Prebiotic fiber enteral supplementation after allogeneic transplantation: feasibility and impact on the microbiome.

The decline in diversity of the gastrointestinal microbiome during hematopoietic stem cell transplantation (HSCT) is associated with poorer clinical outcomes. Although provision of enteral nutrition (EN) is common during HSCT, provision of a prebiotic fiber-containing formula has not been explored. This pilot study compared tolerance, clinical, microbiome, and metabolomic outcomes between patients who received standard EN (n = 10) vs prebiotic fiber EN (n = 20) after allogeneic HSCT. Stool samples were collected at baseline and at periengraftment and were analyzed with shotgun metagenomic sequencing. Provision of prebiotic EN increased daily fiber intake after transplant to an average 22 g/d compared with 4 g/d in the standard-care group. High tolerance of both EN formulas was observed with only 20% (n = 2) of the standard and 15% of the prebiotic group (n = 3) requiring parenteral nutrition (P = 1.0). There was no difference in the amount of EN provided, EN duration, or clinical outcomes. Microbial diversity declined in both groups with no difference post-EN provision (P = .93), however, there was a significant difference in relative abundance of Lactobacillus_C rhamnosus, with an increase in the prebiotic group only (P = .022). The relative abundance of Faecalicatena gnavus increased in the standard group and declined in the prebiotic group (P = .0027). Functional analysis of the microbial genome showed decreased expression of antibiotic resistance genes in the prebiotic group only after EN provision (P = .00035). A longer fiber intervention should be trialed to optimize clinical outcomes and a more diverse microbiome. The trial was registered at www.anzctr.org.au as #ACTRN12621000832875.