Abstract
Palm kernel meal (PKM) has been shown to be a high-quality protein source in ruminant feeds. This study focused on the effects of feed, supplemented with different amounts of PKM (ZL-0 as blank group, and ZL-15, ZL-18, and ZL-21 as treatment group), on the quality and flavor profile of Tibetan sheep meat. Furthermore, the deposition of beneficial metabolites in Tibetan sheep and the composition of rumen microorganisms on underlying regulatory mechanisms of meat quality were studied based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry as well as 16S rDNA sequencing. The results of the study showed that Tibetan sheep in the ZL-18 group exhibited superior eating quality and flavor profile while depositing more protein and fat relative to the other groups. The ZL-18 group also changed significantly in terms of the concentration and metabolic pathways of meat metabolites, as revealed by metabolomics. Metabolomics and correlation analyses finally showed that PKM feed mainly affected carbohydrate metabolism in muscle, which in turn affects meat pH, tenderness, and flavor. In addition, 18% of PKM increased the abundance of Christensenellaceae R-7 group, Ruminococcaceae UCG-013, Lachnospiraceae UCG-002, and Family XIII AD3011 group in the rumen but decreased the abundance of Prevotella 1; the above bacteria groups regulate meat quality by regulating rumen metabolites (succinic acid, DL-glutamic acid, etc.). Overall, the addition of PKM may improve the quality and flavor of the meat by affecting muscle metabolism and microorganisms in the rumen.