In this study, we examined correlations between the deposition of inosine monophosphate (IMP) and mRNA expression of the adenylate kinase 1 (AK1) gene in Jingyuan chicken. The IMP content was determined by high-performance liquid chromatography. Transcriptome sequencing was used to screen the differentially expressed gene AK1 and real-time quantitative polymerase chain reaction (PCR) to determine the expression level of AK1 mRNA associated with IMP synthesis. IMP and inosine content in the breast muscles of both Jingyuan cocks and hens was found to be significantly higher than that in the leg muscles. Similarly, the expression of AK1 mRNA in the breast muscles of cocks and hens was significantly higher than that in the leg muscles. Moreover, AK1 mRNA expression in cock breast muscles was negatively correlated with IMP content, whereas its expression in cock leg muscles was positively correlated with IMP content. In contrast, the expression of AK1 mRNA in hen breast and leg muscles was significantly positively correlated with IMP content. These findings provide a scientific basis for enhancing the meat flavor of Jingyuan chicken and promoting the development and utilization of local variety resources, as well as constituting a basis for screening IMP-regulated genes. Our study will advance our current understanding of AK1 function.

Milk fat composition and content are crucial indicators that influence the taste, flavor and nutritional value of milk, and they are regulated by various non-coding RNAs. To enhance milk quality, it is essential to investigate the regulatory mechanisms underlying milk fat metabolism. This study analyzed significantly up-regulated circ_0009058 and circ_0004021 and significantly down-regulated circ_0011934 and circ_0008056 in bovine mammary epithelial cells (BMECs) with high and low milk fat percentages (MFP). RNase R digestion assays and Sanger sequencing were conducted to confirm their presence and high expression in the mammary tissue of dairy cows. Subcellular localization indicated that these RNA may exhibit regulatory functions through the competing endogenous RNA (ceRNA) network. Consequently, a ceRNA regulatory network was constructed, identifying six hub target genes in the ceRNA network (VAV1, PTPN6, PIK3R1, RHOA, ERBB3, PIK3CG) using the CytoHubba and MCODE plugins in Cytoscape (version 3.9). Quantitative real-time PCR (RT-qPCR) and dual luciferase reporter gene assays validated the existence of the interactive regulatory networks circ_0004021/bta-miR-541/PTPN6, circ_0008056/bta-miR-2309/ERBB3, and bta-miR-10175-3p/RHOA in BMECs. Functional validation of miRNAs within the ceRNA network demonstrated that bta-miR-541 and bta-miR-10175-3p reduced triglyceride and cholesterol levels while inhibiting lipid droplet secretion in BMECs. Conversely, the function of bta-miR-2309 was found to be opposite to that of bta-miR-541 and bta-miR-10175-3p. This study identified several critical candidate ceRNA networks involved in fatty acid metabolism in dairy cows through data analysis and a series of experiments. These functional and mechanistic studies provide a theoretical foundation for improving milk quality.

The objectives of this study were to estimate genetic parameters for stayability in Chinese Holstein cattle and to estimate its genetic correlations with routinely collected traits. Although knowledge and genetic breeding technologies for dairy cattle have advanced, the lifespan of dairy cows has been declining, mainly due to increased production stress and associated health problems. This makes the genetic improvement of Holstein cattle crucial for sustainable production. Stayability is an indicator trait reflecting longevity, measured as the survival probability of dairy cows at specific stages. To evaluate temporal differences in herd retention, we defined 7 stayability traits as the ability of cows to remain in the herd for 36 (S36), 42 (S42), 48 (S48), 54 (S54), 60 (S60), 72 (S72), and 84 (S84) months after first calving. Data from 56,630 cows between 2011 and 2020 across 14 dairy farms in Ningxia were considered for stayability analyses. Survival analysis using non-parametric methods showed that cattle with sterility had the longest survival time, while those with abomasal displacement had the shortest survival time. The heritability estimates (±standard error) for S36, S42, S48, S54, S60, S72 and S84 were 0.048 ± 0.006, 0.063 ± 0.006, 0.074 ± 0.007, 0.099 ± 0.007, 0.115 ± 0.007, 0.088 ± 0.007, 0.118 ± 0.008, respectively. The genetic and phenotypic correlations among stayability traits ranged from 0.382 to 0.975 and from 0.090 to 0.799, respectively. Furthermore, the approximate genetic correlations between stayability and routinely collected traits (8 production, 20 conformation, 13 fertility, 13 health traits) were assessed. Stayability showed low to moderate genetic correlations with most of these traits. In summary, developing a selection index that incorporates stayability is expected to improve the longevity of dairy cows. All unfavorable genetic relationships observed between stayability and other routinely collected traits should be accounted for in a selection index, thereby enhancing the lifespan of Holstein cattle while maintaining or improving productive performance.

Introduction: Pholiota microspora basal stipe powder is a major by-product of mushroom harvesting and is rich in nutrients and bioactive compounds, making it a potential alternative feed ingredient for insect production. However, its effects on the growth and development of Tenebrio molitor remain unclear. Methods: five experimental diets were formulated by replacing wheat bran with P.microspora basal stipe powder at substitution levels of 0%, 25%,50%, 75%, and 100%. Growth and developmental parameters were assessed throughout the larval, pupal, and adult stages. Results: Larval body length, width, and weight increased with instar in all groups, and body length was strongly correlated with body width (r=0.93-0.94). The control group generally exhibited the greatest larval body size and weight, whereas the 100% substitution group showed the lowest values. Differences among treatments were minimal during the 6th-8th instars. From the 9th to 15th instars, larval growth in the 25% substitution group was comparable to that in the control group but significantly greater than that in the 50%, 75%, and 100% substitution groups ( P <0.05). Larval duration increased significantly with substitution level ( P 0.05). Pupal weight decreased as the substitution level increased. Although pupal weight in the 25% substitution group was significantly lower than that in the control group, it was significantly higher than that in the 50%, 75%, and 100% substitution groups ( P <0. 05). Adult body weight was significantly lower in all substitution groups than in the control group ( P <0.05). Discussion: Replacing up to 25% of wheat bran with P. microspora basal stipe powder had minimal effects on T.molitor growth and development, whereas higher levels impaired larval growth and reduced pupal and adult weights. Therefore, a 25% substitution level appears to be the most suitable among the tested levels for incorporating P.microspora basal stipe powder into T.molitor diets.