AbuGhazaleh A A, Schingoethe D J, Hippen A R, Kalscheur K F
Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.
J Dairy Sci. 2003 Nov;86(11):3648-60. doi: 10.3168/jds.S0022-0302(03)73970-8.
The objective of this study was to examine the effect of feeding fish oil (FO) along with fat sources that varied in saturation of 18 carbon fatty acids (high stearic, high oleic, high linoleic, or high linolenic acids) on rumen, plasma, and milk fatty acid profiles. Four primiparous Holstein cows at 85 d in milk (+/- 40) were assigned to 4 x 4 Latin squares with 4-wk periods. Treatment diets were 1) 1% FO plus 2% commercial fat high in stearic acid (HS); 2) 1% FO plus 2% fat from high oleic acid sunflower seeds (HO); 3) 1% FO plus 2% fat from high linoleic acid sunflower seeds (HLO); and 4) 1% FO plus 2% fat from flax seeds (high linolenic; HLN). Diets were formulated to contain 18% crude protein and were composed of 50% (dry basis) concentrate mix, 25% corn silage, 12.5% alfalfa silage, and 12.5% alfalfa hay. Milk production, milk protein percentages and yields, and dry matter intake were similar across diets. Milk fat concentrations and yields were least for HO and HLO diets. The proportion of milk cis-9, trans-11 conjugated linoleic acid (CLA; 0.71, 0.99, 1.71, and 1.12 g/100 g fatty acids, respectively), and vaccenic acid (TVA; 1.85, 2.60, 4.14, and 2.16 g/100 g fatty acids, respectively) were greatest with the HLO diet. The proportions of ruminal cis-9, trans-11 CLA (0.09, 0.16, 0.18, and 0.16 g/100 g fatty acids, respectively) were similar for the HO, HLO, and HLN diets and all were higher than for the HS diet. The proportions of TVA (2.85, 4.36, 8.69, and 4.64 g/100 g fatty acids, respectively) increased with the HO, HLO, and HLN diets compared with the HS diets, and the increase was greatest with the HLO diet. The effects of fat supplements on ruminal TVA concentrations were also reflected in plasma triglycerides, (2.75, 4.64, 8.77, and 5.42 g/100 g fatty acids, respectively); however, there were no differences in the proportion of cis-9, trans-11 CLA (0.06, 0.07, 0.06, and 0.07 g/100 g fatty acids, respectively). This study further supports the significant role for mammary delta-9 desaturase in milk cis-9, trans-11 CLA production.
本研究的目的是研究在日粮中添加鱼油（FO）并搭配18碳脂肪酸饱和度不同的脂肪源（高硬脂酸、高油酸、高亚油酸或高亚麻酸）对瘤胃、血浆和乳脂肪酸组成的影响。选取4头产奶85天（±40天）的初产荷斯坦奶牛，采用4×4拉丁方设计，每期4周。处理日粮分别为：1）1% FO + 2%高硬脂酸商业脂肪（HS）；2）1% FO + 2%高油酸向日葵籽脂肪（HO）；3）1% FO + 2%高亚油酸向日葵籽脂肪（HLO）；4）1% FO + 2%亚麻籽脂肪（高亚麻酸；HLN）。日粮配方中粗蛋白含量为18%，由50%（干基）精料混合料、25%玉米青贮、12.5%苜蓿青贮和12.5%苜蓿干草组成。各日粮组的产奶量、乳蛋白百分比和产量以及干物质采食量相似。HO和HLO日粮组的乳脂肪浓度和产量最低。HLO日粮组乳中顺-9，反-11共轭亚油酸（CLA；分别为0.71、0.99、1.71和1.12 g/100 g脂肪酸）和反式vaccenic酸（TVA；分别为1.85、2.60、4.14和2.16 g/100 g脂肪酸）的比例最高。HO、HLO和HLN日粮组瘤胃中顺-9，反-11 CLA的比例（分别为0.09、0.16、0.18和0.16 g/100 g脂肪酸）相似，且均高于HS日粮组。与HS日粮组相比，HO、HLO和HLN日粮组的TVA比例（分别为2.85、4.36、8.69和4.64 g/100 g脂肪酸）有所增加，其中HLO日粮组增加幅度最大。脂肪补充剂对瘤胃TVA浓度的影响也反映在血浆甘油三酯中（分别为2.75、4.64、8.77和5.42 g/100 g脂肪酸）；然而，顺-9，反-11 CLA的比例没有差异（分别为0.06、0.07、0.06和0.07 g/100 g脂肪酸）。本研究进一步支持了乳腺Δ-9去饱和酶在乳中顺-9，反-11 CLA生成中的重要作用。
