carvacrol enriched inflammatory and T-cell transcriptional responses toLPS in broiler chickens.

Abstract

INTRODUCTION: Enhancing immune responsiveness against pathogens is crucial for maintaining health. In broiler chickens, thedelivery of carvacrol, a phenolic compound found in oregano and thyme, has shown promising immunomodulatory activity. This study investigated the hypothesis that thedelivery of carvacrol would regulate the immune response againstlipopolysaccharide (LPS) in broiler chickens. METHODS: carvacrol (injected at embryonic day 17.5) and/orLPS challenge (repeated intraperitoneal injections at post-hatching d7 and d14) were tested in a 2 &#xd7; 2 factorial arrangement, resulting in four groups: 1)saline without challenge (saline), 2)saline with LPS challenge, 3)carvacrol without challenge, and 4)carvacrol with LPS challenge. Performance parameters were collected, and relative organ weights were measured at d14. Splenic samples were collected 6 h after the second challenge (d14) and used for transcriptomic analyses. RESULTS AND DISCUSSION: The LPS challenge resulted in lower chicken weight gain and higher relative spleen weight. Thedelivery of carvacrol had no impact on these measures. The transcriptomic comparisons for the effects of LPS challenge identified 786 differentially expressed genes (DEGs) between groups 2 and 1 (withoutcarvacrol) and 1,832 DEGs between groups 4 and 3 (withcarvacrol) [false discovery rate (FDR)< 0.05, -0.5 > logFC > 0.5], primarily enriching inflammatory pathways (p< 0.01). The transcriptomic comparisons for the effects ofcarvacrol identified 89 DEGs between groups 3 and 1 and 720 DEGs between 4 and 2 (p< 0.05, -0.5 > logFC > 0.5). Functional analyses (4 vs. 2) showed that thedelivery of carvacrol enriched pathways that can be related to T-cell activation at 6 h after LPS challenge, mainly influenced by the upregulation of DEGs encoding for cytokines and chemokines (< 0.01). Overall, these findings suggest that thedelivery of carvacrol may modulate immune responses toward anLPS challenge, specifically by upregulating the gene expression of cytokines, chemokines, and their receptors, persisting until at least 14 days post-hatching.