Toxic threshold of dietary microcystin (-LR) for quart medaka

Dong Fang Deng, Keke Zheng, Foo Ching Teh, Peggy W. Lehman, Swee J Teh

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


This study was designed to estimate the toxic threshold of male and female fish to microcystins based on different biomarkers. Japanese medaka (Oryzias latipes) were fed dietary Microcystin-LR (0, 0.46, 0.85, 2.01 and 3.93 μg MC-LR/g dry diet for 8 weeks at 25 °C. The results revealed that dietary MC-LR inhibited growth at the end of 8 weeks. The survival of embryos and the RNA/DNA ratio of whole fish decreased significantly (P < 0.05) in fish fed 3.93 μg MC-LR/g dry diet. Heat shock protein (Hsp60) expression was induced in the liver of female and male fish fed diets containing ≥0.85 and 0.46 μg MC-LR/g diet, respectively. The activity of liver caspase 3/7 was significantly higher in female fish fed 3.93 μg MC-LR/g diet and in males fed 2.01 MC-LR μg/g dry diet than fish fed the control diet. The threshold for inhibition of liver protein phosphatase expression was lower in female (2.01 μg/g diet) than that in male fish (3.93 μg/g diet). Histopathological examination showed significant single-cell necrosis in female and male medaka fed diets containing 0.85 and 3.93 μg MC-LR/g diet, respectively. Based on different biomarkers, this study demonstrated that dietary MC-LR is toxic to Medaka and the effects are gender dependent.

Original languageEnglish (US)
Pages (from-to)787-794
Number of pages8
Issue number4
StatePublished - Apr 1 2010


  • Apoptosis
  • Medaka
  • Microcystin
  • Protein phosphatase
  • Reproduction
  • Stress protein

ASJC Scopus subject areas

  • Toxicology
  • Medicine(all)


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