Study On Some Immune Factors Of Candidate Strain Of Anti Emulsification Disease Of Portunus Trituberculatus

Portunus trituberculatus, nutrient-rich , is one of important economic aquatic animals. Emulsification disease of Portunus trituberculatus has seriously effected its aquaculture efficiency. So our laboratory screened Portunus trituberculatus by Vibrio alginolyticus, the pathogens of emulsification disease; and breed F1, F2( short as PSVF1, PSVF2 as followings). F3 ( short as PSVF3 as followings) was pedigree breeded the next year. This paper studied the immune defense mechanism of F1, F2 and F3 focusing on the immune factors such as anti-lipopolysaccharide factor (ALF); hemocyanin; isoenzyme, like acid phosphatase (ACP), alkaline phosphatase (AKP); protective enzymes, like superoxide dismutase (SOD), peroxidase (POD), catalase(CAT) and phenoloxidase (PO). Semi-quantitive RT-PCR was used to analyze the ALF expression; UV Spectrophotometry and enzyme analysis method was respectively used to study the hemocyanin content and the serum enzymes activities. Commom Portunus trituberculatus in the same period was served as control(short as CPF1 as followings). The main results are as followings: 1.The effect of infection 6h by Vibrio alginolyticus on ALF expression in hepatopancreas, serum immunoenzymes activities of PSVF1.ALF expressions in hepatopancreas of PSVF1 and CPF1 reached maximun respectivly at 9h and 12h counting the infection time of 6h, and then gradually decline; serum immunoenzymes activities of PSVF1 and CPF1 reached maximum at 12-36h; The time dependency after infection was obvious. PSVF1 has more immunity advantage on the hemocyanin content and serum immunoenzymes than that of CPF1. 2. Effects of temperature and salinity stress on the content of hemocyanin and serum immunoenzymes activities of PSVF2.The result showed that under temperature and salinity stress, PSVF2 and CPF1 showed strong stress response, and the non-specific immunity was significantly affected; The content of hemocyanin and serum immunoenzymes activities of PSVF2 were higher than that of CPF1, and PSVF2 showed more non-specific immunity advantages. 3.Expressions of ALF during the growth period of PSVF3 ALF expressions throughout the four zoea stages had no significant difference, then rapidly up-regulated at megalops stage (P>0.05), reached maxium at the first and second juvenile crab stages of both PSVF3 and CPF1. ALF transcripts were present in all detected samples during different developmental stages. This suggests that ALF is constitutively expressed in Portunus trituberculatus, it may also play an important role in innate defense against infection. During the whole growth period from zoea to junivile crab, there were no distinctively difference in ALF expressions between PSVF3 and CPF1. However, ALF expressions of megalops and juvenile cab stages of PSVF3 were higher than that of CPF1, this may suggest that PSVF3 showed more immunity advantage beginnig from megalops stages.