抄録
Bifidobacteria are one of the predominant bacteria in the human gut microbiota and are reduced under various pathological conditions. Galacto-oligosaccharides (GOS), a type of non-digestible carbohydrates, are one of the most well-known “prebiotics” that promote the growth of bifidobacteria in the colon, and their consumption may be beneficial for maintaining the balance of the gut microbiota. In this review, from the perspective of “one-health,” we investigate the health benefits of GOS developed by our institution for humans and companion animals. The main component of our GOS is 4′-galactosyllactose (GL), which consists of a galactose β-1,4 bonded to the galactose moiety of lactose present in human breast milk. In human milk, there are two structural isomers of 4′-GL, 3′-GL with a β-1,3 linkage and 6′-GL with a β-1,6 linkage. The mechanism of utilization of these three GLs by Bifidobacterium breve strain Yakult and type strain revealed that three transporters and two β-galactosidases, corresponding to each substrate, are responsible for the uptake and hydrolysis of GLs, respectively. The administration of infant formula containing GOS to formula-fed infants resulted in an increase in bifidobacteria in the feces. Consumption of GOS by healthy human adults with low fecal bacterial cell counts and a low relative abundance of bifidobacteria resulted in an increase in these microbial parameters. Furthermore, GOS increased the frequency of defecation in constipated individuals. Regarding the efficacy of GOS for companion animals, administration of GOS to dogs and cats kept in general households resulted in increased beneficial bacteria such as bifidobacteria in feces and the concentration of fecal short-chain fatty acids and reduced fecal putrefactive products and serum urinary toxins. Additionally, in dogs, the suppressive effects of fecal odor and periodontal disease bacterial activity were observed. These findings suggest that GOS may contribute to the maintenance of health and improvement of quality of life in both humans and companion animals.
