【作者】 覃智斌；

【导师】 左福元；

【作者基本信息】 西南大学 ， 动物营养与饲料科学， 2008， 硕士

【摘要】 本实验研究不同铬源对处于热应激环境中肉牛的生长育肥性能、生理指标及血液生化指标的影响,以比较不同铬源对肉牛抗热应激的效果,为肉牛生产提供参考。选择30头月龄相近、体型结构相似、体重200kg左右的健康西杂二代公牛,采用单因素随机分组设计,将30头牛随机分为6组,1个对照组和5个处理组,每组5个重复,每个重复1头牛。对照组饲喂基础日粮,5个处理组则分别在基础日粮上添加三氯化铬（CrCL₃）、吡啶羧酸铬（CrPic）、烟酸铬（CrNic）、酵母铬（CrY）和甘氨酸铬（CrGly）。实验从2007年7月1日到9月8日,预饲期为10天,正式实验期为60天。根据添加量的不同将实验期分为前期和后期,每个阶段30天;前、后期分别按0.4mgCr/kg和0.8mgCr/kg精料添加铬制剂。研究结果如下:（1）实验期舍内平均温湿指数（TH1）为82.46±4.03,肉牛均处于中度热应激状态。（2）对肉牛体尺指标的影响中,两种剂量的铬制剂分别对体高、体斜长、体直长和胸围都有不同程度的提高;有机铬的效果较无机铬好,尤其以酵母铬、吡啶羧酸铬和烟酸铬的效果较突出。在管围方面,差异均不显著（p＞0.05）,但酵母铬组、烟酸铬组均比氯化铬组及对照组明显增加。（3）对育肥性能的影响中,全期酵母铬组、吡啶羧酸铬组和对照组的日增重分别为0.78±0.03kg、0.72±0.14kg和0.41±0.12kg,酵母铬组和吡啶羧酸铬组的采食量及日增重均较氯化铬组及对照组极显著提高（p＜0.01）;全期酵母铬组、烟酸铬组和对照组的料重比分别为7.77±0.65、8.46±1.17和14.58±4.67,酵母铬组、烟酸铬组及甘氨酸铬组的料重比均较对照组极显著降低（p＜0.01）。（4）对生理指标的影响中,酵母铬组的呼吸频率和直肠温度均较对照组极显著降低（p＜0.01）,烟酸铬组的呼吸频率较对照织极显著降低（p＜0.01）,铬处理组对降低皮肤温度的效果相对对照组差异不明显。（5）对肉牛血清生化指标的影响中,酵母铬组及吡啶羧酸铬组的总蛋白、葡萄糖含量均较氯化铬组及对照组极显著提高（p＜0.01）;酵母铬组、烟酸铬组及吡啶羧酸铬组均比氯化铬组及对照组极显著降低尿素氮、甘油三酯和胆固醇的含量（p＜0.01）;甘氨酸铬组的尿素氮、甘油三酯和胆固醇含量均较对照组显著降低（p＜0.05）。（6）对肉牛血清HSP70含量的影响,前、后期酵母铬组均比对照组显著提高（p＜0.05）。前期烟酸铬组比氯化铬组显著提高（p＜0.05）,两种剂量的其余各组间差异不显著（p＞0.05）。酵母铬组前期比后期提高了1.1%（p＜0.01）,烟酸铬组前期比后期提高了0.9%（p＜0.01）。研究结果表明:三峡库区肉牛夏季处于中度热应激状态,添加不同的铬源制剂对热应激期肉牛的生长、育肥性能具有促进作用,且有机铬的效果好于无机铬。添加铬制剂对降低热应激期肉牛的呼吸频率、直肠温度及平均皮肤温度都有一定的作用。铬制剂能够提高血清葡萄糖和总蛋白含量及降低血清胆固醇、甘油三酯和尿素氮含量,且铬制剂还能够增加热应激期肉牛血清HSP70的表达。在添加量方面,0.4mgCr/kg就可达到抗热应激和促进生长的作用。在铬源中,有机铬效果较无机铬明显,且酵母铬的效果最好,其余依次为吡啶羧酸铬、烟酸铬和甘氨酸铬。更多还原

