Salmonella enterica, serovar Enteritidis (S. Enteritidis), an important zoonotic foodborne pathogen, can affect the microbiota of the chicken intestine and cause many enteric diseases, such as acute gastroenteritis. The gut microbiota contributes to the development and function of the host immune system and competes with pathogenic microbes. The interaction between S. Enteritidis and the host cecal microbiota is still not fully understood. We investigated the microbiome composition in both treated and control groups through 16S ribosomal RNA (rRNA) gene sequencing at 1, 3, 7, 14, 21, 28, and 35 days post-S. Enteritidis inoculation (dpi) in the current study. Chao1 richness and Shannon diversity significantly increased with chicken development in both the treated and control groups (P < 0.05). The Chao1 index was significantly lower in the treated group than that in the control group at 14 dpi (P < 0.05). Phyla Proteobacteria and Firmicutes were most dominant at 1 and 3 dpi. S. Enteritidis inoculation influenced cecal microbiota mainly at 7 and 14 dpi. S. Enteritidis inoculation significantly altered the relative abundance of 18 genera at different time points (P < 0.05) with relative abundance significantly changed after 14 dpi. The abundance of those genera changed dramatically between 28 and 35 dpi in the treated group compared to control group. Positive correlations existed between Bacillus and Blautia and between Coprococcus and Flavonifractor following S. Enteritidis inoculation. Our results indicated that both development and S. Enteritidis have effect on chicken cecal microbiota profiles. S. Enteritidis inoculation in young chicks influences the cecal microbiota mainly at 7 and 14 dpi. The cecal microbiota exhibited immunity to S. Enteritidis inoculation at 28 dpi. These findings will provide basic knowledge of the role that chicken cecal microbiota play in response to S. Enteritidis inoculation.

Background: Intramuscular fat (IMF) content is an important factor in porcine meat quality. Previously, we showed that miR-34a was less abundant in liver tissue from pigs with higher backfat thickness, compared to pigs with lower backfat thickness. The purpose of this present study was to explore the role of miR-34a in adipogenesis.Result: Bioinformatics analysis identified Acyl-CoA synthetase long chain family member 4 (ACSL4) as a putative target of miR-34a. Using a luciferase reporter assay, we verified that miR-34a binds theACSL4mRNA at the 3’UTR. To examine the role of the miR-34a-ACSL4interaction in IMF deposition in the pig, mRNA and protein expression of theACSL4gene was measured in primary intramuscular preadipocytes transfected with miR-34a mimic and inhibitor. Our results showed thatACSL4is expressed throughout the entire differentiation process in pig preadipocytes, similar to the lipogenesis-associated genesPPARγandaP2.Transfection with miR-34a mimic reduced lipid droplet formation during adipogenesis, while miR-34a inhibitor increased lipid droplet accumulation. Transfection with miR-34a mimic also reduced the mRNA and protein expression ofACSL4and lipogenesis genes, includingPPARγ, aP2,andSREBP-1C, but increased the expression of steatolysis genes such asATGLandSirt1. In contrast, the miR-34a inhibitor had the opposite effect on gene expression. Further, knockdown ofACSL4decreased lipid droplet accumulation.Conclusions: Our results support the hypothesis that miR-34a regulates intramuscular fat deposition in porcine adipocytes by targetingACSL4.

Maintaining maximum genetic diversity and preserving breed viability in conserved populations necessitates the rigorous evaluation of conservation schemes. Three chicken breeds (Baier Yellow Chicken (BEC), Beijing You Chicken (BYC) and Langshan Chicken (LSC)) are currently in conservation programs in China. Changes in genetic diversity were measured by heterozygosity, genomic inbreeding coefficients, and autozygosity, using estimates derived from runs of homozygosity (ROH) that were identified using SNPs. Ninety DNA samples were collected from three generations for each breed. In the most recent generation, the highest genetic diversity was observed in LSC, followed by BEC and BYC. Inbreeding coefficients based on ROH for the three breeds declined slightly between the first and middle generations, and then rapidly increased. No inbreeding coefficients exceeded 0.1. Population structure assessments using neighbor-joining tree analysis, principal components analysis, and STRUCTURE analysis indicated that no genetic differentiation existed within breeds. LD decay and ROH at different cut-off lengths were used to identify traces left by recent or ancient inbreeding. Few long ROH were identified, indicating that inbreeding has been largely avoided with the current conservation strategy. The observed losses in genetic diversity and occurrences of inbreeding might be consequences of sub-optimal effective population sizes. The conserved Chinese chicken populations have high genomic diversity under the current conservation program (R: F). Furthermore, this study highlights the need to monitor dynamic changes in genetic diversity in conserved breeds over successive generations. Our research provides new insights into genetic diversity dynamics in conserved populations, and lays a solid foundation for improving conservation schemes.

