Adipose tissue is a crucial economically significant trait that significantly influences the meat quality and growth performance of domestic animals. To reveal the changes in adipose tissue metabolism during the growth of naturally grazing sheep, we evaluated the thickness, adipocyte morphology, fatty acid profile, and metabolite profile of subcutaneous adipose tissue (SAT) from naturally grazing Sunit sheep at 6, 18, and 30 months of age (referred to as Mth-6, Mth-18, and Mth-30, respectively). The fat thickness and adipocyte number were significantly increased with the growth of the sheep (p < 0.05), and the increase of which from Mth-18 to Mth-30 was less than that from Mth-6 to Mth-18. Additionally, the alpha-linolenic acid metabolism was enhanced and fatty acid (FA) elongation increased with growth. The metabolomic analysis revealed 76 differentially expressed metabolites (DEMs) in the SAT in different growth stages. Interestingly, we observed elongation of FAs in lipids correlated with sheep growth. Furthermore, the expression of acylcarnitines was downregulated, and fatty acid amides, aspartic acid, acetic acid and phosphocholine were upregulated in Mth-18 and Mth-30 compared to Mth-6. Altogether, the study found that the difference in SAT in Mth-6 was great compared to Mth-18 and Mth-30. An increase in fat deposition via adipocyte proliferation with the growth of the sheep in naturally grazing. The DEMs of acylcarnitines, fatty acid amides, aspartic acid, acetic acid, and phosphocholine emerged as potential key regulators of adipose tissue metabolism. These findings illustrate the variation in and metabolic mechanism of sheep adipose tissue development under natural grazing, thus providing valuable insights into improving the edible quality of sheep meat and developing the mutton sheep industry.

MicroRNAs (miRNAs) are regarded as important regulators in skeletal muscle development. To reveal the regulatory roles of miRNAs and their target mRNAs underlying the skeletal muscle development of Wuranke sheep, we investigated the miRNA and mRNA expression profiles in the biceps femoris of these sheep at the fetal (3 months of gestation) and 3- and 15-month-old postnatal stages. Consequently, a total of 1195 miRNAs and 24,959 genes were identified. Furthermore, 474, 461, and 54 differentially expressed miRNAs (DEMs) and 6783, 7407, and 78 differentially expressed genes (DEGs) were detected among three comparative groups. Functional analysis demonstrated that the target mRNAs of the DEMs were enriched in multiple pathways related to muscle development. Moreover, the interactions among several predicted miRNA–mRNA pairs (oar-miR-133-HDAC1, oar-miR-1185-5p-MYH1/HADHA/OXCT1, and PC-5p-3703_578-INSR/ACTG1) that potentially affect skeletal muscle development were verified using dual-luciferase reporter assays. In this study, we identified the miRNA and mRNA differences in the skeletal muscle of Wuranke sheep at different developmental stages and revealed that a series of candidate miRNA–mRNA pairs may act as modulators of muscle development. These results will contribute to future studies on the function of miRNAs and their target mRNAs during skeletal muscle development in Wuranke sheep.

Adipose tissue metabolism plays a crucial role in sheep meat quality and the optimization of adipose tissue utilization. To reveal the molecular mechanisms of adipose tissue metabolism during growth in naturally grazing sheep, we investigated the mRNA and miRNA profiles in subcutaneous adipose tissue (SAT) from naturally grazing Sunit sheep at 6, 18, and 30 months of age (Mth-6, Mth-18, and Mth-30). We identified 927 differentially expressed (DE) genes and 134 DE miRNAs in the SAT of sheep at different growth stages. Specifically, the expressions of ACACA, FASN, DGAT2, GPAM, SCD, ELOVL6, HSD17B12, TECR, PKM, TKT, PCK1, CD44, and THBS2S genes were significantly upregulated in Mth-18 and Mth-30 compared to that in Mth-6. These genes promoted fatty acid synthesis, triglyceride synthesis, gluconeogenesis, and extracellular matrix–receptor interaction and decreased glycolysis, leading to increased adipocyte proliferation and fat deposition. Notably, our findings suggested that the reduced activity of the AMPK signaling pathway may be regulated by CAMKK2 and PP2A during sheep growth. Furthermore, our results revealed several DE miRNAs, mml-miR-320b, chi-miR-1388-3p, bta-miR-6715, oar-miR-143, and miR-424, that potentially influence fat metabolism. Overall, this study provides a theoretical basis and new insights into the molecular mechanisms of adipose tissue metabolism during growth in naturally grazing sheep.

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.

Cynanchum thesioides (C. thesioides) is a sand-dwelling edible and medicinal plant whose fruit softens rapidly after harvest, limiting its storage life. In this study, we investigated the efficacy and underlying mechanisms of alternating magnetic field (AMF) treatment as a non-thermal and eco-friendly preservation method for C. thesioides fruit. Freshly harvested fruits were subjected to AMF at varying field intensities (1.07–1.54 mT) and exposure durations (5–25 min). We monitored the physiological indicators (respiration rate, membrane permeability, and firmness) during storage to determine the optimal conditions and performed transcriptome sequencing to identify differentially expressed genes, with qRT-PCR validation of two key cell wall-degrading genes (β-glucosidase (BG) and polygalacturonase (PG)). The results showed that AMF treatment at 1.28 mT for 15 min best maintained the postharvest quality, significantly reducing respiration and membrane leakage while delaying firmness loss. Transcriptomic analysis identified 2480 differentially expressed genes enriched in hormone signaling and cell wall metabolism pathways, and qRT-PCR confirmed that AMF downregulated BG and PG expression, suggesting suppressed cell wall degradation and delayed softening. In conclusion, AMF treatment effectively prolonged the shelf life of C. thesioides by modulating the expression of cell wall-related genes. These findings provide novel insight into magnetic field-induced fruit preservation and support AMF as a green non-thermal postharvest technology.