Kostovska Renata, Drouin Gaetan, Salas Joaquín J, Venegas-Calerón Mónica, Horan Brendan, Tobin John T, O'Callaghan Tom F, Hogan Sean A, Kelly Alan L, Gómez-Mascaraque Laura G
Food Chemistry and Technology Department, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland P61 C996; School of Food and Nutritional Sciences, University College Cork, Co. Cork, Ireland T12 A4T1; VistaMilk SFI Research Centre, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland P61 C996.
Food Chemistry and Technology Department, Teagasc, Moorepark, Fermoy, Co. Cork, Ireland P61 C996.
J Dairy Sci. 2025 Feb;108(2):1261-1284. doi: 10.3168/jds.2024-25462. Epub 2024 Dec 16.
This study compared the effect of 2 pasture-based feeding systems, namely a traditional perennial ryegrass (PRG) diet, and a recently introduced, more sustainable multispecies swards (MSS) diet, on the functional lipid profile of raw milk. In addition to the 2 pasture diets, the study uniquely examined the combined effects of breed, namely Holstein Friesian (HF) or Jersey Holstein Friesian (JFX), and lactation stage in Ireland, spanning from March to November. Bulk milk samples (n = 144 yearly) for the 4 groups examined were collected for 4 wk per each of the 9 mo specified. Changes in total fatty acid (FA) and triglyceride carbon number profiles were determined by GC with a flame ionization detector, and those in polar lipids (PL) content by HPLC-evaporative light scattering-MS. Based on multivariate analysis, both diet (34.0% contribution) and breed (19.1% contribution) influenced milk FA on a yearly basis; however, in early lactation there were no differences in FA profile between the groups. In middle lactation and late lactation (LL), the MSS diet increased proportions of nutritionally beneficial n-6 and n-3 PUFA in milk, including C18:3 n-3 (ALA), C18:2 n-6 (LA) and C22:5 n-3 (DPA). Although proportions of ALA and LA increased in MSS milks, the LA/ALA ratio remained around 1 for the 2 feeding systems, confirming the beneficial modulation of LA and ALA in milks from pasture-based diets. Particularly in LL, the milk of JFX cows tended to have increased de novo FA, compared with HF, suggesting implications for techno-functional properties of dairy products such as butter. The milk of PRG HF group showed improved health-promoting properties, with lower thrombogenicity and atherogenicity indices on a yearly basis. Regarding techno-functional properties, the PRG HF group resulted in higher oleic acid reflecting in lower spreadability index, suggesting that butter made of this group would be more spreadable, compared with the one made from the other milk groups examined. The triglyceride and PL profiles were mainly affected by stage of lactation. Overall, these results show the effects of cow diet, breed, and stage of lactation on milk lipid profile, with important implications for the nutritional and techno-functional characteristics of dairy products.
本研究比较了两种基于牧场的饲养系统，即传统的多年生黑麦草（PRG）日粮和最近引入的、更具可持续性的多物种草皮（MSS）日粮，对原料乳功能脂质谱的影响。除了这两种牧场日粮外，该研究还特别考察了品种（即荷斯坦弗里生牛（HF）或泽西荷斯坦弗里生牛（JFX））与爱尔兰泌乳阶段（从3月至11月）的综合影响。对所考察的4组奶牛，在指定的9个月中，每组每周采集4周的批量乳样（每年n = 144）。采用带火焰离子化检测器的气相色谱法测定总脂肪酸（FA）和甘油三酯碳数分布的变化，采用高效液相色谱 - 蒸发光散射 - 质谱法测定极性脂质（PL）含量的变化。基于多变量分析，日粮（贡献率34.0%）和品种（贡献率19.1%）每年都会影响乳脂肪酸；然而，在泌乳早期，各组之间的脂肪酸分布没有差异。在泌乳中期和后期（LL），MSS日粮增加了乳中营养有益的n - 6和n - 3多不饱和脂肪酸（PUFA）的比例，包括C18:3 n - 3（ALA）、C18:2 n - 6（LA）和C22:5 n - 3（DPA）。尽管MSS乳中ALA和LA的比例增加，但两种饲养系统的LA/ALA比值仍保持在1左右，证实了基于牧场日粮的乳中LA和ALA的有益调节。特别是在泌乳后期，与HF相比，JFX奶牛的乳中从头合成脂肪酸往往增加，这对乳制品如黄油的技术功能特性有影响。PRG HF组的乳具有更好的促进健康特性，每年的血栓形成性和动脉粥样硬化性指数较低。关于技术功能特性，PRG HF组的油酸含量较高，这反映在较低的涂抹性指数上，表明与其他所考察乳组制成的黄油相比，该组制成的黄油更易涂抹。甘油三酯和PL分布主要受泌乳阶段的影响。总体而言，这些结果显示了奶牛日粮、品种和泌乳阶段对乳脂质谱的影响，对乳制品的营养和技术功能特性具有重要意义。
