MiRNAs are vital regulators and play a major role in cell differentiation, biological development, and disease occurrence. In recent years, many studies have found that miRNAs are involved in the proliferation and differentiation of adipocytes. The objective of this study was to evaluate the effect of miR-27a and its target gene CPT1B on ovine preadipocytes differentiation in Small-tailed Han sheep (Ovis aries). Down-regulation of miR-27a significantly promoted the production of lipid droplets, while overexpression of miR-27a led to a reduction in lipid droplet production. In addition, inhibition of miR-27a led to a significant increase in the expression of genes involved in lipid synthesis, including PPAR γ, SCD, LPL, and FABP4. Target Scan software predicted that CPT1B is a new potential target gene of miR-27a. Further experiments revealed that CPT1B gene expression and protein levels were negatively correlated with miR-27a expression. Overexpression of miR-27a led to a significant decrease in CPT1B mRNA levels and inhibited the accumulation of lipid droplets and vice versa. Moreover, overexpression of CPT1B promoted the synthesis of lipid droplets in ovine preadipocytes. Furthermore, luciferase reporter assays confirmed CPT1B to be a miR-27a direct target gene. This study confirmed that miR-27a increases the expression of genes related to lipid synthesis in ovine preadipocytes by targeting CPT1B, thereby promoting the synthesis of lipid droplets. The results of this study can be used to be exploited in devising novel approaches for improving the IMF content of sheep.

The aim of this study was to investigate the effect of dietary supplementation with zinc (Zn) amino acids at different concentrations on immunity, antioxidant capacity, and gut microbiota composition in calves. Twenty-four one-month-old healthy Angus calves of comparable body weight were randomly divided into three groups (four males and four females in each group) based on the amount of Zn supplementation added to the feed the animals received: group A, 40 mg/kg DM; group B, 80 mg/kg DM; and group C, 120 mg/kg DM. The experiment ended when calves reached three months of age (weaning period). The increase in dietary Zn amino acid content promoted the growth of calves, and the average daily weight gain increased by 36.58% (p < 0.05) in group C compared with group A. With the increase in the content of dietary Zn amino acids, the indexes of serum immune functions initially increased and then decreased; in particular, the content of immunoglobulin M in group A and group B was higher than that in group C (p < 0.05), whereas the content of interleukin-2 in group B was higher than that in the other two groups (p < 0.05). In addition, the content of superoxide dismutase and total antioxidant capacity in the serum of calves in group B was higher than that in group C (p < 0.05), and the MDA level was lower than in group C (p < 0.05). Moreover, alpha diversity in the gut microbiota of calves in group B was higher than that in group A and group C (p < 0.05); the dominant phyla were Firmicutes and Bacteroidota, whereas the dominant genera were Unclassified-Lachnospiraceae and Ruminococcus. Linear discriminant analysis showed that the relative abundance of Bacteroides in the gut microbiota of calves in group B was higher than that in group A, and the relative abundance of Prevotellaceae-UCG-003 was higher compared to that in experimental group C. Thus, dietary supplementation of 80 mg/kg of Zn amino acids to calves could improve the immune function and antioxidant capacity, as well as enrich and regulate the equilibrium of gut microbiota, thus promoting the healthy growth of calves.

Delayed muscle development and impaired tissue repair are common occurrences in sheep reared for mutton. Therefore, understanding the regulatory mechanisms involved in muscle growth and development is critical for animal production. Skeletal muscle satellite cells (SMSCs) can simulate the proliferation and differentiation of muscle cells and could be induced to differentiate into myoblasts. β-hydroxy-β-methylbutyric acid (HMB) is an additive commonly used in animal production. This study examined the effect of HMB on myoblast injury repair using flow cytometry, EdU assay, RNA sequencing, Western blot, and ELISA. Our results showed that HMB could inhibit IL-17 expression and, in turn, inhibit NF-κB signaling. By acting on the downstream genes of NF-κB pathway IL-6, TNF-α and IL-1β, HMB inhibits the apoptosis and promotes the proliferation of myoblasts. The findings of this study provide insight into the mechanism by which HMB mediates myoblast injury repair in sheep.

Background: Hu sheep are highly prolific, but litter size remains variable among individuals. How ovarian metabolism and somatic-cell heterogeneity are associated with this variation remains unclear. Ovarian metabolites from high-litter-size (HLS) and low-litter-size (LLS) Hu ewes were profiled by liquid chromatography–mass spectrometry and gas chromatography–mass spectrometry. Ovarian cell populations and transcriptional states were characterized by single-cell RNA sequencing. Integrated analyses were used to relate metabolic differences to specific cell populations and predicted cell–cell communication. RT-qPCR and multiplex immunofluorescence were used to examine selected metabolic genes and the endothelial localization of ESM1. Separate cell experiments assessed the effects of endothelial cell-conditioned medium (EC-CM) and recombinant human IGFBP3 on primary ovine granulosa cells (GCs), with TMEM219 knockdown used to evaluate receptor involvement. Results: HLS ovaries showed higher L-carnitine abundance, whereas several representative sphingomyelin species were more abundant in LLS ovaries (nominal P < 0.05). Integrated analysis identified two EC associated genes: DNAJB4 was downregulated, whereas NDRG1 was upregulated in HLS ovaries ( P < 0.05). At the EC level, gene set enrichment analysis showed significant enrichment of glutathione metabolism and oxidative phosphorylation in the HLS group. EC subclustering further associated these transcriptional programs with ESM1⁺ angiogenic endothelial cells (A-ECs). Multiplex immunofluorescence localized ESM1 to VWF-positive vascular structures and showed a significantly larger ESM1-positive area and more VWF/ESM1 double-positive cells in HLS ovaries ( P < 0.05). Cell–cell communication analysis identified IGFBP3–TMEM219 as a candidate EC–GC interaction. IGFBP3 was detected in EC-conditioned medium, which significantly reduced EdU incorporation and the expression of CYP11A1 , FSHR and STAR ( P < 0.05) in granulosa cells. Recombinant IGFBP3 produced similar responses, and TMEM219 knockdown partially attenuated several of these effects. Conclusions: This study identified an association between exploratory ovarian metabolic patterns and EC heterogeneity, while functional experiments showed that EC-derived IGFBP3 affected GC function partly through TMEM219. These findings suggest that endothelial state and signaling may be relevant to follicular development, although whether IGFBP3–TMEM219 signaling contributes to litter-size variation in Hu sheep remains to be established.