Acetylcholinesterase inhibition and gill lesions in Rasbora caverii, an indigenous fish inhabiting rice field associated waterbodies in Sri Lanka

Abstract

The present study was aimed at applying condition factor (CF), brain acetylcholinesterase (AChE) and gill histology as biomarkers for detecting possible exposure/effect induced by pesticides in fish residing rice field associated waterbodies in Sri Lanka. Biomarkers of an indigenous fish, Rasbora caverii collected from five sampling sites including canals near rice fields, a river and a reservoir (the reference site) were evaluated at four sampling stages covering pesticide application periods during rice cultivation season in 2004. Results indicated that CF of the fish did not show significant alterations regardless of the sampling sites or sampling stages. Site specific differences in AChE activities of the fish were not evident either prior to application of pesticides or at 7 days after Paraquat application to the rice fields. Two days after the application of a mixture of Fenthion and Phenthoate to the rice fields, AChE activity of the fish collected from canals near rice fields was significantly depressed (65-75%) compared to the fish in the reference site. The activities remain depressed to 50-56% even at 65 days after the insecticides application. Laboratory studies showed that prior exposure of R. caverii to Paraquat (2 microg l(-1), 7 days) enhanced the extent of inhibition of brain AChE activity induced by Fenthion (3 microg l(-1)) or a mixture of Fenthion (3 microg l(-1)) and Phenthoate (5 microg l(-1)). Gills of fish collected from canals near rice fields exhibited abnormal multiple divisions at the tips of some secondary lamellae in addition to hyperplasia, hypertrophy and club shaped deformities. Results indicate that application of pesticides in rice culture could manifest a threat to native fish populations residing rice field associated waterbodies. The response of brain AChE and histological changes in the gills of R. caverii allowed differentiating sampling sites after insecticide applications to the rice fields. Hence, R. caverii may be considered as a surrogate species in ecotoxicological risk evaluation of agrochemicals in the region.

Histopathological effects of Cyperdicot and vitamin E supplementation on selected organs of Clarias gariepinus (Burchell, 1822) reared in a tropical fish farm in Nigeria

“…The few changes in condition factor in the present experimental periods could be attributed to this factor. This factor could not be enough sensitive biomarker to measure the environmental stress in natural environments (Wiieyaratne and Pathiratne, 2006). The recorded non-significant effect of vitamin E on the condition factor throughout the experimental periods was also recorded in the freshwater fish rainbow trout (O. mykiss) (Al-Juary et al, 2006).…”

“…Histopathological biomarkers in the gills may be valuable as indicators of the general health of the fish and mirror effects of exposure to a variety of anthropogenic pollutants (Wiieyaratne and Pathiratne, 2006). The histopathological effects on the gills of freshwater fish showed necrosis, abnormalities to gill lamellae, extensive fusions of secondary lamellae, and a thick coat of mucus on the gill filaments upon exposure to Cyperdicot (Rao et al, 2005).…”

Multi-biomarker responses as indication of contaminant effects in Gambusia affinis from impacted rivers by municipal effluents

“…Samples of heads and livers were immediately frozen in liquid nitrogen, and stored at −80°C for subsequent assays. The condition factor of each fish was calculated as CF = (W/L 3 ) × 100, where W is body weight (g) and L is total fish length (cm) (Wijeyaratne and Pathiratne, 2006). The hepatosomatic index (HSI) was calculated as HSI = (LW / W) × 100, where W is body weight (g) and LW is liver weight (g) (Corsi et al, 2003).…”

Fish Cholinesterases as Biomarkers of Organophosphorus and Carbamate Pesticides

“…Thus, AChE from aquatic organisms has been used due to its ability to assess the environmental impact when these compounds are not present in the water (Morgan et al, 1990;Sturm et al, 1999;Ferrari et al, 2004;Wijeyaratne and Pathiratne, 2006). Among these organisms are fish (Rodríguez-Fuentes and Gold-Bouchot, 2000;Fulton and Key, 2001;Oliveira et al, 2007;Rodríguez-Fuentes, Armstrong and Schlenk, 2008).…”