In this study, we investigated the effects of feeding a moderate- or high-energy close-up diet to close-up cows on response of newborn calves to intravenously (i.v.) injected glucagon-like peptide 1 (GLP-1). Newborn Holstein heifer calves (n = 37) from cows fed with a moderate-energy [M, 1.54 Mcal/kg of dry matter (DM) NEl; 14% starch; n = 17] or high-energy (H, 1.63 Mcal/kg of DM NEl; 26% starch; n = 20) diet in the last 28 d prepartum were assigned to one of two treatment groups, which were i.v. injected with saline (MC and HC, n = 9 and 10, respectively) or GLP-1 solution at 1.0 μg/kg BW (MG and HG, n = 8 and 10, respectively) immediately after milk replacer (MR; 26% CP, 16% fat) feeding. Blood samples were obtained through a jugular vein catheter at −10, 0, 10, 20, 30, 40, 50, 60, 90, and 120 min relative to MR feeding at 2, 10, and 20 d after birth, and plasma glucose, insulin, and GLP-1 concentrations were measured. Plasma GLP-1 concentration tended to increase starting from 30 min after MR feeding in the MC relative to the HC group at 10 (0.77 ng/mL vs 0.69 ng/mL for MC and HC, respectively; P = 0.10) and 20 d after birth (0.47 ng/mL vs 0.35 ng/mL for MC and HC, respectively; P = 0.07). Plasma glucose and insulin concentrations after MR feeding did not differ between MC and HC groups at 2 and 20 d after birth but were higher (P < 0.05) in MC (158 mg/dL and 3.64 ng/mL for glucose and insulin, respectively) than in HC (143 mg/dL and 2.46 ng/mL for glucose and insulin, respectively) calves at 10 d after birth. The elevation in plasma glucose concentration after MR feeding was suppressed by direct glucose-lowering action of i.v. injected GLP-1 at 2, 10, and 20 d after birth in M and H calves; this direct glucose-lowering action by GLP-1 was greater (P < 0.05) for H than for M calves at 20 d after birth. These results indicate that feeding a high-energy close-up diet to cows affects glucose status in their female offspring via suppression of postprandial plasma concentrations of GLP-1 and insulin as well as the alteration in the glucose-lowering action of GLP-1 after feeding depending on the day after birth.

在这项研究中，我们研究了给近身奶牛喂食中等或高能量的近身日粮对新生小牛对静脉注射 (iv) 注射胰高血糖素样肽 1 (GLP-1) 的反应的影响。来自用中等能量喂养的奶牛的新生荷斯坦小母牛犊 (n = 37) [M, 1.54 Mcal/kg 干物质 (DM) NEl; 14% 淀粉；n = 17] 或高能量（H，1.63 Mcal/kg DM NEI；26% 淀粉；n = 20）饮食在产前最后 28 天被分配到两个治疗组之一，静脉注射生理盐水（ MC 和 HC，分别 n = 9 和 10）或 GLP-1 溶液 1.0 μg/kg BW（MG 和 HG，分别 n = 8 和 10）在代乳品后立即服用（MR；26% CP，16% 脂肪） ) 喂养。相对于 2、10、10 和 10 分钟的 MR 喂养，在 -10、0、10、20、30、40、50、60、90 和 120 分钟时通过颈静脉导管获得血样。和出生后20 d，测量血浆葡萄糖、胰岛素和GLP-1浓度。相对于 10 时的 HC 组（MC 和 HC 分别为 0.77 ng/mL 和 0.69 ng/mL；P = 0.10) 和出生后 20 天（MC 和 HC 分别为 0.47 ng/mL 与 0.35 ng/mL；P = 0.07）。出生后 2 天和 20 天，MC 组和 HC 组之间在 MR 喂养后的血浆葡萄糖和胰岛素浓度没有差异，但 MC 组更高（P < 0.05）（葡萄糖和胰岛素分别为 158 mg/dL 和 3.64 ng/mL）与出生后 10 天的 HC（葡萄糖和胰岛素分别为 143 mg/dL 和 2.46 ng/mL）相比。M 和 H 犊牛出生后第 2、10 和 20 天静脉注射 GLP-1 的直接降糖作用抑制了 MR 喂养后血浆葡萄糖浓度的升高；GLP-1 的这种直接降糖作用更大（P< 0.05) 对于 H 比 M 小牛在出生后 20 天。这些结果表明，通过抑制餐后 GLP-1 和胰岛素的血浆浓度以及餐后 GLP-1 的降糖作用的改变，给奶牛喂食高能量近距离饮食会影响其雌性后代的葡萄糖状态。喂养取决于出生后的第二天。