【作者】 李新建；

【导师】 高腾云；

【作者基本信息】 河南农业大学 ， 动物营养与饲料科学， 2003， 硕士

【摘要】 本试验研究了烟酸和烟酸铬对奶牛热应激和犊牛断奶应激的影响，并对其机制进行了初步探讨，为烟酸和烟酸铬在生产实践中的应用提供理论依据。 试验Ⅰ：用36头泌乳中期荷斯坦奶牛按配对原则等数分为对照组、烟酸组和烟酸铬组。对照组为基础日粮，烟酸组在基础日粮中添加800mg／kg的烟酸，烟酸铬组在基础日粮中添加10mg／kg的烟酸铬。试验期60天。结果表明：在热应激条件下，烟酸和烟酸铬可以提高奶牛的粗饲料采食量和减缓产奶量下降；使用烟酸铬、烟酸，试验组奶牛产奶量比对照组分别提高12.02％（p＜0.05）、4.86％；在日粮中添加烟酸铬，可以提高乳脂5％、乳蛋白2.8％、非脂固形物1.8％；可提高血清PRL、T₃、T₄激素水平（p＜0.05），可降低皮质醇8.8％（p＜0.05），对胰高血糖素影响不明显（p＞0.05）。在日粮中添加烟酸，T₃、T₄水平分别比对照组提高22.22％（p＜0.05）和11.46％，PRL水平比对照组提高14.27％（p＜0.05），皮质醇激素水平与对照组、烟酸铬组都差异不显著（p＞0.05），胰高血糖素水平比对照组提高了3.12％。 试验Ⅱ：选择2～4胎次泌乳中期的荷斯坦奶牛15头，按照配对原则分为对照组、烟酸组和烟酸铬组。对照组为基础日粮，烟酸和烟酸铬的添加剂量和添加方式同试验Ⅰ。具体分为两个试验：试验A是烟酸组和烟酸铬组的自身对照试验；试验B是三组配对饲养试验，试验期75天。试验A的结果表明：日粮中添加烟酸对乳酸度、柠檬酸含量、总固形物试期比试前分别提高9.1％、28.6％、4.7％，烟酸铬使乳酸度、柠檬酸含量、总固形 物试期比试前分别提高7．3％、30．8％、4．2％；而对生产性能、血液生化和 免疫指标影响不明显O功刀5)试验B的结果显示：（）日粮中添加烟酸和 烟酸铬试验牛粗料采食量明显比不添加分别提高0．4％、1．2％；Q)日粮中 添加烟酸、烟酸铬使奶牛在炎热天气下体温上升幅度相对较小，而对皮温 影响不显著中功刀5入 同时烟酸铬还可以在奶牛热应激状态下保持其正常 的呼吸率；3)日粮中添加烟酸和烟酸铬则使产奶量下降幅度较小，烟酸 铬可以减缓炎热天气下奶牛的乳脂下降趋势，与对照组，烟酸组相比效果 显著厂叼．05＼烟酸和烟酸铬可以减缓炎热大气下奶牛的乳蛋白下降趋势； 烟酸使乳酸度、柠檬酸含量试期比试前分别提高1．2％、6．3％；烟酸铬则使 乳酸度、柠檬酸含量试期比试前分别提高5．2％、23％。而对照组乳酸度、 柠檬酸含量试验前后无变化；使用烟酸J酸铬使乳中挥发性脂肪酸与对照 组相比显著提高中叼刀5人N)烟酸和烟酸铬维持热应激下奶牛血清T卜 T4、COR、PRL水平的基本恒定，从而减缓热应激对奶牛的影响；u)烟 酸和烟酸铬对血清葡萄糖水平无影响中列刀5人 显著降低因高温而上升的 尿素氮和胆固醇水平中叼刀5人 同时使甘油三脂水平试期比试前分别下降 11％、3二％；历)烟酸和烟酸铬显著提高血液中白细胞数目中＜0刀5人 同 时，烟酸铬也显著提高淋巴细胞百分比中＜0刀5人而对血液中其它细胞无 显著影响（p＞0刀5）。 试验＊：选用三月龄断奶荷斯坦犊牛 3 0头，将其等分为三组，对照组 为基础日粮，烟酸组和烟酸铬组分别在基础日粮中添加 400mg／kg的烟酸和 6．4呐的烟酸铬。结果表明：烟酸和烟酸铬在前 10天对犊牛的增重影响 不明显中＞0刀5人 20刁0天，烟酸组和烟酸铬组的平均日增重比对照组分 二 别提高 5％和 27石％；30一0天，烟酸组和烟酸铬组的平均日增重比对照组 分别提高 12．8％和 18．11％；而最后一个阶段，烟酸组和烟酸铬组的平均日 增重比对照组分别提高8．9％和 7．45％。试验期间，烟酸铬组与对照组相比 －提高 T卜 T4、生长激素、胰高血糖素水平分别为 25石8％中＜0．05人 17·31％、 6．73O、9．03o；烟酸组与对照组相比提高 T3、T4水平分别为 11．5O、12．7％。更多还原

