The residual black wolfberry fruit (RBWF), rich in nutrients and active substances, has the potential to serve as an antibiotic alternative. This study evaluated the concentration-dependent effects of RBWF on serum biochemistry, immunity, antioxidant capacity, and meat quality of fattening sheep. Forty 3-month-old sheep were randomly assigned into four groups with 10 replicates in each group and fed experimental RBWF-supplemented diets (0%, 2%, 5%, and 8%). The results showed that RBWF supplementation significantly increased the serum levels of TP, BUN, ALT, AST, IgA, IgM, T-AOC, SOD, and GSH-Px in sheep (p < 0.05), while significantly decreasing the levels of LDH, TG, LDL-c, IgG, and MDA (p < 0.05). Furthermore, dietary RBWF significantly increased the VB1 and IMP levels in the longissimus dorsi muscle of sheep (p < 0.05) and significantly decreased the contents of fat and cholesterol (p < 0.05). Finally, RBWF increased the contents of C20:4 and Glu (p < 0.05). In conclusion, dietary supplementation with RBWF can improve the immune and antioxidant capacity of sheep and has a certain effect on improving the flavor of meat, of which 5% is the best.

Lycium ruthenicum leaves (LRL), as an agricultural by-product rich in bioactive compounds, can be used as an unconventional feedstuff in animal diets and have the potential to improve animal health. This study investigates the effects of dietary supplementation with graded levels of LRL on rumen fermentation, meat amino acid and fatty acid profiles, and rumen bacterial diversity in sheep. Forty three-month-old male Dorper × Hu crossbred F1 lambs with an initial body weight of 29.58 ± 2.06 kg were randomly assigned to four groups (n = 10). Over a continuous 63-day trial period, the lambs were fed diets containing 0%, 5%, 10%, and 15% LRL, respectively. At the end of the trial, rumen fluid and longissimus dorsi muscle samples were collected to assess rumen fermentation characteristics, bacterial community structure, and meat quality. The results showed that: (1) The concentrations of acetate, butyrate, and total volatile fatty acids (TVFA) in the rumen were increased in the LRL5% group (p < 0.05 or p < 0.01). (2) The relative abundance of the phylum Firmicutes and the genus Ruminococcus increased (p < 0.05), while the relative abundance of the genus Prevotella decreased (p < 0.05) in the LRL5% group. (3) Meat L* increased (p < 0.05), and a* decreased (p < 0.05) in the LRL-supplemented groups. (4) The content of sweet amino acids in meat increased in LRL groups (p < 0.05). Moreover, the contents of non-essential amino acids, sweet amino acids, and total amino acids in meat increased linearly with increasing dietary LRL levels (p < 0.05). (5) Compared with the CON group, the content of C18:0 in meat decreased in the LRL5% group (p < 0.05), while the content of C20:1 increased in the LRL10% group (p < 0.05). In conclusion, dietary supplementation with LRL can improve meat quality, rumen fermentation, and rumen bacterial community structure in sheep. The recommended dietary inclusion level of LRL ranges from 5% to 15%.

This study investigated the effects of dietary stevia straw supplementation on meat quality, amino acid and fatty acid content, and rumen microbial diversity in sheep. A total of 50 ram lambs (3–4 months, 27.01 ± 3.8 kg) were randomly assigned to five groups. Each group received a total mixed ration supplemented with 0% (control), 5%, 15%, 25% and 35% dry stevia straw for 72 days. Adding 15% and 25% stevia straw significantly increased the pre-slaughter body weight. EE content was also significantly higher across all experimental groups (p < 0.01), showing a linear increase with supplementation. Glutamic acid content in the 15% group was significantly higher than that in the 25% group (p < 0.05). The addition of stevia straw improved the fatty acid profile: C18:1n9c content in the 5%, 15%, and 25% groups was significantly higher than that in the CK (Control) group (p < 0.05); C18:2n6c content in the 25% group was significantly higher than that in the CK, 5%, and 15% groups (p < 0.05); the content of (C20:1) was extremely significantly higher in all experimental groups compared to the CK group. Additionally, the unsaturated fatty acid content in the 25% group was significantly higher than that in the CK group (p < 0.05). The relative abundances of Bacteroidota and Firmicutes were increased in the 25% and 35% groups, but the differences were not significant (p > 0.05). In conclusion, dietary supplementation of 15–25% stevia straw to the ration can significantly improve the slaughtering performance, meat quality and muscle nutrient composition of fattening sheep. In addition, the addition of stevia straw had no negative effect on the rumen microflora, and the 15% level could increase the abundance and activity of the rumen microflora, so it is recommended to use 15% stevia straw in the ration for sheep during the fattening period.

