Capper J L, Wilkinson R G, Mackenzie A M, Sinclair L A
Animal Science Research Centre, Harper Adams University College, Edgmond, Newport, Shropshire TF10 8NB, UK.
Animal. 2007 Jul;1(6):889-98. doi: 10.1017/S1751731107000067.
Supplementation of pregnant ewes with long-chain n-3 polyunsaturated fatty acids (PUFA) demonstrably improves indicators of neonatal lamb vigour, potentially improving the number of lambs reared per ewe. The present study investigated the effect of supplementing ewes with fish oil and vitamin E (α-tocopherol acetate) throughout both pregnancy and lactation on the performance of lactating ewes and sucking lambs. Forty-eight ewes were supplemented with one of four concentrates containing either Megalac or fish oil plus a basal (50 mg/kg) or supranutritional (500 mg/kg) concentration of vitamin E from 6 weeks pre-partum until 4 weeks post partum in a two-by-two factorial randomised-block design. All concentrates were formulated to contain approximately 60 g/kg supplemental fatty acids. Ewes were housed, penned on sawdust and offered straw ad libitum. Blood samples were taken from ewes and lambs at intervals throughout the experiment and milk samples were obtained at 21 days into lactation. There was no notable effect of dietary vitamin E concentration upon ewe or lamb performance. Ewe dry-matter (DM) intake and yield were unaffected by dietary treatment, although ewes fed fish oil lost less weight during lactation (-1.88 kg compared with -3.97 kg for Megalac-supplemented ewes; P < 0.01). Milk fat concentrations (67.3 g/kg compared with 91.8 g/kg; P < 0.01) and yields (6.65 g/h v. 9.26 g/h; P < 0.01) were reduced in ewes fed fish oil and these decreases were associated with lower litter-growth rates (0.49 g/day compared with 0.54 g/day; P < 0.05). Milk protein yield was increased by fish oil supplementation (3.82 g/h) compared with Megalac supplementation (3.28 g/h; P < 0.05); moreover, there was an interaction between fat source and vitamin E concentration in that both protein concentration and yield were significantly lower in milk from ewes fed treatment with Megalac + basal vitamin E (MB) compared with the other three treatments. Fish oil supplementation increased the concentrations of C18:1 trans-, cis-9, trans-11 conjugated linoleic acid (CLA), C20:5 (n-3) and C22:6 (n-3) within ewe plasma, milk and lamb plasma. The mechanisms by which fish oil supplementation affects milk composition warrants further investigation.
给怀孕母羊补充长链n-3多不饱和脂肪酸（PUFA）可显著改善新生羔羊活力指标，有可能提高每只母羊饲养的羔羊数量。本研究调查了在整个怀孕期和哺乳期给母羊补充鱼油和维生素E（α-生育酚醋酸酯）对泌乳母羊和吮乳羔羊性能的影响。采用二乘二析因随机区组设计，从产前6周直到产后4周，给48只母羊补充四种浓缩料中的一种，其中包含麦麸或鱼油以及基础浓度（50毫克/千克）或超营养浓度（500毫克/千克）的维生素E。所有浓缩料的配方均使其含有约60克/千克的补充脂肪酸。母羊被圈养在铺有锯末的围栏中，并随意提供稻草。在整个实验过程中定期采集母羊和羔羊的血样，并在泌乳21天时采集乳样。日粮维生素E浓度对母羊或羔羊的性能没有显著影响。母羊的干物质（DM）摄入量和产量不受日粮处理的影响，不过，饲喂鱼油的母羊在泌乳期间体重减轻较少（-1.88千克，而饲喂麦麸的母羊为-3.97千克；P<0.01）。饲喂鱼油的母羊的乳脂肪浓度（67.3克/千克，而另一组为91.8克/千克；P<0.01）和产量（6.65克/小时对9.26克/小时；P<0.01）降低，这些降低与较低的窝仔生长率相关（0.49克/天对0.54克/天；P<0.05）。与补充麦麸相比，补充鱼油可提高乳蛋白产量（3.82克/小时）（补充麦麸为3.28克/小时；P<0.05）；此外，脂肪来源和维生素E浓度之间存在相互作用，即与其他三种处理相比，饲喂麦麸+基础维生素E（MB）处理的母羊所产牛奶中的蛋白质浓度和产量均显著较低。补充鱼油可提高母羊血浆、乳汁和羔羊血浆中C18:1反式、顺式-9、反式-11共轭亚油酸（CLA）、C20:5（n-3）和C22:6（n-3）的浓度。补充鱼油影响乳汁成分的机制值得进一步研究。
