Pantophlet A J, Gilbert M S, van den Borne J J G C, Gerrits W J J, Roelofsen H, Priebe M G, Vonk R J
Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University Medical Centre Groningen, PO Box 30001, 9700 RB Groningen, the Netherlands.
Animal Nutrition Group, Wageningen University, PO Box 338, 6700 AH Wageningen, the Netherlands.
J Dairy Sci. 2016 Apr;99(4):3072-3080. doi: 10.3168/jds.2015-10277. Epub 2016 Jan 21.
Calf milk replacer (MR) contains 40 to 50% lactose. Lactose strongly fluctuates in price and alternatives are desired. Also, problems with glucose homeostasis and insulin sensitivity (i.e., high incidence of hyperglycemia and hyperinsulinemia) have been described for heavy veal calves (body weight >100 kg). Replacement of lactose by other dietary substrates can be economically attractive, and may also positively (or negatively) affect the risk of developing problems with glucose metabolism. An experiment was designed to study the effects of replacing one third of the dietary lactose by glucose, fructose, or glycerol on glucose homeostasis and insulin sensitivity in veal calves. Forty male Holstein-Friesian (body weight=114 ± 2.4 kg; age=97 ± 1.4 d) calves were fed an MR containing 462 g of lactose/kg (CON), or an MR in which 150 g of lactose/kg of MR was replaced by glucose (GLU), fructose (FRU), or glycerol (GLY). During the first 10d of the trial, all calves received CON. The CON group remained on this diet and the other groups received their experimental diets for a period of 8 wk. Measurements were conducted during the first (baseline) and last week of the trial. A frequently sampled intravenous glucose tolerance test was performed to assess insulin sensitivity and 24 h of urine was collected to measure glucose excretion. During the last week of the trial, a bolus of 1.5 g of [U-(13)C] substrates was added to their respective meals and plasma glucose, insulin, and (13)C-glucose responses were measured. Insulin sensitivity was low at the start of the trial and remained low [1.2 ± 0.1 and 1.0 ± 0.1 (mU/L)(-1) × min(-1)], and no treatment effect was noted. Glucose excretion was low at the start of the trial (3.4 ± 1.0 g/d), but increased in CON and GLU calves (26.9 ± 3.9 and 43.0 ± 10.6g/d) but not in FRU and GLY calves. Postprandial glucose was higher in GLU, lower in FRU, and similar in GLY compared with CON calves. Postprandial insulin was lower in FRU and GLY and similar in GLU compared with CON calves. Postprandial (13)C-glucose increased substantially in FRU and GLY calves, indicating that calves are able to partially convert these substrates to glucose. We concluded that replacing one third of lactose in MR by glucose, fructose, or glycerol in MR differentially influences postprandial glucose homeostasis but does not affect insulin sensitivity in veal calves.
犊牛代乳粉（MR）含有40%至50%的乳糖。乳糖价格波动剧烈，因此需要替代品。此外，对于体重较重的犊牛（体重>100千克），已发现存在葡萄糖稳态和胰岛素敏感性问题（即高血糖症和高胰岛素血症的发生率较高）。用其他膳食底物替代乳糖在经济上可能具有吸引力，并且可能对葡萄糖代谢问题的发生风险产生积极（或消极）影响。设计了一项实验，研究用葡萄糖、果糖或甘油替代三分之一膳食乳糖对犊牛葡萄糖稳态和胰岛素敏感性的影响。40头雄性荷斯坦-弗里生犊牛（体重=114±2.4千克；年龄=97±1.4天）被饲喂每千克含462克乳糖的代乳粉（CON组），或每千克代乳粉中150克乳糖被葡萄糖（GLU组）、果糖（FRU组）或甘油（GLY组）替代的代乳粉。在试验的前10天，所有犊牛都饲喂CON组代乳粉。CON组继续使用该日粮，其他组则接受其试验日粮8周。在试验的第一周（基线）和最后一周进行测量。进行了频繁采样的静脉葡萄糖耐量试验以评估胰岛素敏感性，并收集24小时尿液以测量葡萄糖排泄量。在试验的最后一周，在各自的日粮中添加1.5克[U-（13）C]底物的大剂量，然后测量血浆葡萄糖、胰岛素和（13）C-葡萄糖反应。试验开始时胰岛素敏感性较低，且一直保持较低水平[1.2±0.1和1.0±0.1（mU/L）-1×min-1]，未观察到处理效应。试验开始时葡萄糖排泄量较低（3.4±1.0克/天），但CON组和GLU组犊牛的葡萄糖排泄量增加（分别为26.9±3.9和43.0±10.6克/天），而FRU组和GLY组犊牛没有增加。与CON组犊牛相比，GLU组犊牛的餐后血糖较高，FRU组较低，GLY组相似。与CON组犊牛相比，FRU组和GLY组犊牛的餐后胰岛素较低，GLU组相似。FRU组和GLY组犊牛的餐后（13）C-葡萄糖大幅增加，表明犊牛能够将这些底物部分转化为葡萄糖。我们得出结论，用葡萄糖、果糖或甘油替代代乳粉中三分之一的乳糖对犊牛餐后葡萄糖稳态有不同影响，但不影响胰岛素敏感性。
