https://www.selleckchem.com/products/WP1130.html However, the average BDEs found using 48 popular DFT and MP2 levels of theory are reliable, 10.8 ± 6.8% mean absolute error (with W-P removed) versus DLPNO-CCSD(T), with the caveat that the individual basis set/pseudopotential/valence basis set combination can vary wildly. Analysis of the absolute error percentages with respect to the level of theory indicates little benefit to going higher on Jacob's Ladder, as simpler methods have lower error versus high-level ab initio techniques such as G4 and DLPNO-CCSD(T).Tan is a local fat-tail sheep that is famous for its great eating quality but with little attention to its meat metabolome. The aim of this study was to investigate Tan-lamb meat metabolome as well as the key rumen bacteria related to the beneficial compound deposition in the muscle using untargeted and targeted metabolomics under different feeding regimes indoor feeding (F), artificial pasture grazing with indoor feeding (GF), and pure artificial pasture grazing (G). The untargeted metabolome was detected by ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry. Ruminal bacterial communities were detected by 16S rRNA sequencing. Using untargeted metabolomics, the main three altered metabolic pathways in the lamb, including amino acid, lipid, and nucleotide metabolisms, were found in the G group compared to the GF and F groups. Increased N-acetyl-l-aspartic acid, N-acetylaspartylglutamate, acetylcarnitine, and l-carnitine, but decreased carnosine and creatinine, were the main newly found G group-associated metabolites, which might contribute to the improved lamb meat functional quality. Compared to the F group, the G group feeding increased the contents of sweet amino acids (e.g., glycine, alanine, serine, and threonine) and umami amino acids (e.g., glutamic acid and aspartic acid) in the muscle, and G and GF groups increased the level of meat polyunsaturated fatty acid (