Polymerization Degrees, Molecular Weights and Protein-Binding Affinities of Condensed Tannin Fractions from a Leucaena leucocephala Hybrid

Abstract

Condensed tannins (CTs) form insoluble complexes with proteins and are able to protect them from degradation, which could lead to rumen bypass proteins. Depending on their degrees of polymerization (DP) and molecular weights, CT fractions vary in their capability to bind proteins. In this study, purified condensed tannins (CTs) from a Leucaena leucocephala hybrid were fractionated into five different molecular weight fractions. The structures of the CT fractions were investigated using 13 C-NMR. The DP of the CT fractions were determined using a modified vanillin assay and their molecular weights were determined using Q-TOF LC-MS. The protein-binding affinities of the respective CT fractions were determined using a protein precipitation assay. The DP of the five CT fractions (fractions F1-F5) measured by the vanillin assay in acetic acid ranged from 4.86 to 1.56. The

Changes in rumen protozoal community by condensed tannin fractions of different molecular weights from aLeucaena leucocephalahybridin vitro

“…Earlier, we reported that higher‐MW fractions of CTs from LLR possessed higher protein‐binding affinities than lower‐MW fractions (Saminathan et al . ). We also observed that higher‐MW CT fractions significantly ( P < 0·05) decreased nitrogen disappearance in rumen fermentation in vitro by forming insoluble CT–protein complexes (Saminathan et al .…”

“…Five different fractions of the pure CTs were obtained by size exclusion chromatography as described by Saminathan et al . (). The CT fractions were freeze‐dried and stored at −4°C in the dark prior to further use.…”

“…Accordingly, we had fractionated a mixture of pure CTs (unfractionated CTs, F0) of LLR by using the size exclusion chromatography and the MW of each fraction was determined by GCMS (Saminathan et al . ). Totally, five fractions with known MWs were obtained (F1 = 1265·8 Da, F2 = 1028·6 Da, F3 = 652·2 Da, F4 = 562·2 Da and F5 = 469·6 Da).…”

The role of condensed tannins in ruminant animal production: advances, limitations and future directions

“…Because CT bind to minerals (Lavin, 2012) and organic molecules such as proteins (Saminathan et al, 2014), carbohydrates (Soares et al, 2012a), and lipids (Delehanty et al, 2007), it is possible that not only do these complexes become unavailable as substrate for use by rumen microbes, but that CT bind to microbial enzymes modulating their activity (Gonçalves et al, 2011). Naumann et al (2013c) demonstrated a weak relationship between protein bound by CT and a decrease in CH 4 .…”

Changes in in vitro ruminal and post‐ruminal degradation of tropical tannin‐rich legumes due to varying levels of polyethylene glycol

“…High levels of condensed tannins (>50 g/kg plant DM) have antinutritional effects such as reduction in dry matter intake (Barahona et al., ), but lower concentrations (<50 g/kg plant dry matter) can be useful due to their capacity to bind protein in the rumen (Saminathan et al., ), increasing nitrogen flow to the small intestine (Waghorn et al., ; Wang et al., ; Min et al., ). Moderate concentrations of CT (20–45 g CT/Kg DM) could improve milk production, ovulation rate and wool growth and reduce internal parasite burdens (Min et al., )…”