CT concentration (% DM)
0.0 0.5 1.0 1.5 2.0
cis-trans ratio (cis:trans) Peffects
- Accession P < 0.001 - Cut P< 0.001 - Site P > 0.05
Variation in condensed tannin composition in sainfoin (Onobrychis viciifolia) accessions as determined by thiolytic degradation and gel permeation chromatography.
Introduction
Attempts at relating responses got from feeding tannin forages to only their condensed tannin (CT) concentration have not been very successful. Structural diffe- rences in CT molecules need to be consi- dered in order to explain the varied responses from feeding trials with CT containing forages.
Objectives
To employ specialised analytic techniques such as high precision liquid chromatography (HPLC) and gel permeation chromatography (GPC) to probe the tannin structures in six different sainfoin accessions and further to determine whether time of harvest (cut) or site of production has an influence on the structure.
B.N. Azuhnwi1,2, B. Boller3, H.D. Hess1, F. Dohme-Meier1, M. Kreuzer2, E. Stringano4and I. Mueller-Harvey4
1 Agroscope Liebelfeld-Posieux Research Station ALP, Posieux, Switzerland 2 ETH Zurich, Institute of Agricultural Sciences, Switzerland
3 Agroscope Reckenholz - Tanikon Research Station ART, Zurich, Switzerland
4 Chemistry and Biochemistry Laboratory , Department of Agriculture, University of Reading.
ALP | 2011
Materials and Methods
• The six sainfoin accession: four single [Moiry (Mo), Sarzens (Sa), Premier (Pr) and Wiedlishbach (We)] and two multiple [Visnovsky(Vk) and Perly (Pe)] flowering accessions.
• Plant material was established in Spring 2007 at 3 sites in Switzerland: Thun (559 m), Ellighausen (520 m) and Reckenholz (440 m).
Harvest (cuts) were done twice: first cut in late May 2008 and second cut 6 weeks later.
• Direct thiolysis of CT in plant material was performed in the presence of benzyl mercaptan followed by HPLC analysis of the thiolytic reaction products. HPLC GPC analysis was used to verify the thiolysis data;
this analysis was performed on tannin fractions which had been extracted with acetone/water and partially purified by Sephadex LH20 chromatography.
• Effects of accession, site and cut were evaluated by analysis of variance based on a three-factorial design.
MDP
0 10 20 30 40 50 60
PC/PD
0 50 100 150 200
CIS:TRANS
Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe
Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe
Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe
Mo Sa Pr We Vk Pe
THUN ELLIGHAUSEN RECKENHOLZ
mean degree of polymerisation (MDP) Peffects:
- Accession P < 0.001 - Cut P < 0.001 - Site P > 0.05
procyanidin-prodelphindin ratio (PC/PD) Peffects:
- Accession P< 0.001 - Cut P < 0.05 - Site P > 0.05
CT concentration Peffects
- Accession P< 0.001 - Cut P < 0.001 - Site P< 0.001
Results
Second cutFirst cutFirst cutSecond cut
Agroscope
Conclusion
The data show some variability in the CT structures in this sainfoin germplasm especially between accessions and across cuts. This variation may help explain the different responses to feeding these forages to animals and needs further investigation in feeding trials.
Mo Sa Pr We Vk Pe Mo Sa Pr We Vk Pe
