The corollary effect of heavy metal accumulation in freshwater ponds on the hematological profile of Nile Tilapia (Oreochromis niloticus)

Abstract

The status of heavy metal buildup in commercial and non-commercial ponds of Nile tilapia (Oreochromis niloticus) and its effect on fish health was evaluated. Pond water and tilapia meat were examined for Pb, As, cadmium Cd and Cu using flame atomic absorption spectrometry; and Hg through manual cold-vapor atomic absorption spectrometry. Standard methods in hematology were applied to estimate red and white blood cell function of fish in relation to heavy metal accumulation. The results revealed significantly higher Cu content in pond water of a commercial farm compared to the Cu content of water from a non-commercial farm, while similar levels of Hg and Pb were recorded. Tilapia meat from commercial ponds had significantly higher Pb and lower levels of Cu compared to meat from a non-commercial farm. Similar levels of Hg were observed in tilapia meat obtained from farms while tilapia meat from non-commercial ponds had significantly higher Cu. Neither As nor Cd were detected in the farms. Hematological evaluation revealed comparable counts of total red blood cell. Red blood cell indices such as hematocrit and mean corpuscular volume were significantly higher in tilapia from the commercial ponds. The amount of hemoglobin per red blood cell was smilar in tilapia from the farms while mean corpuscular hemoglobin concentration was significantly higher in tilapia from the non-commercial farm. Total white blood cell and eosinophil counts of tilapia were similar in the farms. Tilapia from the commercial ponds had significantly high neutrophil and monocyte counts while tilapia from the non-commercial ponds had significantly high lymphocyte counts. The hematological evaluation indicate relationship of cellular components of fish blood and heavy metal accretion from the aquatic environment by Nile tilapia.

Time-dependent hematological responses of Nile tilapia Oreochromis niloticus exposed to an estuarine contaminated water

“…Similar results were observed in O. niloticus exposed to sub-lethal sodium selenite concentrations where leukocytosis was also associated to an increased lymphocyte, neutrophil, and monocyte counts (Ranzani-Paiva, Lombardi, Maiorino, Gonçalves, & Dias, 2014). The increase in cell types of the white series has been reported in other studies where fish were exposed to water contaminated with heavy metals, like in Anguilla anguilla exposed to water contaminated with lead (Santos & Hall, 1990), O. niloticus exposed to metals such copper, borium and lead in the aquatic environment (Garcia, Miguel, Gabriel, & Mingala, 2016), and Ctenopharyngodon idella exposure to copper and chromium (Shah et al, 2020).…”

Assessment of heavy metal contamination of fish from a fish farm by bioconcentration and bioaccumulation factors

“…The presence of heavy metals in the waters and sediments of fish farms comes from many sources including agricultural activities (Garcia et al, 2016) and fish feed (Das et al, 2017). Many studies (Mostafa et al, 2015;Sarker et al, 2016;Adeyemi and Ugah, 2017;Maurya et al, 2018;Junejo et al, 2019) have demonstrated anthropogenic pollution of water and sediments in fish farms by heavy metals.…”

Change of growth performance, hematological parameters, and plasma component by hexavalent chromium exposure in starry flounder, Platichthys stellatus

“…Growth performance is a factor reflecting environmental toxicity in fish, and even a small concentration of heavy metals has a negative effect, triggering physiological changes such as growth and metabolism and reducing health and survival rates (Hussain et al 2010). Hematological parameters are used to effectively monitor the status of fish exposed to various types of toxicity in the aquatic environment (Garcia et al 2016). The main goal of ecotoxicology in aquatic ecosystems is to assess the toxicity of aquatic organisms and humans (Ribeiro et al 2006).…”