Abstract
Microplastics (MPs) pose a significant risk to fish health, yet their effects on meat quality in fish remain poorly understood. To investigate the effects of MPs on meat quality, large-scale loach (Paramisgurnus dabryanus) were exposed to polyethylene MPs (PE-MPs) at 0, 2.5, 5.0, and 10 mg/L for 30 days.
The results showed that PE-MPs exposure significantly reduced condition factor (CF), weight gain rate (WGR), specific growth rate (SGR), hepatosomatic index (HSI), viscerosomatic index (VSI). Flesh quality measurements showed that PE-MP exposure impaired flesh quality, as evidenced by decreased intramuscular fat, essential amino acids content, and polyunsaturated fatty acids levels. Fluorescence spectroscopy combined with particle identification indicated the presence of PE-MPs in muscle, with particle counts increasing over exposure time and concentration. Hematoxylin and eosin (H&E) staining and Real-time quantitative PCR (RT-qPCR) revealed that PE-MPs exposure increased muscle fiber cross-sectional area (CSA), diameter, and spacing, while decreasing type I fiber density. 16S rRNA sequencing analysis showed that PE-MPs ingestion was associated with gut microbiota alterations, which were strongly correlated with muscle fiber characteristics by Spearman analysis.
Fecal microbiota transplantation (FMT) trial revealed that recipients receiving microbiota from PE-MP-exposed donors partially exhibited similar alterations in skeletal muscle fiber characteristics, growth performance, and flesh quality.
Collectively, our findings suggest that PE-MPs exposure may induce gut microbiota alterations, and that these shifts in the gut microbiota were associated with reduced flesh quality and altered muscle fiber characteristics in large-scale loach. These findings provide new insights into the detrimental effects of PE-MPs on flesh quality.
