Sodium butyrate (SB) is used as an acidifier in animal feed. We hypothesized that supplemental SB impacts gastric morphology and function, depending on the period of SB provision. The effect of SB on the oxyntic and pyloric mucosa was studied in 4 groups of 8 pigs, each supplemented with SB either during the suckling period (d 4 to d 28 of age), after weaning (d 29 to d 39-40 of age) or both or never. The number of parietal cells immunostained for H+/K+-ATPase, gastric endocrine cells immunostained for chromogranin A and somatostatin (SST) in the oxyntic mucosa and gastrin-secreting cells in the pyloric mucosa, was assessed. Gastric muscularis and mucosa thickness were measured. Expressions of the H+/K+-ATPase and somatostatin type 2 receptor (SSTR2) genes in the oxyntic mucosa, and of the gastrin gene in the pyloric mucosa were evaluated by real-time RT-PCR. SB increased the number of parietal cells per gland, regardless of the period of administration (P < 0.05). SB addition after, but not before, weaning increased the number of enteroendocrine and SST-positive cells (P < 0.01) and tended to increase gastrin mRNA (P = 0.09). An interaction between the two periods of SB treatment was seen for the expression of H/K-ATPase and SSTR2 genes (P < 0.05). Butyrate intake after weaning increased gastric mucosa thickness (P < 0.05), but not muscularis. Sodium butyrate used orally at a low dose impacted gastric morphology and function presumably in relationship with its action on mucosal maturation and differentiation
