COMET ASSAY OF INFESTATION DEGREE OF CARP YEARLINGS BLOOD LYMPHOCYTES DNA UNDER THE EFFECT OF ECTOPARASITES
Y. V. Loboiko, V. V. Stybel
Lviv National University of Veterinary Medicine and Biotechnologies named
after S. Z. Gzhytskyj, Pekarska st., 50, Lviv, 79010, Ukraine
The results of research of infestation degreeof carp yearlings blood lymphocytes DNA under the invasionby ectoparasites Lernaea cyprinacea and Dactylogyrus vastator and under themixed infestation are presented in the article. Mutagenic properties of ectoparasite infestation on the host body are proved by study results of its genotoxic and cytotoxic influence on the basis of modern DNA-comet assay on the cells of carp blood lymphocytes. To test this hypothesis it had been conducted the research of fragmented DNA level in carp yearlings lymphocytes under the influence of ectoparasites using the DNA-cometmethod. For this purpose there were formed twelve groups with 6 individuals in each with varying degrees of infestation. They were presented by four groups of fish (control and three experimental) under the infestation by ectoparasites Lernaea cyprinacea, Dactylogyrus vastator and under the mixed infestations. Under the invasion by Lernaea cyprinacea the blood lymphocytes apoptotic cells of the fishes of 3rd experimental group exceeded the control 1.2 times (P<0.05). Under the invasion >0.26 ind./g b.w. (4th experimental group) the percentage of «tail moment» was 3.4 times higher than of control one (P<0.01).The number of apoptotic cells exceeded 1.2 times this amount in the blood lymphocytes of control fish (P<0.01). Under the invasion of fish by Dactylogyrus vastator reliable values of the "tail moment" and apoptotic cells in blood lymphocytes were registered in the fish of 4th experimental group, namely 2.6 (P<0.05) and 1.3 times (P<0.05), respectively.
Whenresearching «tail moment» index in lymphocyte cells under the mixed invasion it was set up its reliable growth in 2nd, 3rd and 4th experimental groups, respectively, 2.3-times (P<0.05), 4.3 (P<0.01) and 4.8 times (P<0.001). However, it was registered the reliable increasingofthe apoptotic cells number in blood lymphocytes of the fishes of 3rd and 4th experimental groups in 1.6 (P<0.05) and 1.9 times (P<0.01).
There were observedin our study a certain regularity of ectoparasites effect on fish blood cells, which was characterized by increasing of «tail moment» index and the number of apoptotic cells along with increasing of infestation degree.Apparently, ectoparasites have genotoxic and cytotoxic effect on fish blood cells, cause the growth of single-stranded breaks ofalkali labile sites of nuclear DNA molecule of apoptotic cells in blood lymphocytes, which is directly proportional to the increase in the number of ectoparasites.
Keywords: DNA COMET ASSAY, TAIL MOMENT, APOPTOTIC CELLS, LYMPHOCYTE, YEARLINGSCARP, ECTOPARASITES, LERNAEA CYPRINACEA, DACTYLOGYRUS VASTATOR
