Feeding and swimming modulate iono-and-hormonal regulation differently in goldfish, Carassius auratus and common carp, Cyprinus carpio

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• 作者：Hon Jung Liew^a ; ^b ; ¹ ; ^{honjung@umt.edu.my} ; Amit Kumar Sinha^a ; ¹ ; Nathalie Mauro^a ; Marjan Diricx^a ; Veerle M. Darras^c ; Ronny Blust^a ; Gudrun De Boeck^a
• 关键词：Aerobic ; Exercise ; Cortisol ; Fasting ; Gill ; Osmorespiratory compromise ; Plasma ion ; Ucrit
• 刊名：Comparative Biochemistry and Physiology - Part A: Molecular & Integrative Physiology
• 出版年：2013
• 出版时间：May, 2013
• 年：2013
• 卷：165
• 期：1
• 页码：13-21
• 全文大小：670 K

文摘

Feeding and swimming can influence ion balance in fish. Therefore we investigated their impact on ionoregulation and its hormonal control in goldfish and common carp. As expected due to the osmorespiratory compromise, exhaustive swimming induced increases in gill Na⁺/K⁺ ATPase (NKA) activity in both species, resulting in stable levels of plasma ions. In contrast to our expectations, this only occurred in fed fish and feeding itself increased NKA activity, especially in carp. Fasting fish were able to maintain ion balance without increasing NKA activity, we propose that the increase in NKA activity is related to ammonia excretion rather than ion uptake per se. In goldfish, this increase in NKA activity coincided with a cortisol elevation whilst no significant change was found in carp. In goldfish, high conversion of plasma T₄ to T₃ was found in both fed and fasted fish resulting in low T₄/T₃ ratios, which increased slightly due to exhaustive swimming. In starved carp the conversion seemed much less efficient, and high T₄/T₃ ratios were observed. We propose that thyroid hormone regulation in carp was more related to its role in energy metabolism rather than ionoregulation. The present research showed that both species, whether fed or fasted, are able to sufficiently adapt their osmorepiratory strategy to minimise ions losses whilst maintaining gas exchange under exhaustive swimming.