An antimicrobial peptide is downregulated in the small intestine of Eimeria maxima-infected chickens

作者：Casterlow, S.; Li, H.; Gilbert, E. R.; Dalloul, R. A.; McElroy, A. P.; Emmerson, D. A.; Wong, E. A.^*

来源：POULTRY SCIENCE, 2011, 90(6): 1212-1219.

DOI：10.3382/ps.2010-01110

• coccidiosis
• Eimeria maxima
• liver-expressed antimicrobial peptide-2

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 x 104 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.

• 出版日期2011-6-1
• 单位Virginia Tech; 美国弗吉尼亚理工大学(Virginia Tech); 山西农业大学