278 Effects of Yeast Postbiotic Supplementation on the Gut Bacterial Community Composition of Sows and Microbial Succession of Subsequent Offspring
Authors: Kieser Joel , Fowler Emily , St-Pierre Benoit , Levesque Crystal L 
Published: October 2023

Abstract
Development of the gut microbiome in piglets via microbial succession is critical for maximizing their productivity and providing stability for overcoming weaning stress. The purpose of this trial was to investigate whether a yeast postbiotic could impact the sow fecal microbiome as well as affect microbial succession in piglets. Sows were fed a control (CON) diet, or a diet supplemented with a yeast-based postbiotic (SUP) at 0.5% from d 80 to d 113 of gestation and at 0.2% during lactation (d 114 of gestation to weaning at 20 ± 2 d). Fecal bacterial composition was determined for 12 sows/treatment at d 85 gestation, d 1 lactation, and weaning and 1 piglet/sow at weaning and d 7, d 14, and d 28 post-wean using Illumina MiSeq 2X300 sequencing of PCR-amplicons generated from the V1-V3 regions of the 16S rRNA gene. A comparative analysis of the most highly represented Operational Taxonomic Units (OTU) was performed using the non-parametric Kruskal-Wallis sum-rank test and Wilcoxon pairwise test. In this initial comparative analysis, no significant differences between sows which received CON or SUP diets or piglets were observed (P &gt; 0.05), although, fluctuations in the abundance of specific OTUs were found over time in both sows and piglets. For instance, the abundance of OTU JK_30-00008, predicted to be a strain of Lactobacillus amylovorous, was increased sows at d85 (CON: 9.01%; SUP: 12.04%), dramatically reduced at d 1 of lactation (CON: 1.00%; SUP: 3.03%), then recovered by weaning (CON: 9.41%; SUP: 9.74%). In contrast, the abundance of OTU JK_16-00021, predicted to be an uncultured Peptostreptococcaceae, remained increased in sow fecal samples from both treatment groups at d 85, d 1 lactation, and weaning (CON: 10.6%, 15.05%, and 15.61%; SUP: 8.98%, 13.65%, and 14.47%, respectively). In piglet fecal samples, the most abundant OTUs at weaning, d 7, d 14, and d 28 were: JK_45-00042 (CON: 27.26%; SUP: 20.05%; no affiliation to any currently defined phylum), JK_137-00038 (CON: 11.04%; SUP: 5.76%; unclassified Yersiniaceae), JK_30-00008 (CON: 13.64%; SUP: 14.11%; Lactobacillus amylovorous), and JK_51-00117 (CON: 7.66%; SUP: 5.32%; Prevotella copri), respectively. In piglets, the number of OTUs representing 50% of total sequence relative abundance increased with time (n = 5 OTUs at weaning, n = 18 at d 7, n = 17 at d 14, and n = 43 at d 28) suggesting an increase in diversity with age. Yeast postbiotic in sow diet had limited impact on relative proportions of sow fecal microbiome and offspring microbial succession after weaning with greater piglet diversity expected due to dietary changes. In addition, several of the OTUs in greatest relative abundance in piglets, including JK_45-00042, JK_137-00038, JK_-42, and JK_-49 did not correspond to valid bacterial species. Together, these results underscore the need to identify prevalent unknown bacterial species in microbial community compositional shifts in the period around weaning.