Most of the decapod species of crustacean have comprehensive capacity of osmoregulation, and they can adapt to relative wide ambient salinity range. It is important to understand the underlying mechanisms of their comprehensive adaptability to salinity change because this knowledge is helpful for inland culturing of marine species. As a euryhaline crustacean, the Chinese mitten crab, Eriocheir sinensis, has been well studied in many aspects related to their physiological responses to salinity change, and many useful literature findings have been accumulated. Therefore, E. sinensis can be considered as an animal model for studying osmoregulation mechanism of the decapod species. However, the roles of nutrients in osmoregulation of E. sinensis are still limited. In this paper, male E. sinensis in freshwater (0.3%o) were transferred directly into waters at salinity values of 16%o and 30%o, respectively, and the crabs kept at fresh water served as the control. Each treatment has three replicates. The soluble protein in haemolymph and hepatopancreas, hemocyanin, haemo-lymph glucose and hepatopancreas glycogen at Oh, 6h, 12h, 24h, 48h, 72h and 96h of E. sinensis at different salinities were determined. Soluble protein of haemolymph and hepatopancreas were measured with a Folin reagent based on a standard curve using bovine serum albumin as the standard protein. Hemocyanin was assayed using an ultraviolet absorption methods at 335 nm and calculated according to Nickerson =2.83. Haemolymph glucose was assayed using glucose oxi-rndase-peroxide enzyme (GOD-POD) method. Hepatopancreas glycogen was measured using the anthrone colorimetry method. The results showed that the crabs at salinity 16%o and 30%o had significantly lower soluble protein content of hepatopancreas than those at fresh water (P<0.05) when crabs had encountered salt water for 12h?6h, and the soluble protein content of haemolymph decreased significantly from 6h to 48h, and then increased at 72h. The hemocyanin content showed a significantly decreasing trend from Oh to 24h, and then it increased after 48h. Hepatopancreas glycogen contents at salinity 16%o and 30%o were significantly lower than those at fresh water (P<0.05) from 6h to 96h, while no significant differences were observed between crabs in waters with salinity 16%o and 30%o (P>0.05). Haemolymph glucose content at 16%o reduced significantly (TO.05) from 24h to 48h, and gradually recovered up at 72h, but it showed a significantly decreasing trend from 6h to 12h at salinity 30%o, and then gradually increased after 24h. All these results indicated that E. sinensis could produce physiological and biochemical adaptation to maintain a stable osmotic pressure during acute salinity stress. Carbohydrate and protein play important roles in the osmoregulation of crustaceans. E. sinensis could use carbohydrate first to provide energy under acute salinity stress. The higher the salinity, the faster the haemolymph glucose was consumed, and it also recovered more quickly. This observation suggested that carbohydrate could be a direct source in osmoregulation. The crabs may use protein to maintain the balance of osmotic pressure under high salinity by metabolizing the protein into free amino acids. Beside providing free amino acids, hemocyanin also can carry oxygen to meet the needs for physiological activities. Therefore, more attention should be paid to carbohydrate and protein supplied under salinity stress. The ratio of free amino acids maintaining the balance of osmotic pressure and supplying energy by oxidation and the utilization of lipid in osmoregulation require further study. Since the lipid contents in haemolymph and hepatopancreas were not determined in this study, the role of body lipid in E. sinensis was not discussed here and should be further examined.%实验以淡水(0.3‰)处理组为对照,研究了急性高渗胁迫(盐度16‰和30‰)对中华绒螯蟹(Eriocheir sinensis)雄蟹血淋巴和肝胰腺中可溶性蛋白质、血蓝蛋白、血糖及肝糖原含量的影响.结果显示,与对照组相比,进入16‰及30‰盐度后,蟹的血淋巴中可溶性蛋白质含量从6-48h显著降低(P<0.05),至72h时显著增加(P<0.05),而机体肝胰腺的可溶性蛋白质含量从12h开始至96h显著降低(P<0.05); 血蓝蛋白含量在前24h显著降低(P<0.05),48h开始显著升高(P<0.05); 肝糖原含量在6-96h与对照组相比有显著的降低(P<0.05); 16‰盐度组蟹的血糖含量在24-48h时显著下降(P<0.05),到72h开始逐渐恢复(P>0.05),而30‰盐度组其血糖含量早在6-12h时就有显著的下降(P<0.05),到24h则开始逐渐升高.研究表明,在急性盐度胁迫下,糖类和蛋白质对中华绒螯蟹渗透压调节起重要的作用,其优先利用糖类的分解获得所需的能量,其中盐度越高,机体内葡萄糖的消耗越快,血糖水平的恢复也相应较快.对蛋白质的利用稍次之,机体可利用蛋白质的分解获得其渗透压调节的效应物游离氨基酸以维持渗透压平衡.
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