Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA 24061, USA.
Animal Biosciences and Biotechnology Laboratory, USDA/ARS, Beltsville, MD 20705, USA.
Poult Sci. 2018 Dec 1;97(12):4392-4400. doi: 10.3382/ps/pey286.
Fayoumi chickens are believed to be more disease resistant compared to commercial broiler chickens. The objective of this study was to compare mRNA expression of intestinal nutrient transporters, digestive enzymes, and host defense peptides (HDP) between Eimeria maxima-challenged Fayoumi and Ross broiler chickens. At 21 d of age, Ross broilers and Fayoumi lines M5.1 and M15.2 were challenged with 1,000 E. maxima oocysts. Control birds were not challenged. Duodenum, jejunum, and ileum were sampled (n = 6) at 7 d post challenge. Gene expression was analyzed using relative quantification PCR. Data were analyzed by ANOVA and significance level was set at P < 0.05. There was numerical, but not statistically significant, differential weight gain depression for Ross (15%) and Fayoumi lines M5.1 (21%) and M15.2 (22%) and significant line-specific changes in gene expression. For nutrient transporters, there was downregulation of mRNA for the brush border membrane, amino acid transporters b0,+AT/rBAT, BoAT, and EAAT3 in different segments of the small intestine of Ross and both lines of Fayoumi chickens, indicating that E. maxima challenge likely caused a decrease in nutrient uptake. For HDP, there was downregulation of avian beta defensin (AvBD) 1, 6, 10, 12, and 13 mRNA in the jejunum of the 2 Fayoumi lines, but no change in the Ross broilers. In the duodenum, there was upregulation of AvBD10 mRNA in the Ross and both Fayoumi lines and additionally upregulation of AvBD11, 12, and 13 mRNA in only Fayoumi line M15.2. Liver expressed antimicrobial peptide 2 (LEAP2) mRNA was downregulated in the duodenum and jejunum of Ross and Fayoumi line M5.1 but not in Fayoumi line M15.2. The homeostatic, non-challenged levels of AvBD mRNA were greater in Fayoumi line M15.2 than Ross and Fayoumi line M5.1 in the duodenum and ileum. This study demonstrates tissue- and genetic line-specific transcriptional responses to E. maxima, highlights novel potential candidate genes for response to coccidiosis, and confirms a role for several previously reported genes in response to coccidiosis.
法尤米鸡被认为比商业肉鸡更能抵抗疾病。本研究的目的是比较 Eimeria maxima 攻毒后法尤米鸡和罗斯肉鸡的肠道营养转运体、消化酶和宿主防御肽（HDP）的 mRNA 表达。在 21 日龄时，罗斯肉鸡和法尤米鸡 M5.1 和 M15.2 品系用 1000 个 E. maxima 卵囊攻毒。对照组未攻毒。攻毒后 7 天（n=6）取样十二指肠、空肠和回肠。使用相对定量 PCR 分析基因表达。数据采用方差分析，显著水平设为 P<0.05。罗斯肉鸡（15%）和法尤米鸡 M5.1（21%）和 M15.2（22%）的体重增长明显下降，但差异无统计学意义，且存在线特异性基因表达变化。对于营养转运体，罗斯和法尤米鸡的不同小肠段的刷状缘膜、氨基酸转运体 b0、+AT/rBAT、BoAT 和 EAAT3 的 mRNA 下调，表明 E. maxima 攻毒可能导致营养吸收减少。对于 HDP，法尤米鸡的空肠中 avian beta defensin（AvBD）1、6、10、12 和 13 的 mRNA 下调，但罗斯肉鸡无变化。在十二指肠中，罗斯和法尤米鸡的 AvBD10 mRNA 上调，此外，仅在法尤米鸡 M15.2 中上调了 AvBD11、12 和 13 的 mRNA。肝脏表达的抗菌肽 2（LEAP2）mRNA 在罗斯和法尤米鸡 M5.1 的十二指肠和空肠中下调，但在法尤米鸡 M15.2 中没有下调。非攻毒状态下，法尤米鸡 M15.2 的空肠和回肠中的 AvBD mRNA 水平高于罗斯和法尤米鸡 M5.1。本研究表明，E. maxima 攻毒具有组织和遗传谱系特异性转录反应，突出了一些新的潜在候选基因对球虫病的反应，证实了几个先前报道的基因在球虫病反应中的作用。
