PSVII-26 - Metaproteomic assessment of pre- and post-wean pigs reveals the microbial protein dynamics involved in amino acid biosynthesis.

Abstract: The digestion, absorption, and metabolism of amino acids plays an indispensable role in the growth, immunity, and intestinal development of pigs. The gut microbiota contributes to the generation of amino acids which can be used by the host and may compensate for the lack of essential amino acids in the diet. Disruptions to the homeostatic balance of the microbial community can lead to changes in the metabolic profile and have been associated with increased susceptibility to intestinal diseases. Due to dietary and physiological changes, microbial dysbiosis is common at weaning and alterations to the gut microbiota can affect the synthesis of amino acids that are critical to many host processes. Hence, it is imperative we understand the metabolism of amino acids in piglets during the weaning transition and identify the microbes involved in the production of these organic compounds. Using healthy pigs in combination with metaproteome analysis, we evaluated the abundance of microbial proteins involved in the synthesis of amino acids in response to weaning. Our results show that, microbial proteins associated with the production of L-aspartate/L-asparagine and the essential amino acid L-arginine were higher in nursing pigs in comparison to post-wean pigs. Notably, proteins involved in the biosynthesis of the limiting amino acids, L-lysine and L-threonine were elevated in post-weaned individuals and the genus Anaerovibrio displayed the highest contribution to protein abundance. Production of the amino acids L-serine/glycine, and the essential branched-chain amino acids L-valine and L-isoleucine remained abundant in both timepoints regardless of the day of sampling. In general, microbes from the orders Bacteroidales (genera: Bacteroides), Eubacteriales (Subdoligranulum) and Lachnospirales (Eisenbergiella) were the principal producers of amino acids in nursing pigs, whereas the orders Selenomonadales (Mitsuokella), Bacteroidales (Muribaculum and Prevotella) contributed to amino acid synthesis after weaning. This study demonstrates how weaning impacts the abundance of proteins involved in amino acid biosynthesis and identifies microbial members that can serve as candidates for probiotic applications and other therapeutics.