Intensive farming systems represent a stressful environment for pigs and negatively influence neuroendocrine functions, behavior, and performance. Outdoor farming is an alternative option, which is thought to imply several beneficial effects for the animal. Dietary essential oils are known to be an innovative strategy to improve pig health and performance, and oregano essential oil (ORE) possesses beneficial effects due to its antimicrobial, anti-fungal, and antioxidant properties. We tested the effect of dietary ORE on peripheral blood mononuclear cells (PBMCs) in 36 growing pigs, either reared under indoor or outdoor conditions. Quantitative real-time PCR (RT-qPCR) assay was used to evaluate the effect of diet (control vs. ORE) and the time of sampling (T1−120 days vs. T2−190 days) on the expression of inflammatory and immune-related genes (TNF, IL1β, IL8, IL18, IL10, IL1RN, STAT3, HSP90, ICAM-1, and NFKB1). Under outdoor condition, the majority of transcripts were upregulated (p < 0.05), assuming a general inflammatory status (TNF, HSP90, NFKB1, IL1β, and STAT3). However, an interaction between diet and the farming system was observed: HSP90, NFKB1, and STAT3 were downregulated (p < 0.05) in the outdoor reared pigs when fed the ORE diet. Our study showed that bioactive compounds of ORE exert their activity, especially when the animals are exposed to stressful stimuli. Dietary ORE can be an acceptable strategy to help pigs tolerate the stress related to the harsh, outdoor, rearing conditions.

集约化耕种系统给猪带来了压力环境，并对神经内分泌功能，行为和性能产生负面影响。户外耕作是一种替代选择，据认为这对动物意味着几种有益的作用。饮食中的精油是改善猪健康和性能的创新策略，牛至精油（OREG）具有抗微生物，抗真菌和抗氧化的特性，因此具有有益的作用。我们在室内或室外条件下测试了ORE饮食对36只生长猪的外周血单个核细胞（PBMC）的影响。实时定量PCR（RT-qPCR）分析用于评估饮食（对照vs. ORE）和采样时间（T1-120天vs. T2-190天）对炎症和免疫反应的表达的影响。相关基因（TNF，IL1β， IL8，IL18，IL10，IL1RN，STAT3，HSP90，ICAM-1， 和 NFKB1）。在室外条件下，大多数成绩单都被上调了（p<0.05），并假设其具有一般的炎症状态（TNF，HSP90，NFKB1，IL1β和STAT3）。但是，观察到饮食与耕作系统之间的相互作用：HSP90，NFKB1， 和 STAT3 被下调（p饲喂ORE饲料时，在室外饲养的猪中<0.05）。我们的研究表明，ORE的生物活性化合物发挥其活性，尤其是当动物受到压力刺激时。饮食中的ORE可以是一种可以接受的策略，可以帮助猪只耐受与恶劣的室外饲养条件有关的压力。