Metabolic consequences and gut microbiome alterations in rats consuming pork or a plant-based meat analogue

It is unknown how human health is affected by the current increased consumption of ultra-processed plant-based meat analogues (PBMA). In the present study, rats were fed an experimental diet based on pork or a commercial PBMA, matched for protein, fat, and carbohydrate content for three weeks. Rats on the PBMA diet exhibited metabolic changes indicative of lower protein digestibility and/or dietary amino acid imbalance, alongside increased mesenteric (+38%) and retroperitoneal (+20%) fat depositions despite lower food and energy intake. In contrast, rats on the pork diet demonstrated signs of a disturbed gut–liver axis with increased liver weight (+15%) and blood low-density lipoprotein (+86%), which may have been facilitated by gut microbial changes. The colon of rats on the PBMA diet was characterized by an outgrowth of bacterial groups including Muribaculaceae, Roseburia and various Eubacterium spp. known to improve cholesterol metabolism, whereas a remarkable outgrowth of Akkermansia, Oscillospiraceae and Desulfovibrionaceae in rats on the pork diet may be conducive to colon mucin degradation. Effects on oxidative stress parameters were equivocal, with increased lipid oxidation (+27%) in the colon mucosa of PBMA-fed rats, whereas lower blood levels of the endogenous antioxidant glutathione (−30%) were found in pork-fed. Overall, the present rat study reveals major differences in the physiological and microbiota-related responses to diets containing either conventional pork or PBMA, which could have implications for human health.