Alterations in the epidermis of the carp, Labeo rohita (Cyprinidae: Cypriniformes), infected by the bacteria, Aeromonas hydrophila: A scanning electron microscopic, histopathological and immunohistochemical investigation

Abstract

This study was carried out to comprehend the pathogenicity of the bacteria in the epidermis of Labeo rohita inoculated with Aeromonas hydrophila. Alterations in the histopathology of the epidermis were examined using scanning electron microscopy, light microscopy and the localization of iNOS and caspase 3 + ve cells by means of immunohistochemical methods. Skin samples obtained from infected fish at different intervals 2, 4, 6, 8 and 10 days showed significant changes in the cellular components of the epidermis. Epithelial cells often appeared hypertrophied with fragmented and loosely arranged microridges, and in the process of exfoliation. Mucous goblet cells increased significantly in density. Club cells showed degenerative changes, often with simultaneous confluence of adjacent cells and release of their contents. Increase in density of iNOS and caspase 3 + ve cells indicates inflammatory response and apoptosis. This study could provide valuable information on the pathogenesis of the disease, and disease outbreaks in farmed fish. Further, it could provide useful guidelines for fish farmers to take preventive measures for the control of the disease.

Evaluation of prophylactic efficacy of cinnamaldehyde in murine model against Paradendryphiella arenariae mycotoxin tenuazonic acid-induced oxidative stress and organ toxicity

“…Apoptosis is generally associated with the mycotoxicity 64 . Caspases (cysteine-dependent aspartate protease) has a key role in the process of apoptosis 65 . It also takes part in the regulation of the host response during infection with bacteria, viruses and parasites 66 .…”

Aeromonas hydrophila induction method in adult zebrafish (Danio rerio) as animal infection models

“…The use of freshwater fish and zebrafish infected with A. hydrophila as animal challenge models for the prevention and treatment of infectious illnesses is quite common. According to a study by Srivastava et al [25], LD 50 was observed in Labeo rohita infected with A. hydrophila (2 × 10 7 CFU/mL) 96 h after infection. According to a study by Rodríguez et al [16], adult zebrafish treated with A. hydrophila through IP injection at a bacterial CFS concentration of 10 5 CFU/mL (bacterial suspension 5 × 10 7 CFU/mL) reached a 60% mortality rate in 1 day.…”

“…According to a study by Srivastava et al . [ 25 ], LD 50 was observed in Labeo rohita infected with A. hydrophila (2 × 10 7 CFU/mL) 96 h after infection. According to a study by Rodríguez et al .…”

“…At the beginning of a bacterial infection, bacteria attach to and destroy the scales. Aeromonas hydrophila produces chitinase enzymes during infection to break down the chitin coating (scales covered with chitin) [ 3 , 25 ]. Damaged scales result in the release of mucus, eradicating the existing microbiota.…”

The Nasal Epithelium as a Route of Infection and Clinical Signs Changes, in Rainbow Trout (Oncorhynchus mykiss) Fingerlings Infected with Aeromonas spp

“…The genus Aeromonas is a group of bacteria of importance to aquaculture, which is frequently isolated in aquatic environments [1,2]. They can act as important pathogens in poikilotherm species because they are widely distributed in water bodies [3], and they are part of the normal gut microbiota of aquatic and terrestrial animals [4].…”