Hepatotoxic effect of dietary phytoestrogens on juvenile cultured Russian sturgeon (Acipenser gueldenstaedtii)

Abstract

In the last two decades, much controversy has grown over the use of soybean products in aquafeeds, especially for carnivorous fish like sturgeons. One point of discussion is the effect of soybean phytoestrogens on fish health. There are many aspects of phytoestrogen utilization in aquafeeds, therefore, the aim of this study is to verify if common legume phytoestrogens can affect juvenile cultured sturgeon erythrocyte and hepatocyte genotoxicity and cause liver pathology. Russian sturgeons were fed from 100 till 365 dph11Days post hutching. with daidzein, genistein, and coumestrol supplemented diets in concentrations: 10, 0.05 and 0.001 g kg−1 of feed, respectively. The SCGE22Single Cell Gel Electrophoresis (comet assay). method combined with qPCR of three genes involved in DNA repair and genome maintenance, namely cyp1a1, gaad45a and p53 were analyzed. The results were compared with histopathological evaluation of liver tissue. In fish fed with coumestrol supplemented diet, DNA strand damage was the highest in both erythrocytes and hepatocytes, however, simultaneously the lowest level of oxidative DNA damage was found. Additionally, slightly elevated expression of the p53 gene was observed along with a decreased number of apoptotic hepatocytes, which suggests that low concentration of coumestrol may support DNA repair mechanisms in the liver. Although, daidzein showed a preventive effect only against fibrosis. Isoflavones did not show a significant effect on DNA damage in studied cells. Genistein was found to increase macro- and microvesicular steatosis, portal hepatitis and fibrosis, indicating its negative role in the development of liver injuries. Daidzein alleviated some sturgeon liver damage, especially macrovesicular steatosis and interface hepatitis. However, it increased hepatocyte apoptosis, which may suggest daidzein potentially inducing liver injury, though not manifested by other histopathological lesions. Therefore, it can be concluded that at given concentrations, the tested phytoestrogens did not show clearly hepatoprotective effect in sturgeons.