Novel herbal veterinary narcotics for aquacultures of Clarias gariepinus

Japanese Kampo medicine uses plant extracts as analgesic and natural narcotics. Herbal fishing narcotics have been documented in numerous cultures [1]. The catfish Clarias gariepinus is a species favorable for food production in aquacultures. EU laws forbid slaughtering animals without narcosis. C. gariepinus has proven resistant to all licensed narcotic agents for fish. The active constituents of most surveyed plants are haemolytic saponins which lead to a loss of consciousness in the fish via hypoxia. Only Zanthoxylum piperitum and Barringtonia asiatica were not described as saponin drugs and acted via neurological narcosis in preliminary experiments. In Kampo Z. piperitum is well known for its use as an analgesic, e. g. as the main component of the health insurance covered prescription Daikenchuto in Japan [2], where it was also used as an effective fishing narcotic. Additionally, Cissus quadrangularis was included in this study as it is used in West Africa as an enhancer of the narcotic effects of other fishing poisons [3]. As expected, the positive control, (MS222), had the weakest narcotic effect. Both Z. piperitum and B. asiatica achieved full narcosis after 15 min. The combination of all three plant extracts provided the quickest and fullest sedation after 10 min, indicated by absence of operculum movement, loss of equilibrium, no response to handling and no adverse reactions. All groups made a full recovery after a few minutes in fresh water without adverse effects. Meat samples of euthanized test animals were fried for organoleptic testing. No difference in consistence or taste could be detected.

• References

• 1 Neuwinger HD. Plants used for poison fishing in tropical Africa. Toxicon 2004; 44: 417-430
• 2 Matsushita A, Fujita T, Ohtsubo S, Kumamoto E. Traditional Japanese medicines inhibit compound action potentials in the frog sciatic nerve. J Ethnopharmacol 2016; 178: 272-280
• 3 Gaudin O, Vacherat R. Recherche de la roténone et du pouvoir ichthyotoxique chez quelques plantes du Soudan français. Bull des Sci Pharmacologiques 1938; 40: 385-393