Effects Of High Temperature On Physiology Biochemistry And Screening Related Microsatellite Markers In Large Yellow Croakerlarimichthys Crocea

Serum biochemical parameters were investigated in 12-month-old Larimichthys crocea exposed to high temperature（32℃）for 7,14 days.The effect of high water temperature on feeding and behavioral were observed in two-month old large yellow croaker Larimichthys crocea by slowly heating.Thermal-tolerance and sensitive individuals were analyzed by microsatellite markers using bulked segregant analysis.The key results as fellows:1、When subjected to high temperature（32℃）for 7 days,the activities of alkaline phosphatase（ALP）,glutamyl-transpeptidase（ALT）,glutamate-oxaloacetate（AST）,creatine kinase（CK-MB）,glutamyl-transpeptidase（GGT）and lactate dehydrogenase（LDH）were all increased,and the difference between the case（with high temperature 32℃for 7 days）and the control（25℃）was significant（P<0.01）except ALP;The concentrations of serum Cl^-,Na⁺and Ca²⁺changed very little（P>0.05）while the concentrations of K⁺was decreased significantly compared with the control（P<0.05）;The concentrations of total protein（TP）,cholesterol（CHOL）,triglyceride（TG）,glucose（GLU）and urea nitrogen（BUN）decreased,and the difference between the case and control for concentrations of urea nitrogen（BUN）,cholesterol（CHOL）,triglyceride（TG）and glucose（GLU）were significant（P<0.05）or extremely significant（P<0.01）.When exposed to high temperature（32℃）for 14 days,except the activities of CK-MB and LDH were higher than the control（P<0.01）,the activities of other enzymes were no significant difference compared with the control（P>0.05）;The concentrations of serum Cl^-and Na⁺changed very little while the concentrations of Ca²⁺and K⁺were decreased significantly compared with the control（P<0.05）;The difference between the case and control for concentrations of urea nitrogen（BUN）and cholesterol（CHOL）reached significant level（P<0.05）.According the results above mentioned,CK-MB,LDH,K⁺,BUN,and CHOL were changed significantly between the case and the control both at 7 d and 14 d high temperature treatment,and can be used as biochemical response index for large yellow croaker exposed to high temperature.2、The effect of high water temperature on feeding and behavioral were observed in two-month old large yellow croaker Larimichthys crocea by slowly heating,the results as fellows.With the increase of temperature,the feeding and activity of large yellow croaker increased at first and then decreased.The temperature began to die is 33℃,and the semi-lethal and lethal temperature is 35.5℃,36℃respectively.Thermal-tolerance and sensitive individuals were selected from above experiment using BSA design to screen thermal-tolerance microsatellite markers in large yellow croaker.In all 116 microsatellite markers,7 loci showed difference between thermal-tolerance and thermal-sensitive fish.These loci were verified using30 thermal-tolerance fish and 30 thermal-sensitive fish and final 3 microsatellite loci（LYC0148,LYC0200 and LYC0435）were confirmed.The bands amplify by LYC0148 and LYC0200 in thermal-tolerance fish were significantly higher than that in thermal-sensitive fish.On the contrary,the bands amplified by LYC0435 in thermal-sensitive fish were significantly higher than that in thermal-tolerance fish.This study provided useful molecular markers for thermal-tolerance breeding of large yellow croaker in the future.