<i>Pediococcus acidilactici</i> Y01 reduces HFD-induced obesity <i>via</i> altering gut microbiota and metabolomic profiles and modulating adipose tissue macrophage M1/M2 polarization

Obesity-related metabolic syndrome is intimately associated with infiltrated adipose tissue macrophages (ATMs), gut microbiota, and metabolic disorders. <i>Pediococcus acidilactici</i> holds the potential to mitigate obesity; however, there exist strain-specific functionalities and diverse mechanisms, which deserve extensive exploration. This study aims to explore the potential of <i>P. acidilactici</i> Y01, isolated from traditional sour whey, in alleviating HFD-induced metabolic syndrome in mice and elucidating its underlying mechanism. The results showed that <i>P. acidilactici</i> Y01 could inhibit the increase of body weight gain, the deposition of fat, lipid disorders and chronic low-grade inflammation, improve glucose tolerance and insulin resistance, and could reduce adipose tissue inflammation by decreasing M1-type ATMs and increasing M2-type ATMs. Meanwhile, <i>P. acidilactici</i> Y01 significantly increased the abundance of potentially beneficial intestinal bacteria, such as <i>Akkermansia</i>, <i>Alistipes</i>, <i>Bifidobacterium</i>, <i>Lachnospiraceae_NK4A136_group</i>, <i>Lactobacillus</i>, <i>norank_f__Muribaculaceae</i>, and <i>Parabacteroides</i>, and partially restored the levels of metabolites, such as phosphatidylcholines, glycerophosphocholines, sphingolipids and unsaturated fatty acids. The fecal microbiota transplantation experiment demonstrated that <i>P. acidilactici</i> Y01 ameliorated obesity-related metabolic syndrome by modulating the polarization of M1/M2 ATMs mediated by gut microbiota. Overall, as a dietary supplement, <i>P. acidilactici</i> Y01 has good potential in the prevention and treatment of obesity.