Department of Biomedical and Veterinary Sciences, Virginia Tech, Blacksburg, VA, USA.
Poult Sci. 2011 Jun;90(6):1212-9. doi: 10.3382/ps.2010-01110.
Avian coccidiosis is a major disease of poultry caused by the intestinal protozoa Eimeria. Infection leads to reduced feed efficiency and BW gain, resulting in severe economic losses for the poultry industry. Aviagen line A and line B birds show a differential response to Eimeria infection, with line B birds exhibiting higher lesion scores and mortality. The objective of this study was to examine differential intestinal gene expression between 2-wk-old line A and B chicks in response to a challenge with Eimeria maxima. After challenge with 1 × 10(4) oocysts/chick, more than 40% of line A chicks had lesion scores of 0 to 1 (scale of 0 to 4), similar to control chicks. In contrast, all line B chicks challenged at this same dose had lesion scores of 2 to 4. Total RNA was extracted from the jejunum of control and challenged chicks from both lines A and B. Microarray analysis revealed that liver-expressed antimicrobial peptide 2 (LEAP-2), a component of the innate immune system, was downregulated 20-fold in line A challenged chicks with lesion scores of 2 to 4 compared with line A control chicks, and was downregulated 11- to 71-fold in line B challenged chicks with lesion scores of 2 to 4 compared with line B control chicks. Liver-expressed antimicrobial peptide 2 was downregulated less than 2-fold in line A challenged chicks with lesion scores of 1 compared with line A control chicks, indicating that these chicks were similar to control chicks in their expression level of LEAP-2. Other genes (cytochrome P450, heat shock protein 25, keratin 19, and amino acid transporter ASCT1) showed different patterns of over- or underexpression. The expression of LEAP-2 was verified using real-time PCR, revealing a correlation between lesion score and magnitude of LEAP-2 downregulation for both line A and line B chicks. Thus, LEAP-2 may serve as a useful marker for identification of chickens resistant to E. maxima infection and potentially other Eimeria spp.
禽类球虫病是一种由肠道原生动物艾美耳球虫引起的家禽主要疾病。感染导致饲料效率和体重增加降低，给家禽业造成严重的经济损失。Aviagen 品系 A 和品系 B 鸟类对艾美耳球虫感染表现出不同的反应，品系 B 鸟类的病变评分和死亡率更高。本研究的目的是研究 2 周龄品系 A 和 B 雏鸡在感染最大艾美耳球虫后的肠道基因表达差异。用 1×10(4)个卵囊/只雏鸡攻毒后，超过 40%的品系 A 雏鸡的病变评分为 0 到 1（0 到 4 级），与对照雏鸡相似。相比之下，所有以相同剂量攻毒的品系 B 雏鸡的病变评分均为 2 到 4。从两条线的对照和攻毒雏鸡的空肠中提取总 RNA。微阵列分析显示，肝表达的抗菌肽 2（LEAP-2），先天免疫系统的一个组成部分，在病变评分 2 到 4 的品系 A 攻毒雏鸡中下调 20 倍，而在病变评分 2 到 4 的品系 B 攻毒雏鸡中下调 11 到 71 倍与品系 B 对照雏鸡相比。病变评分 1 的品系 A 攻毒雏鸡的 LEAP-2 下调不到 2 倍，表明这些雏鸡在 LEAP-2 的表达水平上与对照雏鸡相似。其他基因（细胞色素 P450、热休克蛋白 25、角蛋白 19 和氨基酸转运体 ASCT1）表现出不同的过表达或低表达模式。使用实时 PCR 验证了 LEAP-2 的表达，揭示了品系 A 和品系 B 雏鸡的病变评分与 LEAP-2 下调幅度之间的相关性。因此，LEAP-2 可作为鉴定对最大艾美耳球虫感染和潜在其他艾美耳球虫 spp. 具有抗性的鸡的有用标记。
