Dietary Lard at 25% Fat Energy Level Enhances Adipose Tissue Browning and Gut Microbiota Remodeling in Mice Relative to Soybean Oil

To examine the disparities in adipose tissue browning between diets rich in lard and soybean oil under low and recommended caloric intake conditions. In this study, sixty 8‐week‐old male C57BL/6J mice were randomly divided into four groups fed purified diets with 15% and 25% energy provided as lard or soybean oil. After 20 weeks, the mice were dissected and the tissues were collected. Only at the 25% level was there a significant difference in the brown adipose tissue between the two groups of mice fed different oils. The expression of mRNA related to the BAT was tested by qPCR methods. Diversity of microbiota in cecal content was evaluated by the 16S rRNA sequencing. Compared with soybean oil, the BAT weight of the lard group was significantly increased ( p < 0.05), and the protein expression of UCP1 in iWAT was significantly higher ( p < 0.05). The expression levels of adipose browning, thermogenesis and mitochondria genes were significantly increased in the lard group, and lipogenesis‐related genes were significantly decreased ( p < 0.05). The proportions of Akkermansia , Romboutsia , Lactobacillus , and Streptococcus were significantly increased in the lard group ( p < 0.05). This study suggests that at the dietary fat energy level of 25%, feeding with lard could promote the browning of fat, improve lipid metabolism, and increase the abundance of beneficial bacteria in the gut.