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Effects of the dietary protein source on methyl mercury distribution, accumulation and toxicity

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Methylmercury (MeHg) is an ubiquitous environmental contaminant known particularlty for its potential neurotoxicity. Humans exposure to MeHg is mainly through consumption of contaminated fish and seafood. The distribution, accumulation and toxicity of MeHg can be altered through interaction with nutrients present in seafood (e.g. selenium). However, it is not known how fish as a complete dietary protein matrix can affect how MeHg is handled in the body.
Most toxicity studies are performed using feed matrices based on casein. We therefore intend to compare diets based on fish (cod) versus a standard diet based on casein, to investigate if the background diet affects MeHg parameters. Moreover, human diets are not based on single protein matrices, so we will include two additional matrices to determine whether and how the background diet alters tissue distribution and accumulation of MeHg.
Thus, the planned experiment aims to study possible differences in modulation of accumulation and toxic effects of dietary methyl mercury (MeHg) caused by varying the background diet, using BALB/c mice as model organism. The animal experiment involves a number of 75 male BALB/c mice, determined based on statistical power analysis.
As this experiment aims to connect tissue distribution to organismal neurotoxic responses, interpolation of effects observed from tissue or cell cultures is not possible. It is therefore essential that this work is performed using an animal model. The experimental procedure has been refined based on comparable previous studies, and the results of the study will contribute to refinement of future toxicological studies using casein as matrix.
In order to study possible modulation of MeHg toxicity, the dose included in the feeding experiment is sufficient to induce sub-lethal effects, which can cause a moderate strain for the animals. However, no invasive treatments are planned during the experiment and experimental procedures have been refined in order to minimize stress imposed on the animals during behavioral and motor activity testing.
The results from the animal experiment will generate knowledge on the role of the dietary matrix in MeHg toxicology, which will contribute to future risk benefit evaluations of food, and particularly for MeHg exposure from fish and seafood.