Gastrointestinal microbial diversity and short-chain fatty acid production in pigs fed different fibrous diets with or without cell wall-degrading enzyme supplementation

The microbial diversity and short-chain fatty acid (SCFA) production in pigs fed different fibrous diets with or without cell wall-degrading enzyme (phytase, cellulase and xylanase) supplementation were compared using the Illumina MiSeq sequencing technique. Eight growing castrated pigs fitted with a T-shaped cannula at the terminal ileum were randomly assigned to four diets, i.e., wheat bran-based diet (WB), enzyme-supplemented WB, soybean hull-based diet (SH), and enzyme-supplemented SH, according to a 4 x 4 Latin square design. The ileal digesta and feces were collected after 15 days of adaptation in each period. The WB diet increased (P < 0.05) the abundances of Lactobacillus, Veillonella and Ruminococcaceae compared to SH diet, whereas the SH diet led to a higher (P < 0.05) abundances of Streptococcaceae, Peptostreptococcaceae, Laclmospiraceae, Treponema and Methanobrevibacter than that of WB diet. Adding exogenous cell wall-degrading enzyme selectively altered the relative abundance of bacteria in both dietary groups. The SH promoted (P < 0.01) the concentrations of acetate, propionate and total SCFA in the ileal digesta and feces, and enzyme supplementation led to similar results for SCFA production (P < 0.01) but not for acetate in the feces compared to that of WB. These results may provide valuable information on how to utilize fibrous feedstuffs efficiently in animal production.