ABSTRACT

Present experiment was conducted to examine whether the supplementation of different organic sources of Cr (Chromium) would improve the performance of heat-stressed calves. Twenty-four female Hariana calves were divided into four treatments (six calves per treatment): (1) calves fed on basal diet (0 mg Cr/kg DM); (2) calves fed on basal diet supplemented with 1.0 mg Cr/kg DM as Cr-picolinate (Cr-Pic); (3) calves fed on basal diet supplemented with 1.0 mg Cr/kg DM as Cr-polynicotinate (Cr-Polynic); and (4) calves fed on basal diet supplemented with 1.0 mg Cr/kg DM as Cr-yeast (Cr-Yeast). Supplementation of different sources of organic Cr did not alter the physiological response of heat-stressed calves during 120 days of feeding experiment. Different Cr sources did not have any effect on liver function test, protein turn over, plasma cholesterol, glucose, total immunoglobulin (Ig) and cortisol levels. Cr shows beneficial effects on cholesterol metabolism, antioxidant activity and plasma concentration of Zn and Cr. Adding Cr-Polynic in the diet of heat-stressed calves significantly reduced (p < 0.05) plasma insulin concentration. This study suggests that the supplementation of different sources of Cr at 1.0 mg/kg DM (Dry Matter), improves antioxidant status and potency of insulin action in heat-stressed dairy calves.

摘要

本实验旨在检验添加不同有机来源的 Cr（铬）是否会改善热应激小牛的表现。将 24 头雌性 Hariana 小牛分为 4 个处理（每个处理 6 头小牛）：（1）以基础日粮（0 mg Cr/kg DM）喂养的小牛；(2) 以添加 1.0 mg Cr/kg DM 作为 Cr-吡啶甲酸盐 (Cr-Pic) 的基础日粮喂养的小牛；(3) 以添加 1.0 mg Cr/kg DM 作为 Cr-polynicotinate (Cr-Polynic) 的基础日粮喂养的小牛；(4) 以添加 1.0 mg Cr/kg DM 作为 Cr-酵母 (Cr-Yeast) 的基础日粮饲喂小牛。在 120 天的饲喂实验中，添加不同来源的有机铬并未改变热应激犊牛的生理反应。不同 Cr 来源对肝功能检查、蛋白质翻转、血浆胆固醇、葡萄糖、总免疫球蛋白 (Ig) 和皮质醇水平。Cr 对胆固醇代谢、抗氧化活性和 Zn 和 Cr 的血浆浓度具有有益作用。在热应激犊牛日粮中添加 Cr-Polynic 显着降低 (p < 0.05) 血浆胰岛素浓度。这项研究表明，以 1.0 mg/kg DM（干物质）补充不同来源的 Cr，可改善热应激奶牛的抗氧化状态和胰岛素作用的效力。