Fermentation alleviates the adverse effect of peony seed meal on hepatocytes

Peony seed meal (PSM), a protein-rich byproduct of peony seed oil extraction, holds promise as an alternative protein source for animal feed. However, our previous research found that when PSM is used as a protein component in chicken feed without pre-treatment, it caused damage to the chicken body, especially to the liver, which is the main detoxification organ. In the present study, the effect of alcohol extract of PSM (aPSM) on hepatocytes was investigated, and the fermentation method was used to attempt to reduce the adverse effect of PSM. The results of in vitro cultured chicken primary hepatocytes showed that, aPSM (> 10 mg/mL) reduced cell viability and intracellular aspartate aminotransferase (AST) and alanine aminotransferase (ALT), increased extracellular AST and ALT, and also changed the antioxidant indexes superoxide dismutase (SOD) and catalase (CAT) (P < 0.05). All above adverse effects were significantly attenuated when PSM was fermented with Aspergillus Niger and Aspergillus oryzae (P < 0.05). In addition, 795 metabolites of aPSM were detected using plant wide targeted metabonomics (PWTM). By comparing the metabolite profiles before and after fermentation, the types and abundances of bioactive substances in aPSM changed substantially. By screening 551 differential metabolites, Lyso PC was found to adversely affect the hepatocytes viability (P < 0.05), and their contents decreased after fermentation. The above results indicate that the adverse effect of PSM on hepatocytes can be reduced by fermentation, and Lyso PC maybe the potential causal substance. This study analyzed the metabonomics of PSM for the first time using PWTM, providing a theoretical basis for the safe utilization of PSM as a dietary protein source.