Effect of electrical stimulation on the production of cutaneous excreta by the earthworm Lumbricus terrestris L

Abstract

Cutaneous excreta of earthworms are an increasing interest in many areas of scientific research. Our study aims to develop an electrical technique for stimulating the production of these cutaneous excretions more efficient and less harmful than that using chemical stimulation with petroleum ether. This study made it possible to define the optimal electrical parameters ensuring the obtaining of a maximum rate of excretion. These parameters are respectively: a voltage (U) of 20V, a pulse frequency (F) of 100 stimulations per second and a stimulation time (T) of 5 minutes. The comparative study of this new technique of electrical stimulation compared to chemical stimulation shows statistically very comparable excretion production rates (p<0,05). However, electrical stimulation offers considerable advantages relating to the physical integrity of the worms (lower mortality rate than that obtained during chemical stimulation), the short duration of stimulation and the ease of recovery of sticky excretions. In addition, the electrical stimulation technique offers the possibility of reusing the worms in other electrical stimulations after a rest period of 3 weeks.