As the most typical deposited fat, tail fat is an important energy reservoir for sheep adapted to harsh environments and plays an important role as a raw material in daily life. However, the regulatory mechanisms of microRNA (miRNA) and circular RNA (circRNA) in tail fat development remain unclear. In this study, we characterized the miRNA and circRNA expression profiles in the tail fat of sheep at the ages of 6, 18, and 30 months. We identified 219 differentially expressed (DE) miRNAs (including 12 novel miRNAs), which exhibited a major tendency to be downregulated, and 198 DE circRNAs, which exhibited a tendency to be upregulated. Target gene prediction analysis was performed for the DE miRNAs. Functional analysis revealed that their target genes were mainly involved in cellular interactions, while the host genes of DE circRNAs were implicated in lipid and fatty acid metabolism. Subsequently, we established a competing endogenous RNA (ceRNA) network based on the negative regulatory relationship between miRNAs and target genes. The network revealed that upregulated miRNAs play a leading role in the development of tail fat. Finally, the ceRNA relationship network with oar-miR-27a_R-1 and oar-miR-29a as the core was validated, suggesting possible involvement of these interactions in tail fat development. In summary, DE miRNAs were negatively correlated with DE circRNAs during sheep tail fat development. The multiple ceRNA regulatory network dominated by upregulated DE miRNAs may play a key role in this developmental process.
Objective An experiment was conducted to investigate the effects of feed intake restriction during late pregnancy on the function, anti-oxidation capability and acute phase protein synthesis of ovine liver. Methods Eighteen time-mated ewes with singleton fetuses were allocated to three groups: restricted group 1 (RG1, 0.18 MJ ME/kg W0.75 d, n = 6), restricted group 2 (RG2, 0.33 MJ ME/kg W0.75 d), n = 6) and a control group (CG, ad libitum, 0.67 MJ ME/kg W0.75 d, n = 6). The feed restriction period was from 90 days to 140 days of pregnancy. Results The eweâs body weight, liver weights, water, and protein content of liver in the restricted groups were reduced compared with the CG group (p<0.05), but the liver fat contents in the RG1 group were higher than those of the CG group (p<0.05). The increased hepatic collagen fibers and reticular fibers were observed in the restricted groups with the reduction of energy intake. The concentrations of nonesterified free fatty acids in the RG1 and RG2 groups were higher than those of the CG group with the reduction of energy intake (p<0.05), but there were decreased concentrations of lipoprotein lipase and hepatic lipase in both restricted groups compared with the CG group (p<0.05). In addition, the increased concentrations of β-hydroxybutyric acid, triglycerides, malondialdehyde, total antioxidant capacity and activities of superoxide dismutase activity and catalase were found in the RG1 group, and the concentrations of cholinesterase in the RG1 group were reduced compared with the CG group (p<0.05). For the concentrations of acute phase proteins, the C-reactive protein (CRP) in the RG1 group were reduced compared with the CG group, but there were no differences in haptoglobin relative to the controls (p>0.05). Conclusion The fat accumulation, increased hepatic fibrosis, antioxidant imbalance and modified synthesis of acute phase proteins were induced in eweâs liver by maternal malnutrition during late pregnancy, which were detrimental for liver function to accommodate pregnancy. Keywords: Acute Phase Protein; Anti-oxidation Capability; Liver Function; Malnutrition
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 objective of this study was to investigate the effects of sodium alginate (SA) and pressurization levels on pH, water-binding and textural properties of pork muscle gels (PMG) containing salt.Ground lean pork with 1.0% NaCl and a given amount of SA (0.25, 0.5, 0.75 and 1.0%, respectively), was pressurized to 100, 200 or 300 MPa and subsequently gelled by heating.Results showed that addition of SA into pork muscle enhanced water-holding capacity (WHC) of PMG (p<0.05) as SA increased from 0.25% to 1.0%, with pH slightly increased (p>0.05).A decrease (p<0.05) was observed in all textural parameters (hardness, cohesiveness, springiness and chewiness).Pressurization had no effect on the tendency of WHC to increase or the decrease of the textural parameters.However, the effectiveness of pressurization to enhance textural properties of PMG was significant at some SA levels, especially ≥200 MPa and at ≤0.75% SA levels.Different combinations of pressure and SA levels could bring about variation in textural properties of PMG while SA enhanced WHC of pork muscle.The multiformity of the texture will open up a wide range of technological possibilities for the manufacture of pork-based restructured low-fat products.(
