Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
J Dairy Sci. 2010 Nov;93(11):5147-56. doi: 10.3168/jds.2010-3118.
Feeding dairy cows large proportions of cereal grain is commonly associated with rumen acidosis, activation of innate immunity, and perturbation of intermediary metabolism. We previously showed that steeping barley grain in 0.5% lactic acid (LA) decreased the rate of starch degradation, lowered the risk of subacute rumen acidosis, modulated rumen fermentation profile, and increased milk fat content in dairy cows. This study sought to investigate whether feeding of LA-treated barley grain would affect carbohydrate and lipid metabolism as well as innate immunity. Eight rumen-fistulated late-lactation (approximately 217 d in milk, DIM) Holstein cows were randomly assigned, in a 2 × 2 crossover design, to 1 of the 2 dietary treatments consisting of 27% (dry matter basis) rolled barley grain steeped for 48 h in an equal volume (wt/vol) of tap water (CTR) or 0.5% LA (TRT). Each experimental period lasted 21 d, with the first 11 d for diet adaptation. Blood and rumen samples were collected on d 12, 15, 17, and 21 of the experimental period before the morning feeding to evaluate the effects of dietary treatment on preprandial day-to-day variation of plasma and rumen variables. To establish the effect of treatment on diurnal variation of plasma variables, blood samples were collected on the last day of each period at 0, 2, 4, 6, 8, 10, and 12h after the morning feeding (i.e., 0800 h). Results of the day-to-day study showed that cows fed the TRT diet had greater overall preprandial concentrations of glucose, cholesterol, and insulin, and a lower concentration of haptoglobin in plasma. Diurnal data indicated lower concentrations of haptoglobin and serum amyloid A and a tendency for greater plasma lactate in cows fed the TRT diet. A treatment by time interaction was observed for glucose, lactate, insulin, haptoglobin, and lipopolysaccharide-binding protein, suggesting a role for both the processing of grain and the time of sampling on those variables. No effect of diet on plasma concentrations of cortisol, β-hydroxybutyrate, and nonesterified fatty acids or rumen endotoxin was evidenced. Taken together, our results demonstrated that feeding barley grain steeped in 0.5% LA modulated both energy status and innate immunity of dairy cows fed relatively high levels (45% of dry matter) of dietary concentrate.
给奶牛饲喂大量谷物通常与瘤胃酸中毒、天然免疫激活和中间代谢紊乱有关。我们之前的研究表明，将大麦浸泡在 0.5%的乳酸（LA）中可以降低淀粉的降解速度，降低亚急性瘤胃酸中毒的风险，改变瘤胃发酵模式，并增加奶牛的乳脂含量。本研究旨在探讨饲喂 LA 处理过的大麦是否会影响碳水化合物和脂质代谢以及天然免疫。我们将 8 头泌乳后期（产奶约 217 天，DIM）荷斯坦奶牛随机分为 2 种处理组，每组 4 个重复，每个重复 2 头奶牛，采用 2×2 交叉试验设计，2 种处理组日粮分别为 27%（干物质基础）膨化大麦（CTR）或 0.5%LA 处理大麦（TRT）。每个试验期持续 21 天，前 11 天为适应期。在试验期第 12、15、17 和 21 天的早上饲喂前采集血样和瘤胃液样，以评估日粮处理对采食前奶牛血浆和瘤胃变量日变化的影响。为了确定处理对血浆变量日变化的影响，在每个试验期的最后一天，于早上饲喂后 0、2、4、6、8、10 和 12h 采血，建立处理对血浆变量的日变化的影响。结果表明，饲喂 TRT 日粮的奶牛，其血浆中葡萄糖、胆固醇和胰岛素的总浓度在采食前较高，而血红蛋白的浓度较低。昼夜数据表明，饲喂 TRT 日粮的奶牛血液中的血红蛋白和血清淀粉样 A 浓度较低，而乳酸浓度有升高的趋势。处理与时间的交互作用观察到葡萄糖、乳酸、胰岛素、血红蛋白和脂多糖结合蛋白，这表明谷物处理和采样时间都对这些变量有影响。日粮对血浆中皮质醇、β-羟丁酸和非酯化脂肪酸或瘤胃内毒素浓度没有影响。总之，我们的研究结果表明，饲喂经过 0.5%LA 浸泡的大麦，可调节高浓度（45%干物质）日粮精料中奶牛的能量状态和天然免疫。
