Sorghum tannin extract impedes in vitro digestibility and fermentability of nutrients in the simulated porcine gastrointestinal tract.

Sorghum tannins may be potent negative factor to impede the nutrient utilization in sorghum grain fed to pigs. Unfortunately, the site, rate and extent of digestion of sorghum nutrients affected by tannins in the intestine remain unclear. Therefore, this experiment was conducted to determine the effects of sorghum tannin extract on the digestion and fermentation characteristics of nutrients in the in vitro simulated porcine gastrointestinal tract. The results revealed that sorghum tannin extract decreased the chemical enzymatic digestion of nutrients in the simulated anterior intestine, and inhibited the hindgut microbial fermentation including microbial diversities and metabolites (accumulative gas and short-chain fatty acid production) in the simulated posterior intestine of pigs. The experiment implies that the decreased abundances of Lachnospiraceae and Ruminococcaceae by tannins in the hindgut may weaken the fermentation capacity of microflora and thus impair the nutrient digestion in the hindgut, and ultimately may reduce the total tract nutrient digestibility in pigs fed high tannin sorghum.