Degeneration of the alimentary tract in sexually maturing European Anguilla anguilla (L.) and American eels Anguilla rostrata (LeSueur)

Gut morphology was examined in untreated and artifically matured European and American eels. In both species there was a decrease in gut size and gut muscle thickness with increasing sexual maturity. Hormone-treated, fully mature eels displayed advanced degeneration of the muscle layers. Total muscl...

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Bibliographic Details
Published in:Canadian Journal of Zoology
Main Authors: Pankhurst, N. W., Sorensen, P. W.
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 1984
Subjects:
Online Access:http://dx.doi.org/10.1139/z84-165
http://www.nrcresearchpress.com/doi/pdf/10.1139/z84-165
Description
Summary:Gut morphology was examined in untreated and artifically matured European and American eels. In both species there was a decrease in gut size and gut muscle thickness with increasing sexual maturity. Hormone-treated, fully mature eels displayed advanced degeneration of the muscle layers. Total muscle thicknesses decreased from as high as 740 μm in sexually immature eels to less than 100 μm in sexually mature eels. Numbers of villi also decreased with maturity, with mature fish having relative lumenal circumferences that were less than half of those of immature fish. Epithelial structure changed with maturation and the number of mucous cells decreased. It is suggested that the degenerative changes are caused by elevated cortisol levels. Possible effects of gut changes on osmoregulation in seawater are discussed.