**Disclosures and conflicts of interest**

*Prebiotics and Probiotics - Potential Benefits in Nutrition and Health*

MOS plus metformin for management of type II diabetes.

enhance piglet growth and health.

**5. Summary**

the impact of 1 g/d of MOS consumption on fecal microbiota and laxation [57]. They noted an increased ratio of *Bifidobacterium* spp., and enhanced defecation frequency/volume, reducing constipation. A study in mice by Zheng et al. [58] suggested that MOS acted synergistically with metformin, altering the gut microbiota in a manner that would decrease clinical diabetic parameters, including a reduction in blood glucose. This may have promise for future clinical trials and application of

Jahromi et al. [59] examined MOS supplementation (1 g/kg) to broiler chicks, and observed increased levels of *Lactobacillus spp*. and *Bifidobacteria spp*., while reducing levels of *E. coli* and *Enterobacter* by >50%. Navidshad et al. [60] compared MOS derived from yeast cell walls with MOS from palm kernel expeller, assessing their efficacy as a supplement (2 g/kg) to the diet of broiler chicks. The yeastderived MOS improved weight gain, while reducing the intestinal percentage of *E. coli* in the birds. MOS has been reported to have receptors for fimbriae on *E. coli*, which can help to control or limit colonization within the digestive tract [61]. Jahromi et al. [62] also evaluated *In Ovo* injection of MOS, and feeding of MOS to chicks. The single *In Ovo* injection had some short term but limited long term effects, other than an increase in *Bifidobacterium* spp. at 14 days. Feeding MOS in the diet markedly improved levels of *Lactobacillus* and *Bifidobacteria*, while reducing levels of pathogenic strains of *Salmonella*, *E. coli*, and *Campylobacter*. Adding MOS to the diet also improved levels of serum immunoglobulins IgA, IgM, and IgG. The immunomodulatory effect of MOS in chicks was stated to be a significant benefit that could help improve productivity, and reduce disease (thereby reducing use of antibiotics). Zhao et al. [63] studied the impact of supplementing 0.1 wt% MOS or 0.1 wt% FOS in weanling pigs over 28 days. They observed greater average daily weight gain and average daily feed intake in pigs consuming MOS compared to controls. Nutrient digestibility also improved, along with diarrhea score (potentially by inhibiting *E. coli*). Collectively, the authors concluded that MOS could

Increased understanding of enzyme and transporter expression in various microbes, and key differences between the various classes of enzymes and types of transporters, are enhancing our knowledge about microbial selectivity for substrates, including prebiotics. Differences in chemical structure, degree of polymerization, and bonds between subunits affect microbial utilization of prebiotics. Novel prebiotics derived from xylan, arabinan, and mannan are comprised of less common subunits based on 5 carbon sugars (xylose, arabinose), and/or are connected via β-bonds. The unique types of subunits and bond structures confer greater selectivity for beneficial bacteria, and health benefits at a lower dose compared to conventional prebiotics comprised of glucose, fructose and galactose subunits. Clinical trials with XOS and AXOS led to improvements in laxation, triglycerides, cholesterol, and blood glucose, typically at doses from 1 to 3 g per day, far less than the 10–30 g per day required with FOS, GOS, inulin, and resistant starch. Preliminary clinical trials with MOS suggested the potential for weight management and reductions in adipose tissue at doses in the range of 4 g per day. Furthermore, MOS seems to have a unique capacity to inhibit proliferation of *E. coli*, and its addition to livestock feed has improved livestock health with a concurrent reduction in antibiotic use. Ultimately, these novel prebiotics may usher in a new era of prebiotic utilization, driven by their greater selectivity for beneficial

bacteria, and easier product formulation and efficacy at a lower dose.

**66**

The co-authors are both affiliated with Prenexus Health, a company that produces xylooligosaccharide prebiotics.
