Department of Animal Science, 272 Morrison Hall, Cornell University, Ithaca, NY 14853, USA.
J Dairy Sci. 2010 Sep;93(9):4262-73. doi: 10.3168/jds.2010-3142.
The objective of this study was to determine the effects of feeding calves isocaloric, isonitrogenous diets that varied in the amount and type of fatty acids on growth, response to an insulin challenge, and body composition. Thirty-six calves were assigned to a randomized block design with 3 dietary treatments, 10 calves per treatment, and a baseline group of 6 calves. Three different milk-replacer-based diets were designed to deliver less than 2% of the lipid as medium-chain triglycerides (control; diet contained no added medium-chain triglycerides), 32% medium-chain triglycerides primarily as caprylate (CAP oil), and 32% of fatty acids primarily as laurate from coconut oil (CCO). Calves were offered 0.28 Mcal of intake energy/kg of body weight (BW)0.75 from d 1 to 7 and 0.32 Mcal of intake energy/kg of BW0.75 adjusted weekly for BW from d 8 to harvest. Dry matter, intake energy, crude protein, and fat intakes were 53.7 kg, 281.8 Mcal, 14.6 kg, and 13.0 kg; 56.6 kg, 297.2 Mcal, 15.8 kg, and 14.2 kg; and 53.8 kg, 280.4 Mcal, 15.4 kg, and 13.3 kg for the control, CAP oil, and CCO treatments, respectively. Dry matter, energy, protein, and fat intakes did not differ among treatments. At approximately 65 kg of BW, 5 calves per treatment were given an insulin challenge. After the challenge the decrease in plasma glucose concentration was greater for the calves fed the CAP oil diet compared with those fed the control and CCO diets. Calves were harvested at approximately 88 kg of BW. Empty body gains were 0.92, 0.79, and 0.87 kg/d for control-, CAP oil-, and CCO-fed calves, respectively, and the gains of the CAP oil-fed calves were less than those of the control-fed calves. Empty body crude protein, ash, and water were not different among treatments. Empty body retained energy and fat tended to be 5.6 and 8.7% greater for calves consuming the CCO diet than for those fed the control diet. The livers of calves consuming the CCO diet were 330 g heavier and contained 15% more fat than the livers of the control and CAP oil calves. The results of this study demonstrate that the energy demand of the calf to maintain body temperature resulted in increased oxidation of intake energy; thus, overall body composition differences could not be detected. However, the intake of CCO increased the accumulation of lipid in the liver and carcass despite the apparent cold stress conditions.
本研究的目的是确定给 calves 喂食等热量、等氮但脂肪含量和类型不同的日粮对生长、胰岛素挑战反应和体组成的影响。36 头 calves 被分配到一个随机分组设计中，有 3 种日粮处理，每种处理 10 头 calves，还有一个 6 头 calves 的基线组。三种不同的基于 milk-replacer 的日粮旨在提供少于 2%的脂质作为中链甘油三酯（对照；日粮中没有添加中链甘油三酯）、32%的中链甘油三酯主要作为 caprylate（CAP 油）和 32%的脂肪酸主要来自椰子油中的 laurate（CCO）。calves 从第 1 天到第 7 天每天摄入 0.28 Mcal/kg 体重的能量，从第 8 天到收获期每天摄入 0.32 Mcal/kg 体重的能量，体重每周调整一次。干物质、摄入能量、粗蛋白和脂肪摄入量分别为 53.7 公斤、281.8 Mcal、14.6 公斤和 13.0 公斤；56.6 公斤、297.2 Mcal、15.8 公斤和 14.2 公斤；53.8 公斤、280.4 Mcal、15.4 公斤和 13.3 公斤，分别为对照、CAP 油和 CCO 处理。干物质、能量、蛋白质和脂肪摄入量在处理之间没有差异。在大约 65 公斤体重时，每个处理组的 5 头 calves 接受了胰岛素挑战。在挑战后，与对照组和 CCO 日粮组相比，喂食 CAP 油日粮的 calves 的血浆葡萄糖浓度下降更大。calves 在大约 88 公斤体重时被收获。对照、CAP 油和 CCO 喂养的 calves 的空体增重分别为 0.92、0.79 和 0.87 公斤/天，CAP 油喂养的 calves 的增重低于对照组喂养的 calves。空体粗蛋白、灰分和水分在处理之间没有差异。摄入 CCO 的 calves 保留的能量和脂肪分别比摄入对照日粮的 calves 多 5.6%和 8.7%。摄入 CCO 的 calves 的肝脏比对照组和 CAP 油组的 calves 的肝脏重 330 克，脂肪含量多 15%。本研究结果表明，calves 维持体温的能量需求导致摄入能量的氧化增加；因此，无法检测到整体体组成的差异。然而，尽管存在明显的冷应激条件，摄入 CCO 仍增加了肝脏和胴体中脂肪的积累。
