EFFECT OF TANNINS ON THE DIGESTIBILITY OF TWO ISOSYNTHETIC STRAINS OF BIRDSFOOT TREFOIL ( Lotus corniculatus L.) USING IN VITRO AND IN SACCO TECHNIQUES

Abstract

Two new isosynthetic strains of birdsfoot trefoil (Lotus corniculatus L.), containing low or high concentrations of tannin, were tested using in vitro and in sacco digestibility techniques. The high tannin (HT) strain contained an average of five times more tannin on a dry matter basis, than the low tannin (LT) strain. After 24-h in vitro digestion, by a rumen inoculum, there was less (P < 0.01) dry matter disappearance (45.7 vs. 54.4%) from the HT strain. Also, the development of gas pressure was lower (P < 0.01) and production of volatile fatty acids less (P < 0.05) with the HT strain than with the LT strain. Average dry matter loss from four replicated nylon bags was also lower (P < 0.01) for the HT strain than for the LT strain after 8, 12, and 24 h of incubation in rumen. These data indicate that a LT strain of birdsfoot trefoil might improve the forage digestibility. Key words: Birdsfoot trefoil, tannin, digestibility