Optimal amino acid requirements for piglets in antibiotic-free feeding programs

目前世界范围内养猪业的趋势是尽量减少或消除在猪饲料中使用亚治疗水平的抗生素;这一做法尤其用于保育饲料，以控制断奶后腹泻的发生率并保持生长性能。因此，人们对开发替代疗法和营养计划以用于在无杀虫剂喂养计划中饲养的仔猪产生了极大的兴趣。有令人信服的证据表明，在压力条件下（例如疾病感染），动物的反应是将营养物质（尤其是氨基酸）从支持生长转移到支持免疫系统。因此，谨慎的假设是，当仔猪处于不太理想的条件下时，在生长免疫应答中发挥作用的必需氨基酸的可用性将受到限制，这在农场中通常很常见。具体而言，研究表明，当猪在不卫生的条件下饲养或受到疾病攻击时，对这些氨基酸有额外的需求。这表明，目前的氨基酸比例，确定了仔猪饲料中添加维生素可能不适合那些饲养在无维生素喂养计划。因此，拟进行的研究将确定在不卫生条件下仔猪的赖氨酸需要量，并建立含硫氨基酸、苏氨酸和色氨酸与赖氨酸的最佳比例。这将有助于实现设计日粮的目标，以优化仔猪的性能，在无公害饲养计划。该项目将采用广泛的实验、分析和统计技术，从而为高素质人员提供极好的培训机会。

The current trend in the swine industry world-wide is to minimize or eliminate the use of sub-therapeutic levels of antibiotics in pig diets; a practice that has been used especially in nursery diets to control incidences of post-weaning diarrhea and to maintain growth performance. As a result, there has been a great interest to develop alternative therapies and nutritional programs for piglets raised in antibiotic-free feeding programs. There is compelling evidence that under stressful conditions (e.g. disease infection), animals respond by diverting nutrients (especially amino acids) away from supporting growth to supporting the immune system. Therefore, it is prudent to postulate that the availability of essential amino acids that play a role in immunological responses for growth will be limited when piglets are subjected to less than optimal conditions, as is often common in farms. Specifically, studies have indicated that there are additional requirements for such amino acids when pigs are raised under unsanitary conditions or subjected to a disease challenge. This suggests that the current amino acid ratios that were determined for piglets fed antibiotic-supplemented diets may not be suitable for those raised under antibiotic-free feeding programs. Thus, the proposed research will determine the lysine requirement for piglets under unsanitary conditions and establish the optimal ratios to lysine of sulfur amino acids, threonine and tryptophan. This will contribute towards the goal of designing diets to optimize piglet performance under antibiotic-free feeding programs. A wide range of experimental, analytical and statistical techniques will be employed in the project thus providing excellent training opportunities for highly qualified personnel.