Studies on nutritional intervention of rice starch- oleic acid complex (resistant starch type V) in rats fed by high-fat diet

•Rice starch-oleic acid complex had better performance in improving serum lipid profiles and hepatic metabolism.•Rice starch-oleic acid complex contributed to the proliferation and growth of SCFAs-producing bacteria.•Turicibacter and Romboutsia were typical bacteria positively correlated with HDL-c and SOD level.•Bifidobacteria might be a main primary degraders for rice starch-oleic acid complex. In this study, rice starch-oleic acid complex with well-controlled digestibility was chosen as a supplementary diet for rats fed with high fat diet. Our results demonstrated that rice starch-oleic acid complex supplementation significantly decreased body weight, improved serum lipid profiles, hepatic metabolism and altered the composition of gut microbiota of rats, which might be related to the higher resistant starch (RS) level. Interestingly, rice starch-oleic acid complex supplementation contributed to the proliferation and growth of butyrate-producing bacteria. The Spearman’s correlation analysis revealed that the genus Turicibacter and Romboutsia genus were positively correlated to HDL-c and SOD level. Meanwhile, based on the metagenomic data, Bifidobacteria genus might be a main primary degrader after rice starch-oleic acid complex intake, which was associated with the changes of key starch-degradation enzymes. Overall, our results provided basic data for the rational design of rice starch-based foods with nutritional functions and physiological benefits.