Front Nutr. 2026 ;13
1933552
Background: Prolonged preoperative fasting is associated with intestinal dysbiosis, impaired mucosal homeostasis, and delayed postoperative recovery. Combined nutritional supplementation with glutamine, dietary fiber, and oligosaccharides has the potential to protect intestinal function during nutritional stress. In this study, we investigated the effects of this nutritional combination in a rat model of prolonged fasting.
Methods: Male Sprague-Dawley rats received oral supplementation with a combination of glutamine, dietary fiber, and oligosaccharides (GFO) or a 15% glucose solution twice daily for 9 days and were subjected to fasting from days 6 to 9. Jejunal morphology, short-chain fatty acid (SCFA) concentrations, intestinal gene expression, and gut microbiota composition were evaluated.
Results: Fasting significantly reduced body weight, jejunal villous height, cecal weight, and the concentrations of acetate, n-butyrate, and n-valerate. Fasting was also associated with exploratory changes in gut microbiota composition and increased the expression of several Toll-like receptor (TLR), barrier, and autophagy-related genes in the jejunum. Supplementation with glutamine, dietary fiber, and oligosaccharides significantly attenuated the fasting-induced reduction in cecal weight and suppressed the upregulation of TLR5, TLR6, TLR8, CLDN1, CLDN3, OCLN, ZO-1, MUC3, ATG5, ATG12, Beclin1, p62, and LC3. Microbiota analysis showed that the relative abundance of sequences tentatively assigned to Lactobacillus reuteri in the supplemented group was comparable to that in the control group, whereas sequences tentatively assigned to Bifidobacterium animalis were detected predominantly in the supplemented group. The relative abundances of Desulfovibrio, Bilophila, and Mucispirillum schaedleri in the supplemented group appeared closer to those observed in the control group than to those in the fasting group. Furthermore, supplementation significantly increased propionate levels compared with the control group.
Conclusions: Combined supplementation with glutamine, dietary fiber, and oligosaccharides attenuated several fasting-associated intestinal stress responses and was accompanied by exploratory changes in gut microbiota composition and SCFA profiles. These intestinal effects were accompanied by exploratory changes in gut microbiota composition and SCFA profiles, together with attenuation of fasting-associated changes in intestinal stress-related markers, suggesting that this nutritional strategy may help maintain intestinal homeostasis during prolonged fasting and may have potential applications in perioperative nutritional support.
Keywords: autophagy; glutamine dietary fiber and oligosaccharides; gut microbiota; intestinal dysbiosis; intestinal homeostasis; perioperative nutrition; prolonged fasting