Use of an anthelmintic to control parasitic nematodes of Helix aspersa (Müller)

Abstract

Purpose. To estimate the parameters of infestation of Helix aspersa by nematodes, experimentally identify the optimal concentration of anti-helminthic drugs and assess their effectiveness. Methodology. The experimental work on the development of therapeutic measures against nematodes of Helix aspersa (Müller) lasted for 15 days. The results of the experiments were evaluated by the following indicators: extensiveness and intensity of parasite infestation; survival of mollusks,%. Feeding activity was assessed by the relative amount of feed the mollusks ate per day. At the beginning of the experiments, histological examinations of mollusk tissues were performed. Selected samples were preserved in 4% formalin solution and then histological sections were made, which were than frozen with subsequent staining with hematoxylin-eosin. Histological analysis was performed using a light microscope at 8x and 40x magnification and a Sciencelab T500 5.17 M photographic digital camera. Assessment of changes in the histostructure was performed visually and using morformetric analysis on mollusk intestine samples. Two variants of the experiment with albendanzole (variant № 2 and 3) and control were evaluated. Findings. According to the results of the experiments, the best indicators of the anthelmintic effect and survival of snails were obtained using albendazole added to compound feed at a concentration of 0.02% of the live weight of mollusks. At this concentration, complete destruction of mature individuals of Alloionema appendiculatum was noted, as well as a decrease in the infection of snails with helminth eggs from 100% to 10%. The study of the histostructure of tissues and organs of mollusks showed that the use of albendazole at concentrations of 0.01% and 0.02% did not cause noticeable pathological changes in the muscles and brain of mollusks. However, certain structural abnormalities were observed in the cells of the intestinal and liver epithelium, which were detected as vacuolization of the cytoplasm, destruction of cell membranes, lysis and pycnosis of nuclei. The relative number of such cells with the pathology was about 10-15% when using 0.01% albendazole, and increased to 30-50% when using albendazole at a concentration of 0.02% of the live weight of snails. No noticeable anthelmintic effect was found when using trematozole. Scientific novelty. For the first time, the therapeutic effect and the optimal scheme of deworming of mollusks Helix aspersa infected with the parasitic nematode Alloionema appendiculatum were determined experimentally. Practical significance. The obtained results are of interest to enterprises engaged in snail farming. Key words: mollusk Helix aspersa Muller, nematodosis, extensiveness and intensity of invasion, anthelmintic drugs, morpho-histological parameters.