Rosa Fernanda, Busato Sebastiano, Avaroma Fatima C, Linville Kali, Trevisi Erminio, Osorio Johan S, Bionaz Massimo
Department of Animal and Rangeland Sciences, Oregon State University, Corvallis, Oregon, United States of America.
Escuela Agrícola Panamericana El Zamorano, El Zamorano, Francisco Morazán, Honduras.
PLoS One. 2018 Jan 26;13(1):e0191599. doi: 10.1371/journal.pone.0191599. eCollection 2018.
After birth, a newborn calf has to adapt to an extrauterine life characterized by several physiological changes. In particular, maturation of the gastrointestinal tract in a new environment loaded with potential pathogens, which can predispose neonatal calves to develop diarrhea, and is a major cause of morbidity and mortality during the first 4 wks of life. We aimed to investigate the inflammatory adaptations at a transcriptomic level in the gastrointestinal (GI) tract to a mild diarrhea in neonatal dairy calves using RNA isolated from fresh fecal samples. Eight newborn Jersey male calves were used from birth to 5 wks of age and housed in individual pens. After birth, calves received 1.9 L of colostrum from their respective dams. Calves had ad-libitum access to water and starter grain (22% CP) and were fed twice daily a total of 5.6 L pasteurized whole milk. Starter intake, body weight (BW), fecal score, withers height (WH), and rectal temperature (RT) were recorded throughout the experiment. Blood samples were collected weekly for metabolic and inflammatory profiling from wk 0 to wk 5. Fresh fecal samples were collected weekly and immediately flash frozen until RNA was extracted using a Trizol-based method, and subsequently, an RT-qPCR analysis was performed. Orthogonal contrasts were used to evaluate linear or quadratic effects over time. Starter intake, BW, and WH increased over time. Fecal score was greatest (2.6 ± 0.3) during wk 2. The concentrations of IL-6, ceruloplasmin, and haptoglobin had a positive quadratic effect with maximal concentrations during wk 2, which corresponded to the maximal fecal score observed during the same time. The concentration of serum amyloid A decreased over time. The mRNA expression of the proinflammatory related genes TLR4, TNFA, IL8, and IL1B had a positive quadratic effect of time. A time effect was observed for the cell membrane sodium-dependent glucose transporter SLC5A1, for the major carbohydrate facilitated transporter SLC2A2, and water transport function AQP3, where SLC5A1 and AQP3 had a negative quadratic effect over time. Our data support the use of the fecal RNA as a noninvasive tool to investigate intestinal transcriptomic profiling of dairy calves experiencing diarrhea, which would be advantageous for future research including nutritional effects and health conditions.
出生后，新生小牛必须适应宫外生活，这一过程伴随着多种生理变化。特别是在充满潜在病原体的新环境中胃肠道的成熟，这可能使新生小牛易患腹泻，并且是其出生后前4周发病和死亡的主要原因。我们旨在使用从新鲜粪便样本中分离的RNA，在转录组水平上研究新生奶牛犊胃肠道对轻度腹泻的炎症适应性。选用8头新生泽西公牛犊，从出生到5周龄，单独饲养在围栏中。出生后，小牛从各自的母牛那里获得1.9升初乳。小牛可自由饮水和采食开食料（粗蛋白含量22%），每天分两次饲喂共5.6升巴氏杀菌全脂牛奶。在整个实验过程中记录开食料采食量、体重（BW）、粪便评分、鬐甲高度（WH）和直肠温度（RT）。从第0周开始每周采集血样进行代谢和炎症分析，直至第5周。每周采集新鲜粪便样本并立即速冻，直到使用基于Trizol的方法提取RNA，随后进行RT-qPCR分析。使用正交对比来评估随时间的线性或二次效应。开食料采食量、体重和鬐甲高度随时间增加。第2周时粪便评分最高（2.6±0.3）。白细胞介素-6、铜蓝蛋白和触珠蛋白的浓度呈正二次效应，在第2周时达到最高浓度，这与同一时间观察到的最高粪便评分相对应。血清淀粉样蛋白A的浓度随时间下降。促炎相关基因TLR4、TNFA、IL8和IL1B的mRNA表达呈时间正二次效应。观察到细胞膜钠依赖性葡萄糖转运体SLC5A1、主要碳水化合物易化转运体SLC2A2和水转运功能AQP3有时间效应，其中SLC5A1和AQP3随时间呈负二次效应。我们的数据支持将粪便RNA用作一种非侵入性工具，以研究患腹泻的奶牛犊的肠道转录组谱，这将有利于包括营养效应和健康状况在内的未来研究。
