Linoleic acid induces different metabolic modes in two Bifidobacterium breve strains with different conjugated linoleic acid-producing abilities

Abstract

Frequently, Bifidobacterium breve strains are found to be CLA-producers. Previous studies revealed that free linoleic acid inhibited the growth of bifidobacterial strains, however, the reason why bifidobacteria with different CLA-producing abilities exhibit similar adaptive modes to linoleic acid (LA) stress is still unknown. We used B. breve strains CCFM683 and CCFM1025, which exhibit 85% and 0% CLA conversion rates, respectively, together with metabonomics analyses, to elucidate the putative factors involved in the protection against LA stress. We found that the pathways involved in amino acid, carbohydrate, and fatty acid metabolisms were much more active in B. breve CCFM1025. Moreover, l-cysteine, l-methionine, mannitol, and 18-hydroxy-oleate accumulated to a much higher level in B. breve CCFM1025, probably providing primary protection. In particular, the levels of several antioxidant compounds, including l-ascorbate, glutathione, ubiquinol-6, 3-demethylubiquinol-7, and demethylmenaquinol-7, were much higher in B. breve CCFM1025, suggesting that these antioxidants may provide a primary protective effect to the strain without CLA-producing abilities.