Laboratory of Biochemistry, Department of Pathologic, Diagnostic and Clinical Veterinary Medicine, University of Perugia, 06126 Perugia, Italy.
J Proteomics. 2013 May 27;83:144-59. doi: 10.1016/j.jprot.2013.03.017. Epub 2013 Apr 2.
Subclinical mastitis is one of the main causes of alteration in milk content and has a major impact on both animal welfare and economy in the dairy industry. A better knowledge is needed to understand the ovine mammary gland metabolism and its response to bacterial infection. In this study, the proteomic changes in ovine milk as a result of subclinical mastitis were investigated by comparing both whey and fat globule membrane profiles of samples from Staphylococcus chromogenes-positive individuals, with those from non-infected counterparts having high or low somatic cell count; the latter were used as control. 2-DE and combined MS procedures were utilized for this purpose. Although sample bromatological parameters were very similar, proteomic analysis highlighted significant differences between the three experimental groups. Most relevant changes were observed between samples of infected milk and control. Modifications related to the defense response of the mammary gland to the pathogen were evident, with important consequences on nutritional and technological properties of milk. On the other hand, quantitative protein changes between non-infected samples with low and high levels of somatic cells indicated that the latter may result as a consequence of a probable unpaired cellular metabolism due to cellular stress, hormonal variations or previous infections. Putative biomarkers useful for the monitoring of sheep mammary metabolism and for the careful management of ovine subclinical mastitis to avoid its clinical degeneration are proposed and discussed.
Proteomics has been here applied to the differentiation of healthy and subclinical mastitic sheep milk samples, evidencing the response of the mammary gland to S. chromogenes infection. Presented results propose useful protein biomarkers for the detection of ewe mammary infection at its subclinical stages and, subsequently, mastitis recognition and treatment. Differently from bovine, these data confirm that the increase in somatic cell count in sheep milk is not always associated with protein factors that characterize the mammary gland infection; accordingly, somatic cell count cannot be considered as a useful parameter to certainly diagnose subclinical mastitis in ovine.
亚临床乳腺炎是改变奶成分的主要原因之一，对奶牛业的动物福利和经济有重大影响。为了更好地了解绵羊乳腺代谢及其对细菌感染的反应，我们需要更多的知识。在这项研究中，通过比较金黄色葡萄球菌阳性个体的乳清和脂肪球膜谱，研究了亚临床乳腺炎对绵羊乳的蛋白质组变化，这些个体的体细胞计数高或低；后者用作对照。为此目的，使用了 2-DE 和联合 MS 程序。尽管样本的营养参数非常相似，但蛋白质组分析突出了三个实验组之间的显著差异。在感染奶和对照之间观察到最相关的变化。乳腺对病原体的防御反应的相关变化显而易见，对牛奶的营养和技术特性有重要影响。另一方面，低体细胞和高体细胞的非感染样本之间的蛋白质定量变化表明，后者可能是由于细胞应激、激素变化或先前感染导致的细胞代谢失衡所致。提出并讨论了一些有用的潜在生物标志物，用于监测绵羊乳腺代谢和谨慎管理绵羊亚临床乳腺炎，以避免其临床恶化。
蛋白质组学已应用于区分健康和亚临床乳腺炎绵羊乳样，证明了乳腺对金黄色葡萄球菌感染的反应。目前的结果提出了有用的蛋白质生物标志物，用于在亚临床阶段检测母羊乳腺感染，随后识别和治疗乳腺炎。与牛不同，这些数据证实，绵羊乳中体细胞计数的增加并不总是与特征为乳腺感染的蛋白质因素相关；因此，体细胞计数不能被认为是诊断绵羊亚临床乳腺炎的有用参数。
