Jejunum FABP6 expression and potential mechanism response to Salmonella Pullorum inoculation revealed by proteomic profiling and RT-PCR in Chinese Taihe black-bone silky fowls.

Abstract

Salmonella Pullorum (S. Pullorum) incurs high mortality in chicks and disrupts intestinal health, and poses a severe threat to poultry industry and human health. However, in Chinese Taihe Black-Bone Silky Fowls (TBSF), the jejunum biomarker and molecular mechanism responding to S. Pullorum inoculation remain elusive. This study aims to characterize the jejunum proteome changes of TBSF affected by S. Pullorum. Using a data-independent acquisition (DIA) proteomics method, jejunum samples were collected from chicks and analyzed. These samples corresponded to the following treatment groups: the blank control group (TBSF with PBS treatment), and groups challenged with Salmonella Pullorum at doses of 1.39 × 10⁸ CFU/mL (L), 2.78 × 10⁸ CFU/mL (M), and 5.56 × 10⁸ CFU/mL (H). Meanwhile, the LD group (challenged with 1.39 × 10CFU/mL S. Pullorum and administered 0.1g/kg bw 20% florfenicol powder) was used as experimental validation. A total of 8977 proteins were identified. Compared with the blank group, the numbers of differentially abundant proteins were 976 in the L group, 536 in the LD group, 635 in the M group, 673 in the H group, respectively. KEGG analysis showed that proteins affected by S. Pullorum were mainly associated with the signal transduction and infectious disease. EggNOG annotation of proteins showed that regulated proteins were significantly involved in intracellular trafficking, secretion, and vesicular transport, as well as post-translational modification, protein turnover, and chaperones. The results indicate that the alterations in jejunal protein profiles following S. Pullorum challenge are primarily driven by the host's active defense mechanisms against infection. Notably, the protein abundance of FABP6 and ACE2 was significantly higher in the Blank control group compared to all infected groups. This differential expression was further corroborated by RT-PCR analysis, which showed a corresponding increase in FABP6 mRNA levels in the Blank group, confirming FABP6 as a host gene responsive to S. Pullorum. Collectively, this study proposes potential protein biomarkers for the diagnosis of S. Pullorum infection, identifies promising targets for therapeutic development, and provides enhanced mechanistic insight into host-pathogen interactions. that changes of jejunum proteins in response to S. Pullorum are driven by the host's intensified efforts to counteract the infection. The protein abundance of FABP6 and ACE2 was significantly higher in the blank group than in the S. Pullorum-challenged groups. This observation was further validated at the transcriptional level, as RT-PCR analysis confirmed that FABP6 mRNA expression was also elevated in the blank group. These consistent results establish FABP6 as a host gene responsive to S. Pullorum infection. Consequently, this study not only identifies potential protein biomarkers for diagnosing S. Pullorum infection but also proposes novel targets for therapeutic development, thereby enhancing our understanding of the underlying host-pathogen interactions.