Sutuyeva L.R., Shalakhmetova Т.М., Trudeau V.L., Kolumbayeva S.Zh., Lovinskaya A.V. Growth and development of the green toad (Bufo viridis) from the water bodies of the oil producing regions of Kazakhstan

Al-Farabi Kazakh National University, Kazakhstan, Almaty; University of Ottawa, Canada, Ottawa,

Abstract

Environmental pollution with oil and petroleum products leads to a decrease in animal biodiversity
and human diseases. Due to the intense pollution of Kazakhstan’s water bodies located on the territory
of oil producing regions, the purpose of this study was to study the effect of different concentrations of
oil on the growth and development of the green toad (Bufo viridis). This species of anuran amphibians
is widespread in Kazakhstan, which is especially important given the aridity of the lands of the oil-producing regions. A chronic exposure to the concentrations of oil hydrocarbons found in the water of the
reservoirs of the Aktobe, Atyrau and Mangistau regions on the tadpoles of the green toad (Bufo viridis)
was carried out The results of the study revealed suppression of growth (size and weight) and a developmental delay in tadpoles from experimental groups. To determine the reasons for the slowdown in
growth and development, the content of lipid peroxidation products (LHO and MDA) and the activity of
antioxidant defense enzymes in the liver of tadpoles of the green toad (Bufo viridis) were studied. It has
been shown that the production of LHO and MDA increases after exposure of the tadpoles to oil hydrocarbons, while the activity of antioxidant enzymes, on the contrary, decreases, which indicates enhanced
oxidative stress in the liver of the treated tadpoles. Thus, exposure to oil hydrocarbons in concentrations
found in the water bodies of the oil producing regions of Kazakhstan suppresses the growth and development of the green toad (Bufo viridis), one of the reasons of which is the increase of oxidative stress.
Key words: water soluble fraction of oil, Bufo viridis, growth, development, oxidative stress, lipid
peroxidation, antioxidant enzymes.