Impact of Cypermethrin and Carbofuran on the Ovarian Cycle of the Indian Major Carp, Labeo rohita (Hamilton)

Abstract

A short term histological study was conducted to determine the impacts of technical grade synthetic pyrethroid insecticide, cypermethrin and carbamate pesticide, carbofuran on different phases of ovarian maturation of freshwater indigenous carp, Labeo rohita. Adult females of L. rohita were exposed to sublethal doses of carbofuran (0.06, 0.15 mg/L) and cypermethrin (0.16 and 0.40 μL/L) for 4 weeks during the pre-spawning (March), spawning (July) and post-spawning (November) phase. In the spawning phase, the carp showed maximum ovarian damage by both the pesticides while the pre-spawning phase was the next impaired stage. Considering all the phases of ovarian maturation, cypermethrin exhibited greater level of impact than carbofuran in both of its doses. Gonado-somatic indices for all these phases were also measured. In the reproductive cycle of fish, reduction in gonado-somatic index occurred by both the pesticides in all of its doses and the order was spawning > pre-spawning > post-spawning. It is concluded that ovarian maturation in Indian carp is affected by both the pesticides.