Effect Of Low Salinity On Neuroendocrine-immunoregulatory Response In Scylla Paramamosain

Scylla paramamosain is one of the main marine crabs cultivated in many countries,which has great economic value and great development potential.However,because of the frequent occurrence of natural disasters and diseases,S.paramamosain culture faces many challenges,which critically restricts the healthy development of S.paramamosain culture.As we all know,in the process of aquaculture,the outbreak of disease is the result of the interaction of environmental factors in aquaculture water,the immunity of aquaculture animals and the pathogenicity of pathogens,while the response of animal immune system is strictly regulated by the neuroendocrine system.Therefore,it is necessary for us to study the effect of low salinity stress on neuroendocrine immunity of S.paramamosain,which is helpful to improve the disease resistance of S.paramamosain.The effects of low salinity on neuroendocrineimmunoregulatory-immune response were investigated in S.paramamosain.We got the following results:1.The results showed that the corticotropin releasing hormone(CRH)and adreno-cortico-tropic-hormone(ACTH)concentrations in lower salinity groups increased significantly within 12h,meanwhile the dopamine(DA),norepinephrine(NE),(5-hydroxytryptamine(5-HT)are also increased significantly within 12h.2.Immune parameters in the low salinity group,such as total haemocyte count(THC),phagocytic activity,antibacterial activity(U_A),bacteriolytic activity(U_L),C-type lectin gene expression,and hemagglutinating activity decreased significantly within 12h;the relevant parameters of prophenoloxidase-activating system(pro PO-As),including prophenoloxidase-activating factor(PPAF)and the gene expression of prophenoloxidase(pro Po),the pro PO activity and phenoloxidase(PO)activity,except PO activity increased significantly in 12h,other parameters of the system decreased significantly in 12h;in addition,except THC,all parameters recovered to the level of the control group after 48h to96h.With the findings of this study,we speculate that under low salinity stress,the S.paramamosain sense the stress of low saininity and promote the release of CRH,which leads to the release of ACTH to the systemic circulation and through the CRH-ACTH-biogenic amines(BA)axis to release biogenic amine(DA,NE,5-HT)to regulate immune function.The nervous system would temporally release neurotransmitters to modulate the immune response(inhibiting immune function)to maintain the homeostasis in the process.While with the long-term adaptation to the stress,the immune function would recover to the normal.