Impact of Cypermethrin on Fingerlings of Common Edible Carp (Labeo rohita)

1. Introduction

Synthetic pyrethroids are more effective than other insecticides like carbamate and organophosphatase against several pests [1]. Besides controlling hazardous insect pest population synthetic pyrethroids also affect several nontarget organisms [2].

Cypermethrin, a synthetic pyrethroid is a broad-spectrum insecticide, used extensively in households and industrial and agriculture fields [3] for control of several insect pests [4]. Due to indiscriminate use, cypermethrin makes their entrance into natural water bodies through agriculture run-off and ultimately affects the several nontarget aquatic organisms; for instance, it inhibits growth and several metabolic activities of crustaceans [5], adversely affects fish metabolism [6] and hematology [7], and thus adversely affects fish meat quality and fish population [8]. Cypermethrin is also highly toxic against freshwater snail L. accuminata and also affects both their metabolism and reproduction [9, 10].

Srivastava and Kaushik [11] reported that the pesticides accumulating in the vital organs, such as liver and muscle, cause organ dysfunction, culminating in death of fishes. Certain enzymes are essential for metabolic functions, disturbance of enzyme activity in fish serves as early indicator of toxicant impact [12]. Hence, the present work was designed to assess the toxic effect of cypermethrin on fingerlings of Labeo rohita and its sublethal effects on its metabolism. Labeo rohita is common, freshwater, edible fish of capture fishery not only in India but also elsewhere, due to their high nutritive food value.

2. Materials and Methods

2.1. Collection and Maintenance of Experimental Animal

Healthy, fresh fingerlings of fish Labeo rohita ( $6.0\pm 1.5$  cm in total length, $8.0\pm 2.0$  gm in weight) were obtained from the Gorakhnath Government Hatchery Center, Chapia, Gorakhpur, Utter Pradesh, India. The collected fishes were maintained in glass aquaria containing 100 L dechlorinated tap water for seven days to acclimatize under laboratory conditions. The aquarium water was aerated continuously, and food was provided in the form of dried, small pellets of Tokyo, special fish food produced in Japan. Water was changed at every 24 h. Experimental water conditions were atmospheric temperature 31.5–32.5°C; water temperature 28.5–30.0°C; pH 7.2–7.5; dissolved oxygen 7.7–8.2 mg/L; free carbon dioxide 4.5–5.5 mg/L; bicarbonate alkalinity 104.5–106.5 mg/L [13].

Cypermethrin ([S, R]-N-α-cyno-3-phenoxybenzyl-(IR, IS, cis, trans)-2, 2-dimethyl-3, (2, 2-dichlorovinyl) cylcopropane carboxylate) manufactured by M/S Tropical Agrosystem Pvt. Ltd. Chennai, India, and...