Influence of season and pasture feeding on the content of α-tocopherol and β-carotene in milk from Holstein, Brown Swiss and Modicana cows in Sicily
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- Marino, V.M., Schadt, I., La Terra, S. et al. Dairy Sci. & Technol. (2012) 92: 501. doi:10.1007/s13594-012-0069-2
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It has been shown that several factors such as feed source and breed might influence milk fat-soluble antioxidants (AOs). This study investigated pasture feeding effects and dairy cattle breed on the content of α-tocopherol and β-carotene in cows' milk by monitoring two grazing seasons (spring and fall) as well as a summer no-pasture season. Four dairy farms located in Sicily were selected: two with both Holstein and Brown Swiss cows and two with only a Modicana (M) local breed cows. Bulk milk samples of each breed per farm were collected. Milk α-tocopherol and β-carotene were highest during spring (16.2 and 9.7 μg.g−1 of fat, respectively), lowest during fall (11.2 and 0.8 μg.g−1 of fat, respectively) and intermediate during summer (13.3 and 2.5 μg.g−1 of fat, respectively). These results indicate that grazing pasture season has an important impact on milk fat-soluble antioxidant content. In particular, higher milk AO levels in spring compared to fall might be attributed to several factors such as differences in the quality and composition of pasture, differences in pasture intake and even the climate. Breed effect on milk AO contents was not so pronounced. Milk β-carotene levels did not differ significantly among breeds. Saturation of milk β-carotene may explain similar vitamin levels among breeds in spring despite different pasture intakes. It was interesting that significant levels of α-tocopherol were detected in milk from M cows during summer. The latter effect could be masked by the considerably higher pasture intake of M in spring compared to the other two breeds.
季节和牧草对西西里Holstein, Brown Swiss 和 Modicana 奶牛乳中 α-生育酚和 β-胡萝卜素含量的影响
饲料和季节可以影响乳中脂溶性抗氧化剂的含量。本研究考察了春季和秋季(放牧季节)和夏季(非放牧季节)饲料以及奶牛品种对乳中α-生育酚和β-胡萝卜素含量的影响。选择西西里地区的四个牧场作为研究对象,其中两个农场有Holstein (H) 奶牛和Brown Swiss (BS)奶牛,另外两个牧场只有当地的Modicana (M)奶牛。分别对不同牧场和不同品种的奶牛进行采样。实验结果表明,春季乳中α-生育酚和β-胡萝卜素含量最高(分别为16.2和 9.7 μg.g−1 脂肪),秋季乳中α-生育酚和β-胡萝卜素含量最低(分别为11.2和 0.8 μg.g−1 脂肪),夏季乳中含量处于春季和秋季中间(分别为13.3 和2.5 μg.g−1 脂肪)。不同季节的牧草对乳中脂溶性抗氧化剂含量有显著的影响。春季比秋季乳中抗氧化剂含量高可能与牧草的组成和质量差异、牧草摄入量的差异、气候等因素有关。品种对乳中抗氧化剂含量的影响不显著,不同品种之间牛乳β-胡萝卜素含量差异不显著。β-胡萝卜素在乳中的饱和度与乳牛品种和所摄入饲料中维生素含量有关。在夏季, M牛乳中α-生育酚含量较高,但是春节M牛乳中,牧草摄入量对α-生育酚含量影响高于品种的影响。