CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
J Dairy Sci. 2022 Jan;105(1):361-374. doi: 10.3168/jds.2021-20674. Epub 2021 Oct 9.
High-yielding dairy cows experience a negative energy balance and inflammatory status during the transition period. Fat supplementation increases diet energy density, and plasma n-3 polyunsaturated fatty acids (PUFA) have been proposed to improve immune function. This study tested the hypothesis that dietary supplementation with a rumen-protected and n-3 PUFA-enriched fat could ameliorate both the energetic deficit and immune status of postpartum high-yielding dairy cows, improving overall health and reproductive efficiency. At 11 d in milk (DIM), cows were randomly allocated to groups (1) n-3 PUFA (n = 29), supplemented with encapsulated linseed oil supplying additional up to 64 g/d (mean 25 ± 4 g/d) of α-linolenic acid (ALA), or (2) control (n = 31), supplemented with hydrogenated palm oil without ALA content. Fat supplements of the n-3 PUFA and control groups were available through an automated, off-parlor feeding system, and intake depended on the cow's feeding behavior. Plasma ALA concentrations were higher in n-3 PUFA than control cows, following a linear relation with supplement ingestion, resulting in a lower n-6/n-3 ratio in plasma. Metabolic parameters (body condition score and glucose and β-hydroxybutyric acid blood concentrations) were unaffected, but milk yield improved with increased intake of fat supplements. Plasma total adiponectin concentrations were negatively correlated with ingestion of n-3 PUFA-enriched fat supplement, following a linear relation with intake. Conception rate to first AI increased with higher intake of both fats, but a decrease of calving-to-conception interval occurred only in n-3 PUFA cows. Postpartum ovarian activity and endometrial inflammatory status at 45 DIM were unaffected. In conclusion, this study evinced a positive linear relation between rumen-protected linseed fat intake and plasma n-3 PUFA concentrations, which modulated adiponectin expression and improved reproductive parameters.
高产奶牛在过渡期会经历负能量平衡和炎症状态。脂肪补充剂增加了日粮的能量密度，而血浆中 n-3 多不饱和脂肪酸（PUFA）已被提议改善免疫功能。本研究检验了这样一个假设，即日粮中添加一种瘤胃保护且富含 n-3 PUFA 的脂肪可以改善产后高产奶牛的能量不足和免疫状态，从而提高整体健康和繁殖效率。在产后 11 天（DIM），奶牛被随机分配到两组：（1）n-3 PUFA（n=29）组，补充包被亚麻籽油，额外提供高达 64 克/天（平均 25±4 克/天）的α-亚麻酸（ALA）；或（2）对照组（n=31），补充氢化棕榈油，不含 ALA。n-3 PUFA 和对照组的脂肪补充剂可通过自动、场外喂养系统获得，摄入量取决于奶牛的喂养行为。血浆 ALA 浓度在 n-3 PUFA 组高于对照组，呈线性关系，与补充剂摄入有关，导致血浆中 n-6/n-3 比值降低。代谢参数（体况评分和血糖和β-羟丁酸血液浓度）不受影响，但随着脂肪补充剂摄入量的增加，产奶量有所提高。血浆总脂联素浓度与富含 n-3 PUFA 的脂肪补充剂的摄入量呈负相关，呈线性关系。首次人工授精的受孕率随着两种脂肪摄入量的增加而增加，但仅在 n-3 PUFA 组中，产犊至受孕间隔时间缩短。产后 45 天的卵巢活动和子宫内膜炎症状态不受影响。总之，本研究表明，瘤胃保护型亚麻籽油脂肪摄入量与血浆 n-3 PUFA 浓度之间存在正线性关系，这种关系调节脂联素的表达，改善繁殖参数。
