Impact of maternal obesity and prebiotic supplementation on select maternal milk miRNA levels and correlation to offspring outcomes
Abstract Breastmilk composition varies with maternal factors including diet, and confers health benefits to the neonate; however, the mechanisms mediating this protection remain incompletely understood. Our aim was to investigate the effects of supplementing a maternal high fat/sucrose (HFS) diet with prebiotic oligofructose (OFS) on milk composition in rats and associations with offspring body composition and gut microbiota. Obese Sprague-Dawley dams consumed a control, HFS, HFS+OFS (10% wt/wt) or HFS diet weight-matched to the HFS+OFS group (HFS-WM) during pregnancy and lactation. Pups were weaned onto a HFS diet on day 21. Milk was collected at weaning and analysed for protein, leptin, and microRNA (miRNA) levels. Milk produced by HFS dams contained less protein than milk from lean controls which was normalized by OFS. Six miRNAs (miR-222, miR-203a, miR-200a, miR-26a, miR-27a, and miR-103) were differentially expressed in milk according to maternal diet. Milk leptin content was positively correlated with maternal body fat and fecal Enterobacteriaceae in male offspring at 24 weeks of age. Milk protein content was inversely associated with maternal body fat and body weight. miR-200a was positively associated with maternal body fat and Enterobacteriaceae in female offspring at 24 weeks of age. Correlations between milk protein and multiple milk miRNAs and offspring body composition and gut microbiota differed by sex. Overall, our results suggest that obesogenic diets and prebiotic supplementation can alter the protein and miRNA levels in breastmilk in rats and these milk components may explain, in part, the influence of these maternal diets on offspring body composition.