Carbofuran is a highly toxic carbamate insecticide due to its low environmental persistence which can reach the aquatic system threatening aquatic organisms especially fish. The present study was designed to evaluate the half lethal concentration (LC50)/96h of carbofuran in catfish clarias gariepinus and to investigate the ability of carbofuran to induce hepatonephrotoxic side effects in catfish and its possible attenuation with lycopene (LYC). Fish were distributed into six groups, each group containing 12 fish, and received the following treatments. Fish in Group I acted as control group. Fish in Group II administered corn oil orally for 4 weeks. Fish in Groups III administered LYC (18 mg/kg b.w.) orally for 4 weeks. Fish in Group IV exposed to 1/10 LC50 carbofuran for 4 weeks. Fish in Group V administered LYC (9 mg/kg b.w.) orally and exposed to 1/10 LC50 carbofuran for 4 weeks. Fish in Group VI administered LYC (18 mg/kg b.w.) orally and exposed to 1/10 LC50 carbofuran for 4 weeks. Carbofuran treated fish revealed changes in the behavioural aspects. A significant increase in serum biochemical parameters; glucose, cortisol, AST, ALT, cholesterol, urea, creatinine, as well as hepatic and renal MDA and SOD. At the same time, serum AchE, total protein, albumin, total lipids and tissue CAT, GSH and TAC levels were reduced. LYC was able to restore all the altered serum biochemical parameters in addition to hepatorenal malondialdehyde and antioxidant biomarkers in a dose-dependent manner. Therefore, it could be concluded that LYC administration is able to alleviate the damaging effects of carbofuran.
Keywords: Carbofuran; Oxidative stress; Clarias gariepinus; Biochemistry; Lycopene .
1. Introduction
Pesticides are one of the main categories of deleterious substances used worldwide for controlling of pests in agricultural and sand control of insect vectors of human disease [1]-[2], and have many impacts that causing serious damage to aquatic life including fishes that have economic importance [3]-[5]. Among them, Carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) is a widely carbamate pesticide which used to control numerous soil-borne pests and nematodes found in corn, potatoes, graps, rice, alfalfa and other crops [6]. It has very toxic effects to invertebrates, birds and relatively mammalian toxicity [7]. In fish, carbofuran also showed deleterious effects and the LC50 values in different species of fish appear to be varied due to species sensitivity to it [8]-[9]. Carbofuran 96h LC50 to different freshwater fish vary from 88 to 1990 µg/L [10]., whereas many organisms like crustaceans and insects are very sensitive with 96 h LC50 of carbofuran varying from 1.6 to 500 µg/L [11]. In fish, oxidative stress could be carbofuran, leading to the generation of free radicals with an increase of reactive oxygen species (ROS) and variation in the antioxidant profile in many species of fish [12]-[13]. Mitochondria, an aerobic organism is able to generate ROS naturally through oxidative metabolism of mitochondrial respiration [14]; thus, may be produced during detoxification process of insecticides [15]. When, there is an imbalance between the cellular antioxidant enzyme activities and ROS production, the oxidative stress occurred when ROS could not be eliminated or neutralized by the antioxidant system [16]. Almroth et al [17] ascribed that lipid peroxidation is one of the oxidative damage which involved in pesticide-induced toxicity in fish [17]. Antioxidant enzymes such as catalase (CAT) , superoxide dismutase (SOD) are the most abundant antioxidant defenses in fish, where they constitute the first line of protection against oxidative stress. SOD catalyzes the dismutation of superoxide into hydrogen peroxide and oxygen. Hydrogen peroxide is decomposed into water and oxygen by CAT enzyme [18]. Biochemical profiles of blood are good health indicators that provide obvious evidence about the internal environment of the organism [19-21] [4], and often used when fish physiology is applied to detect and recognize the toxicological effects of harmful substances [22]. Soufy et al [23] studied the effects of chronic exposure to carbofuran on mono sex tilapia cultivated in Egyptian fish farms for 8 weeks . Their results revealed biochemical variations in AST,ALT, cholinesterase activities, creatinine and total proteins . Also, Hernández-Moreno et al [24] determined the biochemical alterations of sea bass (Dicentrarchus labrax L.) exposed to carbofuran. Lycopene (LYC), a representative of carotenoids, is a red lipophilic pigment consisting of 11 conjugated double bonds. The most plentiful sources of LYC are tomatoes and its other processed products [25]-[26]. The most known and effective antioxidants in the carotenoid family is LYC [27]-[28], where it can prevent oxidative damage, toxicity and disease by quenching singlet oxygen and other free radicals. The African catfish, Clarias gariepinus is broadly cultivated in Egypt and represent an important economic source of protein . Therefore, the catfish C. gariepinus was selected for the present study due to its culture, maintenance in the laboratory is relatively easy and its economic importance. Therefore, the present study was undertaken to
a) determine LC50 of carbofuran.
b) evaluate the toxic effects of carbofuran on certain biochemical parameters
and oxidative stress parameters in different organs of C. gariepinus.
c) assess the protective role of lycopene against carbofuran toxicity in C. gariepinus.