Genotoxic and pathological effects of malathion in male Japanese quail (Coturnix japonica).

Pesticides (insecticides, herbicides and fungicides) constitute the major source of potential environmental hazards when they become part of food chains (Hussain et al., 2012). Long term exposure to these products causes countless abnormalities and reduces the life span of organisms (Hussain et al., 2011; Hussain et al., 2014). Environmental and ecological risk assessment is important in grain producing areas as wildlife species extensively inhabit in these ecosystems. Avian species have a distinctive place in ecosystem and constitute one of the diverse and evolutionary groups (Mitra et al., 2011). Birds are the best indicators of early warning to environmental problems and threats. Healthy avian populations are the representative of a sound ecosystem (Sekereioglu et al., 2004). Wild as well as migratory birds from different biodiversity are directly or indirectly exposed to lethal doses of pesticides, which are the major factor responsible for avian population decline worldwide. It is difficult to establish a correct estimate of pesticide and insecticide persuaded deaths in birds. Birds may die away from the site of poisoning and their carcasses decompose quickly or may be eaten by the scavengers (Mitra et al., 2011). Malathion (1,2-dicarbethoxyethyl) is a member of organophosphate pesticides (OPs) and is used over various food crops to control pests due to low environmental persistence. In addition, malathion is frequently used for mosquito eradication and control of ectoparasites infesting cattle, poultry, sheep and other domestic animals (Uzun et al., 2009). This pesticide is frequently sprayed over various food crops including maize, cotton and wheat to control pests. Apart from domestic and wild mammals, birds living in the same ecosystems and searching feed in the field treated with malathion are also exposed to this compound (Mitra et al., 2011). Organophosphate pesticides such as malathion are well known to arrest acetylcholinesterase enzyme expressing clinically muscular tremors and torticollis due to degenerative changes in brain tissue (Senger et al., 2005). Degenerative as well as apoptotic changes have also been reported in testes (Maitra and Mitra, 2008; Uzun et al., 2009) and bursa of Fabricius (Nain et al., 2011). Previously, various studies have indicated that exposure to malathion (parathion) significantly reduces testosterone level in rats (Maitra and Mitra, 2008; Uzun et al., 2009). Blood cells reflect all physical and chemical changes in various organisms that are exposed to different groups of insecticides and pesticides (Ambali et al., 2011). Micronuclei (MN) which are cytoplasmic chromatin containing bodies that materialize in cell cytoplasm like a small satellite nucleus, are considered as the best biomarker of DNA damage (Hussain et al., 2014). Previously, different workers have used micronucleus test in visceral and blood cells such as bone marrow, ovary, liver, peripheral blood and fetal cells of different organisms (Hussain et al., 2014). Pak. J. Agri. Sci., Vol. 52(4), 1149-1156; 2015 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas. com.pk