Jocelyn N A, Harris P A, Menzies-Gow N J
Department of Clinical Sciences and Services, Royal Veterinary College, London, UK.
WALTHAM Centre for Pet Nutrition, Melton Mowbray, Leicestershire, UK.
Equine Vet J. 2018 Nov;50(6):836-841. doi: 10.1111/evj.12826. Epub 2018 Mar 22.
The oral sugar test (OST) is used to identify equine insulin dysregulation (ID); however only a dose of 0.15 mL/kg bwt corn syrup has been evaluated.
To determine the effect of varying the dose of corn syrup on insulin and glucose response to the OST and the test's ability to distinguish between ponies with a history of laminitis (PL) and without laminitis (NL).
Randomised crossover experiment.
After an overnight fast, in a three-way randomised crossover study with a 7-day washout, 0.15, 0.3 or 0.45 mL/kg bwt corn syrup was administered orally to eight ponies (5 PL and 3 NL) and blood obtained between 0 and 120 min. Serum [insulin] and [glucose] were measured using previously validated radioimmunoassay and colorimetric assays respectively. The repeatability of and the effect of continued pasture access on the dose that best distinguished PL and NL ponies were then assessed. The effect of dose, laminitis history and fasting on serum [insulin] and [glucose] responses were assessed using mixed-effects models.
The serum [insulin] following 0.15 mL/kg bwt were not significantly different from 0.3 mL/kg bwt at any time point, while serum [insulin] following 0.45 mL/kg bwt significantly (P<0.01) differed from 0.15 and 0.3 mL/kg bwt at all time points apart from 0 min. The serum [insulin] concentration significantly (P<0.01) differed between NL (mean 86 [95% CI 59, 113] μiu/mL) and PL (146 [95% CI 124, 167] μiu/mL) only following 0.45 mL/kg bwt at 60 min. Repeatability of serum [insulin] at 60 min following 0.45 mL/kg bwt dose under fasted conditions was 0.51. Using AUC insulin improved repeatability to 0.83. There was no significant difference between the fasted and at pasture results.
The OST was performed in small numbers of ponies on limited occasions.
A dose of 0.45 mL/kg bwt corn syrup may be preferable to differentiate PL and NL ponies.
口服糖试验（OST）用于识别马的胰岛素调节异常（ID）；然而，仅评估了0.15 mL/kg体重的玉米糖浆剂量。
确定改变玉米糖浆剂量对OST胰岛素和葡萄糖反应的影响，以及该试验区分有蹄叶炎病史（PL）和无蹄叶炎（NL）小马的能力。
随机交叉试验。
在禁食过夜后，在一项为期7天洗脱期的三向随机交叉研究中，对8匹小马（5匹PL和3匹NL）口服0.15、0.3或0.45 mL/kg体重的玉米糖浆，并在0至120分钟内采集血液。分别使用先前验证的放射免疫分析法和比色法测量血清[胰岛素]和[葡萄糖]。然后评估最佳区分PL和NL小马的剂量的重复性以及持续放牧对其的影响。使用混合效应模型评估剂量、蹄叶炎病史和禁食对血清[胰岛素]和[葡萄糖]反应的影响。
在任何时间点，0.15 mL/kg体重后的血清[胰岛素]与0.3 mL/kg体重后的血清[胰岛素]无显著差异，而0.45 mL/kg体重后的血清[胰岛素]在除0分钟外的所有时间点均与0.15和0.3 mL/kg体重有显著差异（P<0.01）。仅在60分钟时给予0.45 mL/kg体重后，NL（平均86 [95%可信区间59, 113] μiu/mL）和PL（146 [95%可信区间124, 167] μiu/mL）之间的血清[胰岛素]浓度有显著差异（P<0.01）。在禁食条件下，给予0.45 mL/kg体重剂量后60分钟时血清[胰岛素]的重复性为0.51。使用胰岛素曲线下面积（AUC）可将重复性提高到0.83。禁食和放牧状态下的结果无显著差异。
OST仅在少数小马身上在有限的情况下进行。
0.45 mL/kg体重的玉米糖浆剂量可能更适合区分PL和NL小马。
