PSX-A-4 - Effects of Dietary Protein Content and Crystalline Amino Acid Supplementation Patterns on Intestinal Bacteria and Their Metabolites in Weaned Pigs Raised Under Different Sanitary Conditions

Abstract: The objective of this experiment was to investigate the effects of dietary crude protein (CP) content and crystalline amino acids (CAA) supplementation patterns on the bacteria and their metabolites in the intestine of weaned pigs raised under clean (CSC) or unclean sanitary conditions (USC). One hundred forty-four piglets (6.35 ± 0.63 kg BW) were assigned to 1 of 3 diets to give 8 replicates, each with 3 pigs, over a 21-days period. Diets consisted of a high CP (HCP; 21%) and two low CP (LCP; 18%) diets supplemented with all 10 essential AA as CAA or only 6 CAA (Lys, Met, Thr, Trp, Val, and Ile). The CSC room was washed weekly, whereas the USC room had sow manure spread in the pens and was not washed throughout the experiment. Digesta from jejunum and colon were analyzed for ammonia N, short-chain fatty acids, and biogenic amines, but only colonic digesta was analyzed for microbiome composition (16s rRNA sequencing on MiSeq). Data were analyzed using R software for 16S rRNA and the MIXED procedure of SAS for microbial metabolites. Sanitation, CP content, and CAA supplementation patterns did not affect colonic bacterial composition or diversity in weaned pigs. Pigs raised under USC had greater (P < 0.05) jejunal ammonia N than those under CSC. Pigs fed LCP diets had reduced (P < 0.05) jejunal ammonia N compared to those fed HCP diet. No difference was found in colonic ammonia N. Interactions between sanitation and dietary CP content were observed (P < 0.05) for jejunal acetate and colonic spermidine and spermine. In conclusion, reducing dietary CP lowered ammonia N content regardless of the sanitation and increased microbial metabolites in weaned pigs raised under USC. However, colonic bacterial composition and diversity were not influenced by dietary CP, sanitary conditions, or CAA supplementation patterns.