Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover
Hyperglycaemia in transition dairy cows: Effects of lactational stage and conjugated linoleic acid supplementation on glucose metabolism and turnover
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DOI：
10.1111/jpn.12771
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发表时间：
2018-04-01
影响因子：
2.7
通讯作者：
Gross, J. J.
中科院分区：
文献类型：
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作者：
Grossen-Roesti, L.;Kessler, E. C.;Gross, J. J.
补充共轭亚油酸（CLA）应该是备用葡萄糖由于反式-10，顺式-12共轭亚油酸异构体的乳脂抑制作用，并允许重新分配营养物质，尽管在哺乳早期的能量缺乏。然而，仍然缺乏知识的动态模式的葡萄糖周转在过渡奶牛。我们假设，奶牛补充共轭亚油酸有改变的葡萄糖周转率和胰岛素敏感性在泌乳早期。我们在荷斯坦奶牛分娩后的第-2周、第+2周和第+4周进行了三次连续的高血压钳夹（HGC），每天补充70 g脂质包封的CLA（6.8 g反式-10，顺式-12和6.6 g顺式-9，反式-11 CLA异构体; CLA; n=11）或56 g对照脂肪（CON; n=11）。从第-3周至第+4周（相对于分娩），每天记录产奶量和干物质摄入量（BMD），同时每周一次获得体重（BW）和乳成分。在HGC期间每周和每30分钟采集一次血样。分析血浆中葡萄糖、脂肪酸（FFA）、β-羟基丁酸酯（BHB）、胰岛素、甘油三酯和胆固醇的浓度。CLA的补充并没有影响性能和代谢参数，除了BHB和胆固醇。此外，胰岛素浓度和胰岛素敏感性受治疗影响。在泌乳早期的HGC期间，与第-2周的HGC相比，胰岛素反应较低，FFA和BHB的下降幅度较大，尽管所有三种HGC在稳态期间达到的葡萄糖目标浓度相似。我们在胰岛素和胆固醇方面的研究结果表明，通过CLA喂养可以保留身体储备，而不会限制动物的性能。此外，CLA对胆固醇和甘油三酯浓度的影响表明对肝脏脂质输出的有益作用，有助于提高循环中主要代谢物的效率。
Supplementing conjugated linoleic acid (CLA) is supposed to spare glucose due to the milk fat-depressing effect of the trans-10, cis-12 CLA isomer, and allows repartitioning nutrients despite an energy deficiency in early lactation. However, there is still a lack of knowledge in terms of the dynamic pattern of the glucose turnover in transition dairy cows. We hypothesized that dairy cows supplemented with CLA have an altered rate of glucose turnover and insulin sensitivity during early lactation. We conducted three consecutive hyperglycaemic clamps (HGC) in weeks -2, +2 and +4 relative to parturition in Holstein cows supplemented daily either with 70g of lipid-encapsulated CLA (6.8g trans-10, cis-12 and 6.6g of the cis-9, trans-11 CLA isomer; CLA; n=11) or with 56g of control fat (CON; n=11). From week -3 up to week +4 relative to parturition, milk yield and dry matter intake (DMI) were recorded daily, while body weight (BW) and milk composition were obtained once weekly. Blood samples were taken once weekly and every 30min during the HGC. Plasma was analysed for concentrations of glucose, fatty acids (FFA), beta-hydroxybutyrate (BHB), insulin, triglycerides and cholesterol. The CLA supplementation did not affect performance and metabolic parameters except for BHB and cholesterol. Furthermore, insulin concentrations and insulin sensitivity were affected by treatment. During the HGC in early lactation, insulin response was lower and decrease in FFA and BHB greater compared with the HGC in week -2 although glucose target concentration achieved during the steady-state period was similar for all three HGC. Our findings in terms of insulin and cholesterol suggest that body reserves are preserved through CLA feeding without restraining animal's performance. Furthermore, CLA effects on cholesterol and triglyceride concentrations indicated beneficial effects on hepatic lipid export contributing to an improved efficiency of prevailing metabolites in circulation.