Authors: Feng Zhao Beibei Wu Gang Yang Tao Zhang Ping Zhuang
Publish Date: 2015/11/27
Volume: 42, Issue: 2, Pages: 749-756
Abstract
Understanding the physiological changes and osmoregulatory strategy is critical for anadromous species to adapt to large changes between freshwater and marine environments In this study juvenile Chinese sturgeon Acipenser sinensis were acclimated for 2 months to freshwater FW c 0 ‰ and brackish water BW 15 ‰ Blood was assessed for changes in osmolality and ions Gill tissue was assayed for Na+ K+ATPase NKA activity and immunohistochemical analysis on mitochondriarich cells MRCs Serum osmolality and ions concentrations Na+ Cl− and K+ examined except K+ increased significantly in those specimens adapted to BW However the variations were within the range of effective hyperosmotic adaptation The specific activity of gill NKA of juveniles adapted to BW was significantly higher c 16 times than that of fish adapted to FW MRCs were mainly presented in the interlamellar region of the filament and at the base of the lamella in either FW or BWacclimated individuals In BW the number and size of MRCs on filaments greatly increased However there was no significant difference in the number and size of the MRCs at the lamella region Results show that juvenile Chinese sturgeon keep osmotic homeostasis in hyperosmotic environments by increasing gill NKA activity and MRCs’ size and number which is similar to other sturgeons and euryhaline teleosts
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