State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, P. R. China.
J Dairy Sci. 2012 Oct;95(10):5821-30. doi: 10.3168/jds.2011-4893. Epub 2012 Aug 23.
Increasing the concentration of α-linolenic acid (LNA; 18:3 cis-9,cis-12,cis-15) in blood might affect fatty acid (FA) metabolism in the mammary gland of dairy cows. The objective was to determine the effects of different arterial concentrations of 18:3 cis-9,cis-12,cis-15 (18:3n-3) achieved via duodenal infusions with LNA on mammary uptake [assessed via arterial-rectificative venous concentration (AC-RVC) differences], synthesis of FA, and mammary gland FA balance in lactating dairy cows. Four primiparous lactating Chinese Holstein cows fitted with duodenal cannulas were administered 2 treatments in a crossover design: LNA-rich FA infusion at varying concentrations (0, 100, 200, and 300 g/d) versus basal infusate control. Arterial concentration of 18:3n-3 increased quadratically (29.24, 134.1, 218.3, and 219.3mg/L of plasma) as LNA infusion levels increased from 0 to 300 g/d. The mammary extraction rate and uptake of 18:3n-3 increased linearly as LNA infusion increased. The AC-RVC difference of total FA and 18:3n-3 increased more rapidly than arterial concentrations with all treatments. Increasing LNA infusion increased linearly the balance of 10:0 and 12:0, whereas it decreased linearly the 14:1 and 15:0 balances. Increasing arterial concentration of 18:3n-3 affects uptake and synthesis of FA in the mammary gland of lactating dairy cows. It is also suggested that the use of AC-RVC difference maybe an acceptable way to investigate mammary gland uptake and synthesis of FA.
增加血液中α-亚麻酸（LNA；18:3 顺式-9、顺式-12、顺式-15）的浓度可能会影响奶牛乳腺中的脂肪酸（FA）代谢。本研究旨在确定通过十二指肠输注 LNA 以不同动脉浓度（18:3 顺式-9、顺式-12、顺式-15（18:3n-3））实现时对泌乳奶牛乳腺摄取[通过动脉-整流静脉浓度（AC-RVC）差异评估]、FA 合成和乳腺 FA 平衡的影响。采用十二指肠插管的 4 头初产泌乳中国荷斯坦奶牛以交叉设计进行了 2 种处理：富含 LNA 的 FA 输注，浓度不同（0、100、200 和 300g/d）与基础输注对照。随着 LNA 输注水平从 0 增加到 300g/d，18:3n-3 的动脉浓度呈二次曲线增加（29.24、134.1、218.3 和 219.3mg/L 血浆）。随着 LNA 输注增加，18:3n-3 的乳腺提取率和摄取量呈线性增加。所有处理中，AC-RVC 差异的总 FA 和 18:3n-3 的增加速度快于动脉浓度。增加 LNA 输注量会使 10:0 和 12:0 的平衡呈线性增加，而 14:1 和 15:0 的平衡呈线性减少。增加 18:3n-3 的动脉浓度会影响泌乳奶牛乳腺中 FA 的摄取和合成。还表明，使用 AC-RVC 差异可能是研究乳腺 FA 摄取和合成的一种可接受的方法。
