Food utilization in the fish Channa striatus exposed to sublethal concentrations of DDT and methyl parathion

Abstract

Sublethal concentrations of DDT and methyl parathion (MP) in the medium significantly affected the rates of feeding, absorption and conversion in Channa striatus. Fish exposed to 250 ppb DDT or MP consumed 23 or 50% less food than those exposed to pesticide-free water. Correspondingly, absorption rate also decreased from 120 cal/g live fish/day in the control to 88 and 59 cal/g/day in those exposed to 250 ppb DDT and MP. Efficiency to convert the absorbed food into body substance dropped from 30% in the control to 6 and 12% in the 250 ppb DDT and MP groups. Metabolic rate of the control averaged to 84 cal/g/day; whereas exposure to DDT did not significantly affect the metabolic rate, a concentration of 250 ppb MP depressed the rate to 52 cal/g/day.