Gill histology of Nile tilapia Oreochromis niloticus following chronic and acute exposure to ammonia

Abstract

Ammonia is a common aquatic pollutant and is toxic to fish. The main nitrogenous compound excreted by fish is also ammonia, which may reach toxic concentrations in high-density fish culture, reducing growth and productivity. In this study, changes in gill structure and mucus cell distribution were examined when juvenile Nile tilapia, Oreochromis niloticus, were exposed to chronic and acute concentrations of ammonia. For chronic exposure, the tilapia were exposed to daily increments in ammonia concentration rising from 0 mg L-1 ammonia on Day 0 to 5 mg L-1 by Day 8; the experiment was terminated on Day 9. There were obvious histopathological changes to the gills over this period including hypertrophy and fusion and of the secondary lamellae. The mucus cell number in gill histology sections were observed to increase until Day 6 then decrease thereafter until the termination of the trial. For the acute exposure, juvenile tilapia were exposed to 5 mg L-1 ammonia for 5 hours. Hourly changes to the gills were monitored, with notable changes to gill filaments and an observed increase in the mucus cell number over the duration of the experiment.

The Effect of Neonicotinoids Exposure on Oreochromis niloticus Histopathological Alterations and Genotoxicity

“…Fish gills are frequently used as bioindicators reflecting water quality and the effects of xenobiotic exposure due to their susceptible structure and direct contact with water (Mallatt 1985 ; Paulino et al 2012 ). In agreement with the previous studies, the Aceta-exposed fish, herein, showed hyperplasia, fusion of secondary lamellae and edematous forms in gills (Figueiredo-Fernandes et al 2007 ; Yoon et al 2015 ; Nofal et al 2019 ; Ghayyur et al 2020 , 2021 ). Furthermore, imid-exposed fish showed the epithelial thickening of gill lamellae and dilatation of congested capillaries (Visoottiviseth et al 1999 ).…”

Molecular and Histological Studies of Salinity effect on gills and liver of Coptodon zillii in Egypt

“…Different types of pollutants and heavy metals were affected on the histological structure of spleen, liver, kidney and muscle of fish depending on its concentration, time of exposure, and other's environmental conditions (Barbara and Malgorzata, 2006;Ayas et al, 2007;EL-Naggar et al, 2011). Large surface area of fish gills is in direct and continuous contact with the external environment; so they are significantly affected by chemical and physical changes in its aquatic environment (Yoon et al, 2015;Neuraste et al, 2017) ).…”

Blood Characteristics and Tissue Histology of Oreochromis niloticus Fed Ipomoea batatas Leaf

“…In this study, histological effects in gill tissues agrees to findings of previous authors (Yones et al, 2019;Ruiz et al, 2020), where hyperplasia of the lamella, widespread infiltration of inflammatory cells and epithelial lifting and fusion of lamellar tips were observed after exposure to ammonia. No evidence of gills histology normalization in any of the treatment were demonstrated by all the formulated feed diets, suggesting the inability of the feed components to secrete and continuously replace their mucus layer as a biological barrier (Yoon et al, 2015). For kidney tissue examination, evident decrease in MMCs was observed in all fish receiving sweet potato-incorporated diets.…”