Abstract

Two experiments were conducted in order to compare the effect of condensed tannins (CT) in sainfoin (Onobrychis viciifolia) and sulla (Hedysarum coronarium) on the flux of amino acids (AA) through the gastrointestinal tract of sheep. In each experiment, one group of sheep (PEG group; CT inactive) received an intraruminal infusion of polyethylene glycol (PEG) to inactivate the CT present in the forages, while the other group received an intraruminal infusion of water (Tannin group; CT active). The CT in sainfoin (38.1 g/kg DM) had no significant effect on apparent AA absorption from the small intestine. However, in the sulla-fed sheep, AA absorption in the small intestine was significantly increased by CT (P<0.05; CT = 64.4 g/kg DM). In both forages a shift in AA digestion from the rumen to the small intestine was seen with increased abomasal fluxes of AA in the Tannin group of sainfoin- (92 versus 101 g/day in the PEG and Tannin group, respectively; P<0.05) and sulla-fed (65 versus 83 g/day; P<0.001) sheep. Differences in the digestion and absorption of AA in the two forages may be associated with differences in chemical structure of the CT.

EN, Bermingham, KJ Hutchinson, DK Revell, IM Brookes, and WC McNabb

Proceedings of the New Zealand Society of Animal Production, Volume 61, Christchurch, 116-119, 2001