【Abstract】 The purpose of this study is to discuss the effects of niacin and chromium nicotinate on the heat-stressed dairy cows and weanling-stressed calves ,the mechanisms were also concerned.In experiment I, 36 Holstein dairy cows were randomly divided into control group, niacin group and chromium nicotinate group according to their parturition numbers, milk yield and lactation period. The test lasted 60 days, the concentrate of niacin group was added with 800mg/kg Niacin, the chromium nicotinate group was 10mg/kg chromium nicotinate while there was no addition in the control group.The results showed feeding niacin and chromium nicotinate could lessen the decline tendency of milk yield which were raised respectively by 12.02% (p < 0.05) and 4.86%, compared with the control group and increase the roughage intake of heat-stressed dairy cows to some extent; The milkfat percentage, lactoprotein, SNF were raised respectively by 5%, 2.8%, 1.8% by feeding chromium nicotinate. PRL, T3, T4 levels of the serum were all significantly increased (p < 0.05 ) and COR level of the serum was significantly dropped by 8.80% (p < 0.05) by feeding chromium nicotinare; PRI^ TS> T4> GLUlevels of the serum were raised by 14.27% (p < 0.05) , 22.22% (p < 0.05), 11.46%, 3.12% respectively and the COR level of serum was not significantly dropped by niacin addition, compared with the control.In experiment II, 15 Holstein dairy cows which parturition numbers was from 2 to 4 were randomly divided into control, niacin, chromium nicotinate groups according to their parturition numbers, milk yield and lactation period. There were 5 dairy cows in every group. The niacin group was added with 800mg/kg Niacin, the chromium nicotinate group was added with lOmg/kg chromium nicotinate while there was nothing addition in the control. This experiment which was divided into test A and test B lasted 75 days.In test A, feeding niacin could raised acidity and CitraAcid and TS content of milk by 9.1%> 28.6%> 4.7% in the testing anaphase, compared with the testing prophase. Feeding chromium nicotinate could raised acidity and CitraAcid and TS content of milk by 7.3%^ 30.8%> 4.2% in the testing anaphase, compared with the testing prophase. However, there were no effects on the other by niacin and chromium nicotinate .In test B, (1) Feeding niacin and chromium nicotinate could raise the roughage intake by 0.4%, 1.2%, compared with the control group. (2) Increasing tendency of rectal temperature were alleviated by niacin and chromium nicotinate, however, there were no effects on temperature of body surface; Feeding chromium nicotinate kept respiratory rate comparatively stable on heat-stress dairy cows. (3) Feeding niacin and chromium nicotinate lessened the decline tendency of milk yield and lactoprotein; Acidity of milk was raised by 1.2%, 5.2% respectively; CitrAcid content of milk was raised by 6.3%, 23% respectively in the testing anaphase, compared with the testing prophase; Acidity and CitraAcid content ofmilk of the control had no changes in the testing period; FFA of milk was evidently raised (p<0.05), compared with the control group. Mlikfat percent was markedly dropped(p<0.05) by feeding chromium nicotinate. (4) The levels of T3, PEL in serum were markedly raised (p<0.05) and the level of COR in serum was markedly dropped (p<0.05) in the niacin and chromium nicotinate groups, compared with the control. (5) There was no effect on serum glucose (p>0.05), but serum urea nitrogen, cholesterol decreased (p<0.05) significantly and serum triglyceride decreased by 11%> 3.1% in the niacin and chromium niotinate groups respectively as compared to the control. (6) Feeding chromium nicotinate evidently raised leucocyte numbers and lymphocyte percent of blood (p<0.05); Leucocyte numbers of blood were evidently raised hi the niacin group as compared to the control group (p<0.05);In experiment III, 30 Holstein weanling calves in similar body weight were divided into the control group, niacin, chromium nicotinate groups. Effects of niacin and chromium nicoti更多还原