EFFECTS OF SELECTED REED CANARY GRASS ALKALOIDS ON IN VITRO DIGESTIBILITY

Abstract

A range of concentrations of pure samples of the alkaloids, gramine, hordenine, 5-methoxy-dimethyl tryptamine and N-methyl tryptamine which are normal constituents of reed canary grass were added to in vitro rumen fluid fermentations. Powdered cellulose and ground reed canary grass were used as substrates and fermentation periods were 24 and 48 h. No consistent relationship was found between the concentration of any of the above alkaloids and in vitro digestion values for either of the substrates or fermentation periods. In other studies, 24- and 48-h in vitro digestions were carried out on reed canary grass clones harvested at early heading and 6-wk regrowth. These clones showed a very wide range of gramine, hordenine and total alkaloid levels. No relationship was found between the concentration and type of alkaloids in the clones and their in vitro digestibility. These findings are in keeping with earlier similar work and it was concluded that reported poor animal performance with reed canary grass is probably due to factors other than alkaloid interference with the rumen microflora.