【作者】 徐龙；

【导师】 靳烨；

【作者基本信息】 内蒙古农业大学 ， 农产品加工及贮藏工程， 2013， 博士

【摘要】 通过五头装有瘤胃和十二指肠瘘管的安格斯肉牛,按照2×2+1日粮因子5×5拉丁方设计,测定肉牛瘤胃的pH值动态变化、VFA产量、氮素代谢、脂肪酸瘤胃氢化、日粮因子在消化通道中的流通和消化率的变化,进行了日粮中玉米DDGS和莫能菌素的含量的变化对肉牛的瘤胃发酵、能量代谢和脂肪酸代谢的影响的研究。结果表明：含有玉米DDGS的日粮与对照相比,有增加干物质采食量(DMI)的趋势(P<0.1),粗蛋白(CP)瘤胃消化率极显著的降低(P<0.01),但CP的总的表观消化率却极显著的增加(P<0.01)。随着日粮中玉米DDGS含量的增加(0,20%,40%),十二指肠中有机质(OM)的流量显著的增加(P<0.05),并且瘤胃中的OM, NDF和淀粉的消化率极显著地呈线性的增加(P<0.01),但对总的表观消化率没有影响。日粮中玉米DDGS的增加对总挥发性脂肪酸(VFA)的构成没有影响,但是显著的呈线性的降低(P<0.05)醋酸与丙酸的比例。随着日粮中玉米DDGS含量的增加,氮的摄入量,十二指肠总氮的流量,显著的增加(P<0.05),并且微生物氮转化率也显著的增加(P<0.05)。当日粮中莫能菌素含量从28增加到48mg/kg时,极显著的降低了DMI和OM的流量(P<0.01),显著的增加了OM的瘤胃消化率(P<0.05),但并不影响OM的总的消化率。随着日粮中玉米DDGS的增加,脂肪酸摄入量极显著的增加(P<0.01); CLAc9,t11、C18:3c9,c12,c15、单不饱和脂肪酸(MUFA)和多不饱和脂肪酸(PUFA)的十二指肠流量显著的呈线性的增加(P<0.01),然而,随着日粮中莫能菌素含量的增加,脂肪酸的摄入量有减少的趋势(P<0.10)；C18：2c9,c12、C18:3c9,c12,c15、MUFA和PUFA的十二指肠流量显著的降低(P<0.05)。通过200头杂交繁育的肉牛,按照2x2+1因子配比,测定肉牛的体重变化、生长指标、胴体参数和牛肉脂肪酸含量,进行了用硬质小麦和软质小麦替换日粮中的大麦和日粮中莫能菌素含量的变化对肉牛生长性能,胴体品质及牛肉脂肪酸组成的影响的研究。结果表明：日粮中用小麦替换日粮中的大麦对DMI没有显著影响,但日粮中莫能菌素的增加极显著的降低了(P<0.01) DMI,莫能菌素从28增加到48mg/kg时DMI降低了6%。各处理间,肉牛的最终体重,平均日增重(ADG)和重料比(G：F)没有显著差异。饲喂大麦日粮的肉牛的屠宰率显著的高于(P<0.05)饲喂小麦日粮,其他肉牛的胴体品质并没有受到日粮不同处理的影响。与饲喂硬质小麦的日粮相比,饲喂软质小麦日粮的肉牛具有相对较低的(P<0.05)背脂厚度和较高的(P<0.05)净肉量。用小麦替代日粮中的大麦,并没有影响肉牛肋部横膈膜肌(PCD)中MUFA和PUFA的总量,但显著降低了(P<0.05)PCD脂肪中C18：1t11和C18:3c9,12,c15的组成比例。综上所述,增加育肥日粮中的DDGS能够增加能量和蛋白供给,并且由于增加了肉牛的PUFA的摄入量和十二指肠流量,而增加了日粮PUFA的供应。小麦能够在不对肉牛生长性能、胴体性能和牛肉中脂肪酸成分产生负面影响的情况下替代日粮中的大麦。日粮中莫能菌素的含量从28增加到48mg/kg减少了DMI从而提高了饲料利用率,但对提高肉牛生产效率的作用却有限。更多还原

【Abstract】 Five ruminally and duodenally cannulated Angus heifers were used in a5x5Latin square with2×2+1factorial arrangement to determine the effects of increasing inclusion of corn dried distillers grain with solubles (DDGS) and monensin (Mon) supplementation on rumenal fermentation, energy metabolism, fatty acid metabolism by determined pH, volatile fatty acid (VFA), nitrogen metabolism and biohydrogenation in rumen and nutritions flow. The results showed that:intake of dry matter (DM) tended to be less (P<0.10), and ruminal degradability of crude protein (CP) was less (P<0.01), but the total digestibility of CP was greater (P<0.01) for corn DDGS than for the control diets. With increasing corn DDGS inclusion (0,20%,40%) in diets, flow of organic matter (OM) to duodenum was increased (P<0.05), ruminal digestibilities of OM, neutral detergent fiber (NDF) and淀粉were linearly (P<0.01) decreased, but the total digestibility was not different, total VFA concentration was not affect, but ratio of acetate to propionate was linearly decreased (P<0.05),intake of N and flows of total N were increased (P<0.05) and microbial N efficiency was linearly (P<0.04) improved. With increasing Mon dosage from28to48mg/kg in diets,dry matter intake (DMI) was reduced (P<0.05), flow of OM to duodenum was decreased (P<0.01), ruminal digestibility of OM was increased (P<0.05), the total digestibility of OM was not affected, molar proportion of acetate and NH3-N concentration were increased (P<0.05). With increasing com DDGS inclusion in diets, intakes of total and individual fatty acid were linearly increased (P<0.01), flows (g/d) of CLA c9,t11, C18:3c9,c12,c15, monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) to the duodenum were linearly increased (P<0.01) However, intakes of total and individual FA tended (P<0.10) to be decreased, the flows of C18:2c9,c12, C18:3c9,c12,c15, MUFA and PUFA were decreased (P<0.05) with increasing Mon dosage in diets.Two hundred crossbred steers were assigned to5treatments with2×2+1factorial arrangement to determine the effects of increasing monensin supplementation and varying in wheat type on growth performance, carcass trait and composition of fatty acid in carcass of feedlot steers. The results showed that:DMI was not different between barley and wheat or between soft and hard wheat diets. However, increasing Mon reduced (P<0.01) DMI by6%. Final BW, average daily gain (ADG) and gain:feed intake (G:F) were not different between treatments. Carcass characteristics were generally not affected by treatments except that dressing percentage was slightly greater (P<0.05) for barley than for wheat diet. Additionally, steers fed soft wheat had less (P<0.05) back fat and greater (P<0.05) meat yield compared with hard wheat diet. Substitution of wheat for barley grain did not affect the total MUFA and PUFA, but decreased (P<0.05) C18:1t11and C18:3c9,c12,c15in the pars costalis diaphragmatic (PCD) muscles from beef cattle.These results indicate that increasing DDGS in finishing diet increases energy and protein availability and increases the provision of PUFA to feedlot cattle due to increased intake and flows of PUFA to the duodenum. Wheat can effectively replace barley grain in finishing ration without negatively influencing growth performance, carcass traits and fatty acid composition in meat. Feeding Mon at48vs.28mg/kg DM potentially improves feed efficiency and decreases intake and duodenal flows of FA as a result of reduced DMI, but had little effect on ruminal fermentation and had limit benefits to production efficiency even though DMI was reduced.更多还原