Avian colibacillosis is a bacterial disease caused by avian pathogenic Escherichia coli (APEC) that results in great losses in the poultry industry every year. Individual Silkie chickens of the same breed that are given the same feed in the same feeding conditions have different levels of resistance or susceptibility to APEC. Differences in gut microbes, gut metabolites, and gene expression in the spleen of APEC-resistant and APEC-susceptible chickens were compared, and multiple omics associations were analyzed to explore the mechanism of resistance to APEC in Silkie chickens. Compared with those in the APEC-susceptible group, the APEC-resistant group showed significantly increased abundances of many gut microorganisms, including Bacillus, Thermoactinomyces, Arthrobacter, and Ureibacillus, which were positively correlated with norvaline, l-arginine, and valyl-glycine levels. Intestinal tryptophan, indole, and indole derivative-related differentially abundant metabolites played an active role in combatting APEC infection. In the spleen, "response to stimulus" was the most significantly enriched GO term, and "cytokine‒cytokine receptor interaction" was the most significantly enriched KEGG pathway. The arginine biosynthesis and PPAR signaling pathways were the KEGG pathways that were significantly enriched with differentially abundant metabolites and differentially expressed genes. This study provides new insight into the prevention and treatment of APEC infection in Silkie chickens and lays a foundation to study the mechanism of APEC infection in poultry.

This study aimed to elucidate the genetic basis of lipid composition in the breast muscles of poultry, including AA broilers, dwarf guinea fowl, quails, and pigeons, and the impact of artificial selection on lipid traits. By employing lipidomics and transcriptomic sequencing, the research analyzed the chest muscle tissues of these four poultry. A total of 1542 lipid molecules were identified, with 711 showing significant differences among species. These lipids primarily belonged to subclasses such as TG, PC, Phosphatidylethanolamine (PE), Ceramides (Cer), and Diglyceride (DG), with each species demonstrating distinct profiles in these subclasses. Additionally, 5790 orthologous genes were identified, with 763, 767, 24, and 8 genes in AA broilers, dwarf guinea fowl, quails, and pigeons, respectively, exhibiting positive selection (Ka/Ks > 1). Notably, 114 genes related to lipid metabolism displayed significant differential expression, particularly between AA broilers and dwarf guinea fowl. The findings revealed that the metabolic pathways of PC and LPC lipid molecules in the glycerophospholipid pathway, as well as TG lipid molecules in the glycerolipid pathway, exhibited marked interspecies differences, potentially contributing to variations in breast muscle lipid composition. These results provide a solid foundation for understanding the lipid composition and molecular regulatory mechanisms in diverse poultry, offering valuable insights for further research in poultry lipid metabolism and artificial breeding programs.

Avian pathogenic Escherichia coli (APEC) is a bacterial disease that harms the poultry industry worldwide, but its effect on Chinese Silkie has not been reported. Studies on whether there are differences in Silkie individual resistance to APEC and the regulatory role of spleen miRNAs lay the foundation for strategies against APEC. Therefore, 270 Silkie chickens were infected with the median lethal dose of an E. coli O1, O2, and O78 mixture. These chickens were divided into a susceptible group (Group S) and a recovery group (Group R) according to whether they survived 15 days postinfection (dpi). Moreover, 90 uninfected APEC Silkie served as controls (Group C). The splenic miRNA expression profile was examined to evaluate the role of miRNAs in the APEC infection response. Of the 270 Silkies infected with APEC, 144 were alive at 15 dpi. Cluster analysis and principal component analysis (PCA) of splenic miRNAs revealed that the four Group R replicates were clustered with the three Group C replicates and were far from the three Group S replicates. Differentially expressed (DE) miRNAs, especially gga-miR-146b-5p, play essential roles in immune and inflammatory responses to APEC. Functional enrichment analyses of DEmiRNAs suggested that suppression of immune system processes (biological processes) might contribute to susceptibility to APEC and that FoxO signaling pathways might be closely associated with the APEC infection response and postinfection repair. This study paves the way for screening anti-APEC Silkies and provides novel insights into the regulatory role of miRNAs in APEC infection.

In this study, we aimed to explore the intestinal microbiota structure of Xichuan black-bone chickens (XBCs) and evaluate the effect of fecal microbiota substitute transplantation (FMST) by comparing it with traditional fecal microbiota transplantation (FMT). Metagenomic sequencing was used to analyze the microbiota composition and diversity of different intestinal segments (duodenum, jejunum, ileum, cecum, and rectum) of adult XBCs. Probiotic strains were subsequently isolated and screened from the cecal contents under anaerobic conditions to prepare FMST preparations. In total, 90 1-day-old XBCs were randomly divided into the FMT group, FMST group and control group (CK) for the transplantation experiment. The results revealed that the cecum had the highest species richness among all intestinal segments, with a mean species number of 7593.2. Three probiotic strains, namely, Lactobacillus crispatus, Weissella paramesenteroides and Bacillus amyloliquefaciens, were successfully screened and identified. In the transplantation experiment, the FMT group exhibited optimal α diversity of the cecal microbiota, while compared with the FMT group, the FMST group had significantly reduced expression of pro-inflammatory cytokines (IL-6, TNF-α, and IL-1β) and increased expression of intestinal tight junction proteins (claudin-1 and ZO-1). In conclusion, the cecum of XBCs has the most abundant microbial resources. Under the short-term intervention model tested herein, the custom FMST formulation delivers superior intestinal protective effects and shows promising potential as a standardized alternative to conventional FMT, which is highly important for the standardized application of fecal microbiota transplantation in poultry production.