Ichthyopathological examination of the giant snakehead (Channa micropeltes Cuvier, 1831)

The results of an ichthyopathological examination of juvenile giant snakehead imported from Indonesia are presented. Bacteriological analysis of parenchymal organs (liver and kidneys) in fish revealed Aeromonas sp., Acinetobacter sp., Acinetobacter baumannii, Pseudomonas alcaligenes, Moraxella sp., Staphylococcus sp. The kidneys are most susceptible to bacterial contamination. In the isolated 22 bacterial strains, there was no sensitivity to the 13 tested antibiotics. The high level of organ contamination and the identified bacterial species characterizes the presence of a complex of microorganisms in the snakehead that can cause bacterial hemorrhagic septicemia (bacterial carrier).During a parasitological examination, Ichthiobodo sp. flagellates were found in the mucus from the surface of the body and gills of fish and monogenes of Silurodiscoides sp., in the intestine, liver and gall bladder — cestodes of Polyoncobothrium ophiocephalinum. The snakeheads were most intensively infected with cestodes. The invasion rate was 100% with an average invasion rate of 8 specimens/fish, the minimum number of parasites was 1 specimen/fish, and the maximum was 17 specimens/fish. The length of the cestodes extracted from the intestines of the snakeheads ranged from 140 to 220 mm. The body of the cestode is segmented, in the segments there are sexual complexes with already mature eggs. The eggs were thinwalled, and when they left the reproductive complex they were at different stages of embryonic development. The therapeutic treatments of fish with salt and chloramine had a short-term effect, deworming with fenomix led to partial release of the intestines, but did not affect the cestodes in the liver and gall bladder. The mechanical and toxic effects of helminths led to the death of the entire batch of imported snakehead. Given the high infection rate of parasites and bacteria in juvenile giant snakehead and the complexity of developing therapeutic and preventive measures, larvae should be imported at an early stage of development, before switching to a mixed diet. The import of snakeheads infected with P. ophiocephalinum cestode may lead to the spread of this helminth in Russia.