title: Assessment of Anti-nutritive Activity of Tannins in Tea By-products Based on In vitro Rumen Fermentation.
abstract: Nutritive values of green and black tea by-products and anti-nutritive activity of their tannins were evaluated in an in vitro rumen fermentation using various molecular weights of polyethylene glycols (PEG), polyvinyl pyrrolidone (PVP) and polyvinyl polypyrrolidone as tannin-binding agents. Significant improvement in gas production by addition of PEG4000, 6000 and 20000 and PVP was observed only from black tea by-product, but not from green tea by-product. All tannin binding agents increased NH3-N concentration from both green and black tea by-products in the fermentation medium, and the PEG6000 and 20000 showed relatively higher improvement in the NH3-N concentration. The PEG6000 and 20000 also improved in vitro organic matter digestibility and metabolizable energy contents of both tea by-products. It was concluded that high molecular PEG would be suitable to assess the suppressive activity of tannins in tea by-products by in vitro fermentation. Higher responses to gas production and NH3-N concentration from black tea by-product than green tea by-product due to PEG indicate that tannins in black tea by-product could suppress rumen fermentation more strongly than that in green tea by-product.
authors.affiliation: Graduate School of Bioresources, Mie University, Mie, 514-8507, Japan ; Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 470-0151, Japan .
authors.forename: Makoto
authors.initials: M
authors.lastname: Kondo
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 470-0151, Japan . ; Tokai Gakuen University, Nagoya 468-0014, Japan .
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Hirano
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 470-0151, Japan .
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Ikai
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 470-0151, Japan . ; School of Agriculture, Iwate University, Iwate 020-8550, Japan .
authors.forename: Kazumi
authors.initials: K
authors.lastname: Kita
authors.affiliation: Faculty of Animal Science, Bogor Agricultural University, Bogor 16680, Indonesia .
authors.forename: Anuraga
authors.initials: A
authors.lastname: Jayanegara
authors.affiliation: Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 470-0151, Japan .
authors.forename: Hiro-Omi
authors.initials: HO
authors.lastname: Yokota
keywords: In vitro Rumen Fermentation; Tannin; Tannin Binding Agent; Tea By-product