TITLE:
In vitro ruminal fermentation of leaves from three tree forages in response to incremental levels of polyethylene glycol
AUTHORS:
Andell Edwards, Victor Mlambo, Cicero Horatio Octavius Lallo, Gary Wayne Garcia, Michael Davanan Diptee
KEYWORDS:
Tannin-Binding Agents; In vitro Ruminal Gas Production; Organic Matter Digestibility; Tannin Bioactivity; Optimum Inclusion Rate
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.2 No.3,
July
26,
2012
ABSTRACT: Polyethylene glycol (PEG), a phenol binding agent has been used extensively to measure the biological activity of tannins in forage species. The optimum inclusion rate of PEG, per unit weight of sample varies from species to species. Determining optimum inclusion levels can prevent wastage and reduce the cost of diagnosing the biological activity of tannins, especially in developing countries. This study was designed to determine the optimum PEG inclusion levels required to completely ameliorate In vitro ruminal bioactivity of tannins in leaves from Leucaena leucocephala, Gliricidia sepium and Trichanthera gigantea using the Reading Pressure Technique. Fermentation parameters were generated by fitting gas production data to the Orskov and McDonald (1979) non-linear equation: . An asymptotic response to incremental levels of PEG was observed with cumulative gas production at 48 h post inoculation. The minimum level of PEG required to maximize In vitro ruminal fermentation of tree leaves was found to be 200 mg PEG/g DM for all tree species. Gas production rate constant for the insoluble fraction (c) showed an increase (P In vitro organic matter degradability (iOMD) declined (P In vitro ruminal tannin biological activity in leaves of the three tree species.