Research in: Agricultural & Veterinary Sciences

Acanthocephalosis is a significant parasitic disease affecting salmonid fish, particularly those reared in aquaculture. The present study investigates the pathomorphological changes in the intestines of trout (Salmo caspius) infected with acanthocephalans in fish farms across Azerbaijan. Between 2012 and 2024, 668 trout specimens from six aquaculture facilities were examined using complete parasitological dissection and histological techniques with hematoxylin and eosin staining. Microscopic analysis revealed that the parasites’ proboscides penetrated deeply into the intestinal wall, causing extensive destruction of the mucosal and submucosal layers, epithelial detachment, haemorrhages, oedema and inflammatory infiltration. The encapsulation of the parasites characterised chronic lesions, the formation of connective tissue capsules and granulomatous inflammation, indicating a prolonged host-parasite interaction. Acute stages exhibited purulent-necrotic inflammation, total mucosal lysis and vascular injury. These structural alterations disrupt intestinal absorption and peristalsis, predisposing fish to secondary bacterial infections and reducing their physiological efficiency and commercial value. The findings underscore the necessity for ongoing parasitological monitoring and preventive measures in Azerbaijan’s trout farms to mitigate the effects of acanthocephalan infections on aquaculture productivity and fish health.