ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Veterinary Infectious Diseases
Embryonic thermal manipulation enhances splenic immunity and regulates inflammatory responses to Escherichia coli in broiler chickens
Provisionally accepted
- 1Department of Basic Veterinary Medical Sciences at the Jordan University of Science and Technology, Irbid, Jordan
- 2Department of Applied Biological Sciences, Faculty of Science and Art, Jordan University of Science and Technology, Jordan, Irbid, Jordan
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Escherichia coli (E. coli) infections continue to pose a significant health and economic burden to the poultry industry, with increasing restrictions on antibiotic use underscoring the need for alternative strategies to improve host resilience. Thermal manipulation (TM) during embryogenesis has been proposed as an economical strategy to enhance thermotolerance, stress resilience, and immune functionality in broilers. This study aimed to investigate the effect of TM during embryonic development on the immune response of broiler chickens following an E. coli challenge. A total of 740 Ross broiler eggs were assigned to either a control incubation (37.8°C, 56% RH) or TM (39°C and 65% RH for 18 h daily, on embryonic days 10–18). After hatching, chicks were subdivided into saline-or E. coli-injected groups. Splenic expression of pro-inflammatory mediators (iNOS and TNF-α), signaling receptors (NF-κB, p65, TLR-2, and TLR-4), and immunoregulatory cytokine (TGF-β) was quantified by RT-qPCR. At the same time, serum levels of acute-phase proteins (α1-acid glycoprotein (AGP) and C3) and total circulating immunoglobulins (IgA, IgM, and IgY) were assessed by ELISA. TM significantly modulated post-challenge immune responses, including downregulation of iNOS, TNF-α, NF-κB, TLR-2, and TLR-4, and upregulation of TGF-β. Notably, TM was associated with a stronger and more sustained circulatingimproved mucosal immunity by producing a stronger and more sustained IgA response after infection. Additionally, TM lowered serum acid glycoprotein AGP levels under the E. coli challenge, which indicates reduced systemic Formatted: Font: Italic, Complex Script Font: Italic Formatted: Font: Not Italic, Complex Script Font: Not Italic inflammation. These findings show that embryonic TM boosts both splenic and systemic immune regulation while reducing excessive inflammatory responses to bacterial challenges in broilers.
Keywords: broiler, Escherichia coli, immune response, Spleen immunity, Thermalmanipulation
Received: 11 Nov 2025; Accepted: 10 Feb 2026.
Copyright: © 2026 Al-Zghoul, Okour, Alghizzawi, Saleh and Hundam. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Mohammad Al-Zghoul
Seif Hundam
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