【Abstract】 This experiment was designed to study the effects of adding different sources of the chromium on the growth and feeder performance,physiological index and blood biochemical index of beef cattle in heat stress, and to compare with each other for the effects of different sources chromium in two levels. Also, supplied some information for the production of the beef cattle.We chose 30 head cross-breed bulls of 200kg, that were same age and similar three-dimensional structure. This experiment was applied single factor design. 30 head bulls were divided into 6 groups, among these included 5 handle groups and 1 control group. Each group contained 5 repetitions and one repetition included 1 head bull. The control group was fed basis diet, and handle groups was fed the diet of adding chromium on the basis diet. The five handle groups were added CrCL₃,CrPic,CrNic,CrY and CrGly to basis diet respectively. The experiment stage was 70 days which from 1 July to 8 September in 2007. The preparation period was 10 days and formal experiment period was 60 days. The experiment stage was divided into earlier stage and later stage according to the difference of the adding levels and every stage was 30 days. Adding 0.4mgCr/kg in earlier stage and 0.8mgCr/kg in later stage.The study results as follows:（1） The average environment temperature THI was 82.46±4.03 in whole stage. So all the beef cattle were in the situation of midrange heat stress.（2） To the beef cattle’s body rulers: The two levels of chromium to beef cattle’s effects of body index such as body height, body slope length, body straight length and chest circumference had obviousily boost, and the effects of the organ-chromium had better than inorganic-chromium. In tube surround, the difference were not significance, but CrY had better effects obviously than CrNic,CrCL₃ and the control group’s.（3） To the cram performance: The daily gain of CrY, CrPic and the control group were 0.78±0.03kg,0.72±0.14kg and 0.41±0.12kg in whole stage. CrY and CrPic have extreme significance raise than the CrCL₃ and the control group in the dry matter intake and daily gain（p<0.01）. The feeds/gain of CrY, CrNic and the control group were 7.77±0.65,8.46±1.17 and 14.58±4.67 in whole stage. CrY, CrNic and CrGly have extreme significance raise than the control group in feeds/gain（p<0.01）.（4） To the physiological index: CrY have extreme significance lower than the conrol group in breathing rate and rectal temperature（p<0.01）. CrNic have extreme significance lower than the control group in breathing rate too（p<0.01）. The effect of the groups of adding chromium to depress the skin temperature was not obviously to the control group.（5） To the blood-serum biochemical indicators: CrY, CrPic have extreme significance raise than CrCL3 and the control group in the content of TP, GLU（p<0.01）.CrY, CrNic and CrPic have extreme significance lower than CrCL₃ and the control group in the comtent of the UN, TG and CHOL（p<0.01）.CrGly have better significance lower than the control group in the content of the UN, TG and CHOL（p<0.05）.（6） To the blood-serum HSP70 content: CrY had better significance raise than the control group in the two adding levels（p<0.05）. CrNic had better significance raise than CrCL₃ at the level of0.4mgCr/kg（p<0.05）.The study results showed that the beef cattle was in midrange heat stress state in the region of SanXia in summer. And adding different chromium had some promotion to beef battle’s growth, feeder performance under heat stress circumstance. Furthermore, the effectiveness of the organ-chromium had better than inorgan-chromium. So adding chromium on the basis diet that it can depressed the respiration rate, rectal temperature and mean skin temperature of beef cattle under heat environment. Also chromium can elevated the content of the GLU and TP and depressed the content of the TC, TG and UN, and promoted the expression of the HSP70. Above all, the organ-chromium had better effects than inorgan-chromium, and CrY had the best effect. as follows that were CrPic, CrNic and CrGly.更多还原