Profiles of Odd- and Branched-Chain Fatty Acids and Their Correlations With Rumen Fermentation Parameters, Microbial Protein Synthesis, and Bacterial Populations Based on Pure Carbohydrate Incubation in vitro

The objectives of this study were to evaluate changes in profiles odd- and branched-chain fatty acids (OBCFA), including pentadecanoic acid (C15:0), 13-methyltetradecanoic ( iso -C15:0), 12-methyltetradecanoic anteiso 14-methylpentadecanoic -C16:0), heptadecanoic (C17:0), 15-methylhexadecanoic -C17:0), 14-methylhexadecanoic -C17:0) during vitro fermentation pure carbohydrates mixtures the buffer-rumen fluid. second objective was correlate OBCFA profile corresponding ruminal parameters, microbial crude protein (MCP) synthesis, bacterial populations. Five containing different cellulose: starch (C:S) ratios, i.e., 0:100, 25:75, 50:50, 75:25, 100:0, incubated for 6, 12, 18, 24 h . results showed that there significant interaction P < 0.05) between C:S incubation time all profiles, except iso-C17:0. highest concentration total (3.94 mg/g dry matter; DM) observed residues after when while lowest (1.65 produced 6 50:50. correlation analysis revealed iso-C16:0 might be a potential marker estimation volatile (ρ = 0.78) MCP synthesis 0.82) rumen. Compared degrading bacteria, cellulolytic bacteria had stronger correlations with concentrations, strongest found population Ruminococcus flavefaciens C15:0 0.70). Notably, is first paper reporting relationship rumen products based on , thus avoid confounding interference from dietary fat presence vivo studies. However, more in-depth experiments are needed substantiate current findings.