Branchial and extra-branchial ammonia excretion in goldfish (Carassius auratus) following thermally induced gill remodeling

Amanda A. Smith, Alex M. Zimmer, Chris M. Wood

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Under cold acclimated conditions, goldfish (Carassius auratus) express an interlamellar cell mass (ILCM) which limits diffusive ion loss but may also impede branchial ammonia excretion (J amm). In the present study, goldfish were subjected to a 2-week 5 or 25°C acclimation in order to modulate the degree of ILCM gill coverage and determine potential effects on J amm. 25°C-fish displayed gill coverage which was significantly lower than the 5°C-fish, though the ILCM was not completely absent in these fish. 5°C-fish demonstrated J amm values approximately 60% lower than those of 25°C-fish. The magnitude of anterior (branchial) J amm strongly correlated with gill coverage (r 2=0.83), suggesting that the ILCM may impede branchial J amm. Divided chamber experiments demonstrated that relative to the 25°C-fish, 5°C-fish relied more upon posterior routes of excretion. In response to high external ammonia (HEA; 1.5mM NH 4HCO 3) exposures, 25°C-fish displayed ammonia uptake while 5°C-fish maintained excretion against HEA, suggesting that the ILCM may act as a barrier preventing ammonia uptake. In summary, the ILCM appears to impede branchial J amm, such that 5°C-rely more on extra-branchial routes of excretion. We hypothesize that gill remodeling in these fish may be intimately tied to physiological adjustments on the whole-body scale.

Original languageEnglish (US)
Pages (from-to)185-192
Number of pages8
JournalComparative Biochemistry and Physiology - A Molecular and Integrative Physiology
Issue number3
StatePublished - Jul 2012


  • Ammonia excretion
  • Gill remodeling
  • Goldfish
  • High external ammonia (HEA)
  • Interlamellar cell mass (ILCM)

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Physiology


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