Embryonic thermal manipulation improved early immunity in broiler chickens

Area of Science:

• Poultry Science
• Immunology
• Animal Physiology

Background:

• Chicken immunity is age-dependent and crucial for combating infections.
• Embryonic thermal manipulation (TM) is a promising strategy for sustainable broiler production.
• Previous research established TM's effects on thermotolerance, metabolism, growth, microbial diversity, and immunity.

Purpose of the Study:

• To investigate the effects of embryonic TM on immunity-related gene expression in the spleen, bursa, and thymus of broiler chickens.
• To analyze changes in cytokine, TLR, and signaling marker expression at different time points post-hatching.

Main Methods:

• 600 fertile Cobb 500 eggs were divided into Control (37.5 °C) and TM (38.5 °C from ED 12-18, then 37.5 °C) groups.
• Gene expression analysis was performed on spleen, bursa, and thymus tissues from 60-day-old chicks at days 7, 14, and 21 post-hatching.
• Quantitative PCR was used to measure the expression levels of various immune-related genes.

Main Results:

• Spleen: TM group showed lower expression of cytokines (IL-10, IL-12, IL-18) and TLRs at day 7, but upregulated TLR-2A and TGF-β3 at day 21.
• Bursa: TM group exhibited higher expression of IL-1β, TLR-5, TLR-15, TLR-21, IFN-α, and NF-κB at day 7, with significant upregulation of IL-18 at day 14 and IL8L1, IL-10, TLR-1, CD-45 at day 21.
• Thymus: TM group showed higher TLR15 expression at day 14 and lower IL-10 expression at day 21.

Conclusions:

• Embryonic TM significantly modulates early immune gene expression in broiler chickens.
• TM enhances early immunity by upregulating essential immune-related genes in the spleen, bursa, and thymus.
• These findings support TM as a strategy to improve broiler immunity and health.