饮水温度对湘西黄牛体温、营养物质表观消化率和血液生化指标的影响

Effects of Drinking Water Temperature on Body Temperature,Apparent Digestibility of Nutrients and Blood Biochemical Indexes of Xiangxi Yellow Cattle

本研究以南方秋季为环境背景,探究不同饮水温度对湘西黄牛体温、营养物质表观消化率和血液生化指标的影响。试验选用4头装有永久性瘤胃瘘管的湘西公黄牛[体重(325.25±35.33) kg]为试验对象,采用4×4拉丁方试验设计,设有0、10、20、30℃饮水组(T0、T10、T20和T30组)。试验共4期,每期10 d,每期的最后3 d收集粪便和血液样品。试验使用牛中耳鼓膜测温设备和环境温湿度传感器来监测24 h内肉牛体温和环境温湿度变化。结果显示:肉牛24 h平均体温随着饮水温度的上升呈上升趋势,且T30组极显著高于其他组(P<0.01)。T20组的干物质(DM)、粗蛋白质(CP)表观消化率显著或极显著高于T10组(P<0.05或P<0.01),有机物(OM)表观消化率显著或极显著高于T0、T10和T30组(P<0.05或P<0.01),粗脂肪(EE)表观消化率显著高于T0组(P<0.05)。T20组肉牛血浆中丙二醛(MDA)含量与T0和T30组没有显著差异(P>0.05),但极显著高于T10组(P<0.01)。肉牛血浆中甲状腺素(T_(4))含量随饮水温度的升高而逐渐增多,T0组显著或极显著低于其他组(P<0.05或P<0.01)。T30组肉牛血浆中生长激素(GH)含量最低,显著低于T0和T10组(P<0.05)。综上可知,饮水温度影响肉牛日平均体温和饲粮营养物质表观消化率,日平均体温随饮水温度的升高而升高,饲粮营养物质表观消化率整体来看以饮水温度为20℃时较高;饮水温度引起肉牛血浆中MDA、T_(4)与GH含量的变化,提示饮水温度不仅通过物理刺激,而且通过机体氧化还原和内分泌变化影响饲粮中营养物质的消化。

In this study,the effects of different drinking water temperatures on body temperature,apparent di-gestibility of nutrients and blood biochemical indexes of Xiangxi yellow cattle was investigated with the back-ground of autumn in South China.Four Xiangxi male yellow cattle[body weight:(325.25±35.33)kg]with permanent rumen fistulas were selected as test subjects.A 4×4 Latin square test design was adopted,and 0,10,20 and 30℃drinking water groups(T0,T10,T20 and T30 groups)were provided.The trial consisted of four 10-day periods,with stool and blood samples collected during the last three days of each period.The temperature measurement equipment and ambient temperature and humidity sensor were used to monitor the changes of body temperature and ambient temperature and humidity of beef cattle within 24 h.The results showed that the 24 h average body temperature of beef cattle increased with the increase of drinking water tem-perature,and the 24 h average body temperature of T30 group was extremely significantly higher than that of other groups(P<0.01).The apparent digestibility of dry matter(DM)and crude protein(CP)of T20 group was significantly or extremely significantly higher than that of T10 group(P<0.05 or P<0.01);the apparent digestibility of organic matter(OM)of T20 group was significantly or extremely significantly higher than that of T0,T10 and T30 groups(P<0.05 or P<0.01);the apparent digestibility of ether extract(EE)of T20 group was significantly higher than that of T0 group(P<0.05).The content of malondialdehyde(MDA)in plasma of T20 group was not significantly different from that of T0 and T30 groups(P>0.05),but extremely significantly higher than that of T10 group(P<0.01).The content of thyroxin(T4)in plasma gradually in-creased with the increase of drinking water temperature,which of T0 group was significantly or extremely sig-nificantly lower than that of other groups(P<0.05 or P<0.01).The content of growth hormone(GH)in plas-ma of T30 group was the lowest,and it significantly lower than that of T0 and T10 groups(P<0.05).In con-clusion,the daily average body temperature and digestibility of dietary nutrients are affected by drinking water temperature.The daily average body temperature is increased with the increase of drinking water temperature,and the digestibility of dietary nutrients is the highest when the drinking water temperature is 20℃.The chan-ges of MDA,T4 and GH contents in beef cattle plasma caused by drinking water temperature suggest that drinking water temperature affects dietary nutrient digestibility not only through physical stimulation,but also through oxidation-reduction and endocrine changes.