【作者】 李大刚；

【导师】 李杰；

【作者基本信息】 东北农业大学 ， 动物营养与饲料科学， 2003， 硕士

【摘要】 本研究由4个试验组成，选用安装永久瘘管的6月龄山羊4只，采用4×4拉丁方试验设计，分别饲喂对照组饲粮、乙酰氧肟酸（AHA）25mg／kg饲粮、丝兰皂甙（YU）36mg／kg饲粮、对苯二酚（HQ）40mg／kg饲粮。研究了三种脲酶抑制剂对瘤胃氮代谢、营养物质在瘤胃消失率、营养物质表观消化率的影响。 试验1．在上述添加量的条件下分别在试羊采食前及采食后的2、4、6、8小时取瘤胃液样品进行分析，瘤胃液pH值的变化趋势是饲喂后各组均降低，饲喂6小时后pH又有所回升。饲喂前及饲喂后2小时HQ组NH₃—N浓度分别降低15.24％、14.32％（p＜0.05）。在两倍上述添加量条件下AHA组、YU组和HQ组瘤胃液NH₃—N浓度在饲喂后2小时与对照组相比分别降低33.21％、24.15％、31.69％（p＜0.05）。各种脲酶抑制剂延缓尿素分解的作用不明显。HQ组与对照组相比乙酸浓度增加了8.66％（P＜0.05），HQ组与各组相比丙酸浓度有所增加且达到了显著水平（P＜0.05），瘤胃液中乙酸／丙酸的比例各组之间无显著差异（P＞0.05）。 试验2．用尼龙袋法研究不同脲酶抑制剂对全混合日粮干物质（DM）、粗蛋白（CP）、中性洗涤纤维（NDF）、酸性洗涤纤维（ADF）瘤胃48小时消失率的影响。结果表明，与对照组相比，AHA组和HQ组DM的消失率分别提高13.87、16.58％（P＜0.05），AHA组CP的消失率提高6.89％（P＜0.05），AHA组和HQ组NDF的消失率分别提高9.39％、13.44％（P＜0.05），HQ组ADF的消失率提高13.67％（P＜0.05）。 试验3．研究不同脲酶抑制剂对饲粮DM、CP、NDF、ADF表观消化率的影响。结果表明，与对照组相比，HQ组DM表观消化率提高12.31％（P＜0.05），AHA组和HQ组蛋白质表观消化率分别提高6.27％和4.46％（P＜0.05），NDF的表观消化率与对照组相比：AHA组和HQ组分别提高6.58和5.93％（P＜0.05），AHA组和HQ组ADF的表观消化率分别提高了7.48％和4.95％（P＜0.05）。 试验4．研究三种不同脲酶抑制剂在动物饲喂2小时后对瘤胃微生物数量的影响。试验结果表明三种脲酶抑制剂对瘤胃细菌总数没有影响，但丝兰皂甙组与对照组相比能降低瘤胃原虫数量，差异达到显著水平（P＜0.05）。更多还原

【Abstract】 Four 20kg six-month old goats with permanent remen cannula were used to study the effect of three kinds of urease inhibitors acetohydroxamic acid (AHA), hydroquinone (HQ), yucca extract (YU) on nitrogen metabolism, nutrient degradability in rumen and nutrient digestibility. The goats were feed one of four diets with 1% Urea that contained basic diet, AHA 25mg/kg ,YU 120mg/kg ,HQ 40mg/kg. The experiment design was a 4+4 Latin Square. Trial 1 pH value. Ammonia concentration and Urea-N concentration of ruminal fluid were sampled at 0, 2, 4, 6 and 8 h after feeding. The result showed that pH values were decreased after feeding and begin to get back after feeding 6h. HQ decrease Ammonia concentration 15.24%(p<0.05) before feeding,decrease 14.32% after feeding 2h (p<0.05). AHA, YU, HQ each decrease 33.12%, 24.15%, 31.69% of Ammonia concentration after postfeeding 2h on the higher dose. Add urease inhibitors in dietary can control the Ammonia concentration of ruminal fluid fluctuation violently. There are no significantly difference on the Urea-N concentration.The AHA.YU and HQ can increased the concentration of WA at 2h pastfeeding (p<<0.05).The propionic acid concentrations of ruminal fluid is significantly increase in HQ diet than control treatment. The acetic acid to propionic acid did not change greatly (p>0.05).Trial 2 The experiment dietary, the experiment animals and The experiment design were the same as the Trial 1. The effect of the AHA, YU and HQ on the degradability of DM,CP, NDF and ADF in the rumen were evaluated. The result showed that the AHA and HQ increase the degradability of DM 13.87% and 16.85%, AHA increased the degradability of CP was 6.89%(p<0.05). AHA and HQ increase the degradability of NDF 9.39% and 13.44% compared with control treatment (P<0.05).Compared with control treatment HQ increase the degradability of ADF was 13.67%(P<0.05).Trial 3 The experiment dietary. The experiment animals and The experiment design were the same as the Trial 1. In this experiment the effect of AHA, YU,HQ on the nutrient apparent digestibility of DM, CP, NDF and ADF were studied.The result showed that the HQ can increase the digestibility of DM 12.31%(p<0.05). The AHA and HQ compared with control treatment increase the digestibility of CP 6.27% and 4.46%(P<0.05). AHA and HQincrease the apparent digestibility of NDF 6.58% and 5.93%(P<0.05).Trial 4 The experiment dietary, The experiment animals were the same as the Trial 1. The design was comparison. This experiment was designed to determine the effect of AHA.YUand HQ on total counts of rumen microorganism in goat rumen. The result showed that the urease inhibitors did not changed the populations of bacteria (p>0.05). Yucca extract can decrease the population of protozoa significantly(P<0.05).Master candidate: Li DagangSupervisor: Prof. Li JieMajor: Animal nutrition and feed science更多还原