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Mesenchymal stem cells can differentiate into adipocyte precursor cells, and the balance of stem cell differentiation determines the quantity of adipocytes. Early-stage adipose tissue expression profiling revealed abnormal expression of DKK3in the high-fat group. Moreover, DKK3is enriched in the Wnt/β-catenin signaling pathway, and studies have shown that DKK3can serve as a gene involved in early regulation of adipogenesis. Therefore, this study focuses on exploring how DKK3regulates the molecular mechanism of adipocyte differentiation through the Wnt/β-catenin signaling pathway. In this experiment, the role of DKK3in the differentiation of bone marrow mesenchymal stem cells into adipocyte precursors was validated using in vitro cultured chicken bone marrow mesenchymal stem cells. The results showed that overexpression of DKK3led to a significant downregulation of Wnt/β-catenin signaling pathway-related marker gene expression (P< 0.05), a significant upregulation of adipogenic differentiation-related genes (P< 0.05), an increase in lipid droplet content, a significant increase in OD value (P< 0.05), a significant upregulation of mitochondrial oxidative respiratory-related marker gene expression (P< 0.05), and a significant downregulation of mitochondrial autophagy-related marker genes (P< 0.05). Conversely, the results were opposite after interfering with DKK3gene expression. In this study, 4 SNP sites, including g.8419139, g.8419556, g.8419560, and g.8419598, were detected in the 7th exon of DKK3, among which the g.8419598 (C > T) site was significantly correlated with abdominal fat weight and abdominal fat rate in 100-day-old Ma Huang chickens (P< 0.001).

Oxidative stress influences several physiological and pathological cellular events, includingcell differentiation, excessive growth, proliferation, apoptosis, and inflammatory response.Therefore, oxidative stress is involved in the pathogenesis of various diseases, including pulmonaryfibrosis, epilepsy, hypertension, atherosclerosis, Parkinsons disease, cardiovascular disease,and Alzheimers disease. Recent studies have shown that several microRNAs (miRNAs) are involvedin the development of various diseases caused by oxidative stress and that miRNAs may beuseful to determine the inflammatory characteristics of immune responses during infection and disease.In this review, we describe the known effects of miRNAs on reactive oxygen species to induceoxidative stress and miRNA regulatory mechanisms involved in the uncoupling of Keap1-Nrf2complexes. Finally, we summarized the functions of miRNAs in several antioxidant genes. Understandingthe crosstalk between miRNAs and oxidative stress-inducing factors during physiologicaland pathological cellular events may have implications for the design of more effective treatmentsfor immune diseases.

With the implementation of the policy of “centralized slaughtering and chilled to market” and the development of the livestock processing industry, numerous researchers have begun to focus on the selection and breeding of broilers bred for slaughter. The selection of breeds with excellent slaughtering performance and high meat production performance has become one of the most important selective breeding goals. In our previous study, we conducted transcriptome sequencing on chicken breast tissues with high and low breast muscle rates and found higher early growth response protein 1 (EGR1) expression in breast tissues with a low breast muscle ratio, thus hypothesizing that the EGR1gene is involved in the growth and development process of chicken muscle tissues. Therefore, we analyzed the gene functions and polymorphisms of EGR1to investigate its association with slaughter traits. We used various experimental methods, including RT-qPCR, Cell Counting Kit 8, 5-ethynyl-2’-deoxyuridine, western blot, flow cytometry, and immunofluorescence, to validate EGR1’s role in chicken primary myoblasts. The results of our functional validation experiments indicate that EGR1is highly expressed in breast tissues with a low breast muscle content and plays a key role in regulating of muscle growth and development by promoting proliferation and inhibiting the differentiation of chicken primary myoblasts. In addition, we explored the relationship between the EGR1gene polymorphisms and slaughter traits using mixed linear models for the first time. In a population of Jiangfeng M3 lineage partridge chickens, we identified 4 EGR1single-nucleotide polymorphisms, 2 of which were significantly associated with slaughter traits, including live weight, slaughter weight, semi-eviscerated weight, eviscerated weight, leg weight, wing weight, and breast muscle rate. In summary, ectopic expression of EGR1promotes the proliferation and differentiation of chicken primary myoblasts. In addition, polymorphisms in EGR1were associated with slaughter performance, providing a potential basis for further utilization of EGR1as a breeding marker.

The differences in physiological and immunological parameters and pathological damage to organ tissues exposed to chronic heat stress provide the basis for evaluating heat resistance of different chicken breeds (white recessive rock [WRR] and The Lingshan [LS]). Ninety broilers of each breed were divided equally into a chronic heat stress group and a no heat stress group. The effects of chronic heat stress on the physiological and immunological parameters of broilers were analyzed using flow cytometry, ELISA, RT-qPCR, etc. Under heat stress conditions: (1) H and H/L values were significantly increased (P< 0.01) in the 2 breeds, and were higher in the WRR broilers than in the LS broilers at a late stage (P< 0.05). Although the corticosterone levels were also significantly increased (P< 0.01) in both breeds, they were lower in the 49 d WRR broilers than in the LS broilers (P< 0.01). The number of leukocytes were significantly increased in the 49 d WRR broilers (P< 0.01), whereas the number of CD3+, CD8+ cells, and erythrocytes were significantly reduced (P< 0.05). A significantly (P< 0.01) lower number of CD3+, CD4+ T-lymphocytes, and CD4+/CD8+ were present in WRR compared to that in the LS broilers. (2) The HSP70transcript was significantly increased in the WRR broilers (P< 0.01), and was higher than the level in the LS broilers. The expression level of HSP70 protein was significantly (P< 0.05) increased in WRR broilers. (3) The WRR broilers developed cardiac and leg muscle inflammatory cellular hyperplasia and local inflammatory lesions, as well as cerebral meningitis and inflammatory hyperplasia of the brain tissue. The LS broilers developed mild cerebral inflammatory hyperplasia and mild inflammatory cellular proliferation in the leg muscle. In conclusion, under heat stress conditions, the relative physiological and immunological parameters were worse in the WRR broilers than in the LS broilers. The WRR broilers showed poor heat tolerance as evidenced from the expression of HSP70and the extent of histopathological damages.

Investigations into the association between chicken traits and genetic variations provide helpful breeding information to improve production performance and economic benefits in chickens. The single nucleotide polymorphism technique is an important method in agricultural molecular breeding. In this study, we detected 11 SNPs in the CD36gene, 2 SNPs (g.-1974 A>G, g.-1888 T>C) located in the 5′ flanking regions, 8 SNPs (g.23496 G>A, g.23643 C>T, g.23931 T>C, g.23937 G>A, g.31256 C>A, g.31258 C>T, g.31335 C>T, g.31534 A>C) located in the intron region, 1 SNPs (g.23743 G>T) located in the exon region and it belongs to synonymous mutation. In SNPs g.23743 G>T, the abdominal fat weight and abdominal fat weight rate of the GG genotype were lower than that of the TT genotype. In SNPs g.23931 T>C, the full-bore weight rate and half-bore weight rate of the TT genotype were higher compared with the CC genotype. And the SNPs g.-1888 T>C, g.23496 G>A, g.23643 C>T, g.31335 C>T and g.31534 A>C were significantly associated with skin yellowness traits, the cloacal skin yellowness before slaughter of the TT genotype was higher than that of the TC and CC genotype in SNPs g.-1888 T>C. Furthermore, 3 haplotypes of the above eleven SNPs were calculated and they correlated with heart weight, stomach weight, wing weight, leg skin yellowness and shin skin yellowness before slaughter. Finally, the CD36expression profile displayed the expression pattern of CD36mRNA variation in different tissues.