Gaining insight into the gene expression patterns during ovarian follicle development will benefit the improvement of the laying performance as well as the better understanding of avian reproductive physiology. To better understand the molecular regulation of ovarian development, a systematic profiling of miRNAs and mRNAs from the ovary at four key stages of development (at ages of 60 days (A), 100 days (B), 140 days-not yet laying eggs (C) and 140 days-just starting to lay eggs (D)) were performed. A total of 73 differentially expressed miRNAs (DEMs) (14 for B vs. A, 8 for C vs. B and 51 for D vs. C, respectively) and 2596 differentially expressed genes (DEGs) (51 for B vs. A, 20 for C vs. B and 2579 for D vs. C, respectively) between the four consecutive stages were identified. At the same time, 174 DEMs (22 for C vs. A, 74 for D vs. A and 78 for D vs. B, respectively) and 3205 DEGs (118 for C vs. A, 2284 for D vs. A and 2882 for D vs. B, respectively) between nonconsecutive stageswere also identified. Among these DEGs, some are involved in the Wnt and TGF-beta signaling pathways, known to affect ovarian development and ovulation. An integrative analysis of miRNA and mRNA profiling data identified 3166 putative miRNA-mRNA regulatory pairs containing 84 DEMs and 1047 DEGs. Functional annotation of the networks provides strong evidence that the miRNA regulatory networks may play vital roles in ovarian development and ovulation. Ten differentially expressed miRNAs and ten genes were validated by real-time quantitative PCR. The miRNA-mRNA pairs gga-miR-200a-3p-SFRP4, gga-miR-101-3p-BMP5, gga-miR-32-5p-FZD4 and gga-miR-458b-5p-CTNNB1 were identified as new candidate interaction pairs potentially associated with ovarian development.

Objective: Ovarian follicular development, which dependent on the proliferation and differentiation of granulosa cells (GCs), is a complex biological process in which miRNA plays an important role. Our previous study showed that miR-458b-5p is associated with ovarian follicular development in chicken. The detailed function and molecular mechanism of miR-458b-5p in GCs is unclear.Methods: The luciferase reporter assay was used to verify the targeting relationship between miR-458b-5p and catenin beta-1 (CTNNB1), which is an important transcriptional regulatory factor of the Wnt/β-catenin pathway. The cell counting kit-8 (CCK-8) assay, flow cytometry with propidium iodide (PI) and annexin V-fluorescein isothiocyanate (FITC) labeling were applied to explore the effect of miR-458b-5p on proliferation, cell cycle and apoptosis of chicken GCs. Quantitative real-time polymerase chain reaction and Western blot were used to detect the mRNA and protein expression levels.Results: We demonstrated that the expression of miR-458b-5p and CTNNB1 showed the opposite relationship in GCs and theca cells of hierarchical follicles. The luciferase reporter assay confirmed that CTNNB1 is the direct target of miR-458b-5p. Using CCK-8 assay and flow cytometry with PI and Annexin V-FITC labeling, we observed that transfection with the miR-458b-5p mimics significantly reduced proliferation and has no effects on apoptosis of chicken GCs. In addition, miR-458b-5p decreased the mRNA and protein expression of CD44 molecule and matrix metallopeptidase 7, which are the downstream effectors of CTNNB1 in Wnt/β-Catenin pathway and play functional roles in cell proliferation.Conclusion: Taken together, the data indicate that miR-458b-5p regulates ovarian GCs proliferation through Wnt/β-catenin signaling pathway by targeting CTNNB1, suggesting that miR-458b-5p and its target gene CTNNB1 may potentially play a role in chicken ovarian follicular development.

Body measurement traits (BMTs), which are classical quantitative traits of vital responses to body growth, have been studied in pigs, cattle, and sheep for several decades. In chickens, BMTs mainly cover body slope length, keel length, chest width, chest depth, tibia length, and tibia diameter; however, their genetic markers are yet to be considered. In this study, the Wenshang Barred chicken, a meat-egg-type native breed in China, was used to investigate the association between BMTs and the expression of growth-related genes, including GH, IGF1, IGF2, GHRL, IGF1R, IGFBP2, GHF-1, and TSHB. The results revealed that the single nucleotide polymorphism (SNP) rs3138025 in GH was significantly associated with keel length (P = 0.0455 < 0.05), rs313810945 in IGF2 was significantly correlated with chest width (P = 0.0454 < 0.05) and chest depth (P = 0.0259 < 0.05), and rs317298536 in TSHB significantly affected chest depth (P = 0.0399 < 0.05). The SNPs were associated with traits reflecting body size and were potentially involved in bone growth, which was consistent with studies in humans, rodents, and other vertebrate species. In addition, a borderline significant association was found between rs317298536 and body weight (P = 0.0604). These polymorphic sites may be treated as candidate genetic markers in breeding programs involving Wenshang Barred chickens.