Toxic effects of waterborne benzylparaben on the growth, antioxidant capacity and lipid metabolism of Nile tilapia (Oreochromis niloticus)

Benzylparaben (BzP) is a potential endocrine disruptor; however, its antioxidant defense, lipotoxicity and underlying mechanism of BzP in aquatic organisms are unknown. This study investigated the impacts of waterborne low-, environmental-related and high-level benzylparaben on the growth, antioxidant capacity, lipid metabolism and lipidomic response of Nile tilapia (Oreochromis niloticus). Juvenile tilapia (0.60 ± 0.11 g) were exposed to 0, 5, 50, 500 and 5000 ng/L benzylparaben for 8 weeks in quadruplicate for each group. Benzylparaben increased the body crude fat content but decreased brain acetylcholinesterase activity in O. niloticus. Benzylparaben caused oxidative stress, leading to hepatic morphology damage and lipid metabolism disorders in fish. Lipidomic analysis identified 13 lipid classes in fish liver. Benzylparaben exposure induced metabolic disorders of glycerol phospholipids, glycerolipids and sphingomyelins in fish liver. These findings indicate that environmentally related benzylparaben levels (5 to 50 ng/L) could induce an antioxidant response, result in triglyceride accumulation, and increase adipocyte formation and fatty acid intake in tilapia. However, high benzylparaben concentrations inhibit lipid deposition, presumably due to the effects of the antioxidant system, and induce tissue inflammation. Therefore, this study provides new insights into the toxic effects and potential mechanism of benzylparaben in fish, especially from the aspect of lipid metabolism.