Abstract
Three bacteria producing conjugated linoleic acid (CLA) were isolated from dog and cat feces. The first isolate was presumed to be a species of Streptococcus or Lactococcus, and the second isolate was probably Eubacterium aerofaciens. These two bacteria have not been known as CLA-producing bacteria. The third isolate was identified as a type II strain of Butyrivibrio fibrisolvens. Of the three isolates, B. fibrisolvens was found to have the highest capacity to produce CLA. To increase CLA production in the large intestine, it may be effective to increase the cell number of this strain of B. fibrisolvens. Addition of the isolated strain of B. fibrisolvens to a culture of mixed fecal microorganisms markedly increased CLA production. Experiments with six different strains of B. fibrisolvens indicated that the rates of linoleic acid (LA) isomerization and CLA reduction are correlated to the amounts of LA isomerase and CLA reductase in cells. These results suggest that CLA production, oraccumulation, can be greatly increased by enhancing the synthesis of LA isomerase and suppressing the synthesis of CLA reductase.
