Intramuscular connective tissue (IMCT) collagen is an important factor in meat quality. This study analyzed the characteristics of type I and III collagen in the IMCT of the semitendinosus (SD) and longissimus dorsi (LD) of Wuzhumuqin sheep at different growth stages (6, 9, 12, and 18 months). Utilizing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy (FTIR), collagen types I and III were successfully isolated and shown to contain an intact triple helix structure. Immunofluorescence revealed that these collagens were located in the endomysium and perimysium. Collagen-related genes were significantly expressed in sheep aged 9 and 12 months. The amino acid content increased with age in type I collagen whereas it decreased in type III collagen. Furthermore, type III collagen contained more hydroxyproline (Hyd) than type I collagen. Differential scanning calorimetry (DSC) revealed that the thermal stability of collagen increased with age, accompanied by a decrease in solubility. Semitendinosus muscle had more collagen cross-linkages than LD muscle due to the high pyridinoline (Pyr) content in the endomysium. Finally, a correlation analysis highlighted the multiple correlations between characteristics in different types of collagen during sheep growth. In summary, the collagen characteristics in the IMCT of sheep were impacted by collagen type, muscle type, and age. Furthermore, the various correlations between these characteristics may play an important role in the development of IMCT.

The tail fat of sheep is the most typical deposited fat, and it can be widely used in human daily life, such as diet, cosmetics, and industrial raw materials. To understand the potential regulatory mechanism of different growth stages of tail fat in Sunite sheep, we performed high‐throughput RNA sequencing to characterize the long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression profiles of the sheep tail fat at the age of 6, 18, and 30 months. A total of 223 differentially expressed genes (DEGs) and 148 differentially expressed lncRNAs were found in the tail fat of 6‐, 18‐, and 30‐month‐old sheep. Based on functional analysis, we found that fat‐related DEGs were mainly expressed at 6 months of age and gradually decreased at 18 and 30 months of age. The target gene prediction analysis shows that most of the lncRNAs target more than 20 mRNAs as their transregulators. Further, we obtained several fat‐related differentially expressed target genes; these target genes interact with different differentially expressed lncRNAs at various ages and play an important role in the development of tail fat. Based on the DEGs and differentially expressed lncRNAs, we established three co‐expression networks for each comparison group. Finally, we concluded that the development of the sheep tail fat is more active during the early stage of growth and gradually decreases with the increase in age. The mutual regulation of lncRNAs and mRNAs may play a key role in this complex biological process.

Alxa Bactrian camel meat is an organic diet that provides balanced nutrition and is easy to digest and absorb. Despite its potential, it is currently underutilized. To develop a new type of camel jerky, this study utilized a single‐factor design method to optimize the formula and fermentation process parameters of Alxa Bactrian camel jerky. Additionally, the physical and chemical composition, nutritional components, protein degradation, and microbial changes of the camel jerky were analyzed to evaluate the nutritional benefits of the new camel jerky created using modern fermentation technology. The results show that the optimal addition amounts of camel fermented jerky ingredients are 2.2% black pepper, 3% salt, 1.8% white sugar, and 9% cooking wine, whereas the optimal fermentation conditions by compound starter culture are 0.07% starter, 23 h of fermentation time, and a 30°C fermentation temperature. Compared to the single starter, the compound starter significantly increased the protein content, total amino acids, unsaturated fatty acids, trace elements, and a*, L*, and e‐values of jerky; however, it also decreased the water activity (a_w), thiobarbituric acid, and pH values of jerky during storage. Compound starter strains can compensate for the shortage of single starters and improve the overall quality of meat products. These findings could provide new insights and serve as a reference for the development of camel meat products and hold significant importance for the growth of the camel industry.

Objective: This study aimed to elucidate the lipid composition, characteristics, and metabolic mechanisms of subcutaneous adipose tissue (SAT) in natural grazing Mongolian cattle during its development.Methods: The experimental animals consisted of castrated Mongolian cattle, divided into two groups: 10 months old (10 M, n = 12, average weight: 113.26±0.87 kg) and 34 months old (34 M, n = 12, average weight: 390.44±1.23 kg). All animals were selected from the same herd in the Eren Nur grasslands, Xilingol, Inner Mongolia, China. Browning-related genes in SAT were determined using quantitative reverse transcription polymerase chain reaction with 3 replicates for each cattle, and six animals from each group were randomly selected for non-targeted lipidomic techniques to analyze the changes in lipid metabolism with 6 replicates.Results: The yellowness value and relative expression of mitochondrial biogenesis-specific markers, thermogenic markers, uncoupling protein-2 (UCP2), and beige adipocyte marker genes in the SAT increased with age. Multivariate analysis revealed 172 significantly different lipids (SDLs). Triacylglycerols and phosphatidylcholines showed high relative contents. Glycerol and sterol lipid levels were predominantly upregulated during development, whereas phospholipids and sphingolipids were primarily upregulated at 10 M. Developmental time greatly influenced the fatty acid composition of neutral lipids, phospholipids, and free fatty acids. Pathway analysis demonstrated that the 172 SDLs were primarily involved in glycerophospholipid, glycerolipid, ether lipid, and sphingolipid metabolism.Conclusion: The developmental stage significantly affected the lipid quantity, composition, and metabolism of SAT in Mongolian cattle. Certain functional lipids, such as mediumlong-chain triglycerides, fatty acid ester of hydroxyl fatty acid, and vitamin D, were detected in the yellow fat of natural grazing Mongolian cattle. These findings provide a comprehensive reference for the metabolic characteristics of yellow fat in Mongolian cattle, contributing to the meat industry chain.

The color of carcass fat is an important factor in meat quality. To investigate the characteristics and changes in lipid metabolism of SAT in Mongolian cattle at 34 M of age compared with the control group, we evaluated the color, relative expression of genes associated with browning, and profiles of lipid metabolites by using qPCR and non-targeted lipidomics techniques. Overall, the yellowness value and relative expression of mitochondrial biogenesis–specific markers, thermogenic, UCP2, and beige adipocyte marker genes in the SAT of 34 M cattle were higher than those control (p < 0.05). Using multivariate analysis, 172 significantly different lipids (SDLs) were identified. Triacylglycerols (TGs) and phosphatidylcholines (PCs) had high relative contents with abundant unsaturated fatty acids. The upregulation of TGs observed in the SAT of 34 M cattle mainly consisted of medium- and long-chain fatty acids. Pathway analysis demonstrated that 172 SDLs were primarily involved in glycerophospholipid, glycerolipid, ether lipid, and sphingolipid metabolism. In summary, yellow fat of naturally grazed cattle was impacted by many factors such as lipid metabolism, browning genes expression and age. These findings provide new insight into the characteristics and metabolic pathways of adipose tissue in natural grazing Mongolian cattle.