胃促生长素Ghrelin在不同盐度胁迫下对黑鲷(Acanthopagrus schlegelii)部分免疫指标的影响

鱼类Ghrelin的研究主要集中在摄食和生长方面,在免疫方面的研究甚少。本文以沿海经济鱼类黑鲷(Acanthopagrus schlegelii)为研究对象,检测了不同盐度(10、20、30)环境下腹腔注射Ghrelin(生理浓度,10ng/100g体重)对黑鲷部分免疫指标(超氧化物歧化酶SOD、溶菌酶活性LYS、血清补体3含量C3、免疫球蛋白M含量Ig M和丙二醛含量MDA)的影响。结果如下:在30盐度(正常盐度)时,腹腔注射Ghrelin对SOD和C3无显著影响(P0.05),1h后Ig M含量显著提高(P0.05),2h后LYS和MDA也明显增加(P0.05);在20盐度(轻盐度胁迫)时,腹腔注射Ghrelin不影响Ig M含量(P0.05),1h后SOD、LYS、C3均有明显上升(P0.05),而MDA则显著下降(P0.05),影响持续时间较长;在10盐度(重盐度胁迫)时,腹腔注射Ghrelin对所检测的5种免疫指标均有显著影响,其中1h后LYS、C3、Ig M含量明显提高(P0.05),3h后MDA下降,6h后SOD明显升高(P0.05)。以上结果表明:在低盐度肋迫下,Ghrelin可显著提高海水鱼黑鲷血清中SOD、LYS、C3和Ig M水平,降低MDA水平(P0.05),使黑鲷免疫力提高,以缓解其对低盐度胁迫的适应。因此,Ghrelin在海鱼的淡化驯养中具有潜在的应用前景,有望开发为一种海鱼淡化驯养的饲料添加剂。

EFFECTS OF GHRELIN ON IMMUNE INDEXES OF BLACK SEABREAM ACANTHOPAGRUS SCHLEGELII UNDER DIFFERENT SALINITY STRESS

Salinity stress experiment was conducted to determine the effects of Ghrelin on the immune indexes (SOD, LYS, C3, IgM and MDA) of black seabream Acanthopagrus schlegelii. In this experiment, Fish were injected with 10ng/100g (physiological concentration) Ghrelin and exposed at different salinity[10, 20, 30 (control)]. The main results were as follows:(a) In salinity 30 (normal salinity) groups, there were no significant effects on SOD and C3 (P>0.05) of Ghrelin, while IgM was significantly stimulated after injection 1h (P<0.05), and LYS and MDA were significantly increased after injection 2h (P<0.05). (b) In salinity 20 (light salinity stress) group, there were no significant effects on IgM (P>0.05) of Ghrelin, while SOD, LYS and C3 were significantly stimulated after injection 1h (P<0.05), MDA levels was significantly reduced after injection 3h, 6h and 12h (P<0.05). (c) In 10 salinity (hard salinity stress) group, there were significant effects on all immune indexes detected (SOD, LYS, C3, IgM, and MDA). LYS, C3, and IgM were significantly stimulated after injection 1h (P<0.05), MDA level was reduced after injection 3h and the SOD level was significantly increased after injection 6h (P<0.05). On the light salinity stress, SOD, LYS, C3, and IgM were all significantly stimulated while MDA was significantly reduced by Ghrelin, which can improve the immunity of black seabream to alleviate the salinity stress damage. Thus, Ghrelin has a potential application as a feed addicitive in fish desalination domestication.