Department of Agriculture, University Farm, Utsunomiya University, Mohka, 321-4415, Japan.
United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu, 183-8538, Japan.
J Anim Sci. 2024 Jan 3;102. doi: 10.1093/jas/skae166.
We investigated the effects of a calf starter supplemented with calcium salts of medium-chain fatty acids (MCFA-Ca) on growth and plasma hormone concentration in calves. Twelve Holstein calves were randomly assigned to two dietary groups (without supplementation [CON] and supplemented with MCFA-Ca [MCFA]) from 4 d of age. Calves were fed 1.0 kg/d of milk replacer until 5 wk of age and were completely weaned at 7 wk of age. Calves in the MCFA group received a calf starter containing 1% MCFA-Ca. dry matter intake (DMI) was measured daily, and body weight was measured weekly. Rumen fluid was collected at 13 wk of age to measure pH and volatile fatty acid concentration. Preprandial blood samples were collected weekly to measure the basal plasma hormone and metabolite concentrations. At 4, 8, and 13 wk of age, peri-prandial blood samples were collected every 30 min, from 60 min before feeding to 120 min after feeding, to observe metabolic responses to feeding. In addition, insulin sensitivity was assessed using euglycemic-hyperinsulinemic clamps at 4, 8, and 13 wk of age in three calves from each treatment. There were no differences in starter and hay DMI between the treatments. However, the average daily gain (ADG) after weaning was higher in the MCFA group than in the CON group. Weekly changes in plasma parameters did not differ between the treatments. Plasma concentrations of preprandial ghrelin and postprandial total ketone bodies at 13 wk of age were higher in the MCFA group than in the CON group. At 8 wk of age, peri-prandial plasma insulin concentrations were lower in the MCFA group than in the CON group. There were no differences between the treatments in terms of insulin sensitivity. The present study suggested that feeding weaning calves MCFA-Ca increases the ADG during the postweaning period, which may be mediated by endocrine signals, such as enhanced ghrelin secretion and decreased insulin secretion, without altering insulin sensitivity.
我们研究了在犊牛代乳料中添加中链脂肪酸钙（MCFA-Ca）对犊牛生长和血浆激素浓度的影响。从 4 日龄开始，将 12 头荷斯坦犊牛随机分为两组（不添加[CON]和添加 MCFA-Ca[MCFA]）。犊牛在 5 周龄前每天饲喂 1.0kg 代乳料，7 周龄时完全断奶。MCFA 组的犊牛饲喂含有 1% MCFA-Ca 的犊牛料。每天测量干物质采食量（DMI），每周测量体重。在 13 周龄时采集瘤胃液，测量 pH 值和挥发性脂肪酸浓度。每周采集餐前血样，测量基础血浆激素和代谢物浓度。在 4、8 和 13 周龄时，每隔 30min 从饲喂前 60min 到饲喂后 120min 采集餐后血样，观察对饲喂的代谢反应。此外，在 4、8 和 13 周龄时，在每组 3 头犊牛中用正葡萄糖-高胰岛素钳夹技术评估胰岛素敏感性。两组间犊牛料和干草采食量无差异。然而，断奶后的平均日增重（ADG）在 MCFA 组高于 CON 组。两组间血浆参数的周变化无差异。在 13 周龄时，MCFA 组的餐前 ghrelin 和餐后总酮体浓度高于 CON 组。在 8 周龄时，MCFA 组的餐前血浆胰岛素浓度低于 CON 组。两组间胰岛素敏感性无差异。本研究表明，在断奶后给犊牛饲喂 MCFA-Ca 可增加断奶后时期的 ADG，这可能是通过内分泌信号介导的，例如增强 ghrelin 分泌和降低胰岛素分泌，而不改变胰岛素敏感性。
