Al Amaz Sadid, Shahid Md Ahosanul Haque, Jha Rajesh, Mishra Birendra
Department of Human Nutrition, Food and Animal Sciences, College of Tropical Agriculture and Human Resources, University of Hawai'i at Manoa, Honolulu, HI, United States.
Front Vet Sci. 2025 Jan 28;12:1537116. doi: 10.3389/fvets.2025.1537116. eCollection 2025.
Genetic selection in broiler chickens has led to increased muscle mass without comparable respiratory and cardiovascular system development, limiting the birds' capacity to withstand high ambient temperatures and making them vulnerable to heat stress (HS). Early embryonic Thermal Manipulation (TM) has been suggested as an effective and sustainable way to mitigate the adverse effects of HS. This study investigated how these interventions influenced the immune status of broiler chickens exposed to HS.
Cobb 500 fertile eggs ( = 600) were incubated according to guidelines. On embryonic day (ED) 12, the eggs were split into two groups: (1) Control, kept at standard temperature until hatch day (ED 21) and (2) Thermal Manipulation (TM), exposed to 38.5°C with 55% humidity for 12 h daily from ED 12 to ED 18. After hatching, chicks were divided into (1) Control, (2) TM, (3) Control under Heat Stress (CHS), (4) TM under Heat Stress (TMHS), (5) Control with Heat Stress and Supplementation (CHSS), and (6) TM with Heat Stress and Supplementation (TMHSS). For the first 21 days, all chicks were raised under normal conditions. From day 22 to day 35, groups CHS, TMHS, CHSS, and TMHSS experienced chronic heat stress (32-33°C for 8 h daily), while the Control and TM groups remained in a thermoneutral environment (22-24°C).
TM significantly increased ( < 0.05) and expression in the spleen. TM and baicalein supplementation significantly decreased ( 0.05) expression. In the bursa, TM significantly increased ( 0.05) expression. The combination of TM with baicalein significantly increased ( 0.05) and decreased ( 0.05) expression. Interestingly, TM alone significantly decreased ( 0.05) expression under HS condition. In the thymus, TM significantly decreased ( 0.05) and , while incorporating baicalein with TM decreased ( 0.05) expression.
TM improved the immune status of broiler chickens under normal conditions. When combined with baicalein, TM mitigated the negative effects of heat stress by boosting key immune-related gene expression in the spleen, bursa, and thymus.
肉鸡的基因选择导致肌肉量增加，而呼吸和心血管系统却没有相应发展，这限制了鸡只耐受高环境温度的能力，使其易受热应激（HS）影响。早期胚胎热调控（TM）被认为是减轻热应激不利影响的一种有效且可持续的方法。本研究调查了这些干预措施如何影响受热应激的肉鸡的免疫状态。
按照指南孵化600枚科宝500种蛋。在胚胎第12天（ED12），将蛋分为两组：（1）对照组，在标准温度下保存至孵化日（ED21）；（2）热调控组（TM），从ED12至ED18每天在38.5°C、湿度55%的环境下暴露12小时。孵化后，雏鸡分为：（1）对照组，（2）TM组，（3）热应激下的对照组（CHS），（4）热应激下的TM组（TMHS），（5）热应激并补充营养的对照组（CHSS），（6）热应激并补充营养的TM组（TMHSS）。在最初的21天里，所有雏鸡在正常条件下饲养。从第22天至第35天，CHS、TMHS、CHSS和TMHSS组经历慢性热应激（每天8小时32 - 33°C），而对照组和TM组保持在热中性环境（22 - 24°C）。
TM显著增加（<0.05）脾脏中 和 的表达。TM和黄芩苷补充显著降低（ 0.05） 表达。在法氏囊中，TM显著增加（ 0.05） 表达。TM与黄芩苷联合显著增加（ 0.05） 并降低（ 0.05） 表达。有趣的是，单独的TM在热应激条件下显著降低（ 0.05） 表达。在胸腺中，TM显著降低（ 0.05） 和 ，而将黄芩苷与TM结合降低（ 0.05） 表达。
TM改善了正常条件下肉鸡的免疫状态。与黄芩苷联合使用时，TM通过提高脾脏、法氏囊和胸腺中关键免疫相关基因的表达减轻了热应激的负面影响。
