N-Acetyl-D-glucosamine improves the intestinal development and nutrient absorption of weaned piglets via regulating the activity of intestinal stem cells

Early weaning in piglets can cause a series of negative effects. This causes serious losses to the livestock industry. N-Acetyl-D-glucosamine (D-GlcNAc) plays an important role in regulating the homeostasis of the intestine. This study aimed to investigate the effects of D-GlcNAc on the growth performance and intestinal function of weaned piglets. Twenty-four weaned piglets ([Yorkshire × Landrace] × Duroc, 6.58 ± 0.15 kg, n = 8) at 21 d old were fed 3 diets supplemented with 0 (control), 1 and 3 g/kg D-GlcNAc. The intestinal organoid model was used to verify the regulatory mechanism of D-GlcNAc on intestinal epithelial cells. On the whole, supplementation of D-GlcNAc in the piglet diet has no significant effect on the growth performance and diarrhoea of weaned piglets (P > 0.05). The apparent digestibility of nutrients and mRNA abundance of nutrient transporters in the 1 g/kg D-GlcNAc group were increased significantly (P < 0.05). D-GlcNAc did not affect villus height (VH) and crypt depth (CD) but resulted in a numerically shorter VH and shallower CD, which lead to an increase in ileal VH:CD ratio (P < 0.05). Cell shedding rates in the ileum villi increased (P < 0.05). The relative length and weight of the small intestine of weaned piglets increased (P < 0.05). In vitro studies found that the budding rates of organoids treated with 0.1 mmol/L D-GlcNAc increased on the d 3 and 5 (P < 0.05). The average budding numbers per budding organoid treated with 0.1 and 10 mmol/L D-GlcNAc increased on d 3 (P < 0.05). D-GlcNAc upregulated leucine rich repeat containing G protein-coupled receptor 5 (Lgr5+) and Chromogranin A mRNA abundance in organoids (P < 0.05). Mucin 2 (Muc2) expression increased when treated with 1 and 10 mmol/L D-GlcNAc (P < 0.05). In conclusion, dietary D-GlcNAc cannot improve the growth performance of weaned piglets. However, it can promote the growth and development of the intestinal tract and improve the digestion and absorption capacity of the intestine, which is achieved by affecting the activity of intestinal stem cells.