EFFECT OF SUB-LETHAL CONCENTRATIONS OF CODIAEUM VARIEGATUM LATEX ON FRESHWATER TARGET SNAIL LYMNAEA ACUMINATA AND NON-TARGET FISH CHANNA PUNCTATUS

Abstract

The latex of Codiaeum variegatum plant (Euphorbiaceae) was found to have high molluscicidal activity against freshwater snail Lymnaea acuminata. Exposure of sub-lethal doses (0.15 DW,mg/L and 0.30 DW,mg/L for 24h) and (0.06 DW,mg/L and 0.12 DW,mg/L for 96h) of latex of this plant on snail Lymnaea acuminata caused significant reduction in the activity of enzyme acetylcholinesterase, acid and alkaline phosphatase in the nervous, hepatopancreas and ovotestis tissues after 24h and 96h exposure periods. The non-target fish Channa punctatus, which shares the habitat with these snail also when exposed to sub-lethal doses of snails (0.15 DW,mg/L and 0.30 DW,mg/L for 24h) caused significant reduction in the activity of enzyme acetylcholinesterase, acid and alkaline phosphatase in muscle, liver and gonadal tissues of fish after 96h exposure periods. Withdrawal study shows that there is a partial recovery in snail's tissues and near complete recovery in fish tissues after 7th day of the withdrawal of treatment.


Key Words: Lymnaea acuminata; Codiaeum variegatum; Euphorbiaceae Acetylcholinesterase; Phosphatases


Nigerian Journal of Natural Products and Medicine Vol.7 2003: 20-24