Abstract：
Bovine milk is an important food component in the human diet due to its nutrient-rich metabolites. However, bovine subclinical mastitis alters the composition and quality of milk. In present study, California mastitis testing, somatic cell count, pH, and electrical conductivity were used as confirmatory tests to detect subclinical mastitis. The primary goal was to study metabolome and identify major pathogens in cows with subclinical mastitis. In this study, 29 metabolites were detected in milk using gas chromatography−mass spectrometry. Volatile acidic compounds, such as hexanoic acid, hexadecanoic acid, lauric acid, octanoic acid, n-decanoic acid, tricosanoic acid, tetradecanoic acid, and hypogeic acid were found in milk samples, and these impart good flavor to the milk. Metaboanalyst tool was used for metabolic pathway analysis and principal component estimation. In this study, EC and pH values in milk were significantly increased (p < 0.0001), whereas fat (p < 0.04) and protein (p < 0.0002) significantly decreased in animals with subclinical mastitis in comparison to healthy animals. Staphylococcus aureus was the predominant pathogen found (n = 54), followed by Escherichia coli (n = 30). Furthermore, antibiotic sensitivity revealed that Staphylococcus aureus was more sensitive to gentamicin (79.6%), whereas Escherichia coli showed more sensitivity to doxycycline hydrochloride (80%).
摘要：
牛乳因其富含营养的代谢产物而成为人类饮食中的重要食物成分。然而,牛亚临床乳腺炎改变了牛奶的成分和质量。在目前的研究中,加州乳腺炎测试,体细胞计数,pH值,和电导率被用作确认试验来检测亚临床乳腺炎。主要目标是研究代谢组并鉴定患有亚临床乳腺炎的奶牛中的主要病原体。在这项研究中,用气相色谱-质谱法检测牛奶中29种代谢物。挥发性酸性化合物,如己酸，十六烷酸,月桂酸,辛酸,正癸酸,三芥酸,十四烷酸,在牛奶样本中发现了高酸，这些赋予牛奶很好的味道。元分析工具用于代谢途径分析和主成分估计。在这项研究中,乳中的EC和pH值显着增加（p＆lt;0.0001），而与健康动物相比，患有亚临床型乳腺炎的动物的脂肪（p＆lt;0.04）和蛋白质（p＆lt;0.0002）显着降低。金黄色葡萄球菌是发现的主要病原体（n=54），其次是大肠杆菌（n=30）。此外，抗生素敏感性显示金黄色葡萄球菌对庆大霉素更敏感(79.6%)，而大肠杆菌对盐酸多西环素更敏感(80%)。
