Dietary supplementation of glycerol monolaurate improves growth performance, meat quality, and gut microbiota in black pigs

This study investigated the effects of glycerol monolaurate (GML) on growth performance, meat quality, and gut microbiota in black pigs. A total of 135 castrated Dongliao black pigs (age, 170 ± 5 d; initial body weight, 82.41 ± 1.65 kg; male:female = 72:63) were weighed and randomly assigned into three groups (3 replicates/group, 15 pigs/replicate). Pigs were fed either a basal diet (control group) or the basal diet supplemented with 250 and 750 mg/kg GML for 56 d. The results showed that GML supplementation linearly increased final body weight (P = 0.031) and quadratically changed the feed conversion ratio (P = 0.025) without causing glucolipid metabolism disorders. In addition, GML improved meat quality and promoted protein (P = 0.034) and amino acid (AA) deposition (P = 0.005) in the muscle. These beneficial effects were attributed to improvements in the intestinal micro-environment, as GML significantly increased the relative abundances of Terrisporobacter and Romboutsia (P < 0.05), and elevated the concentration of total bile acids related to gut microbiota (P = 0.001). Overall, these findings demonstrate the potential of GML as a functional feed additive to improve growth performance and meat quality of finishing pigs, with 750 mg/kg GML showing greater efficacy than 250 mg/kg.