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Abstract

A wide variety of chemicals especially metals contaminate the aquatic ecosystem and stimulate a variety of toxicity mechanisms, such as oxidative damage to proteins, DNA and lipids. Very limited efforts have been made to investigate the genotoxic effects of metals in fish. Therefore, the present study was conducted to determine copper induced genotoxic damage in peripheral blood erythrocytes of 150-day old four freshwater fish species viz. Labeo rohita, Cirrhina mrigala, Catla catla and Ctenopharyngodon idella by using micronucleus test. For this purpose, 96-hr LC50 and lethal concentration of copper for all the four fish species were determined. Each fish species was exposed to four different sub-lethal concentrations (17, 25, 33, 50% of 96-hr LC50) of copper, separately, for a period of 30 days. Results showed exposure concentration dependent increases in the frequencies of micronuclei and other nuclear abnormalities. Findings of the experiment also confirmed that the micronucleus test acts as a useful tool in determining the potential genotoxicity of metals in erythrocytes of various fish species. Among four fish species, Cirrhina mrigala showed significantly higher frequency of micronuclei with the mean value of 16.98±11.70%, followed by that of Ctenopharyngodon idella, Catla catla and Labeo rohita. However, frequency of other nuclear abnormalities followed the order: Labeo rohita > Cirrhina mrigala > Ctenopharyngodon idella > Catla catla.

Micronucleus Assay as a Biomarker to Diagnose Lead, Chromium and Cadmium Induced Genotoxicity in Erythrocytes of Carnivorous Fish, Wallago attu

“…Small alphabet superscripts show the difference between treatments within the same row While capital alphabet shows significant (P < 0.05) among different durations of exposure within the same column. Similar results were observed byKousar and Javed (2015) who noted the copper induced concentration specific formation of MN and NAs frequency in RBCs of three fish species exposed for 30-days. Similarly, Oreochromis niloticus showed higher frequency of MN and NAs in RBCs during initial hours of Cd and Zn exposure after that both were decreased in duration dependent manner(Abu-Bakar et al, 2014) Rasal et al (2011).…”

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“…Moreover, decreased values of erythrocytes, hemoglobin concentration, and serum total proteins could also be due to exhaustion and reduced hemopoietic and metabolic activities in fish exposed to arsenic and urea. The hematopoietic system and blood parameters are known to be the best biomarkers to monitor the pathophysiological status of organisms exposed to different toxicants (Kousar and Javed, 2015). Furthermore, increased values of mean corpuscular volume in our study can be related to increased number of immature erythrocytes suggestive of macrocytic anemia (Carvalho and Farnandes, 2006).…”

Study of the frequencies of erythrocyte abnormalities as in situ biomarkers of genotoxic risk of chemicals in special fish stock in water supply reservoirs

“…Manson's solution was used to detect basophilic stippling, and Perl's Prussian blue staining was used to determine the pigment content and Feulgen stain to identify chromosomal material or DNA. For each individual, erythrocytes were examined under 1000× magnification and scored into categories, most of which were evaluated for their use as pollution bioindicators using the MNT and the nuclear erythrocyte abnormalities test in erythrocytes (Ale et al., 2004; Ali et al., 2008; Al‐Sabti, 1986a, 1986b; Anbumani & Mohankumar, 2011; Azevodo et al., 2012; Baršienė et al., 2006; Braham et al., 2017; Carrasco et al., 1990; Das & Nanda, 1986; Gomes et al., 2015; Göney & Gazeloglu, 2020; Hussain et al., 2018; Ivanova et al., 2016; Jiraungkoorskul et al., 2007; Kousar & Javed, 2015; Matsumoto et al., 2006; Metcalfe, 1988). The criteria for scoring MN and binuclei (BN) were adapted from Fenech et al., 2003; the diameter of MN should be less than one‐third of the main nucleus.…”