| In the life history of freshwater mussels,it's glochidia need to parasitic to the appropriate host fish,and then parceled to gills and fins,therefore,it can completion of metamorphosis,development,growth and become to juveniles.So far,the mechanism of interaction between the larvae and host fish,has not been well understood.In the practice of actual production,selection the suitable host fish is one of the key techniques that artificial propagation of specific mussels.This paper selection the main use of freshwater mussel in China:Triangle sail mussel(Hyriopsis cumingii)and Cristaria plicata as the research object,in order to study of the effects of the host respiratory metabolism and nutrition indexes,we use Hyriopsis cumingii glochidia parasitic to yellow catfish(Pelteobagrus fulvidraco),in order to research the host immune response generated,we use cristaria plicata glochidia parasitic to common carp(Cyprinus carpio),Pelteobagrus fulvidraco and bighead(Aristichthys nobilis).1.There is no significant effect of yellow catfish's oxygen consumption rate with glochidia parasitic,only have a degree of decline;and produce a significant effect of ammonia excretion rate(P<0.05),and the degree of ammonia excretion rate increase with the larvae amount increase.Therefore,in parasitic 4 and 8 days,parasitic group O/N ratio were significantly lower than those of non-parasitic groups(P<0.05).2.There is a significant effect on host fish's serum electrolytes and biochemical parameters with parasitic and starvation stress.There were no significantly affected on Cl-,Na+ and K+with glochidia parasitic stress,and the effect of the stress on the P5+,Mg2+ and Ca2+ was significantly(P<0.05);The 6 kinds of electrolyte have no significant effect with hunger stress(P>0.05);Host fish serum creatinine,total protein,albumin,triglyceride,total cholesterol content produce significantly decrease with larvae parasitic(P<0.05);but no significant effect on glucose(Glu),high density lipoprotein(HDL)and low density lipoprotein(LDL)(P>0.05);Starvation led to a decline in creatinine(Cre),blood sugar(Glu),total protein(TP)and albumin(Alb),but triglycerides(TG),total cholesterol(TC),high density lipoprotein and low density lipoprotein increased significantly(P<0.05).3.Glochidia parasitic have significant influence on the main nutrient indexes of yellow catfish.We use Hyripsis cumingii glochidia parasitic on natural host(yellow catfish),then study on the main nutritional index changes during before,interim and after parasitic stress,that in serum,liver and muscle;The results show that parasitic stress leads to plasma total protein(TP)and total amino acids(T-AA)decreased significantly(P<0.05),and reduced no significant effect on free fatty acid(NEFA)and glycogen(P>0.05);In the late stage of parasitic,TP,T-AA and NEFA in liver decreased significantly(P<0.05),but,glycogen did not significantly change(P>0.05);There have no significant effect on every index of glochidia parasitic stress(P>0.05).4.The natural hosts do not cause larva to fall off in advance,but,non-host fish well fall off early.Parasitic stress leads to non-host white cell count(WBC),lymphocyte(Lym)and eosinophile cells(EOS)increased significantly(P<0.05),but,host fish not.Has no significant effect on red blood cell(RBC).Parasitic stress to host or non-host were not produce significant changes on alkaline phosphatase(ALP),complement 3 or 4(C3,C4)and immunoglobulin protein(Ig).Parasitic stress reduce the interferon(IFN),antioxidant enzymes increased significantly(P<0.05),but,no significant changes in natural hosts.In conclusion,it suggests that glochidia parasitic stress generate significantly impact in respiratory metabolism,nutrient metabolism and immune of host fish.There are many factors on the selection of bivalve larva with host fish,respiration and nutrition maybe the control factors that larva quantity,and immune may the key control factor that glochidia can complete metamorphosis and development in host fish. |
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