ORIGINAL RESEARCH article
Front. Physiol.
Sec. Avian Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1670073
Embryonic thermal manipulation improved early immunity in broiler chickens
Provisionally accepted
- University of Hawai'i at Manoa, Honolulu, United States
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Immunity in chickens is age-dependent and develops gradually over time. The initial defense by the host is a crucial mechanism for combating microbial infections. Embryonic thermal manipulation (TM) represents a promising approach for sustainable broiler production. Our previous work provided significant insights into the effects of TM on embryonic thermotolerance, metabolism, growth performance, microbial diversity, and immunity. This follow-up study used a subset of hatchlings previously used in our TM-related studies. This study aims to investigate the effects of TM on immunity-related genes in the spleen, bursa, and thymus. A total of 600 fertile Cobb 500 eggs were incubated for 21 d. After candling, 238 eggs underwent TM at 38.5°C from embryonic day (ED) 12–18, then transferred to a hatcher at 37.5°C from ED 19 to 21, while 236 eggs were incubated at 37.5°C throughout till 21 d. After hatching, 60-day-old unsexed chicks were housed in 12 pens (10 birds/pen, 6 replicates per treatment). The treatments included 1) Control and 2) TM. All birds were raised under standard conditions for the first 21 d. In the spleen, at d 7, the TM group showed significantly lower expression of cytokines (IL-10, IL-12, IL-18), TLRs (TLR-1, TLR-2A, TLR-4, TLR-21), and signaling markers (TBK-1, CD-3, NF-κB, TGF-β, TGF-β3) compared to the Control. At d 21, TM birds exhibited significantly lower (P < 0.05) expression of IL-4, IL-6, IFN-γ, and AvBD-6, while TLR-2A and TGF-β3 were significantly upregulated compared to the Control group. In bursa, at d 7, the TM group showed significantly higher expression of IL-1β, TLR-5, TLR-15, TLR-21, IFN-α, and NF-κB, while IL-6 was significantly downregulated. At d 14, IL-18 was significantly upregulated, and TLR-21 was significantly downregulated in the TM group. At d 21, IL8L1, IL-10, TLR-1, and CD-45 were significantly upregulated, whereas NF-κB expression was significantly downregulated compared to the Control group. In the thymus, at d 14, TLR15 was significantly higher, and at d 21, IL-10 was significantly lower in the TM compared to the Control group. In conclusion, embryonic TM enhanced early immune gene expression in broilers by upregulating essential immune-related genes in the spleen, bursa, and thymus.
Keywords: Cytokines, Embryogenesis, Immunomodulation, lymphoid, Ontogeny
Received: 21 Jul 2025; Accepted: 08 Sep 2025.
Copyright: © 2025 Amaz, Poudel, Pandey, Burlakoti, Jha and Mishra. 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: Birendra Mishra, University of Hawai'i at Manoa, Honolulu, United States
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.