Fine structure and differentiation of the alimentary canal in captive-bred Japanese eel Anguilla japonica preleptocephali

Yuichi Ozaki, Hideki Tanaka, Hirohiko Kagawa, Hiromi Ohta, Shinji Adachi, Kohei Yamauchi

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The fine structure of the alimentary canal in preleptocephali produced by artificially matured Japanese eel was examined. At 1 day posthatch (dph), the alimentary canal was found only above the dorsal side of the yolk mass, and the epithelium was composed of a single layer of epithelial cells. By 5 dph, the alimentary canal was divided into three segments based on the structure of the epithelial cells: foregut, midgut and hindgut, corresponding to the future esophagus, intestine and rectum, respectively. After 7 dph, the epithelium in the foregut was surrounded by a circular muscle layer, suggesting a role in the transportation of food materials. The epithelial cells of the midgut exhibited well-developed membranous structures, which are deduced to be invaginations of the cytoplasmic membrane. Pinocytotic invaginations and vacuoles were observed in the epithelial cells of the hindgut; this observation suggests that this region is involved in the uptake of food. Significant changes in morphological features of the epithelial cells in each segment were observed until 7 dph; however, these were not evident between 7 dph and 13 dph. Consequently, the differentiation of the alimentary canal was completed by 7 dph, and preleptocephalus had developed the ability to absorb food by 7 dph.

Original languageEnglish
Pages (from-to)13-19
Number of pages7
JournalFisheries Science
Issue number1
Publication statusPublished - 2006 Feb
Externally publishedYes


  • Alimentary canal
  • Fine structure
  • Japanese eel
  • Preleptocephalus

ASJC Scopus subject areas

  • Aquatic Science


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