Background: The iono- and osmoregulatory capacities of marine teleosts, such as European sea bass (Dicentrarchus labrax) are expected to be challenged by high carbon dioxide exposure, and the adverse effects of elevated CO could be amplified when such fish migrate into less buffered hypo-osmotic estuarine environments. Therefore, the effects of increased CO on the physiological responses of European sea bass (Dicentrarchus labrax) acclimated to 32 ppt, 10 ppt and 2.5 ppt were investigated.
Methods: Following acclimation to different salinities for two weeks, fish were exposed to present-day (400 µatm) and future (1000 µatm) atmospheric CO for 1, 3, 7 and 21 days. Blood pH, plasma ions (Na+, K+, Cl-), branchial mRNA expression of ion transporters such as Na/K-ATPase (NKA), Na/K/2Cl co-transporters (NKCC) and ammonia transporters (e.g. Rhesus glycoproteins Rhbg, Rhcg1 and Rhcg2) were examined to understand the iono- and osmoregulatory consequences of elevated CO.
Results: A transient but significant increase in the blood pH of exposed fish acclimated at 10 ppt (day 1) and 2.5 ppt (day 21) was observed possibly due to an overshoot of the blood HCO accumulation while a significant reduction of blood pH was observed after 21 days at 2.5ppt. However, no change was seen at 32 ppt. Generally, Na + concentration of control fish was relatively higher at 10 ppt and lower at 2.5 ppt compared to 32 ppt control group at all sampling periods. Additionally, NKA was upregulated in gill of juvenile sea bass when acclimated to lower salinities compared to 32 ppt control group. CO exposure generally downregulated NKA mRNA expression at 32ppt (day 1), 10 ppt (days 3, 7 and 21) and 2.5ppt (days 1 and 7) and also a significant reduction of NKCC mRNA level of the exposed fish acclimated at 32 ppt (1-3 days) and 10 ppt (7-21 days) was observed. Furthermore, Rhesus glycoproteins were generally upregulated in the fish acclimated at lower salinities indicating a higher dependance on gill ammonia excretion. Increased CO led to a reduced expression of Rhbg and may therefore reduce ammonia excretion rate.
Conclusion: Juvenile sea bass were relatively successful in keeping acid base balance under an ocean acidification scenario. However, this came at a cost for ionoregulation with reduced NKA, NKCC and Rhbg expression rates as a consequence.
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http://dx.doi.org/10.1007/s11033-024-09460-2 | DOI Listing |
Fish Shellfish Immunol
December 2024
College of Fisheries, Henan Normal University, Xinxiang 453007, China; Observation and Research Station on Water Ecosystem in Danjiangkou Reservoir of Henan Province, Nanyang 474450, China; Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA. Electronic address:
Largemouth bass (Micropterus salmoides) has become one of the most important freshwater economic fish farmed almost all over China in recent years. At the same time, the increasing outbreaks of diseases in its aquaculture process have caused substantial economic losses to this industry. However, at present, the genetic basis of disease resistance, including resistance against Aeromonas veronii infection, in largemouth bass is very limited.
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December 2024
Key Laboratory of Aquatic Product Processing, Ministry of Agriculture and Rural Affairs of The People's Republic of China, National R&D Center for Aquatic Product Processing, South China Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510300, China; Key Laboratory of Efficient Utilization and Processing of Marine Fishery Resources of Hainan Province, Sanya Tropical Fisheries Research Institute, Sanya 572018, China. Electronic address:
Fermented sea bass, recognized for its firmness and chewy texture, provides a distinct sensory experience.This study investigated the texture and microstructural properties of fermented sea bass during fermentation. Proteomics analysis identified the key proteins involved in firmness development, revealing the molecular mechanisms behind these changes.
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December 2024
Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, V9T 6N7, Canada.
The potential risk posed by infectious agents (IAs) associated with netpen aquaculture to wild fishes is determined based on the "release" of IAs from netpens into the environment, the "exposure" of the wild fish to those released agents, and the "consequence" for wild fish experiencing infection by those agents. Information available to characterize these three factors is often lacking, and the occurrence of transmission from aquaculture to wild fish as well as potential consequences of such transmission are difficult to observe. In this study, we utilized environmental DNA (eDNA) to characterize the release of dozens of IAs from, and exposure of Pacific salmon to, Atlantic salmon aquaculture.
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December 2024
State Key Laboratory of Marine Food Processing and Safety Control, Dalian Polytechnic University, Dalian 116034, Liaoning, China; Academy of Food Interdisciplinary Science, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, Liaoning, China; National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116034, Liaoning, China. Electronic address:
The present study was to investigate the effect of the astaxanthin high internal phase Pickering emulsion (H-AXT) on DEHP-induced liver lipid metabolism disorder and to demonstrate its possible protective mechanism. We have developed an antioxidant activity emulsion system to deliver astaxanthin into the liver to maximize its ability to protect the liver. In vitro, H-AXT intervention inhibited oxidative stress restored the level of mitochondrial membrane potential to 90 % of that of normal LO2 cells, and alleviated the imbalance of energy metabolism by protecting mitochondrial structure and function.
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November 2024
Key Laboratory of Smart Agricultural Technology in the Southwest Mountains, Ministry of Agriculture and Rural Affairs (Co-Construction by Ministry and Province), Chongqing Academy of Agricultural Sciences, Chongqing 400715, China.
Ammonia, a ubiquitous contaminant in aquatic ecosystems, poses multifaceted threats to fish species at elevated concentrations. In order to investigate the toxic effects of chronic ammonia stress on the liver of juvenile , the present experiment was conducted to investigate the differences in changes in liver tissue structure, enzyme activities, and metabolomes after 28 days of ammonia exposure (0, 4, 8, and 16 mg/L). The findings revealed that ammonia exposure induced significant oxidative stress in the liver, manifesting in decreased activities of antioxidant enzymes SOD and GSH-Px, elevated levels of GSH, GST, and MDA, and heightened activities of immune enzymes LZM, ALP, and ACP.
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