Cross-feeding among bifidobacteria on glycomacropeptide

Bifidobacteria are considered beneficial for infant health, however, they are less prevalent in gut microbiota of formula-fed than in breast-fed infants. This study investigated the bifidogenic effects of cow's glycomacropeptide (GMP) and metabolic enzymes that Bifidobacterium bifidum JCM1254 uses when grown in the GMP-containing medium. Bifidobacterium bifidum JCM1254 was able to be grown in the GMP-containing medium, and the growth was abolished when glycans were chemically cleaved. Abundance of carbohydrate metabolism-related proteins, including sialidase, were higher when Bifidobacterium bifidum JCM1254 was cultured in the GMPcontaining medium than in the glucose-supplemented medium. Bifidobacterium breve ATCC15700 and Bifidobacterium longum subsp. infantis ATCC15697 were grown in the GMP-containing medium spent by Bifidobacterium bifidum JCM1254, and N-acetylneuraminic acid liberated by Bifidobacterium bifidum JCM1254 decreased when Bifidobacterium breve ATCC15700 was cultured in the spent medium. Collectively, GMP glycans are "cross-fed" among bifidobacteria, and carbohydrate metabolism-related proteins, expressed by Bifidobacterium bifidum, is involved in the cross-feeding.