The effect of infant formula–based powder containing milk fat globule membrane on the 4-kingdom cornerstone microbiota in the feces and the immune ability of suckling rats

Growing evidence demonstrates that the 4-kingdom intestinal microbiota (FKIM) play a critical role in improving the body's immune processes. Three batches of experiments were conducted to study the effects of infant formula-based powder (IFBP) containing milk fat globule membrane (MFGM), human milk oligosaccharides, and probiotics, respectively, on the FKIM of suckling rats, with the IFBP serving as the control. Compared with the control, 3 functional components could increase the body weight and improve the composition of FKIM. Notably, suckling rats supplemented with MFGM had significantly higher abundance and number of cornerstone species across the FKIM in feces than those in the other groups, and the levels of immune factors in serum were also significantly increased. After MFGM intervention, the abundance of cornerstone species of 99 genera in the feces was significantly correlated with the levels of immune factors in the serum. Among the cornerstone species, there are 11 bacteria, 6 eukaryotes, 2 archaea, and 1 virus that serve as biomarkers to distinguish the fecal microbiota of suckling rats fed with IFBP containing and not containing MFGM. Milk fat globule membrane can improve immunity by regulating functional pathways such as NOD-like receptor signaling and primary immunodeficiency. Milk fat globule membrane can stabilize the cornerstone species in the suckling rats' feces and enhance their immune ability by modulating the intestinal cornerstone species related to serum immunity, and their functional pathways, providing a theoretical basis for developing infant formula with immune-regulating functions.