Impact of Dietary Fatty Acid Composition on the Intestinal Microbiota and Fecal Metabolism of Rats Fed a High-Fructose/High-Fat Diet

<b>Background/Objectives</b>: An inappropriate intake of dietary fats can disrupt the homeostasis of intestinal microbiota, affect the host's metabolic status, and increase the risk of chronic diseases. The impact of dietary fat types on the composition and metabolic functionality of the intestinal microbiota has become a research focus over recent years. The objective of this study was to explore the effects of regular peanut oil (PO) and high-oleic-acid peanut oil (HOPO) on the composition and metabolic function of the intestinal microbiota. <b>Methods</b>: A dietary intervention test was conducted on SD rats fed a high-fat/high-fructose (HFF) diet. The composition and metabolic functionality of the intestinal microbiota of the experimental rats were investigated by 16S rRNA gene sequencing and fecal metabolomics. <b>Results</b>: Compared with saturated fat, PO and HOPO enhanced the diversity of intestinal microbiota in HFF diet-fed rats. Compared with PO, HOPO significantly increased the relative abundance of <i>Lachnospiraceae_NK4A136_group</i> and <i>Harryflintia</i> (<i>p</i> < 0.05), which are able to generate butyrate and acetate. Compared with saturated fat, 318 and 271 fecal biomarkers were identified in PO and HOPO groups, respectively. In contrast, 68 fecal biomarkers were identified between the PO and HOPO groups. The inhibition of harmful proteolytic fermentation in the colon may represent the main regulatory mechanism. With regard to metabolic status, HOPO provided better control of body weight and insulin sensitivity than PO. <b>Conclusions</b>: Compared with saturated fat, peanut oils better regulated the composition and metabolic function of the intestinal microbiota. In addition, HOPO exhibited better regulatory effects than PO.