Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506, USA.
J Dairy Sci. 2013 Jun;96(6):3907-15. doi: 10.3168/jds.2012-6207. Epub 2013 Mar 30.
Flaxseed is a potent source of the n-3 fatty acid α-linolenic acid (ALA), yet most ALA is lost during ruminal biohydrogenation when ground flaxseed is fed to ruminants. Heat processing and urea formaldehyde condensation polymer (UFCP) treatment of flaxseed were investigated as possible means of protecting ALA from ruminal degradation. Ground flaxseed (GF), heated ground flaxseed (HGF), or UFCP-treated ground flaxseed (UFCPGF) were incubated for 0, 4, 8, and 12h in 4 ruminally cannulated multiparous lactating Holstein cows. Compared with GF, HGF and UFCPGF decreased ruminal disappearance of dry matter, crude protein, and ALA. Pepsin-digestible protein remaining after 12h of ruminal incubation was greater for UFCPGF and HGF than for GF. Twenty-four lactating Holstein cows (207 ± 37 d in milk, 668 ± 66 kg of body weight, and 1.33 ± 0.56 lactations) were then used in a randomized complete block design experiment with a basal feeding period to assess effects of flaxseed treatment on ALA enrichment of plasma and milk as well as lactational performance. No evidence existed that supplementation of HGF and UFCPGF affected dry matter intake, milk fat content, milk protein content, or energy-corrected milk yield, but UFCPGF marginally decreased milk yield compared with HGF. Plasma concentration of ALA was not affected by treatment. Concentrations of n-3 fatty acids and conjugated linoleic acids in milk fat were increased by UFCPGF relative to HGF, but ALA yield was not affected. Taken together, in situ results suggest that heat-treated flaxseed, with or without UFCP treatment, slowed ruminal disappearance of ALA. Feeding UFCP-treated flaxseed failed to alter ALA content of plasma or milk ALA yield relative to heating alone.
亚麻籽是 n-3 脂肪酸 α-亚麻酸（ALA）的重要来源，但当将粉碎的亚麻籽喂给反刍动物时，大部分 ALA 在瘤胃生物氢化过程中损失。本研究探讨了热处理和脲醛缩合聚合物（UFCP）处理作为保护 ALA 免受瘤胃降解的可能方法。将粉碎的亚麻籽（GF）、热处理粉碎的亚麻籽（HGF）或 UFCP 处理粉碎的亚麻籽（UFCPGF）在 4 头瘤胃有瘘管的泌乳荷斯坦奶牛中分别进行 0、4、8 和 12h 体外孵育。与 GF 相比，HGF 和 UFCPGF 降低了干物质、粗蛋白和 ALA 的瘤胃消失率。经过 12h 瘤胃孵育后，UFCPGF 和 HGF 的胃蛋白酶可消化蛋白残留量大于 GF。然后，将 24 头泌乳荷斯坦奶牛（泌乳期 207±37d，体重 668±66kg，产奶次数 1.33±0.56 次）随机分为完全区组设计试验，采用基础饲养期评估亚麻籽处理对血浆和牛奶中 ALA 富集以及泌乳性能的影响。HGF 和 UFCPGF 的添加并未影响干物质采食量、乳脂含量、乳蛋白含量或校正能量奶产量，但 UFCPGF 对产奶量的影响略低于 HGF。处理对血浆 ALA 浓度没有影响。与 HGF 相比，UFCPGF 增加了乳脂中 n-3 脂肪酸和共轭亚油酸的浓度，但 ALA 产量没有变化。总之，体内结果表明，热处理亚麻籽，无论是否经过 UFCP 处理，均能减缓 ALA 在瘤胃中的消失速度。与单独加热相比，添加 UFCP 处理的亚麻籽并未改变血浆或牛奶 ALA 含量或 ALA 产量。
