This study proposes a novel knowledge graph, PGMKG, to identify and summarize relationships between gut microbiota and pig feed efficiency. The graph aims to assist researchers in optimizing feed efficiency through microbiota-targeted strategies by identifying key microbes. A specialized ontology is established based on scientific literature, defining entity categories, attributes, and relationship types. The ontology comprises 11 classes describing pig, gut microbial, experimental, feed, and growth performance information, as well as other details such as proteins and genes.