Seeking to improve feed efficiency in pigs through microbial modulation via fecal microbiota transplantation in sows and dietary supplementation of offspring with inulin

As previous studies have demonstrated a link between the porcine intestinal microbiome and feed efficiency (FE), microbiota manipulation may offer a means of improving FE in pigs. A fecal microbiota transplantation procedure (FMTp), using fecal extracts from highly feed efficient pigs, was performed in pregnant sows (n=11), with a control group (n=11) receiving no FMTp. At weaning, offspring were allocated, within sow treatment, to 1) control (n=67; no dietary supplement) or 2) inulin (n=65; 6-week dietary inulin supplementation) treatments. The sow FMTp, alone or in combination with offspring inulin supplementation, reduced offspring body weight by 8.1-10.6 Kg at ∼140 days of age, but there was no effect on feed intake. It resulted in better FE, higher bacterial diversity and higher relative abundances of potentially beneficial bacterial taxa (Fibrobacter, Prevotella) in offspring. Due to FMTp and/or inulin supplementation, relative abundance of potential pathogens (Chlamydia, Treponema) in the ileum, and cecal concentrations of butyric acid were significantly lower. Maternal FMTp led to a greater number of jejunal goblet cells in offspring. Inulin supplementation alone did not affect growth or FE, but up-regulated duodenal genes linked to glucose and volatile fatty acid homeostasis and increased mean platelet volume, but reduced ileal propionic acid, granulocyte counts, and serum urea. Overall, FMTp in pregnant sows, with/without offspring dietary inulin supplementation, beneficially modulated offspring intestinal microbiota (albeit mostly low relative abundance taxa) and associated physiological parameters. Although FE was improved, the detrimental effect on growth limits the application of this FMTp/inulin strategy in commercial pig production. IMPORTANCE As previous research suggests a link between microbiota and FE, modulation of the intestinal microbiome may be effective in improving FE in pigs. The FMTp in gestating sows, alone/in combination with offspring post-weaning dietary inulin supplementation, achieved improvements in FE, and resulted in higher relative abundance of intestinal bacteria associated with fiber degradation, and lower relative abundance of potential pathogens. However, there was a detrimental effect on growth, although this may not be wholly attributable to microbiota transplantation, as antibiotic and other interventions were also part of the FMT regime. Therefore, further work with additional control groups is needed to disentangle the effects of each component of the FMTp in order to develop a regime with practical applications in pig production. Additional research based on findings from this study may also identify specific dietary supplements for promotion/maintenance of the microbiota transferred via maternal FMTp, thereby optimizing pig growth and FE.