Title: Effects of ammonia exposure on immunity indicators of haemolymph and histological structure of hepatopancreas in Chinese mitten crab(Eriocheir sinensis)
Abstract: In intensive culture system,accumulation of ammonia-N,which is the principal end-product of nitrogenous metabolism,has deleterious effects on aquatic animals.The relationship between ambient ammonia and immunity capacity in aquatic animals is well-documented,but there is a dearth of information relating to the immune and histological alterations induced by ambient ammonia from Eriocheir sinensis.In the present study,the effects of ambient ammonia on the immune response of E.sinensis body weight(71.25±1.13)?g,was investigated.The crabs were allocated to four groups with different NH+4-N levels:10 mg/L(LC group),50 mg/L(MC group) and 100 mg/L(HC group),which were obtained by diluting 50 g/L NH4Cl,and the control(basic concentration of 1 mg/L NH4Cl).The relative immunity indicators of haemolymph were measured on days 1,3,5 and 15 following the stress and histological structure of hepatopancreas was observed on day 15.The results were as follows:(1) After 1-3 days treatment with ammonia exposure,density of hemocyte cell(DHC) in these three treatments decreased significantly compared with control(P0.05).With time elapsed,DHC peaked on day 5 and there was no significant difference among different treatments(P0.05).However,on day 15,DHC in group HC was lower significantly than that in control(P0.05).Within short time(within 1 day) following the stress,superoxide dismutase(SOD) and catalase(CAT) activity were stimulated in LC group while inhibited in HC group.After 5 d,the change of SOD activity was similar to that of DHC.Whereas CAT activity dropped to the lowest on day 5,and significant difference presented in these three treatments compared with control(P0.05).Progressive increases in malodiadehyde(MDA) level was observed with time elapsed.Moreover,the augmentation of MDA changed with different concentration of ambient ammoniaN that the higher concentration,the more augmentation of MDA;(2) the histological structure of hepatopancreas was affected by ammonia exposure.In these three treatments,the number of B cells of hepatopancreas decreased while the transferred vacuoles increased,and nucleus were deformed with its numbers increasing.The basement membranes of some hepatopancreas tubular in HC group were so ruptured that substances in cells leaked.The cellularity was dim and nucleus were karyorhexised.Such alterations could affect vital physiological functions,such as absorption,storage and secretion of the hepatopancreas,which in turn could ultimately affect the survival and growth of E.sinensis.Therefore,the results indicate that ammonia exposure can affect the immunity function and histological structure,which will provide the theoretical basis for the mechanism of ammonia stress on crabs.
Publication Year: 2007
Publication Date: 2007-01-01
Language: en
Type: article
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Cited By Count: 18
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