摘要
Gill morphological changes and physiological responses in juvenile large yellow croaker(Larimichthys crocea)were examined upon exposure to low salinity after indoor culture of the fish at salinities of 2,4,6,8,and 24‰(control group).The thickness of the lamellae was significantly higher in the low-salinity groups than in the control group;in contrast,the interlamellar space was significantly lower in the low-salinity groups than in the control group.Additionally,a significant negative correlation was found between the thickness of lamellae and interlamellar spaces(P<0.01).Mitochondria-rich cells(MRCs)were mainly found in the filament at 24‰salinity and proliferated in the lamellae at lower salinities,suggesting that filament and lamellar MRCs are responsible for ion secretion and absorption,respectively.Meanwhile,the activity of Na+/K+-ATPase(NKA)was significantly elevated with the decrease in salinity from 24‰to 4‰(P<0.05),which was consistent with MRCs proliferation.Finally,the activity of NKA declined at 2‰salinity(P<0.05),indicating the limit of osmoregulation,which was consistent with the degeneration and necrosis of the lamellae.Additionally,different levels of gill histopathological lesions,including pavement cell(PVC)exfoliation,lamellar epithelial lifting,edema,fusion,aneurism,and necrosis,were observed from salinities of 24 to 4‰,likely reducing the respiratory efficiency and compromising the health of juvenile fish.In conclusion,large yellow croaker juveniles could improve the osmoregulatory capacity by increasing lamellar MRCs and NKA activity with the decrease in salinity from 24 to 4‰.However,the associated histopathological lesions are likely to negatively influence the fish by affecting respiration and osmoregulation,especially when the salinity is below 4‰.
作者
Guangliang Teng
Weiqing Huang
Chenglong Ji
Yunlong Chen
Xiujuan Shan
滕广亮;黄伟卿;吉成龙;陈云龙;单秀娟(College of Fisheries and Life Science,Shanghai Ocean University,Shanghai,201306,China;Laboratory for Marine Fisheries Science and Food Production Processes,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;Yellow Sea Fisheries Research Institute,Chinese Academy of Fishery Science,Qingdao,266071,China;College of Life Science,Ningde Normal University,Ningde,352100,China;Ningde Dingcheng Fishery Company Limited,Ningde,352000,China;Yantai Institute of Coastal Zone Research,Chinese Academy of Sciences,Yantai,264003,China)
基金
This work was supported by the National Key R&D Program of China(2018YFD0900906)
the AoShan Talents Cultivation Program Supported by the Qingdao National Laboratory for Marine Science and Technology(2017ASTCP-ES07)
the Key Laboratory of Sustainable Development of Marine Fisheries,Ministry of Agriculture,P.R.China(2018HY-XKQ01)
the STS project of Fujian Province(2017T3016)
the Ningde Normal University Special Fund Program(2019ZX406)
the Fujian Province Think Tank of Science and Technology(decision-making consulting)key projects(FJKX-A1618).