Breed-associated differences in roasted-lamb flavour are often described from volatile profiles alone, whereas the links among lipid precursors, volatile abundance and olfactory activity remain less clear. Here, fatty acid profiling, headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) and gas chromatography–olfactometry–mass spectrometry (GC–O–MS) were combined to compare eight Chinese sheep breeds under standardised roasting conditions, although rearing conditions differed among groups. Major unsaturated fatty acids, particularly C18:1n-9, C18:2n-6, C18:3n-3 and C20:4n-6, differed markedly among breeds. Aldehydes and pyrazines dominated the roasted volatilome, but their relative contributions varied. GC–O–MS revealed a shared roasted/nutty aroma backbone, with 2,3-dimethylpyrazine detected across all breeds, whereas lipid-derived odorants including hexanal, nonanal, octanal, (E)-2-octenal and 1-octen-3-ol showed greater breed-associated variation. Some breeds exhibited pyrazine-dominant profiles, whereas others showed greater contributions from lipid-derived aldehydes and alcohols. Unsaturated fatty acids were more closely associated with lipid-derived volatiles than with pyrazines. These findings indicate that breed-associated differences in roasted-lamb aroma are characterised mainly by shifts in the relative contribution of lipid oxidation products and Maillard-derived odorants against a shared aroma-active background.

Breed-associated differences in roasted lamb flavour are often described from volatile profiles alone, whereas the links among lipid precursors, volatile abundance and olfactory activity remain less clear. Here, fatty acid profiling, headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME–GC–MS) and gas chromatography–olfactometry–mass spectrometry (GC–O–MS) were combined to compare eight Chinese sheep breeds under standardized roasting conditions. Major unsaturated fatty acids, particularly C18:1, C18:2n-6, C18:3n-3 and C20:4n-6, differed markedly among breeds. Aldehydes and pyrazines dominated the roasted volatilome, but their relative contributions varied. GC–O–MS revealed a shared roasted/nutty aroma backbone, with 2,3-dimethylpyrazine detected across all breeds, whereas lipid-derived odorants including hexanal, nonanal, octanal, (E)-2-octenal and 1-octen-3-ol showed greater breed-associated variation. Some breeds exhibited pyrazine-dominant profiles, whereas others showed greater contributions from lipid-derived aldehydes and alcohols. Unsaturated fatty acids were more closely associated with lipid-derived volatiles than with pyrazines. These findings indicate that breed-associated differences in roasted lamb aroma are characterised mainly by shifts in the relative contribution of lipid oxidation products and Maillard-derived odorants against a shared aroma-active background.

4-Alkyl branched-chain fatty acids (BCFAs), including 4-methyloctanoic acid (4-MOA), 4-ethyloctanoic acid (4-EOA), and 4-methylnonanoic acid (4-MNA), are important contributors to the characteristic odor of sheep meat. Their concentrations and composition are closely related to meat flavor quality and consumer acceptance. Understanding the mechanisms that regulate BCFA formation and accumulation is therefore important for improving sheep meat flavor. In this study, the concentrations of these three BCFAs were measured in muscle samples from Altay (ALT), Turpan (TLF), Inner Mongolian (NM), Tan, and Hu sheep. Untargeted muscle metabolomic data from ALT and TLF sheep were integrated with publicly available datasets, including metabolomic data from Tan sheep under different feeding conditions and transcriptomic and metabolomic data from Hu and Zang sheep. These datasets were used to investigate BCFA-related metabolic networks and candidate regulatory factors associated with ecological environment, nutritional conditions, and genetic background. The results show clear differences in BCFA accumulation among the sheep populations. All three BCFAs were below the limits of detection in ALT, TLF and NM sheep. Both 4-MOA and 4-EOA were detected in Tan sheep, whereas all three BCFAs were detected in Hu sheep. The concentrations of 4-MOA and 4-EOA in Hu sheep were approximately 14.4- and 12.5-fold higher than those in Tan sheep, respectively (p < 0.001). Multi-omics integration showed that BCFA-related metabolic variation was mainly associated with branched-chain amino acid metabolism, short-chain carbon metabolism, the tricarboxylic acid (TCA) cycle, and lipid metabolism. MMUT, ACAT1, and EHHADH were identified as candidate regulatory genes. These genes are involved in methylmalonyl-CoA conversion, acetyl-CoA/acetoacetyl-CoA metabolism, and fatty acid β-oxidation, respectively. Changes in energy demand, substrate utilization, and precursor availability may alter the partitioning of BCFA precursor carbon between central energy metabolism and lipid metabolism, thereby affecting BCFA formation and accumulation. In summary, MMUT, ACAT1, and EHHADH may influence the formation and accumulation of 4-MOA, 4-EOA, and 4-MNA by regulating key metabolic reactions and carbon partitioning between the TCA cycle and lipid metabolism. Ecological environment and dietary conditions may further contribute to this process by modifying energy metabolism and precursor substrate supply. These findings provide a theoretical basis for understanding BCFA-related flavor formation and for improving sheep meat flavor through genetic selection and nutritional regulation.