Changes in the proximate composition of Labeo rohita (Ham.) exposed to sublethal concentrations of monocrotophos

Abstract

The seasonal utilization of paddy field for fish culture is quite common in kerala
and West Bengal. In recent years, with the advent of high yielding varieties of
paddy, the use of pesticide has become widely prevalent. Monocrotophos is one
of the commonly used organophosphate pesticides in the paddy fields of Kerala.
Juveniles rohu, Labeo rohita (46.82± 0.52 mm total length , 1012.29±43.12 mg
wet weight) were subjected to static lethal and sublethal bioassay. The 48 hr
LC 50 value was found to be 104.02 mg/l at 28± 2°C. Juvenile rohu were exposed
to sublethal monocrotophos concentrations (2,5,10,15,20,30 and 40 mg/l)
for 32 days at 28 ± 2°C without aeration. Treatement media were replaced everyday.
Fish were fed a pelleted diet at 6% wet body weight per day. Juveniles
exposed to 2,5,10,15,20 and 30 mg/l monocrotophos concentrations had significantly
higher moisture and ash content and lower protein, lipid and carbohydrate
contents, as body nutrients were depleted.