Genetic diversity in chestnuts of Kashmir valley The aim of this study was to investigate the testicular and genotoxic effects of chlorpyrifos, an organophosphate insecticide, in adult male Japanese quail. For this purpose a total of 75 sexually mature birds were procured and randomly kept in five equal groups. Chlorpyrifos was given @ 0, 6, 8, 10 and 12 mg/kg BW orally for 36 days to experimental birds present in all groups (A-E). Adverse effects such as gasping, depression, watery droppings, decreased foam production, tremors and less frequency of mounting with pen mates were evident in a dose-dependent manner. Chlorpyrifos decreased feed intake, body weight and relative weight of testes, liver and kidneys as compared to control birds. Histopathological examination of seminiferous tubules of testes at higher concentration of chlorpyrifos (10 and 12 mg/kg BW) revealed less number of spermatogenic cell layers, increased number of degenerated spermatozoa and multinucleated giant cells. Furthermore, histopathological examination of liver tissues indicated extensive cytoplasmic vacuolation. Moreover, mild to moderate congestion with sporadic tubular epithelial cell necrosis was observed in kidneys. Significantly increased comet tail length confirmed DNA damage at higher concentration of chlorpyrifos in isolated lymphocyte and bone marrow cells. It was concluded that chlorpyrifos at 10 and 12 mg/kg BW rendered various clinical, pathological alterations in internal organs and was also involved in genotoxicity. Keywords: Chlorpyrifos, quail, pathology, bone marrow, Comet assay, genotoxicity INTRODUCTION In the modern age, the farmers extensively use pesticides, insecticides and herbicides during pre and post-harvest of various food crops to save their crops from insects/pests. These synthetic compounds induce stress that contributes to different physical and biochemical disorders including decrease reproductive efficiency, poor erythropoiesis, oxidative disorder and genotoxic effects (Hussain et al., 2012; 2013). Severe stress in association to pesticides/herbicides induces serious risk to environment, animals, human beings and the birds living in same ecology (Hussain et al., 2011; Ahmad et al., 2012; Babar et al., 2012). Pesticides are synthetic organic compounds that have played imperative role in home and public health management throughout the world (Mitra et al., 2011; Khan et al., 2012) and are a major source of public health hazard and deaths in developing countries (Saxena and Saxena, 2010; Tecles et al., 2013). Among different chemicals being employed in agriculture, the organophosphate insecticides are the major neurotoxic compounds. Extensive application of organophosphorus pesticides in agro-production sector, grain storage and public health management causes accumulation of the residues of these chemicals in different daily consume able food materials such as vegetables, cereal crops, natural water systems and act as the major sources of contact (Edwards et al., 2013). Organophosphorus pesticides result negative impact directly or indirectly on mammals, avian species and have a serious threats to ecosystem due to physicochemical alterations (Iqbal et al., 2012; Muhammad et al., 2012). Chlorpyrifos is an important member of organophosphate pesticides and is extensively used to control insects in cereal crops, grain storage, poultry houses to hold back termites, livestock and public health management (Moye and Pritsos, 2011). Chlorpyrifos (O, O’-dithyl-O-3, 5, 6-trichloro-2-pyrydyl phosphorothionate) is usually metabolized in liver and its metabolites are excreted through the kidneys (Barr et al., 2005). Acute or sub chronic administration of chlorpyrifos enhances the generation of acetylcholine that potentiates cholinergic activity and marked decline in the production of acetylcholinesterase thus imposes neurotoxicity (Kousba et al., 2007). The neurotoxic effects produce nervous signs including gait abnormalities, decreased tail-pinch response in rats and mice (Wang et al., 2009; Tripathi and Srivastav, 2010). Hepatotoxic and nephrotoxic effects have also been reported at different concentrations of chlorpyrifos in rats (Mehta et al., 2008). Little information is available regarding the genotoxic and gonadotoxic effects of chlorpyrifos in avian species in the accessible literature. Therefore, in this study, we report gonatoxic and genotoxic effects induced by subchronic oral Pak. J. Agri. Sci., Vol. 51(4), 1005-1010; 2014 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas.com.pk TESTICULAR AND GENOTOXIC EFFECTS INDUCED BY SUBCHRONIC ORAL ADMINISTRATION OF CHLORPYRIFOS IN JAPANESE QUAIL (Coturnix japonica) Muhammad Auon 1 , Fazal Mahmood 1 , Ahrar Khan 1,* and Riaz Hussain 2 1 Department of Pathology, Faculty of Veterinary Science, University of Agriculture, Faisalabad-38040, Pakistan; 2 University College of Veterinary and Animal Science, The Islamia University of Bahawalpur, Pakistan. * Corresponding author's e-mail: ahrar1122@uaf.edu.pk