Effects of salinity on haematological biochemistrical indices and liver tissue in juvenile Oncorhynchus keta

In order to simulate the catadromous migration environment of the juvenile salmon (Oncorhynchus keta), five experimental groups containing different salinities (0, 5, 10, 15 and 20) were set up. The juvenile salmons with average body mass of (26.57 +/- 6.32) g and average full length of (14.44 +/- 1.05) cm were cultured for 130 days, and then the haematological biochemistrical indices was analyzed and the structure of liver tissue was observed to investigate the changes in physiological indices during the catadromous migration of juvenile salmon. The results showed that serum osmolality and the concentration of Na+, Cl- illustrated the same tendency with water salinity variation. Specifically, the serum Na+, C- and Mg2+ levels in the salinities of 15, 20 were significantly different from those in the salinity 5 and the freshwater and serum K+ in different salinities were all obviously lower than that in the freshwater. Also, the blood glucose level in salinity 10 was significantly higher than that in salinity