The Impact of Human Milk Oligosaccharides on Antibiotic-Induced Microbial Dysbiosis and Gut Inflammation in Mice

<b>Background/Objectives</b>: Antibiotics have a significant impact on the gut microbiota, and we hypothesized that human milk oligosaccharides may alleviate antibiotic-induced gut microbiota dysbiosis. <b>Methods</b>: Six groups of eight mice were administered drinking water with or without ampicillin for one week. We then introduced the human milk oligosaccharide 2'-fucosyllactose (2'FL), either alone or in combination with difucosyl-lactose (DFL), for two weeks after the termination of ampicillin treatment. <b>Results</b>: Ampicillin reduced microbiota diversity and the abundance of specific bacteria. One week after the termination of ampicillin treatment, the 2'FL + DFL mixture counteracted the ampicillin-induced reduction in diversity, although this effect was not sustained. Over the subsequent two weeks, the 2'FL + DFL mixture had a significant impact on the relative abundances of <i>Lactobacillus</i> spp. and <i>Bacteroides</i> spp. Ampicillin also reduced caecal propionate levels, downregulated the gene <i>Gzmb</i> for Granzyme B, and upregulated the gene <i>Reg3a</i> for Regenerating islet-derived protein 3 alpha, all of which were counteracted by the 2'FL + DFL mixture. Ampicillin had a minor impact on ileal cytokine levels. The 2'FL + DFL mixture showed a cytokine effect indicating reduced adaptive and innate inflammation. Ampicillin reduced water intake and growth in the mice. The oligosaccharides did not affect water intake, but the 2'FL + DFL mixture slightly reduced body weight. <b>Conclusions</b>: The 2'FL + DFL mixture appears to hold potential for counteracting some of the side effects of ampicillin treatment.