## 4 Metabolomics for Metabolite Detection in Aquatic Food Products
### Chemical Contaminants
Research findings indicate that supplementation with 1%, 3%, and 5% hydrolysis fish peptides significantly reduced the copper bioaccumulation in largemouth bass. Key findings highlight that the differential metabolites were mainly lipids and lipid-like molecules, which were closely related to lipid metabolism pathways. Moreover, metabolomic analysis in shrimp (_Litopenaeus vannane_) that were exposed to ammonia and performed by GC-MS showed that amino acid metabolism was significantly changed, nucleotide metabolism was significantly decreased, and finally that lipid metabolism was disrupted [129]. [PERSON] et al. [72] used \({}^{1}\)H NMR-based metabolomics to thoroughly explore the metabolic disorders caused by microplastics in Mediterranean mussel (_Mytilus galloprovin \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Substance** & \
\begin{tabular}{c} **Maximum Levels US** \\ **(ppm)** \\ \end{tabular} &
\begin{tabular}{c} **Maximum Levels EU** \\ **(mg/kg Wet Weight)** \\ \end{tabular} & **Food Commodity** \\ \hline Arsenic & 76–86 & & Molluscs, crustaceans \\ Cadmium & 3–4 & 0.05–1.0 & Fish, molluscs \\ Lead & 1.5–1.7 & 0.2–1.0 & Fish, molluscs \\ Methyl mercury & 1.0 & 1.0 & All fish \\ PCB & 2.0 & & All fish \\ DDT, TDE & 5.0 & & All fish \\ Diedrin & 0.0 & & All fish \\ Dioxin & & 0.000004 & All fish \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Environmental chemical contaminants. Tolerances and critical limits in fish and fish products [125]. cialis_) gills. Data indicated that amino acid and energy metabolism was changed, and osmoregulatory processes along with the cholinergic neurotransmission were disturbed. With the same metabolomic technology, [PERSON] et al. [130] investigate the effects of environmental microplastics on commercial fish _Serranus scriba_ ([PERSON], 1758). More specifically, the distinct change patterns of metabolites in the liver of _Serranus scriba_ were identified, and a total of 36 metabolites primarily involved in energy, amino acid, and osmolyte metabolism were significantly affected. In another metabolomic study, combined effects of polyethylene microplastics and two pharmaceuticals (citalopram and bezafibrate) on Mediterranean mussels (_M. galloprovincialis_) were explored. Following the LC-HRMS analyses, findings suggest that the metabolic profiles of mussels showed a strong effect of pharmaceuticals, independently of polyethylene microplastics co-exposure. Nevertheless, polyethylene microplastics in themselves impacted metabolic pathways, like neurotransmitters or purine metabolism [73]. Recently, effects from the exposure of juvenile Chinook salmon (_Oncorhynchus sthauwtscha_) to effluent from an urban wastewater treatment plant were investigated. LC-MS metabolomic technology was used, and research findings indicate alteration in biochemical pathways in several metabolites, including those that were important for energy generation and utilization. With regard to the altered pathways mentioned, it is worth noting that they are crucial for fish health and could become an early indicator of potential negative impact on growth, reproduction, behavior, and immune function [68].