Effects of Metformin and Quercetin on the Thermogenesis and Muscle Metabolism of Piglets.

Metformin is usually used to treat type 2 diabetes, and it is also known to have beneficial effects on body weight and composition. However, the mechanism of its function has not been clarified yet. The aim of this study is to investigate the effects of metformin on the thermogenesis, muscle metabolism, and muscle fiber type of newborn piglets. Total 24 newborn piglets were randomly divided into 4 groups: control group (C, n=6) with no treatment until weaning; Metformin group (M, n=6) with 50mg/kg metformin until weaning; Quercetin group (Q, n=6) with 50mg/kg quercetin until weaning; Metformin + Quercetin group (MQ, n=6) with 50mg/kg metformin + 50mg/kg quercetin until weaning. During the weaning, the surface and rectal temperatures were recorded at 0, 1, 2, 4, 7, 14, 21d. After weaning, all the piglets were fed with the same nursery diet for 6 weeks. After 6 weeks of the nursery, all the piglets were slaughtered, and the longissimus dorsi muscle of each pig was collected to determine gene expression. The results showed that the surface temperature of C group was higher than M, Q, and MQ groups at day-21 (P<0.01, Figure 1), and rectal temperatures of M, Q, and MQ groups were higher than C from day-1 to day-21 (P<0.05, Figure 2). The gene expression of UCP3 and SLN in the M group was higher than C and Q (P<0.05, Figure 3). The MyHC I expression of the MQ group was higher than the C group (P<0.05, Figure 3). The results indicate that feeding metformin and quercetin during weaning increased the rectal thermogenesis and impacted the gene expression related to muscle metabolism and muscle fiber type.