Abstract The taste and tenderness of meat are the main determinants of carcass quality in many countries. This study aimed to discuss the mechanisms of intramuscular fat deposition in grazing and house-breeding cattle. We performed transcriptome analysis to characterize messenger RNA and microRNA (miRNA) expression profiles. A total of 456 and 66 differentially expressed genes (DEGs) and differentially expressed (DE) miRNAs were identified in the adipose tissue of grazing and house-breeding cattle. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the association of DEGs with fatty acid metabolism, fatty acid degradation, peroxisome proliferator-activated receptors signaling pathway, adenosine monophosphate-activated protein kinase signaling pathway, adipocytokine signaling pathway, and the association of DE miRNAs with mitogen-activated protein kinase signaling pathway. Apolipoprotein L domain containing 1, pyruvate dehydrogenase kinase 4, and sphingosine-1-phosphate lyase 1 genes may be the key regulators of fat metabolism in grazing cattle. Finally, we found that miR-211 and miR-331-5p were negatively correlated with the elongation of very long-chain fatty acids protein 6 (ELOVL6 ), and miR-331-5p might be the new regulator involved in fat metabolism. The results indicated that ELOVL6 participated in various functions and pathways related to fat metabolism. Meanwhile, miR-331-5p, as a new regulator, might play an essential role in this process. Our findings laid a more in-depth and systematic research foundation for the formation mechanism and characteristics of adipose tissue in grazing cattle.
Changes in muscle fiber types in M.biceps femoris of Ujumqin sheep at different moths of age were examined by histochemical staining.The aim of the experiment was to explore the changing regularity of muscle fiber types during the growth of Ujumqin sheep.The skeletal muscle was fixed in paraformaldehyde fixative solution and histological slides were prepared and incubated separately in acidic and alkaline incubation solutions,then washed with barbital sodium buffer and placed in(NH4)2S solution for further incubation.histological slides were dehydrated with gradient ethanol and finally mounted with neutral balsam prior to microscopic observation.Results showed that the percentage of type Ⅱa muscle fiber in the M.biceps femoris exhibited no significant difference between 3 and 6 months as well as between 12 and 18 months of age(P0.05) and the highest level was observed in the M.biceps femori of 12-year-old sheep.Type Ⅱb muscle fiber showed the highest percentage in the M.biceps femori of 18-year-old sheep,which,on the contrary,showed the lowest percentage of type Ⅰ muscle fiber.
Changes in shear force value, transverse sections, myofibrils and intramuscular connective tissue of bovine skeletal muscle exposed to the combination of high-pressure up to 400 MPa and heat (30 and 60°C) were studied.The shear force value decreased by pressure-heat treatment up to 200 MPa at 30 and 60°C, and then slightly increased over 200 MPa at 30°C.Shear force values of treated muscles were lower than those of untreated ones.Gaps between muscle fibers in the untreated muscle were a little clear, and then they became very clear in the treated muscles up to 200 MPa at 30 and 60°C.However, the gaps reduced significantly over 200 MPa at 30°C.The remarkable rupture of I-band and loss of M-line materials progressed in the myofibrils with increasing pressure applied.However, degradation and loss of the Z-line in myofibrils observed in the muscle treated at 60°C was not apparent in the muscle treated at 30°C.The length of the sarcomere initially contracted by pressure-heat treatment of 100 MPa at 30°C seemed to have recovered with increase of the pressure up to 400 MPa.In the muscle treated at 60°C, the length of sarcomere gradually decreased with increase of the pressure up to 400 MPa.In the treated muscles, changes in the honeycomb-like structure of endomysium were observed and accelerated with increase of the pressure.A wavy appearance clearly observed at the inside surface of endomysium in the untreated muscles gradually decreased in the treated muscles with increase of the pressure.Tearing of the membrane was observed in the muscles treated over 150 MPa at 30°C, as observed in the sample pressurized at 100 MPa at 60°C.The roughening, disruption and fraying of the membrane were observed over 200 MPa at 60°C.From the results obtained, the combination of high-pressure and heat treatments seems to be effective to tenderize tough meat.The shear force value may have some relationship with deformation of intramuscular connective tissue and myofibrils.
Abstract 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.
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