Stress-induced immunosuppression inhibits immune response to infectious bursal disease virus vaccine partially by miR-27b-3p/SOCS3 regulatory gene network in chicken

CircITSN2-miR-17-5p/20a-5p/20b-5p-PD-L1 regulatory network is a potential molecular mechanism of PD-L1 gene involving in immune response to IBDV

RESEARCH HIGHLIGHTS

PD-L1 gene is correlated with IBDV immune response in chickens.PD-L1 is a key gene regulating the immune functions of the heart, lung, and proventriculus.CircITSN2-miR-17-5p/20a-5p/20b-5p-PD-L1 is a potential mechanism in IBDV immunity.

Immunomodulatory and growth-promoting effects of Rauwolfia serpentina root powder in broiler chicks challenged with Salmonella Gallinarum

Background

Amid growing concern about antimicrobial resistance due to the irrational use of antibiotics in treating common poultry diseases, particularly Salmonella which is a foodborne pathogen in humans. This study investigates the effects of ethnoveterinary supplementation of Rauwolfia serpentina (L. Benth. ex Kurz) powder (RSP) on three key immune-related genes; Suppressor of cytokine signaling 3 (SOCS3), the quiescence-related gene P20K (P20K), and the major histocompatibility complex Class IIβ (MHC class IIβ), gut morphology and growth performance of broiler chicks infected with Salmonella Gallinarum.

Methods

Two hundred and forty day-old Hubbard classic chickens were randomly assigned to four groups: non-challenged control (NC), and Salmonella Gallinarum challenge group (SGC), and two treatment groups fed a basic diet supplemented with 1.5% Rauwolfia serpentina powder (RSP) with SGC (RSP-1) and 3% RSP with SGC (RSP-2), respectively, from day 3 till 28 days of age. Each treatment was replicated 4 times with 15 bird/replicate pen. On day 7, all the birds in the RSP-1, RSP-2 and SGC groups received 1 ml of BHI broth containing 2 × 108 CFU of Salmonella Gallinarum via oral gavage. While control birds received an equivalent volume of sterile BHI broth. Gene expression analysis was conducted using real-time PCR to measure the expression of key immune-related genes: SOCS3, P20K, and MHC Class IIβ in spleen, liver, and caeca. Additionally, histopathological assessments of gut and growth performance parameters including feed intake, body weight gain, and feed conversion ratio (FCR) were monitored throughout the experimental period.

Result

The gene expression analysis at 3 and 21 days post-challenge revealed that SGC birds had significantly higher SOCS3, P20K, and lower MHC class IIβ expression (p < 0.001) in the caecum, liver, and spleen of broiler chickens. In contrast, the RSP-1 and RSP-2 groups showed significantly lower SOCS3 and P20K expression (p < 0.001), alongside improved gut morphology, weight gain, and FCR compared to the SGC group, with these benefits increasing over time.

Conclusion

In conclusion, these findings suggest that Rauwolfia serpentina supplementation modulates key immune-related gene expression (SOCS3, P20K, and MHC class IIβ), enhances intestinal health, and improves growth performance in broilers challenged with Salmonella Gallinarum.

Integration of metabolomics and transcriptomics to reveal anti-immunosuppression mechanism of Lycium barbarum polysaccharide

It is well documented that immunosuppression in chickens increases the risk of secondary infections and immunodeficiencies, resulting in significant financial setbacks for the poultry sector. It is crucial to determine if Lycium barbarum polysaccharide (LBP) can counteract immune suppression in young chickens, considering its known ability to modulate immune responses. The aim of this study was to investigate the antagonistic effect and mechanism of LBP on immunosuppression in chicks. A total of 200 seven-day-old Hyland Brown laying hens were used to develop an immunosuppression model and to investigate the optimal time of use and optimal dosage of LBP. A further 120 seven-day-old Hyland Brown laying hens were used to investigate the mechanism of antagonism of LBP against immunosuppression at the optimal time and dosage. The results demonstrated that LBP significantly elevated body weight, spleen index, and peripheral lymphocyte transformation rate, and ameliorated pathological spleen damage in immunosuppressed chickens. A total of 178 differential genes were significantly upregulated following LBP intervention, with a significant enrichment in immune-related pathways, including the chemokine signalling pathway, the C-type lectin receptor signalling pathway, the B-cell receptor signalling pathway, platelet activation, natural killer cell-mediated cytotoxicity, and Th1 and Th2 cell differentiation. A total of 20 different metabolites were identified by metabolomics, which were mainly involved in vitamin metabolism, lipid metabolism, nucleic acid metabolism and amino acid metabolism. The integrated examination of transcriptomic and metabolomic data revealed that the glycerophospholipid metabolic pathway stands out as the most significant among all metabolic pathways. The results demonstrated that LBP regulate the immune system in a multi-pathway and multi-target way.

Effects of immunosuppression-associated gga-miR-146a-5p on immune regulation in chicken macrophages by targeting the IRKA2 gene

Stress-induced immunosuppression (SIIS) is one of the common problems in intensive poultry production, which brings enormous economic losses to the poultry industry. Accumulating evidence has shown that microRNAs (miRNAs) were important regulators of gene expression in the immune system. However, the miRNA-mediated molecular mechanisms underlying SIIS in chickens are still poorly understood. This study aimed to investigate the biological functions and regulatory mechanism of miRNAs in chicken SIIS. A stress-induced immunosuppression model was successfully established via daily injection of dexamethasone and analyzed miRNA expression in spleen. Seventy-four differentially expressed miRNAs (DEMs) was identified, and 229 target genes of the DEMs were predicted. Functional enrichment analysis the target genes revealed pathways related to immunity, such as MAPK signaling pathway and FoxO signaling pathway. The candidate miRNA, gga-miR-146a-5p, was found to be significantly downregulated in the Dex-induced chicken spleen, and we found that Dex stimulation significantly inhibited the expression of gga-miR-146a-5p in Chicken macrophages (HD11). Flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU), cell counting kit-8 (CCK-8) and other assays indicated that gga-miR-146a-5p can promote the proliferation and inhibit apoptosis of HD11 cells. A dual-luciferase reporter assay suggested that the Interleukin 1 receptor associated kinase 2 (IRAK2) gene, which encoded a transcriptional factor, was a direct target of gga-miR-146a-5p, gga-miR-146a-5p suppressed the post-transcriptional activity of IRAK2. These findings not only improve our understanding of the specific functions of miRNAs in avian stress but also provide potential targets for genetic improvement of stress resistance in poultry.