Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into five groups: (1) negative control fed basal diet alone (NC), (2) positive control receiving basal diet plus 50 mg/kg of chlortetracycline (CTC), (3) basal diet plus 150 mg/kg COEC (COEC150), (4) plus 300 mg/kg COEC (COEC300), and (5) plus 450 mg/kg COEC (COEC450). The supplement trial was continued for 42 days. The results showed that CTC, COEC300 and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli in the cecal digesta at 21 d was lower in the CTC, COEC300 and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the Escherichia coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450 mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses and inhibit the proliferation of cecal pathogenic bacteria.

中文翻译：

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补充包衣牛至精油和肉桂醛化合物可改善生长性能，增强免疫反应并抑制肉鸡盲肠大肠杆菌增殖


植物精油由于高挥发性和易氧化而不稳定，而微胶囊化为增加天然精油的稳定性和保持其功能提供了一种潜在的有效策略。本研究检查了饲喂包衣牛至精油和肉桂醛 （COEC） 化合物对肉鸡生长、免疫器官发育、肠道形态、粘膜免疫功能和盲肠微生物群的影响。将 300 只一日龄雄性 Arbor Acres 肉鸡分为五组：（1） 阴性对照单独饲喂基础日粮 （NC），（2） 阳性对照接受基础日粮加 50 mg/kg 金霉素 （CTC），（3） 基础日粮加 150 mg/kg COEC （COEC150），（4） 加 300 mg/kg COEC （COEC300），以及 （5） 加 450 mg/kg COEC （COEC450）。补充剂试验持续了 42 天。结果表明，与NC组相比，CTC、COEC300和COEC450处理降低了肉鸡在育肥期和整个试验期的饲料转化率，增加了21 d空肠绒毛的高度，在21或42 d增加了杯状细胞和IgA产生细胞的数量（P < 0.05）。COEC300处理组成员在 21 d 时胸腺体重指数和空肠长度指数高于 NC 或 CTC 组的鸟类 （P < 0.05）。CTC 和所有 COEC 处理在 42 d 时降低了空肠粘膜中丙二醛含量 （P < 0.05）。与 NC 组相比，CTC 、 COEC300 和 COEC450 处理组 21 d 盲肠消化中大肠埃希菌种群数量较低 （P < 0.05）。 与 CTC 组相比，COEC 补充剂剂量依赖性地加速体重增加，改善空肠形态，降低空肠粘膜中的丙二醛含量，增加空肠杯状细胞和 IgA 产生细胞的数量，并在 21 或 42 d 时减少盲肠消化中的大肠埃希菌群 （P < 0.05）。因此，我们得出结论，在无抗生素日粮中饲喂 300 或 450 mg/kg 的肉鸡可以提高生长性能，增强免疫反应并抑制盲肠病原菌的增殖。