Performance, intestinal microflora, and wall morphology of weanling pigs fed sodium butyrate

Adding organic acids to piglet diets is known to be helpful in overcoming post-weaning syndrome and butyric acid is known to be the main energy source for the epithelial cells of the large intestine and the terminal ileum. This study investigated the effect of sodium butyrate (SB) on in vitro and in vivo swine microflora, piglet growth performance, and intestinal wall morphology. During a 24-h in vitro cecal fermentation, total gas production and maximum rate of gas production were linearly reduced by SB (P < 0.001). Ammonia in cecal liquor was linearly increased by SB after 4 h, 8 h and 24 h of fermentation (P < 0.001). In the vivo study, 48 piglets housed in individual cages were allotted to four treatment groups (12 animals per treatment) for six weeks. Piglets received a basal diet with a) no addition (control) or with SB at b) 1,000 ppm, c) 2,000 ppm, and d) 4,000 ppm. After six weeks, six animals per treatment were killed and samples of intestinal content and mucosa were collected. Sodium butyrate did not improve the animal growth performance. However, pigs receiving the diet containing SB at 4,000 ppm showed a numerical greater final BW (28.8 vs 26.8 kg) and ADFI (835 vs 773 g) than control animals. In the cecum, SB increased pH and iso-butyric acid concentration (linear, P < 0.05) and tended to increase ammonia concentration (P = 0.056). Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria as well as intestinal mucosa morphology were not affected by feeding SB. This study showed that SB influenced the cecal microflora in an in vitro system reducing the total gas production but increasing ammonia concentrations. When fed to piglets, SB did not improve the animal growth performance, increased cecal pH and tended to increase cecal ammonia concentrations. Further studies will be needed to better understand the mechanisms underlying the effects observed when SB is fed to piglets.