Comparison of the dietary fiber digestibility and fermentability of feedstuffs determined by conventional methods and in vitro gas production technique in pigs

This study evaluated the accuracy of an in vitro 2-step method combined with an in vitro gas production technique (2+IVGPT) for the estimation of dietary fiber (DF) digestibility coefficient and fermentability of feedstuffs in the large intestine of growing pigs. Digestibility coefficients of corn, wheat, soybean meal, and wheat bran, estimated by the in vitro methods, including the 2-step, 3-step, 2+IVGPT, and in vivo were compared. The fermentation characteristics of feedstuffs were also determined through the 2+IVGPT. The results showed that the in vivo DF digestibility coefficient of wheat bran was 0.39, which was similar to the result estimated by the 2+IVGPT (0.40). In regard to the fermentation characteristics, the lowest maximum rate of gas production (R-max) was obtained for wheat bran (11.0 ml h(-1)). To conclude, in vivo total tract digestibility of DF in the fibrous feedstuff (e.g. wheat bran) could be accurately estimated by the 2+IVGPT.