Abstract: An object of the present invention is to provide a technique for further promoting growth of bacteria belonging to the genus Bifidobacterium. By combining lactoferrin and/or lactoferrin hydrolyzate, and human milk oligosaccharides, a synergistic growth promoting effect of the bacteria belonging to the genus Bifidobacterium is achieved. Preferably, the human milk oligosaccharides include one or more selected from the group consisting of 2?-fucosyllactose, 3-fucosyllactose, and lactodifucotetraose. In addition, preferably, the bacteria belonging to the genus Bifidobacterium include one or more selected from the group consisting of Bifidobacterium breve, Bifidobacterium infantis, and Bifidobacterium longum.

Abstract: An object of this present invention is to provide a composition for inhibiting norovirus infection which can inhibit norovirus from infecting a human, and the object is achieved by a composition for inhibiting norovirus infection containing one or more kinds of bacteria selected from the group consisting of Bifidobacterium breve, Bifidobacterium longum subsp. infantis, Bifidobacterium animalis, Bifidobacterium bifidum, Bifidobacterium catenulatum, Lactobacillus gasseri, Lactobacillus helveticus, Lactobacillus delbrueckii subsp. Bulgaricus and Lactobacillus paracasei as an active ingredient.

Abstract: A peptide dimer comprising a peptide consisting of the amino acid sequence of SEQ ID NO: 1 and a peptide consisting of any one of the amino acid sequences of SEQ ID NOS: 2 to 4, wherein the peptide consisting of the amino acid sequence of SEQ ID NO: 1 and the peptide consisting of any one of the amino acid sequences of SEQ ID NOS: 2 to 4 are bound through a disulfide bond between a cysteine residue of each peptide is used as an active ingredient of an agent for promoting proliferation of one or more bacterium selected from the group consisting of Bifidobacterium infantis and Bifidobacterium breve.

Abstract: A peptide dimer comprising a peptide consisting of the amino acid sequence of SEQ ID NO: 1 and a peptide consisting of any one of the amino acid sequences of SEQ ID NOS: 2 to 4, wherein the peptide consisting of the amino acid sequence of SEQ ID NO: 1 and the peptide consisting of any one of the amino acid sequences of SEQ ID NOS: 2 to 4 are bound through a disulfide bond between a cysteine residue of each peptide is used as an active ingredient of an agent for promoting proliferation of one or more bacterium selected from the group consisting of Bifidobacterium infantis and Bifidobacterium breve.