Induction and recovery of morphofunctional changes in the intestine of juvenile carnivorous fish (Epinephelus coioides) upon exposure to foodborne benzo[a]pyrene

Bonny B.H. Yuen, Chris K C WONG, N. Y.S. Woo, Doris W.T. Au*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

37 Citations (Scopus)


The sublethal toxicity of dietary benzo[a]pyrene, B[a]P, on fish growth and intestinal morphofunctional changes [as measured by epithelial turnover, cell proliferation, hyperplasia, de novo crypt formation and protein absorption efficiency (i.e. expression of proton/peptide co-transporter, PepT-1, on the mucosal brush border)] were studied for the carnivorous orange-spotted grouper (Epinephelus coioides). Juvenile fish were force-fed daily with pellets containing environmentally realistic concentrations of B[a]P (dissolved in corn oil) at 0.25 μg/g body weight (low-dose) and 12.5 μg/g body weight (high-dose) for 4 weeks, followed by a control diet for a further 4 weeks to assess recovery. Although growth inhibition was observed in fish treated with high-dose B[a]P during the exposure period, no mortality was observed throughout the 8-week experiment. Significant hyperplasia of basal enterocytes of mucosal folds was detected shortly after 3-day exposure to the high-dose B[a]P. Moreover, a faster epithelial turnover was measured in the high-dose B[a]P exposed fish at exposure week 1, which was followed by an increase of basal cell proliferation and a reduction of PepT-1 expression at exposure week 2. The formation of de novo crypts, resemblance to the cancer predisposition syndrome "juvenile polyposis", was significantly higher in the intestine of high-dose treated fish as compared to the control at exposure week 2 and onwards. Abnormal cytoplasmic extrusions were frequently observed in mucosal folds of high-dose fish at exposure week 4. In the low-dose treatment group, only the expression of PepT-1 was significantly reduced at exposure week 2 and an early adaptive response was observed at exposure week 4. Despite all these intestinal disturbances were reversible in fish upon the abatement to dietary B[a]P (within 1-4 weeks), environmental realistic levels of foodborne B[a]P could induce sublethal toxicity to E. coioides, and probably impose potential risk to the marine environment. As an increase in de novo crypts was observed towards the end of the 4-week depuration period, the long-term impacts of dietary B[a]P on fish intestinal neoplasm formation worth further investigation.

Original languageEnglish
Pages (from-to)181-194
Number of pages14
JournalAquatic Toxicology
Issue number3
Publication statusPublished - 15 May 2007

Scopus Subject Areas

  • Aquatic Science
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Dietary B[a]P
  • Histopathology
  • Immunohistochemistry
  • Intestine
  • Recovery


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