123 President Oral Presentation Pick: Identification of correlated metabolomic and microbiomic responses that connect dietary energy level with pig growth

Corn, soybean meal, DDGS and extracted lipids are common staple ingredients in swine feed. Purpose-based proportioning of these ingredients in the formulation can achieve distinct levels of net energy (NE) and amino acids (AA), as well as fiber and micronutrients, in feed. In this study, diets were formulated using a 2 × 2 factorial design on NE and AA, in which the diet with high AA (HAA) had more soybean meal than the diet with low AA (LAA), while the diet with high NE (HNE) had more choice white grease and less DDGS than the diet with low net energy (LNE). Total 160 pigs (4 pigs/pen) were fed for 90 days under a three-phase feeding program. In each phase, 4 groups of pigs (10 pens/group) were fed four respective diets of HNE+HAA, HNE+LAA, LNE+HAA, and LNE+LAA. On day 90, body weights were recorded to calculate ADG, and cecal digesta were collected for LC-MS-based metabolomic analysis and 16S RNA sequencing-based microbiomic analysis. The one-way ANOWA of ADG data showed that ADG was increased by NE (p < 0.05), but not by AA. Multivariate analysis (MVA) of metabolomics and microbiomics data also showed that NE, but not AA, caused apparent changes in the metabolome and microbiome of cecal digesta. The metabolites and microbes connecting NE level with ADG, including citrulline, hexadecenoic acid, Bacteroides stercoris, and Ruminococcus bromii, were identified through examining the markers that separate HNE and LNE feedings in the MVA models of cecal metabolome and microbiome as well as the markers that were significantly correlated with ADG in the Pearson correlation analysis. Overall, the results from this study revealed specific metabolomic and microbiomic changes associated with dietary NE level and growth performance, which could serve as a foundation for further analysis on the metabolic and prebiotic functions of feed ingredients.