Joint Effects Of Several Environmental Factors On Growth, Feeding And Hsp70Gene Expression Level In Pinctada Martensii (Dunker)

(1) The optimal conditions on the juvenile growth and survival in Pinctada martensii（Dunker） were determined by response surface methodology in this work. The compositiondesign was applied to evaluate the effects of two independent variables （temperature,salinity）. Correlation analysis of the mathematical-regression model indicated thatquadratic polynomial model could be employed to optimize the juvenile growth andsurvival in Pinctada martensii （Dunker）. Following models ware postulated in the study:IGR=-151.4289+3.7791T+7.5142S+0.0079T×S-0.0692T²-0.1294S²AGR=-881.387+18.5432T+46.9178S+0.0532T×S-0.3542T²-0.8145S²SR=-697.191+24.8590T+29.2500S+0.0623T×S-0.4637T²-0.5212S²R-Squared of instantaneous growth rate is95.96%, R-Squared of accumulationgrowth rate is97.67%and R-Squared of survive rate is94.59%, evincing that theoverarching predictive capability of the models were very satisfactory, and could bepracticably applied. The result of survive in Pinctada martensii showed that interactiveeffects of temperature and salinity is not significant （P>0.05）. The optimal conditions toobtain instantaneous growth rate (15.76%.d^-1), accumulation growth rate (79.35μm.d^-1) andsurvive rate （96.46%）, while temperature is28.63°C, salinity is29.75, desirability is98%.（2） The optimal conditions for Pinctada martensii’ clearance rate and feeding ratewere determined by response surface methodology in this work. CCF design was appliedto evaluate the effects of three independent variables (temperature16-34°C, salinity20-44and algal density0.5×10⁵-3.5×10⁵cells.ml^-1). Correlation analysis of themathematical-regression model indicated that quadratic polynomial model could beemployed to optimize the Pinctada martensii’ clearance rate and feeding rate. Fromresponse surface plots, temperature, salinity and algal density exhibited interactive effectson the Pinctada martensii’ clearance rate and feeding rate. The results showed that thelinear and quadratic effects of temperature on the clearance rate are extremelysignificant（P<0.01）; the linear effects of salinity on the clearance rate is significant（P<0.05）, the quadratic effects of salinity on the clearance rate is extremelysignificant（P<0.01）; the linear effects of algal density on the clearance rate is notsignificant（P>0.05）, the quadratic effects of algal density on the clearance rate is extremelysignificant（P<0.01）; the interactive effects of temperature and algal density on theclearance rate is significant （P<0.05）; the interactive effects of temperature and salinity,salinity and algal density on the clearance rate are not significant （P>0.05）. the lineareffects of temperature on the feeding rate is significant（P<0.05）, the quadratic effects oftemperature on the feeding rate is extremely significant（P<0.01）; the linear and quadraticeffects of salinity on the feeding rate are extremely significant（P<0.01）; the linear andquadratic effects of algal density on the feeding rate are extremely significant（P<0.01）; theinteractive effects of temperature and algal density on the feeding rate is significant（P<0.05）; the interactive effects of temperature and salinity, salinity and algal density onthe feeding rate are not significant （P>0.05）.The optimal conditions to obtain the highestclearance rate(0.135L.h^-1) and feeding rate(1.593×107cells.h^-1), while temperature is28.61℃, salinity is31.18and algal density is27.36×10cells.L^-1, when clearance rate andfeeding rate got the highest, desirability is86%.Following models were postulated in thestudy:CR=-407.2457+13.9660T+16.3580S+11.4731A+0.0331T×S+0.0705T×A+0.0179S×A-0.2958T²0.2851S²-0.3503A²FR=-36.0771+1.5008T+1.0601S+1.4321A-0.0017T×S+0.0059T×A-0.0026S×A-0.0287T²-0.0173S²-0.0316A²R-Squared of clearance rate is99.56%and R-Squared of feeding rate is99.53%,evincing that the overarching predictive capability of the models were very satisfactory,and could be practicably applied. The experiment result offers theory basis for Pinctadamartensii artificial culture.（3） The optimal conditions on the expression of gill、adductor and mantle Hsp70genein Pinctada martensii were determined by response surface methodology in this work. Thecomposition design was applied to evaluate the effects of two independent variables（temperature16-40°C, salinity10-50）. Correlation analysis of the mathematical-regressionmodel indicated that quadratic polynomial model could be employed to optimize theexpression of gill Hsp70gene. From response surface plots, temperature and salinityexhibited interactive effects on the expression of gill、adductor and mantle Hsp70gene inPinctada martensii. The results showed that linear effects of temperature and quadraticeffects of temperature on the expression of gill、adductor and mantle Hsp70gene areextremely significant（P<0.05）; linear effects of salinity on the expression of gill、adductorand mantle Hsp70gene is not significant （P>0.05）, quadratic effects of salinity on the expression of gill、adductor and mantle Hsp70gene is significant effect（P<0.05）; theinteractive effects of temperature and Salinity on the expression of gill、adductor andmantle Hsp70gene are not significant （P>0.05）. The optimal conditions to obtain thelowest expression of gill、adductor and mantle Hsp70gene （0.5276）, while temperature is26.78°C, Salinity is29.33. When expression of gill、adductor and mantle Hsp70gene gotthe lowest, Desirability is98%. Following models ware postulated in the study:GHsp70=3.0957-0.1269T-0.0592S-0.0001T×S+0.0024T²+0.0011S²AHsp70=3.0398-0.0910T-0.0454S+0.0001T×S+0.0014T²+0.0006S²MHsp70=2.5830-0.0738T-0.0362S+1.04T×S+0.0013T²+0.0006S²R-Squared is98.69%and Adj R-Squared is97.38%, evincing that the overarchingpredictive capability of the model was very satisfactory, and could be practicably applied.The experiment result offers theory basis for high expression of gill、adductor and mantleHsp70gene in Pinctada martensii protecting cell’s internal environment stability andenhanceing the resistance.