Department of Animal and Food Sciences, Oklahoma State University, Stillwater, OK 74078, USA.
USDA, ARS, U. S. Meat Animal Research Center, Clay Center, NE 689333, USA.
J Anim Sci. 2021 Dec 1;99(12). doi: 10.1093/jas/skab314.
The objective of this study was to determine whether increasing propionate alters dry matter intake (DMI), glucose clearance rate, blood metabolites, insulin concentrations, and hepatic gene expression in steers fed a finishing diet. Holstein steers (n = 15; BW = 243 ± 3.6 kg) were individually fed a finishing diet ad libitum. Steers were allocated by body weight (BW) to receive: no Ca propionate (Control), 100 g/d Ca propionate (Low), or 300 g/d Ca propionate (High) in the diet. Orts were collected and weighed daily to determine DMI. Blood samples were collected on days 0, 7, and 21, and BW recorded on days 0, 14, and 28. An intravenous glucose tolerance test (IVGTT) was conducted on days 14 and 28 of the trial. Liver biopsies were collected on day 33 for gene expression analysis. Blood samples were analyzed for whole blood glucose and lactate, plasma non-esterified fatty acids (NEFAs), and insulin concentrations. Data were analyzed using a mixed model with treatment, day and their interaction included, with day and minute as a repeated measure. The control treatment had greater (P < 0.01) DMI than low and high steers. Body weight was increased in control steers on days 14 and 28 compared with the steers receiving the High treatment (P = 0.03 for the interaction). Blood glucose concentrations tended (P = 0.09) to be higher on day 21 than days 0 and 7 but was not affected by treatment (P = 0.58). Plasma NEFA concentrations were lower (P = 0.05) for control steers than other treatments, and greater (P = 0.002) on day 0 than days 7 and 21. Blood lactate concentrations were greater (P = 0.05) on day 7, than days 0 and 21, but not affected by treatment (P = 0.13). High steers had greater plasma insulin concentrations in response to the IVGTT than steers on the other treatments (P = 0.001). There was no treatment (P ≥ 0.16) or day effect (P ≥ 0.36) on glucose peak, plateau, or clearance rate. High steers had greater expression of solute carrier family 16 member 1 (SLC16A1; P = 0.05) and tended to have greater hepatic expression of solute carrier family 2 member 2 (SLC2A2; P = 0.07). These data indicate that increased propionate may decrease DMI and insulin sensitivity.
本研究旨在确定丙酸根的添加是否会改变育肥日粮中干物质采食量（DMI）、葡萄糖清除率、血液代谢物、胰岛素浓度和肝脏基因表达。选择荷斯坦公牛（n=15；BW=243±3.6kg），单独进行自由采食育肥日粮。根据体重（BW）将牛群分为：对照组（Control）不添加丙酸钙，低剂量组（Low）每天添加 100g 丙酸钙，高剂量组（High）每天添加 300g 丙酸钙。每天收集粪样并称重以确定 DMI。分别在试验的第 0、7 和 21 天采集血样，并在第 0、14 和 28 天记录 BW。在试验的第 14 和 28 天进行静脉葡萄糖耐量试验（IVGTT）。在第 33 天收集肝脏活检样本进行基因表达分析。血液样本用于检测全血葡萄糖和乳酸、血浆非酯化脂肪酸（NEFAs）和胰岛素浓度。采用处理、天和它们的交互作用包含在内的混合模型进行数据分析，天和分钟作为重复测量。与低剂量和高剂量组相比，对照组的 DMI 更高（P<0.01）。与接受高剂量处理的牛相比，对照组的牛在第 14 和 28 天 BW 增加（处理间的交互作用 P=0.03）。与第 0 天和第 7 天相比，第 21 天的血糖浓度趋于（P=0.09）更高，但不受处理的影响（P=0.58）。对照组的血浆 NEFA 浓度低于其他处理组（P=0.05），且第 0 天高于第 7 天和第 21 天（P=0.002）。第 7 天的血乳酸浓度高于第 0 天和第 21 天（P=0.05），但不受处理的影响（P=0.13）。与其他处理组相比，高剂量组对 IVGTT 的胰岛素反应更高（P=0.001）。葡萄糖峰值、平台期或清除率不受处理（P≥0.16）或天（P≥0.36）的影响。高剂量组溶质载体家族 16 成员 1（SLC16A1；P=0.05）的表达增加，且溶质载体家族 2 成员 2（SLC2A2；P=0.07）的肝脏表达倾向于增加。这些数据表明，增加丙酸根可能会降低 DMI 和胰岛素敏感性。
