Gómez-Cortés P, Bach A, Luna P, Juárez M, de la Fuente M A
Instituto del Frío (Consejo Superior de Investigaciones Científicas), Ciudad Universitaria s/n 28040 Madrid, Spain.
J Dairy Sci. 2009 Sep;92(9):4122-34. doi: 10.3168/jds.2008-1909.
The objective of this study was to assess the effects of dietary supplementation of extruded linseed on animal performance and fatty acid (FA) profile of ewe milk for the production of n-3 FA- and conjugated linoleic acid-enriched cheeses. A Manchega ewe flock (300 animals) receiving a 60:40 forage:concentrate diet was divided into 3 groups supplemented with 0, 6, and 12 g of extruded linseed/100 g of dry matter for the control, low, and high extruded linseed diets, respectively. Bulk and individual milk samples from 5 dairy ewes per group were monitored at 7, 14, 28, 45, and 60 d following supplementation. Manchego cheeses were made with bulk milk from the 3 treatment groups. Milk yield increased in dairy ewes receiving extruded linseed. Milk protein, fat, and total solids contents were not affected by linseed supplementation. Milk contents of alpha-linolenic acid increased from 0.36 with the control diet to 1.91% total FA with the high extruded linseed diet. Similarly, cis-9 trans-11 C18:2 rose from 0.73 to 2.33% and its precursor in the mammary gland, trans-11 C18:1, increased from 1.55 to 5.76% of total FA. This pattern occurred with no significant modification of the levels of trans-10 C18:1 and trans-10 cis-12 C18:2 FA. Furthermore, the high extruded linseed diet reduced C12:0 (-30%), C14:0 (-15%) and C16:0 (-28%), thus significantly diminishing the atherogenicity index of milk. The response to linseed supplementation was persistently maintained during the entire study. Acceptability attributes of n-3-enriched versus control cheeses ripened for 3 mo were not affected. Therefore, extruded linseed supplementation seems a plausible strategy to improve animal performance and nutritional quality of dairy lipids in milk and cheese from ewes.
本研究的目的是评估补充挤压亚麻籽日粮对母羊生产性能以及羊奶脂肪酸（FA）组成的影响，以便生产富含n-3脂肪酸和共轭亚油酸的奶酪。将300只接受60:40粗饲料:精饲料日粮的曼彻格母羊群分为3组，分别为对照组、低挤压亚麻籽日粮组和高挤压亚麻籽日粮组，每100克干物质分别补充0、6和12克挤压亚麻籽。在补充后第7、14、28、45和60天，对每组5只泌乳母羊的混合奶样和个体奶样进行监测。用3个处理组的混合奶制作曼彻格奶酪。接受挤压亚麻籽的泌乳母羊产奶量增加。补充亚麻籽对牛奶蛋白质、脂肪和总固体含量没有影响。α-亚麻酸的牛奶含量从对照组日粮的0.36%增加到高挤压亚麻籽日粮的总脂肪酸的1.91%。同样，顺-9反-11 C18:2从0.73%上升到2.33%，其在乳腺中的前体反-11 C18:1从总脂肪酸的1.55%增加到5.76%。这种模式出现时，反-10 C18:1和反-10顺-12 C18:2脂肪酸的水平没有显著变化。此外，高挤压亚麻籽日粮降低了C12:0（-30%）、C14:0（-15%）和C16:0（-28%），从而显著降低了牛奶的致动脉粥样化指数。在整个研究过程中，对亚麻籽补充的反应持续保持。成熟3个月的富含n-3的奶酪与对照奶酪的可接受性特征没有受到影响。因此，补充挤压亚麻籽似乎是一种可行的策略，可以提高母羊牛奶和奶酪中动物的生产性能以及乳脂的营养质量。
