Histology and ultrastructure of hepatic nodular alterations in Clarias gariepinus (Burchell, 1822)

Abstract

This study aimed to assess the macroscopic appearance, histology and ultrastructure of liver nodular alterations in sharptooth catfish Clarias gariepinus (Burchell, 1822) from a hyper‐eutrophic freshwater impoundment. The livers of 25 fish were sampled for microscopy analyses, otoliths were collected for age estimation, and the hepatosomatic index (HSI) was calculated. The light microscopic analysis of the nodular tissue revealed hepatocellular and nuclear pleomorphism, pyknotic nuclei, variation in cytoplasmic appearance and focal areas of cellular alterations (FCAs). An increase in the size and number of melano‐macrophage centres, intracellular deposits, steatosis and giant cells was also identified. The ultrastructural alterations identified included cell membrane disruption, irregular shaped nuclei with augmentation of the nucleolus and deformed nuclear envelopes. In addition, we found dilation, proliferation, fragmentation and vesiculation of the cisternae of the rough endoplasmic reticulum (RER). Furthermore, there was an increase in degenerative mitochondria (transparent matrix), swelling of mitochondria and proliferation of both peroxisomes and lysosomes. The histological and ultrastructural alterations identified did not explain the variation in macroscopic colour of the nodules. We did not find a strong positive correlation between age and HSI; however, the oldest fish (18 years) did present the most nodules.

Assessment of the Reproductive Health Status of Clarias Gariepinus (Burchell, 1822) in a River Impacted by Mercury from Clandestine Gold Mining: A Case Study of Bagoue River, Côte d’Ivoire

“…The high level of mercury in liver could explain these results. Indeed, liver histological changes associated with mercury or other pollutants exposure have been sufficiently documented in many studies (Schwindt et al, 2008;Marchand et al, 2009;Vergilio et al, 2012;Van Dyk et al, 2012;Oliva et al, 2013;Maceda-Veiga et al, 2013;Stentiford et al, 2014;Dane et al, 2017;Lukhwareni et al, 2018). Most of the alterations identified in liver are reversible.…”

“…9, No. 1 and Mé ndez-Armenta, 2008;Agohessi et al, 2015;Oreins, 2016;Sayed and Younes, 2017;Pè lè bè et al, 2017;Van Dyk, 2018;Funmilayo et al, 2019;Heba and Mohamed, 2019). Alteration due to the overall disorganization of seminiferous tubes structure and fibrosis (the highest prevalence rate) could be explained by damage to the interstitial cells surrounding the seminiferous tubes.…”