The effect of D. dendriticum invasiveness on the antioxidant system of omul from the Selenga River population

The article presents data on the influence of the degree of invasion by D. dendriticum plerocercoids on the parameters of the antioxidant blood system of omul of the Selenga River population. Infection with helminths affected the haematological parameters of omul blood. In the blood of omul infected with D. dendriticum, there is a significant decrease in the content of total protein, haemoglobin, red blood cells and white blood cells. Moreover, the severity of these indicators depended on the level of infection of the omul. The most significant decrease in these indicators is noted in omul with a high degree of invasion. The results of studying the composition of white blood cells show a substantial reduction in the content of lymphocytes and an increase in the number of segmenting clear neutrophils in omul with a high degree of invasion, as well as eosinophilia in all groups of infected fish, which is characteristic for parasitic attacks. The summary antioxidant activity significantly increased in the group of fish with a low degree of invasion (2-3 copies of plerocercoids). However, as the degree of attack increased (average degree–5-10 copies of plerocercoids; high degree–18 or more copies of plerocercoids), this indicator does not differ from that in uninfected individuals. Significant differences in blood catalase activity (catalase number) are not found between uninfected and infected omul. Information on changes in the antioxidant system parameters can serve as non-specific markers concerning the state of the fish organism, adaptation to changing environmental conditions and, ultimately, the quality of raw fish foodstuffs.