The prebiotic potential of RS-3 preparations for pre- and post-weaning piglets

Piglets undergo stress during the weaning period, resulting in an imbalance in gut microbial composition and activity, and potentially post-weaning diarrhoea. Supporting maturation of gut microbiota is a strategy preparing piglets for weaning, and could be achieved by providing dietary fibres such as resistant starch (RS) in the creep feed. We investigated the prebiotic potential of four well-characterised retrograded starches (RS-3 preparations) for pre- and post-weaning piglets. These RS-3 preparations were in vitro fermented using pooled faecal inoculum of 3-week-old (pre-weaning) and 7-week-old (post-weaning) piglets. RS-3 preparations containing a high amount of digestible starch (≥ 75 %) were fully fermented by both faecal inocula within 48 h. Such substrates generated mostly butyrate when fermented by pre-weaning piglet faecal inoculum, whereas mostly propionate was found during fermentation by post-weaning inoculum. Bacterial genera Prevotella and Megasphaera increased in relative abundance after fermentation by both inocula, whereas Streptococcus and Selenomonas increased in relative abundance only when fermented by pre-weaning or post-weaning piglet faecal inocula, respectively. Highly resistant or so-called intrinsic RS-3 (≥ 80 % RS) was hardly degraded by pre-weaning inoculum, whereas it was slowly fermented by post-weaning piglet faecal microbiota, leading to an increase in relative abundance of specific Prevotella and Roseburia phylotypes (amplicon sequence variants). This study shows that partially resistant RS-3 preparations might be beneficial dietary fibres for pre-weaning piglets by promoting short-chain fatty acids production, while intrinsic RS-3 was hardly fermentable. Intrinsic RS-3 substrates might have prebiotic potential for post-weaning piglets by stimulating potential health-beneficial Prevotella and Roseburia.