Two typical fish products—fermented mandarin fish and semi-dried yellow croaker—are associated with biogenic amines (BAs), which are harmful to human health. The objective of this study was to investigate the bacterial ecology of the two fish products and to determine their capacity for producing BAs. Putrescine and cadaverine were major BAs detected in the fish products. Concentrations of BAs were significantly corrected with microbial count (p < 0.05). BA-producing isolates (33) in the two fish products were all multiple BA producers. Several of them, including Lactobacillus sakei, Bacillus cereus and Hafnia alvei isolated from fermented mandarin fish, as well as Shewanella baltica, Aeromonas veronii, and Photobacterium phosphoreum isolated from semi-dried yellow croaker, showed remarkable BA-producing capacity. Hafnia alvei produced the greatest abundance of putrescine, cadaverine, tyramine and 2-phenylethylamine. Lactobacillus sakei mainly produced tryptamine and putrescine. Photobacterium phosphoreum showed the strongest histamine-producing capacity.

Using a three-factor orthogonal design, we investigated the transcriptomic and histological responses of triploid rainbow trout (Oncorhynchus mykiss) gills across three salinities (10, 20, and 30 ppt) over 60 days, with temperature and body size as background conditions. Results showed that 20 ppt was associated with extensive transcriptional reprogramming, with 3333 differentially expressed transcripts (DETs), whereas 30 ppt induced only 120 DETs; WGCNA further identified salinity-correlated modules involved in ion transport and ribosome biogenesis. Histological alterations remained within physiological ranges with no salinity-dependent severity gradient, as confirmed by semi-quantitative scoring. These findings demonstrate that triploid rainbow trout gills employ distinct molecular strategies at medium versus high salinity. Within the 10–30 ppt range examined, 20 ppt was the salinity at which transcriptional reprogramming was most active, suggesting that this intermediate salinity warrants further investigation as a potential acclimation stage.

Two typical types of fish products including fermented mandarin fish and semi-dried yellow croaker are associated with biogenic amines (BAs), which are harmful to human health. The objective of this study was to investigate the bacterial ecology in the two fish products and to research its capacity of BAs-producing. PUT and CAD were major BAs detected in fish products. Concentrations of BAs were significantly corrected with microbial count (P < 0.05). BA-producing isolates (31) in two fish products were all multiple BAs producers. Several of them including Lactobacillus sakei, Bacillus cereus and Hafnia alvei isolated from fermented mandarin fish, as well as Shewanella baltica, Aeromonas veronii, and Photobacterium phosphoreum isolated from semi-dried yellow croaker showed a remarkable BA-producing capacity. Hafnia alvei produced the most abundant of CAD, PUT, TYR and 2-PHE. Lactobacillus sakei mainly produced TRY and PUT. Photobacterium phosphoreum showed the strongest HIS producing capacity.

Thermal elevation and residual chlorine pollution are two anthropogenic stressors that co-occur in estuarine waters affected by coastal power plant effluents. A 30-day exposure experiment was established with six treatment combinations comprising three temperatures (27 °C, 28 °C, and 30 °C) and two residual chlorine concentrations (0 mg/L and 0.02 mg/L) on Meretrix meretrix. Sampling was conducted on days 0, 10, 20 and 30 of the trial. The results indicated that elevated temperature (30 °C) significantly suppressed shell height and total body weight, while residual chlorine (0.02 mg/L) exerted time-dependent effects on shell length and width, with a significant interactive effect on shell length only at day 30. Crude lipid content declined with increasing temperature and residual chlorine exposure, whereas moisture and ash contents showed significant two-way interactions at all sampling time points. Intestinal amylase activity was continuously regulated by both stressors, with interactive responses on days 10 and 20, and was significantly suppressed under combined high temperature and residual chlorine stress. Collectively, we infer that combined exposure to elevated temperature and residual chlorine impairs shell growth, muscle biochemical composition and intestinal amylase activity of M. meretrix. Long-term experiments are required to further clarify the joint toxic effects of thermal stress and residual chlorine on the clam species.