Integrating gut and IgA‐coated microbiota to identify <i>Blautia</i> as a probiotic for enhancing feed efficiency in chickens

This study explores the role of IgA-coated bacteria in improving feed efficiency in chickens, offering a novel perspective for probiotic screening. Chickens with high feed efficiency were found to have a greater abundance of Gram-positive bacteria, while low feed efficiency chickens exhibited higher levels of Gram-negative bacteria and potential pathogens. Through fecal microbiota transplantation (FMT) and integrating analysis of cecal and IgA-coated microbiota, we precisely identified <i>Blautia</i> as a key genus linked to improved feed efficiency. Further validation demonstrated that <i>Blautia coccoides</i>, a representative species of this genus, enhances feed efficiency and activates B cells to produce Immunoglobulin A (IgA), both in vivo and in vitro. Our findings provide new insights into the potential of IgA-coated bacteria as functional probiotics, offering a promising strategy for enhancing feed efficiency in animal production.