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, <i>Roseburia</i> and various <i>Eubacterium</i> spp. known to improve cholesterol metabolism, whereas a remarkable outgrowth of <i>Akkermansia</i>, 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.