonia nitrogen；in6.5~9.0pH value range，the Release of phosphorus decreasessignificantly（P<0.05） and that of nitric nitrogen and ammonia nitrogen increasessignificantly(P<0.01)with rising pH value.The Release rate of ammonia nitrogenreaches to a maximum in a pH around8.5，while the Release rate of nitrite changesLittle.Feeding state has significant impact on metabolism of young shrimp.Comparedby in hunger,the Release rate of phosphorus、nitrite、nitric nitrogen and ammonianitrogen by young shrimp in satiation increase separately by94.7%、50.0%、60.0%、 94.7%，which shows that there is a significant increase in protein metabolism inyoung shrimp’s feeding.Absorption of postlarvae metabolites: the differences of nitrate uptake rate indifferent density groups, different algae are not significant (P>0.05), maintained at0.005~0.007mg·L-1·h-1; along with density increased,absorption rate of nitritenitrogen by Chlorella pyrenoidosa increases significantly (P<0.05). The density ofgroup2,3,4, absorption rate of nitrite nitrogen among the three kinds ofalgae:Platymonas subcordiformis,Chaetoceros muelleri,Chaetoceros gracilis, are notsignificant (P>0.05). Four kinds of algae in105cell/mL nitrite are significant (P<0.05).absorption rate of nitrite nitrogen among the three kinds of algae are0.0012±0.001mg·L-1·h-1,0.0005±0.0001mg·L-1·h-1,0.0004±0.0001mg·L-1·h-1,0.0001±0.0000mg·L-1·h-1.Upon examination,the four kinds of density,Chlorella pyrenoidosa,Platymonassubcordiformis,in104cell/mL,the absorption rate of ammonia and the others’ aresignificant(P<0.05), respectively, are0.095±0.003mg·L-1·h-1,0.114±0.012mg·L-1·h-1max-imum; absorption rate of ammonia by Chaetoceros muelleri in different densityare significant(P<0.05), along with density increased,absorption rate of ammonia byChaetoceros muelleri and Chaetoceros gracilis significantly rise,in105cell/mL,are0.133±0.003mg·L-1·h-1,0.051±0.019mg·L-1·h-1.In102cell/mL,103cell/mL, the absorption rates of ammonia by four kinds ofalgae have significant difference(P<0.05), and Chaetoceros muelleri’s absorption rateis the largest,is0.095±0.003mg·L-1·h-1,0.114±0.000mg·L-1·h-1;in104cell/mL,compared with others,absorption rate of ammonia nitrogen by Chlorella pyrenoidosahave significant difference (P<0.05), is0.095±0.003mg·L-1·h-1, absorption rate ofammonia by Platymonas subcordiformis and Chaetoceros muelleri have nosignificant difference (P>0.05), compared with others,absorption rate of ammonianitrogen by Chaetoceros gracilis have significant difference (P<0.05), is0.043±0.008mg·L-1·h-1;in105cell/mL, absorption rate of ammonia nitrogen by four kinds of algaehave significant difference (P<0.05),and Chaetoceros muelleri’s absorption rate is thelargest,is0.133±0.003mg·L-1·h-1.Upon examination, the density of ChLorellapyrenoidosa have significantly effect on absorption of phosphorus(P<0.05), and in104cell/mL, the absorption rate reach to0.033±0.002mg·L-1·h-1maximum;comparedwith other densities,the absorption rate of phosphorus by Platymonassubcordiformis,in105cell/mL have significant difference(P<0.05),is0.006±0.002mg·L-1·h-1; Along with the increase of density,the absorption rate of phosphorus by Chaetoceros muelleri increase significantly(P<0.05),and in105cell/mL,the absorptionrate achieve maximum,0.0012±0.000mg·L-1·h-1;compared with other densities,theabsorption rate of phosphorus by Chaetoceros muelleri,in105cell/mL have significantdifference(P<0.05),is0.009±0.000mg·L-1·h-1.The absorption rate of phosphorus byfour kinds of algae in each density exist significant difference (P<0.05), and Chlorellapyrenoidosa’s absorption rate is the largest,is0.033±0.002mg·L-1·h-1.The absorption rates of nitric nitrogen, based nitrogen, ammonia nitrogen andphosphorus in each group have significant difference(P<0.05), among them, group.Fis the largest,is0.008±0.001mg·L-1·h-1,0.004±0.0004mg·L-1·h-1,0.139±0.01mg·L-1·h-1and0.006±0.001mg·L-1·h-1,the results showed that absorption effect of postlarvaemetabolites by algae-bacteria joint group is the most significant.To improve seedling water and wastewater quality,the best algae choice is:Chaetoceros gracilis, density for1.0×105cell/mL:it significantly(P<0.05) reduce theconcentration of NO2--N, NH3-N, PO43--P, COD and E value:seedling water by93%,81%,49%,62%and95%,wastewater by94%,81%,73%,51%and93%respectively when compared with the control group.By comparison, two kinds ofprobiotics in improving seedling water and wastewater quality, the best bacteriachoice is:Bacillus subtilis,density for1.0×108cful/mL:it significantly(P<0.05) reducethe concentration of NO2--N, NH3-N, PO43--P, COD and E value:seedling water by52%,94%,88%,49%,87%and98%, wastewater by45%,88%,64%,89%,55%and98%respectively when compared with the control group.In Chaetoceros gracilis seedling way, it significantly(P<0.05) reduce theconcentration of NO3--N, NO2--N, NH3-N, PO43--P, COD and E value by22%,48%,25%,19%,37%,62%respectively when compared with normal seedling way. So wecan think that it makes better, by Chaetoceros gracilis seedling, than by normalseedling way. |
PDF Full Text Request