Enumeration of Bacteroides succinogenes in the rumen of sheep fed maize-straw diets

Estimates of Bacteroides succinogenes in the rumen of two sheep fed a maize-straw diet exceeded 108 per g of rumen ingesta and were even higher when the straw was supplemented with pelleted maize grain. A number of B. succinogenes strains were characterized in some detail and very few were found to ferment starch. Cells of freshly isolated strains lost viability more rapidly when grown on agar medium than did cells of strains which had been subjected to more transfers.