DIFFERENCES IN ACCUMULATION OF NICKEL IN INFECTED AND UNINFECTED WITH POMPHORHYNCHUS LAEVIS SPECIMENS OF ALBURNUS ALBURNUS FROM THE FRESHWATER ECOSYSTEM OF DANUBE RIVER, BULGARIA.

During the ecological study of 28 specimens bleak (Alburnus alburnus (Linnaeus, 1758)) by applying standard techniques for parasites was found infestation with the acantocephalan Pomphorhynchus laevis (Müller, 1776). Aim of the present study is to establish the content of nickel in water, sediments, tissues and organs of A. alburnus and its parasite Pomphorhynchus laevis, and the possibilities of accumulation and circulation in the freshwater ecosystem of Danube River. From the tissues and organs of the studied specimens Alburnus alburnus, the content of nickel in samples of liver are higher than in the skin and muscles (in both infected and uninfected specimens). Differences were observed not only in nickel content, but also in the amendment of nickel content of infected (Ni Liver> Ni Muscles > Ni Skin) and uninfected (Ni Liver> Ni Skin> Ni Muscles) specimens of bleak. The obtained values for nickel content in liver, muscles and skin of A. alburnus infected with P.laevis were found to be lower than the obtained values for nickel content in liver, muscles and skin of uninfected specimens of bleak. The acanthocephalan Pomphorhynchus laevis showed significantly higher content of nickel than its host tissues and organs. Significant correlation (p<0.05) was fixed for relationships between CP. laevis Ni- CSkin Ni. [ABSTRACT FROM AUTHOR]