Detection, diagnosis, Koch’s postulate, hepatorenal and antioxidant indicators for some systemic pathogenic fungi invading the liver and kidneys of African catfish ( Clarias gariepinus ) in Egypt with a histopathological approach

Abstract

Recently, systemic fungal infections have emerged as significant causes of fish morbidity and mortality. Hence, the current study investigates the occurrence of some pathogenic systemic fungi inducing severe lesions in the liver and kidneys of African catfish. Two hundred diseased African catfish were collected from private fish farms in Egypt, and only 120 fish were infected with 212 different fungal isolates at a rate of 60%. The seasonal survey revealed isolation of 72 isolates of yeast (Candida albicans) and 140 isolates of moulds including non‐pigmented moulds, Aspergillus ochraceous and Aspergillus flavus, as well as pigmented mould (Cladosporium herbarum). The isolated fungi induced characteristic post‐mortem lesions. To date, this is the first report for isolation of C. herbarum and C. parapsilosis from Nile catfish liver and kidneys. Various techniques were performed to identify the fungi including gross observation, microscopic examination of tissue squashes, in vitro culture and histopathology. Koch's postulate was fulfilled to confirm the fungal pathogenicity. The challenged fungi altered the hepatorenal indicators (ALP, AST, ALT, urea and creatinine) and oxidative stress biomarkers (MDA, CAT and SOD). The results indicate the virulence of the isolated fungi, and future studies are needed for treatment trials.

Physiological Performance, Antioxidant and Immune Status, Columnaris Resistance, and Growth of Nile Tilapia That Received Alchemilla vulgaris-Supplemented Diets

“…The World Health Organization has declared the spreading of multi-resistant bacterial strains. To avoid the resistance of the pathogen to antibiotics [ 4 ], plants are a non-antibiotic, safe, and cheap source that exhibits potent antibacterial activity in aquaculture [ 5 , 6 , 7 , 8 ]. Another significant reason for utilizing plant extracts is their natural multi-constituents that are well-documented and verified for promising fish growth and immune-antioxidant traits [ 9 , 10 , 11 ].…”

Toxicological insight of metiram: immuno-oxidative, neuro-behavioral, and hemato-biochemical changes during acute exposure of Nile tilapia (Oreochromis niloticus)

“…It is a condition in which the host body’s antioxidant defense mechanisms are out of balance with the generation of ROS following exposure to xenobiotics [ 87 , 88 ]. Because it plays a vital role in detoxifying harmful substances and preparing metabolic products for breakdown, the liver often possesses the highest antioxidant defenses when compared to other organs [ 89 , 90 ]. In this investigation, acute MET exposure in Nile tilapia resulted in higher lipid peroxides (MDA) levels and lower antioxidant defenses (TAC, SOD, and GPx) activity.…”

Silica nanoparticles alleviate the immunosuppression, oxidative stress, biochemical, behavioral, and histopathological alterations induced by Aeromonas veronii infection in African catfish (Clarias gariepinus)

“…TAC indicates oxidative damage or increased vulnerability to oxidative stress (Young 2001 ). MDA is one of the most substantial products of oxidation and is mainly monitored as a marker of oxidative stress (Mendes et al 2009 ; Mahboub et al 2022a ). Herein, we report the dangerous impact of A. veronii on the antioxidant defense mechanism via altering oxidative/antioxidant biomarkers (elevating MDA and decreasing GPx and TAC).…”