Data from: Ruminal planktonic, weakly, and tightly feed-adhered bacterial community as affected by two <em>Trichoderma reesei</em> enzyme preparations fed to lactating cattle

<p>The use of exogenous fibrolytic enzymes (<strong>EFE</strong>) to improve feed efficiency and milk production in cattle has been previously studied with positive results. However, the effect of these enzymes on the ruminal microbiome is not well understood. This study evaluates the effects of two <em>T. reesei</em> EFE preparations on the taxonomic profile, diversity, relative abundance, and shifts of planktonic or free-floating (<strong>LIQ</strong>), weakly (<strong>AS</strong>), and tightly feed-adhered (<strong>SOL</strong>) ruminal bacteria of lactating cows. Three lactating cows were fed three treatments (<strong>TRT</strong>): one control (<strong>CON</strong>) without enzymes and two enzyme preparations [cellulase/xylanase mix (<strong>MIX</strong>) and high-xylanase (<strong>XYL</strong>)] sprayed daily on the total mixed ration. The experiment was designed as a 3 × 3 Latin square with 23-day periods. Rumen contents were collected on day 23, and bacteria from three ruminal content fractions (<strong>FRC</strong>) were evaluated: LIQ, AS, and SOL. The fixed effects of TRT, FRC, and their interaction were evaluated as a 3 × 3 factorial design. Sequencing analysis was performed using the ‘dada2’ package in R to infer amplicon sequence variants (ASV). Alpha diversity (Observed ASV and Chao1) was higher in XYL compared to CON. However, no TRT effect was observed on beta diversity. The relative abundance (RA) of the family <em>Prevotellaceae</em> increased, while that of <em>Ruminococcaceae</em> and <em>Rikenellaceae</em> decreased in XYL compared to MIX and CON. Bacterial community structure (beta diversity) was affected by FRC (<em>P</em> = 0.03), indicating a difference between LIQ communities compared to SOL and AS, but no effects of FRC were observed on alpha diversity. <em>Lachnospiraceae</em> RA was greater in SOL, followed by AS, and lower in LIQ (<em>P</em><0.001), while <em>Spirochaetaceae</em> RA was greater in SOL and AS compared to LIQ (<em>P</em> = 0.003. Prevotellaceae was positively correlated with alpha diversity measures and negatively correlated with <em>Oscillospiraceae</em> and <em>Rikenellaceae</em>. Although differences in bacterial RA were observed with EFE supplementation, no significant correlations were observed between the top 15 bacterial families and previously published measurements of in situ rate of digestion, ruminal pH, total VFA, acetic acid, and propionic acid concentrations. The effects of EFE supplementation on rumen bacterial RA were independent of the ruminal content fraction.</p>