Asparagine synthetase regulates the proliferation and differentiation of chicken skeletal muscle satellite cells.

Objective: Asparagine synthetase (ASNS) is an aminotransferase responsible for the biosynthesis of aspartate by using aspartic acid and glutamine. ASNS is highly expressed in fast-growing broilers, but few studies have reported the regulatory role of ASNS in muscle development. Methods: To explore the function of ASNS in chicken muscle development, the expression of ASNS in different chicken breeds and tissues were first performed by real-time quantitative reverse transcription polymerase chain reaction (RT-PCR). Then, using real-time quantitative RT-PCR, western blot, EdU assay, cell cycle assay and immunofluorescence, the effects of ASNS on the proliferation and differentiation of chicken skeletal muscle satellite cell (SMSC) were investigated. Finally, potential mechanisms by which ASNS influences chicken muscle fiber differentiation were identified through RNA-Seq. Results: The mRNA expression pattern of ASNS in muscles mirrors trends in muscle fiber cross-sectional area, average daily weight gain, and muscle weight across different breeds. ASNS knockdown inhibited SMSC proliferation, while overexpression showed the opposite. Moreover, ASNS attenuated SMSC differentiation by activating the Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway. Additionally, 5-aminoimidazole-4-carboxamide1-ß-D-ribofuranoside (AICAR) treatment suppressed the cell differentiation induced by siRNA-ASNS. RNA-Seq identified 1968 differentially expressed genes (DEGs) during chicken SMSC differentiation when overexpression ASNS. Gene Ontology (GO) enrichment analysis revealed that these DEGs primarily participated in 8 biological processes, 8 cellular components, and 4 molecular functions. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified several significantly enriched signaling pathways, such as the JAK-STAT signaling pathway, TNF signaling pathway, Toll-like receptor signaling pathway, and PI3K-Akt signaling pathway. Conclusion: ASNS promotes proliferation while inhibits the differentiation of chicken skeletal muscle satellite cells. This study provides a theoretical basis for studying the role of ASNS in muscle development.

Effects of dietary supplement of ε-polylysine hydrochloride on laying performance, egg quality, serum parameters, organ index, intestinal morphology, gut microbiota and volatile fatty acids in laying hens.

BACKGROUND: ε-polylysine hydrochloride (ε-PLH) is a naturally occurring antimicrobial peptide extensively utilized in the food and medical industries. However, its impact on animal husbandry remains to be further explored. Therefore, the present study aimed to determine the effect of ε-PLH on laying hens' health and laying performance. RESULTS: Dietary supplementation with ε-PLH to the diet significantly increased average egg weight during weeks 1-8. Meanwhile, compared with the control group, supplementation with ε-PLH decreased the feed egg ratio during weeks 9-12 and egg breakage rate during weeks 9-16 ，whereas it increased eggshell strength during weeks 1-4 and 13-16 . The ε-PLH 0.05% group increased yolk percentage during weeks 5-8 and yolk color during weeks 1-4 . Furthermore, ε-PLH supplementation significantly increased the concentrations of total protein, albumin, globulin and reproductive hormones estradiol, as well as decreased interleukin-1 beta and malondialdehyde in the serum. Compared with the control group, supplementation with 0.05% ε-PLH significantly increased the relative abundance of Cyanobacteria and Gastranaerophilales and decreased the abundance of Desulfovibrio and Streptococcus in the cecum microbiota. In addition, ε-PLH 0.1% supplementation also increased acetic acid content in the cecum. CONCLUSION: Dietary supplementation with ε-PLH has a positive impact on both productive performance and egg quality in laying hens. Furthermore, ε-PLH can also relieve inflammation by promoting the immunity and reducing oxidative damage during egg production. ε-PLH has been shown to improve intestinal morphology, gut microbial diversity and intestinal health. © 2023 Society of Chemical Industry.

Identification of the differentially expressed genes in the leg muscles of Zhedong white geese (Anser cygnoides) reared under different photoperiods.

Light is a factor affecting muscle development and meat quality in poultry production. However, few studies have reported on the role of light in muscle development and meat quality in geese. In this experiment, 10 healthy 220-day-old Zhedong white geese were reared for 60 d under a long photoperiod (15L:9D, LL) and short photoperiod (9L:15D, SL). The gastrocnemius muscles were collected after slaughter to evaluate muscle fiber characteristics and meat color, and RNA-seq analysis. The results showed that compared to the LL group, the SL group had large muscle fiber diameter and cross-sectional area, few muscle fibers per unit area, high meat color a* value, and low L* value at 24 h postmortem. On comparing the 2 groups, 70 differentially expressed genes (DEGs) were identified. Compared to the SL group, the LL group had 25 upregulated and 45 downregulated genes. Gene Ontology (GO) enrichment analysis showed that these DEGs were mainly involved in cell, cell part, binding, cellular processes, and single-organism processes. Several significantly enriched athways were identified in the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, such as the calcium and PI3k-Akt signaling pathways. The expression of five randomly selected DEGs was verified using quantitative real-time PCR, and the results were consistent with the RNA-seq data. This study provides a theoretical basis for studying the molecular mechanisms by which light affects muscle development and meat color in geese.