Change of Seasonal Variation and Feeding of Bait Containing Piperine on Reproduction and Certain Biochemical Changes of Fresh Water Snail Lymnaea acuminata

Piperine, the active molluscicidal component of Piper nigrum caused a significant reduction in the fecundity, hatchability and survival of the snail Lymnaea acuminata in each month of the year Nov- 2011 to Oct-2012. Feeding of bait containing 40% of 24hLC50 of piperine with attractant starch caused maximum (1124 eggs/ 20 snails) and minimum (327 eggs/ 20 snails) fecundity in the month of June and November, respectively. Whereas feeding of bait containing 40% of 24hLC50 of piperine with attractant serine caused maximum (1028 eggs/ 20 snails) and minimum (352 eggs/ 20 snails) fecundity in the month of June and November, respectively. Treatment with the piperine also prolong the hatching time of snails. Sublethal treatment of piperine caused a significant (p<0.05) reduction in protein, amino acids, DNA, RNA and AChE in the ovotestis/ nervous tissue of treated snails with respect to control after 96h exposure period. Feeding of Piperine+Serine+Agar (80 % of 24h LC50) caused maximum reduction in protein (21.67% of control), amino acid (27.25% of control), DNA (24.67% of control) and RNA (22.70% of control) levels. Whereas feeding of Piperine+Starch+Agar (80% of 24h LC50) caused maximum reduction in protein (25.41% of control), amino acid (24.22% of control), DNA (30.43% of control) and RNA (24.39% of control) levels. Simultaneously, inhibition in acetylcholinesterase (AChE) activity in nervous tissue was also noted. Maximum inhibition in AChE activity (29.87% of control) was observed in snail exposed to feeding of bait formulation of Piperine+Starch+Agar (80 % of 24h LC50).