Diao Qiyu

饲用高水溶性磷酸一二钙对断奶仔猪生长性能、饲粮消化率、血清和骨骼指标的影响

本研究以磷酸氢钙（DCP）为参照物，以断奶仔猪生长性能、饲粮消化率、血清和骨骼指标为对象，评价饲用高水溶性磷酸一二钙（MDCP）的相对生物学利用率。试验采用2×5因子随机试验设计，选择432头4~5周龄、体重相近的杜×长×大杂交断奶仔猪为试验动物，随机分为9组，每组6个重复，每个重复8头猪。每种磷酸盐设5个磷添加水平，分别为0、0.05%、0.10%、0.15%、0.20%，共9个处理（0添加组共用）。试验预试期3 d，正试期35 d。结果表明：1）仔猪平均日采食量、平均日增重及死亡率等指标在磷源和磷添加水平之间均不存在显著交互作用（ P >0.05）。试验第15~35天，MDCP组仔猪平均日采食量显著高于DCP组（ P P P >0.05）。2）不同磷酸盐和磷添加水平之间对仔猪饲粮干物质、钙和磷的表观消化率均无显著交互作用（ P >0.05）。MDCP组饲粮钙和磷的表观消化率均显著高于DCP组（ P P P >0.05），也无显著交互作用（ P >0.05）。试验第14天时，血清磷、钙和甲状旁腺素（PTH）含量在不同磷源和磷添加水平之间存在显著交互作用（ P P P P P >0.05）。血清钙、磷和PTH含量与磷添加水平之间存在显著的线性回归关系（ P P >0.05），也无显著交互作用（ P >0.05）。股骨灰分与磷添加水平之间存在显著的线性回归关系（ P < 0.05）。以股骨灰分含量为指标，根据回归方程斜率比计算出MDCP相对于DCP的生物学利用率为255%。综上所述，以试剂级DCP的生物学利用率为100%，以磷酸盐中磷的表观消化率和真消化率为指标，MDCP的相对生物学利用率均为120%；设定血清指标和股骨灰分含量为指标，MDCP的相对生物学利用率分别为104%和255%。

饲粮非纤维性碳水化合物(NFC)与中性洗涤纤维(NDF)比例对育成期杜寒杂交母羊生长性能、营养物质消化率和甲烷产量的影响

旨在借助开路式循环呼吸测热系统研究饲粮不同非纤维性碳水化合物/中性洗涤纤维（NFC/NDF）比例对育成期（48~55 kg）杜寒杂交母羊生产性能、营养物质消化率及甲烷产量的影响。选用30只体重（48±0.50）kg的杜泊（♂）×小尾寒羊（♀））母羊，采用单因素试验设计，将试验动物随机分到饲粮NFC/NDF=0.78组（精粗比为35：65，自由采食）、NFC/NDF=1.03组（精粗比为50：50，限饲）和NFC/NDF=2.17组（精粗比为65：35，限饲）3个处理组中，每个处理组10只羊。试验期为32 d，包括17 d预试期和15 d正试期。试验分为自由采食组和限饲组两种饲养模式，各组的能量和粗蛋白质采食量均相同，以饲粮NFC/NDF为0.78自由采食组的平均日增重作为NFC/NDF为1.03组和2.17组的限饲标准。试验羊只定期晨饲前称重，记录每日采食量；在正试期内测定甲烷产量、饲粮能量和饲粮营养物质表观消化率。结果表明：1）限饲条件下饲粮NFC/NDF为2.17组的饲料转化效率显著高于自由采食条件下饲粮NFC/NDF为0.78组的饲粮转化效率（P 0.05）。2）当饲粮NFC/NDF比例由0.78增加至2.17时，3个处理组的干物质表观消化率、有机物表观消化率、总能表观消化率和总能代谢率皆显著提高（P 0.05）。另外，随着饲粮NFC/NDF比例的增加，NFC/NDF=2.17组的NDF表观消化率显著高于NFC/NDF=0.78组和NFC/NDF=1.03组（P 0.05）。3）NFC/NDF=2.17组的甲烷日排放量为32.53 L·d-1，显著低于NFC/NDF=0.78组的58.03 L·d-1和NFC/NDF=1.03组的63.17 L·d-1（P 0.05），3组的单位代谢体重的甲烷日排放量具有相同的变化规律。随着饲粮NFC/NDF比例的增加，NFC/NDF=2.17组的单位干物质采食量的甲烷排放量、单位有机物采食量的甲烷排放量和单位可消化有机物的甲烷排放量皆显著低于NFC/NDF=1.03组（P 0.05）；单位总能摄入量的甲烷能排放量、单位消化能摄入量的甲烷能排放量、单位代谢能摄入量的甲烷能排放量具有相同的变化规律。NFC/NDF=1.03组的单位中性洗涤纤维采食量的甲烷排放量和单位可消化中性洗涤纤维采食量的甲烷排放量显著高于NFC/NDF=0.78组和NFC/NDF=2.17组（P 0.05）。另外，单位日增重的甲烷排放量和单位可消化酸性洗涤纤维的甲烷排放量在3个处理组之间无显著差异（P>0.05）。综合生长性能、饲粮各营养物质表观消化率、能量代谢及甲烷排放水平，对育成期（48~55 kg）杜寒杂交母羊限制饲喂NFC/NDF为2.17的饲粮是最佳的碳减排措施。

