Scholte Cynthia M, Rezamand Pedram, Tsai Chia-Yu, Amiri Zahra M, Ramsey Kirk C, McGuire Mark A
Department of Animal and Veterinary Science, University of Idaho, Moscow 83844.
Department of Animal and Veterinary Science, University of Idaho, Moscow 83844.
J Dairy Sci. 2017 Mar;100(3):2104-2118. doi: 10.3168/jds.2016-11605. Epub 2016 Dec 29.
During the periparturient period, elevated circulating nonesterified fatty acids (NEFA) from excessive lipid mobilization affect not only the circulating fatty acid (FA) composition, but also that of the peripheral blood mononuclear cells (PBMC) and polymorphonuclear leukocytes (PMNL). However, the changes to specific lipid fractions remain unknown. We hypothesized that elevated lipid mobilization will alter FA profiles and gene expression of selected proinflammatory mediators in PBMC and PMNL. Starting -28 d relative to expected calving (d 0), treatment cows (n = 18) received a dry cow ration plus an additional 10 kg of corn/head per day, while the control cows (n = 16) received the dry cow ration (no additional corn) supplemented with 400 mg of monensin/head per day to minimize lipid mobilization. Postpartum, treatment cows were feed deprived for 8 h on d +3. For FA analysis, serum was collected on d -28 and -7 relative to expected parturition and d +1, +3, +6, +15, and +21 postpartum, in addition to milk samples. Immune cells, PBMC and PMNL, were isolated on d -28, +3, +12, and +21 for FA analysis and gene expression analysis by reverse-transcription PCR. Serum, PBMC, and PMNL lipids were fractionated into NEFA and phospholipids (PL). The FA composition of milk, serum, PBMC, and PMNL was analyzed by gas chromatography. Data were analyzed as repeated measures ANOVA using mixed model procedures in SAS (9.3) with significance declared at P ≤ 0.05. Several FA varied by treatment and across time and parity. Within the serum PL fraction, FA associated with altered immune function, C18:3n-6, C20:4, C20:5, total n-3, and the ratio of n-6 to n-3 varied significantly by a treatment × parity × time interaction. Overall, FA composition of NEFA and PL fractions from PBMC and PMNL did not significantly reflect FA of serum. Gene expression for IL-1β in PBMC was greater for control, whereas ICAM, IL-1β, IL-6, and TNF-α were greater in primiparous than multiparous cows, without a detectable treatment effect. Whereas gene expression of CASP, IL-8R, and SELL in PMNL changed over time, no treatment effect was detected. In summary, high-energy prepartal diets altered FA profile in serum, milk, PBMC, and PMNL lipids; however, gene expression of selected proinflammatory mediators was not significantly affected.
在围产期，因过度脂肪动员导致循环中非酯化脂肪酸（NEFA）升高，这不仅会影响循环脂肪酸（FA）的组成，还会影响外周血单核细胞（PBMC）和多形核白细胞（PMNL）的脂肪酸组成。然而，特定脂质组分的变化仍不清楚。我们假设脂肪动员增加会改变PBMC和PMNL中选定促炎介质的FA谱和基因表达。从预计产犊日（第0天）前28天开始，处理组奶牛（n = 18）每天在干奶牛日粮基础上额外添加10千克玉米/头，而对照组奶牛（n = 16）接受干奶牛日粮（不额外添加玉米），并每天每头补充400毫克莫能菌素以尽量减少脂肪动员。产后，处理组奶牛在第3天禁食8小时。为进行FA分析，除了采集牛奶样本外，还在预计分娩前第28天和第7天以及产后第1天、第3天、第6天、第15天和第21天采集血清。在第28天、第3天、第12天和第21天分离免疫细胞PBMC和PMNL，用于FA分析和通过逆转录PCR进行基因表达分析。血清、PBMC和PMNL脂质被分离为NEFA和磷脂（PL）。通过气相色谱分析牛奶、血清、PBMC和PMNL的FA组成。数据使用SAS（9.3）中的混合模型程序进行重复测量方差分析，显著性水平设定为P≤0.05。几种FA因处理方式以及时间和胎次而异。在血清PL组分中，与免疫功能改变相关的FA，即C18:3n - 6、C20:4、C20:5、总n - 3以及n - 6与n - 3的比值，因处理×胎次×时间的相互作用而有显著差异。总体而言，PBMC和PMNL中NEFA和PL组分的FA组成并未显著反映血清中的FA。PBMC中IL - 1β的基因表达在对照组中更高，而ICAM、IL - 1β、IL - 6和TNF - α在初产奶牛中比经产奶牛更高，未检测到处理效应。而PMNL中CASP、IL - 8R和SELL的基因表达随时间变化，但未检测到处理效应。总之，产前高能日粮改变了血清、牛奶、PBMC和PMNL脂质中的FA谱；然而，选定促炎介质的基因表达未受到显著影响。
