Features of the parasitic system formation in common carp in the aquaculture of the north-eastern and eastern regions of Ukraine

Abstract

The research aimed to determine the peculiarities of the formation of the parasitic system in common carp in the aquaculture of the North-Eastern and Eastern regions of Ukraine. According to the results of the research, 27 species of parasites were found in common carp (12 — protozoa, 6 — monogeneans, 3 — trematodes, 2 — cestodes, 4 — parasitic crustaceans). Three species (11.1%) of registered parasites were invasive. 22 species (81.5%) of detected common carp’s parasites develop directly and 5 (18.5%) — with the participation of definitive and intermediate hosts. 26 species (96.3%) of common carp’s parasitic fauna were found in crucian carp and 21 species (77.8%) in other coarse fish species (roach, rudd, bleak, perch). It has been established that among the protozoa, pathogens from the genera Trichodina, Chilodonella, and Ichthyophthirius were of epizootic importance for young common carp; Eimeria carpelli, Ichthyobodo necator, Myxobolus ellipsoides, and Myxobolus dogieli had relevance. The level of prevalence in common carp fingerlings during outbreaks of chylodonelosis was 72%, two-year-olds — 65%, three-year-olds — 27%, during outbreaks of ichthyoftiriosis — 45%, 56%, and 24%, respectively. Prevalence of Trichodina acuta and Trichodina nigra in common carp fingerlings was, respectively, 52% and 38%, Ichthyobodo necator — 16%, Eimeria carpelli — 22%, Myxobolus ellipsoides, and Myxobolus dogieli — 17–18%. Among the pathogens of helminthic diseases in the aquaculture, monogenetic suckers (Dactylogyrus anchoratus, Dactylogyrus extensus, Dactylogyrus vastator, Gyrodactylus cyprini, and Gyrodactylus katharineri), as well as cestodes (Bothriocephalus acheilognathi and Khawia sinensis) were the most epizootic significance for common carp. Prevalence of parasites from the genus Dactylogyrus reached 68–87% in fingerlings, from the genus Gyrodactylus — 21–36%. The highest level of Bothriocephalus acheilognathi infection (82%) was registered in fingerlings. The maximum prevalence of Khawia sinensis (62%) was observed in two-year-olds. Outbreaks of diseases caused by crustaceans Lernaea cyprinacea and Argulus foliaceus with a high level of prevalence have been reported in fish from fingerlings to three-year-olds. The level of prevalence of Lernaea cyprinacea was 69%, Argulus foliaceus — 22%