Microplastic exposure, oxidative stress, and potential heme protein vulnerability in teleost fish: implications for oxygen transport and seafood quality

초록

Microplastics (MPs) are a growing concern due to the impact they have on fish physiology and safety of seafood. This review brings together recent research related MP induced oxidative stress in teleost fish and implications for muscle nutritional quality and the role of heme containing oxygen transport proteins. MPs are found primarily in the liver (32% of samples), as well as muscle, and enter fish primarily via gill uptake and ingestion. Laboratory tests consistently show increased oxidative stress markers such as malondialdehyde (MDA 1.8-3.78-fold) and protein carbonyls (1.8-2.4-fold) as well as decreased antioxidant enzyme activities (SOD, CAT, GPx decreased by 38%-52%). This oxidative imbalance could enhance the possibility of the heme iron to undergo autoxidation and globin modification, but there is no direct evidence at this time as measurements of heme iron redox state, P50 values and methemoglobin generation have not been performed. Metabolomic analysis also shows changes in the levels of amino acids, such as a decrease in tryptophan and tyrosine, suggesting impaired metabolic processes with unfamiliar relevance to heme biosynthesis. This review differentiates between established oxidative and inflammatory effects and the hypothesized effects on heme proteins, and emphasizes the critical need for direct biophysical measurements such as methemoglobin, P50, heme speciation to gain a better understanding of fish welfare and seafood nutritional quality.

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