| Chinese mitten crab (Eriocheir sinensis) is a very important economic aquatic animal in our country. With the expansion of the scale in recent years, aquaculture, environment deterioration is serious, leading to increase the crab diseases, a crab breeding caused tremendous economic losses. There are three reasons for crab's diseases:crab's own immunity, pathogens and the quality of water where crabs are living in. Environmental factors play an important role, not only affects the crab's resistance to disease but also affect bloom of the pathogens.For crustaceans, water pollution which causes the environmental stress is the important reason for the decline of the immunity. The changes of the body or the increase of the prevalence can be markers of environmental stress. The research on crustaceans's environmental stress focuses on nitrogen, temperature, pH value, heavy metals and other environmental factors,Toxic effects of NP on Eriocheir sinensis have rarely been studied. NP is common in the water, having good chemical stability, and easy to accumulate in the organisms. With the development of the industry, the pollution is increasingly serious. High dose of NP have found in Plenty of the rivers of our country, the living environment of Eriocheir sinensis is threatened. Many studies have shown that NP can be toxic on organisms in many aspects, like the endocrine, reproductive and developmental, cancer, immune and so on. Therefore, it's neccessery to explore the NP stress effect on shrimps and crabs, for providing theoretical guidance to the establishment of appropriate evaluation system.1. NP exposure to can lead to a significant decline of THC in Chinese mitten crab, and relationship between NP dose and THC was nagative. In the time-effect experiment of 300mg/kg NP, THC were exposed down at the first 3d; while it recovery after 6d, after this day, it arised significantly, and close to the control group on 14d.2. Low dose (≤100mg/kg) of NP can increase ProPO and PPAF gene expression in hemocyte of Eriocheir sinensis, but above this concentration, the induction effect decreased. The inductive effect on ProPO and PPAF of NP with time-effect relationship. The expression conatant rise after injection 6d, then become decrease. 3. Low dose of NP can increase the expression of crustin mRNA of Eriocheir sinensis. The expression crustin crab which pre-exposure to low doses of NP for 1d, infection with Aeromonas hydrophila, much higher than non-exposure group, but in the group which exposure to NP for 14d the expression of crustin gene is lower the the non-infected group. Show short time-effects of immune stress.4:The three antioxidant enzymes (SOD, CAT and GPX) are sensitive to NP. low doses can increase their activity. low dosage of NP can increase the expression of antioxidant enzymes, while the higher dosage inhibit it. In addition, we also observed that, the toxicity of NP changes by the exposed time. that is slowly increased at first, then decreased in the process.5. NP have estrogenic effect in Eriocheir sinensis. Not only to enhance the VTG gene expression level in female carb, but also can induce VTG gene expression in the male crab. VTG gene expression increased can been detected in 10mg/kg dose NP, and in the group of 500mg/kg dosage NP, the expression reach the highest level.Comprehensive analysis the experimental results we can see that low doses of NP may stimulate the immune stress response in Chinese mitten crab, this stress weakened with the metabolic elimination of NP in the body, and it will have a certain negative effects for the immunity of Eriocheir sinensis. High concentrations of NP, by reducing hemocyte to effect. the immune function of Eriocheir sinensis. Similar to the vertebrates, NP has estrogenic effects on Eriocheir sinensis. |
PDF Full Text Request