Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada; Graduate School of Biosphere Science, The Research Center for Animal Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8528, Japan.
J Dairy Sci. 2019 Mar;102(3):2254-2265. doi: 10.3168/jds.2018-15578. Epub 2019 Jan 17.
Feeding of butyrate was found to have a positive effects in enhancing gut development and improving growth performance of calves. Equally, glucagon-like peptide 1 and 2 (GLP-1 and GLP-2), secreted from gastrointestinal L-cells in response to nutrient intake, were found to play a significant role in regulating blood glucose homeostasis and improving gut health. However, limited information is available about the relationship between butyrate and release of GLP-1 and GLP-2 in dairy calves. The objective of this study was to evaluate the effects of a pulse-dose ruminal infusion of butyrate on plasma GLP-1 and GLP-2 concentrations in dairy calves. Five ruminally cannulated mature Holstein bull calves (7.2 ± 0.10 mo, and 330 ± 16.0 kg of body weight; mean ± standard deviation) were used in a 5 × 5 Latin square with 4-d periods. On d 1 of each period at 0800 h, calves were ruminally infused with 1 of 5 treatments: 0 (saline), 0.3, 0.6, 0.9, and 1.2 g of butyrate per kg of body weight. Before butyrate infusion, calves were not offered feed overnight, and sequential blood and rumen fluid samples were taken before and after infusion on d 1 of each period. Ruminal butyrate and total volatile fatty acid concentrations increased linearly (2.65, 12.19, 20.99, 30.19, and 36.30; 23.68, 33.07, 40.94, 51.13, and 56.31 µmol/mL, for butyrate and total volatile fatty acids, respectively) in a dose-dependent manner, whereas propionate and isobutyrate increased quadratically. Ruminal and plasma butyrate, β-hydroxybutyrate, GLP-1, GLP-2, insulin, and glucose concentrations were all affected by treatment, time (except GLP-2), and interaction of treatment with time (except GLP-1). The area under the curve (AUC) summarized at different time points relative to the baseline (AUC30, AUC60, AUC120, and AUC240) for ruminal and plasma butyrate, and BHB, increased linearly with the dose of butyrate infused. However, AUC30, AUC60, AUC120, and AUC240 for plasma GLP-2 concentration were affected in a cubic manner unlike the linear effect on AUC30 and AUC60 for GLP-1. Plasma GLP-2 was not correlated with plasma butyrate (r = 0.16), GLP-1 (r = 0.03), or BHB (r = -0.05). This findings suggest that pulse-dosing of butyrate slightly increased both GLP-1 and GLP-2 concentrations at specific time points and this might be promoted by direct or indirect effect of butyrate on the intestinal L-cells.
丁酸盐的喂养被发现对增强肠道发育和提高小牛的生长性能有积极影响。同样，胃肠道 L 细胞响应营养摄入而分泌的胰高血糖素样肽 1 和 2（GLP-1 和 GLP-2）也被发现在调节血糖稳态和改善肠道健康方面发挥重要作用。然而，关于丁酸盐与奶牛犊牛 GLP-1 和 GLP-2 释放之间的关系，信息有限。本研究旨在评估脉冲式瘤胃输注丁酸盐对奶牛犊牛血浆 GLP-1 和 GLP-2 浓度的影响。使用 5 头瘤胃插管成熟荷斯坦公牛犊（7.2±0.10 个月，体重 330±16.0 公斤；平均值±标准偏差）进行了 5×5 拉丁方试验，每个试验期为 4 天。在每个试验期的第 1 天 0800 h，犊牛接受了 5 种处理之一的瘤胃输注：0（盐水）、0.3、0.6、0.9 和 1.2 g 丁酸盐/公斤体重。在丁酸盐输注之前，犊牛整晚不喂食，在每个试验期的第 1 天输注前后连续采集血液和瘤胃液样本。瘤胃丁酸盐和总挥发性脂肪酸浓度呈剂量依赖性线性增加（2.65、12.19、20.99、30.19 和 36.30；23.68、33.07、40.94、51.13 和 56.31 μmol/mL，分别为丁酸盐和总挥发性脂肪酸），而丙酸和异丁酸则呈二次增加。瘤胃和血浆丁酸盐、β-羟丁酸、GLP-1、GLP-2、胰岛素和葡萄糖浓度均受处理、时间（GLP-2 除外）和处理与时间的相互作用影响。相对于基线（AUC30、AUC60、AUC120 和 AUC240）的不同时间点的曲线下面积（AUC）总结，瘤胃和血浆丁酸盐和 BHB 的 AUC 均呈线性增加，与输注的丁酸盐剂量呈正相关。然而，不同于 GLP-1 的 AUC30 和 AUC60 的线性影响，血浆 GLP-2 浓度的 AUC30、AUC60、AUC120 和 AUC240 呈立方方式受影响。血浆 GLP-2 与血浆丁酸盐（r=0.16）、GLP-1（r=0.03）或 BHB（r=-0.05）均不相关。这些发现表明，丁酸盐的脉冲给药略微增加了特定时间点的 GLP-1 和 GLP-2 浓度，这可能是丁酸盐对肠道 L 细胞的直接或间接作用促进的。
