EFFECTS OF GRAPE SEED TANNIN EXTRACT SUPPLEMENTATIONS TO FEEDS ON SOME IN VITRO RUMEN FERMENTATION PARAMETERS

The aim of this study was to determine the effect of grape seed tannin extract (GSTE) in the doses of 0, 25, 50, 75 g/kg dry matter (DM) feed on in vitro gas production (GP), volatile fatty acid (VFA) production and the digestibilities of true dry matter (TDMD) and neutral detergent fiber (NDFD) of alfalfa hay and barley grain. The supplementation of diets with 25 g/kg DM GSTE did not affect (p>0.05) potential gas production, TDMD, NDFD and ruminal total VFA of cultures compared with the diet without GSTE. Compared with the diet without GSTE, the addition of GSTE at >= 50 g/kg DM to alfalfa hay diets or at 75 g/kg DM to barley grain diets reduced (p<0.01) potential gas production, TDMD, total VFA. Diet and GSTE had significant interactions (p<0.05) in total VFA and potential gas production. It was concluded that the effects of GSTE on in vitro ruminal fermentation were dose-dependent in both diet, but its effects on in vitro ruminal fermentation were more pronounced with alfalfa digestion than with barley grain.