Watts Jason S, Rezamand Pedram, Sevier Dallace L, Price William, 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. 2013;96(11):6932-6943. doi: 10.3168/jds.2012-6430. Epub 2013 Sep 12.
Feeding rations supplemented with fats may provide an opportunity to manipulate the health and performance of dairy cows; however, the relative effects of specific fats, such as trans fatty acids (TFA), are poorly understood. The objective of this study was to investigate the effects of a ration supplemented with TFA on the fatty acid (FA) profile of peripheral blood mononuclear cells (PBMC), plasma lipids, and milk; the gene expression of inflammatory markers; production of acute phase proteins; and production performance in early lactating dairy cows. Trans fat was fed at 0, 1.5, and 3% of dry matter, replacing (1:1 wt:wt) saturated fatty acids (SFA). Multiparous lactating Holstein cows at 7 d in milk (n=12) were randomly assigned to a treatment sequence in a 3 × 3 balanced Latin square design; each period lasted 14 d. Milk and heparinized blood were collected on d 0 (pretreatment) and on d 10 and 14 of each period. Plasma was collected and solid-phase extraction was used to isolate plasma phospholipids and nonesterified fatty acids. Additionally, PBMC were isolated for FA analysis and gene expression analysis by reverse transcription-PCR using bovine RPS9 as the endogenous control. The FA composition of PBMC, plasma lipid fractions, and milk were analyzed by gas chromatography. Data were analyzed using the MIXED procedure (SAS Institute Inc., Cary, NC). As dietary TFA increased, the percentage of some 18:1 trans isomers increased in PBMC, plasma lipids, and milk. Dietary TFA had no detectable effect on mRNA expression of proinflammatory TNFα or IL6. Expression of IL1β and ICAM1 decreased with increasing TFA. In addition, supplementation of TFA did not affect percentages of milk fat, protein, lactose, or solids-not-fat, or somatic cell count. Overall, dietary TFA increased the trans FA present in PBMC, plasma lipids, and milk; however, dietary TFA decreased PBMC expression of some of the proinflammatory markers tested at the mRNA level compared with SFA in early lactating dairy cows. Together, these findings provide evidence that over short period of times, dietary TFA might be slightly less immune-stimulatory than dietary SFA.
补充脂肪的日粮可能为调控奶牛的健康和生产性能提供契机；然而，特定脂肪（如反式脂肪酸，TFA）的相对作用却鲜为人知。本研究的目的是调查补充TFA的日粮对初产泌乳奶牛外周血单核细胞（PBMC）的脂肪酸（FA）谱、血浆脂质和牛奶的影响；炎症标志物的基因表达；急性期蛋白的产生；以及生产性能。以0%、1.5%和3%的干物质饲喂反式脂肪，替代（1:1重量比）饱和脂肪酸（SFA）。产奶7天的经产泌乳荷斯坦奶牛（n = 12）按照3×3平衡拉丁方设计随机分配到一个处理序列中；每个周期持续14天。在每个周期的第0天（预处理）、第10天和第14天采集牛奶和肝素化血液。收集血浆并采用固相萃取法分离血浆磷脂和非酯化脂肪酸。此外，分离PBMC用于FA分析，并以牛RPS9作为内参通过逆转录PCR进行基因表达分析。采用气相色谱法分析PBMC、血浆脂质组分和牛奶的FA组成。使用MIXED程序（SAS Institute Inc.，北卡罗来纳州卡里）分析数据。随着日粮TFA增加，PBMC、血浆脂质和牛奶中一些18:1反式异构体的百分比增加。日粮TFA对促炎TNFα或IL6的mRNA表达没有可检测到的影响。IL1β和ICAM1的表达随TFA增加而降低。此外，补充TFA对乳脂肪、蛋白质、乳糖或非脂固形物的百分比或体细胞计数没有影响。总体而言，日粮TFA增加了PBMC、血浆脂质和牛奶中存在的反式FA；然而，与初产泌乳奶牛日粮中的SFA相比，日粮TFA在mRNA水平上降低了一些所检测促炎标志物的PBMC表达。总之，这些发现提供了证据，表明在短时间内，日粮TFA的免疫刺激作用可能略低于日粮SFA。
