The effect of stress on the stomach of the European eel, Anguilla anguilla L.

• Published in: Journal of Fish Biology
• Main Author: Peters, G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1982
• Subjects: Anguilla anguilla
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1982.tb02855.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1982.tb02855.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1982.tb02855.x

The gastrointestinal tract is a system that is very sensitive to stress‐like conditions in mammals. Fish display physiological reactions to stress that are fundamentally similar to those of the‘General Adaptation Syndrome’ in higher vertebrates. An investigation was therefore undertaken to determine if morphological changes equivalent to those affecting the stomachs of mammals also occur in fish under stress. Conflict for social dominance served as the stressor. The unavoidable confrontation with a dominant fish in a tank proved to produce great stress for the subordinate eel. This was demonstrated by a number of physiological and haematological parameters. Stressed eels have shrunken stomachs, the consistency of which is translucent and soft. The mucous membrane folds flatten or disappear. The mucous epithelium atrophies and during this process numerous residual bodies appear. The cell‐to‐cell contact loosens. The gastric glands degenerate developing large intracellular cavities, vacuolated ER and swollen mitochondria. The connective tissue proliferates replacing the necrotic glands. The submucosal vessels contract, thereby disturbing the circulation. The consequences of the gastric atrophy (increased self‐digestion, reduction of the immunological barrier, interference with protein digestion, endocrine function, etc.) are discussed.