Effects of yeast culture and fibrolytic enzymes supplementation on in vitro fermentation characteristics of low-quality cereal straws

¹ Key Laboratory of Subtropical Agro-ecological Engineering, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan 410125, P. R. China
² Babcock University, P.M.B. 21244, Ikeja, Lagos, Nigeria
³ Hunan Agricultural University, Changsha, Hunan 410128, P. R. China
⁴ Hunan Yahua Dairy Industry Co. LtD, Changsha, Hunan 410005, P. R. China
⁵ New Hope Group, Chengdu, Sichuan 610041, P.R. China

^* To whom correspondence should be addressed. E-mail: zltan{at}isa.ac.cn.

	Abstract

Effects of yeast culture and fibrolytic enzymes preparation (containing cellulase and xylanase) on in vitro fermentation characteristics of rice straw, wheat straw, maize stover, and maize stover silage was examined using an in vitro gas production technique. Four levels of yeast culture and fibrolytic enzymes supplements (0, 2.5, 5.0, and 7.5 g/kg straw DM, respectively) were tested in a 4 x 4 factorial arrangement. Supplementation of yeast culture increased the cumulative gas production (GP) incubated for 48 h, theoretical maximum of gas production (A), rate of gas production (B), IVDMD, and in vitro OM disappearance (IVOMD), and decreased the lag time (LAG) for each type of straw. Fibrolytic enzymes supplementation tended to increase GP, A, and B, prolonged LAG of gas production, and enhanced IVDMD and IVOMD for 4 types of cereal straws, with the significance of this effect being dependent on the level of supplemented enzymes. There were significant interactions between fibrolytic enzymes and yeast on all in vitro gas production parameters, IVDMD, and IVOMD of each type of straws. The outcome of this research indicated that the application of fibrolytic enzymes preparation and yeast culture could improve in vitro gas production fermentation of cereal straws.

Key Words: In vitro gas production, Rumen fluid, In vitro digestibility