饲粮营养限制对羔羊肠道组织形态以及血清胰岛素样生长因子-1和胰高血糖素样-2浓度的影响

本试验旨在研究饲粮营养限制对羔羊肠道组织形态及血清中胰岛素样生长因子-1（IGF-1）和胰高血糖素样-2（GLP-2）浓度的影响。选取64只17日龄湖羊羔羊随机分为4组，饲喂不同营养水平的代乳品和开食料，分别为对照（CON）组、20%蛋白质限制（PR）组、20%能量限制（ER）组、20%蛋白质+20%能量限制（BR）组，每组4个重复，每重复4只羔羊，公母各占1/2。于羔羊20日龄、40日龄和60日龄采集血清用于测定IGF-1和GLP-2的浓度，40日龄和60日龄时每组分别选取4只羔羊进行屠宰，屠宰后取十二指肠、空肠和回肠组织观察小肠组织形态结构。结果表明：1）PR组、ER组、BR组40日龄小肠重量显著低于CON组（P 0.05）。综上所述，饲粮营养限制抑制了羔羊十二指肠、空肠组织形态发育，同时能量限制可降低血清GLP-2的浓度。

Establishment of young ruminants rearing system and its key scientific issues

The growth and health performance of young animals has deep effect on the realization of their later genetic capacity. However, the rearing performance of young ruminants is far from the requirements of ruminant industry development in China, especially the prolonged suckling period, high mortality rate, and low growth rate of young ruminants severely hindered the development of ruminant industry. Technically, our poor comprehension of the nutritional physiology and nutrient requirements, standardized feeding and management strategies, specialized production, and modernized feeding equipment R&D for young ruminants are the bottlenecks existed in young ruminants rearing process. To solve these industry and technical problems of young ruminants, it is urgent and significant to do further effective research work and deep our understanding of young ruminant nutrition and physiology accomplished with guideline of question-orientation and supply-side structural reform, and it is also a pivotal step to finally promote the healthy and sustainable development of ruminant industry. More importantly, from the perspective of the ruminant industry development, it is essential to initialize an industry innovation alliance and an effective research service system based on the young ruminant industry development to support the extension of technical achievements and enhancement of the international competitiveness of the young ruminant industry. At the same time, it is vital to confirm the research work focusing on the development of young ruminants, including the nutritional physiology, nutrients requirements, and key products for the rearing of young ruminants. To improve the rearing effectiveness of young ruminants, the establishment of scientific and systematic young ruminants rearing system, which is a system to dig the genetic capacity for later fattening or milking performance by the early weaning and scientific feeding and management based on our deep comprehension of the development traits of the gastrointestinal tract and nutrient requirements etc., is a guarantee for the sustainable development of young ruminant industry. Facing the development of young ruminants in the future, therefore, it is suggested that some key scientific issues in young ruminant rearing process need to be strengthened, including the theoretical research of young ruminant rearing based on nutrition-gene expression and modern multi-omics technology, deep explore the mechanism of early nutritional regulation on their later potential growth and development, and the relationship between ewe nutrition regulation and young ruminant growth and health. Hereon, the sorting out of these related issues are meaningful for enhancing the content of science and technology in national young ruminant rearing field and promoting the development of ruminant industry forward large-scale, intensity and wisdom. At last, for the first time as the organizer of the China’s top science forum, Xiangshan Science Conferences, in Animal husbandry field, we propose again the establishment of young ruminant rearing system with joint supporting by scientist, enterpriser, and government departments to promote and guide the development of ruminant industry in China and even in the world.