摘要
The objectives of these experiments were to determine the bypass value of rumen-protected lysine and performance responses of beef cattle fed encapsulated lysine. During experiment 1 singe-flow continuous culture fermenters were fed a Lys-deficient control (CON), a Lys-sufficient diet supplemented with rumen-protected soybean meal (RPSBM; AminoPlus, Ag Processing Inc., Omaha, NE), or a Lys-sufficient diet containing a commercially available rumen-protected Lys product (RPLYS; USA Lysine, Kemin Industries Inc., Des Moines, IA). Results from continuous culture showed greater degradation of RPLYS than RPSBM and CON. During Experiment 2, an in vitro dry matter digestibility study showed DM degradation was 23% greater for pure USA Lysine than another encapsulated lysine product (AjiPro 2G, Ajinomoto Heartland, Inc., Omaha, NE). The next objective was to test if AjiPro would increase plasma Lys levels in vivo (and therefore indicate its successful ruminal bypass and small intestinal absorption). Experiment 3 involved a 3 x 3 Latin Square study conducted on cannulated crossbred steers fed a combination of rumen-protected soybean meal and two increased levels of the rumen-protected product, where it was fed to meet 100% (AJ100) and 150% (AJ150) absorbable AA to effective energy (EE) ratio. Plasma Lys levels were greater when steers were fed diets containing AjiPro in comparison to when they were fed a negative control (NEGCON) which did not contain the product and was deficient in absorbable Lys. From both the in vitro dry matter degradation experiment and the 3 x 3 Latin Square study, we determined AjiPro to be an effective source of bypass Lys, and consequently used it to conduct a growing through finishing study. During Experiment 4, we evaluated steer performance when fed diets balanced for predicted Lys requirement to EE ratio through its supplementation in several dietary treatments. Control treatments included a negative control (NEGCON) that was deficient in absorbable Lys and contained no rumen-protected products; and a positive control (POSCON) where rumen-protected soybean meal was used to balance absorbable AA to EE ratio. Three additional dietary treatments included similar amounts of rumen-protected soybean meal and incremental amounts of AjiPro formulated to provide 50% ( AJ50), 100% (AJ100), or 150% (AJ150) of the absorbable Lys provided by POSCON. Starting on d 151 of the growth study, steers were weighed on 2 consecutive days every 14 d and assigned a final BW when no longer profitable (defined as when cost of gain exceeded value of gain). Steers remained profitable for greater days for NEGCON, POSCON and AJ100 than AJ150. Steers consuming POSCON had lesser ADG (kg/d) than all other treatments during the early finishing phase (d 75 to 112). However, steer ADG (kg/d) during late finishing (d 112 to 179) was greater for steers fed diets optimized for Lys requirement (POSCON and AJ100) than all other treatments. Between d 112 to 179, POSCON had greater G:F than all other treatments but did not differ from AJ100. When encapsulated Lys was under or over-supplemented, finishing steers became less profitable sooner. Feed efficiency increased with use of rumen-protected products during late finishing (d 112 to 179) in diets formulated to meet Lys requirement, but this did not impact overall steer performance from growing through finishing. A more accurate understanding of steer AA requirement and subsequent AA metabolism will allow more precise and effective use of rumen-protected products.
摘要译文
这些实验的目的是确定瘤胃保护的赖氨酸的旁路值和饲喂包埋的赖氨酸的肉牛的性能反应。在实验1中，给单流连续培养发酵罐喂食Lys缺乏对照（CON），Lys充足的饮食加瘤胃保护的豆粕（RPSBM;或内布拉斯加州奥马哈市Ag Processing Inc.生产的Lys-饮食中含有瘤胃保护的Lys产品（RPLYS；美国赖氨酸，Kemin Industries Inc.，得梅因，得克萨斯州。连续培养的结果表明，RPLYS的降解程度大于RPSBM和CON。在实验2中，一项体外干物质消化率研究表明，纯美国赖氨酸的DM降解比另一种封装的赖氨酸产品（AjiPro 2G，Ajinomoto Heartland，Inc。，奥马哈，内布拉斯加州）高23％。下一个目标是测试AjiPro是否会增加体内血浆Lys的水平（从而表明其成功的瘤胃旁路和小肠吸收）。实验3涉及对饲喂瘤胃保护的豆粕和两种水平较高的瘤胃保护产品的组合的空心杂种ers牛进行的3 x 3拉丁方研究，在饲喂中满足100％（AJ100）和150％（ AJ150）可吸收AA与有效能量（EE）之比。饲喂含AjiPro的ste牛的血浆Lys水平高于饲喂不含该产品且缺乏可吸收Lys的阴性对照（NEGCON）。通过体外干物质降解实验和3 x 3 Latin Square研究，我们确定AjiPro是绕过Lys的有效来源，因此通过最终研究将其用于生长。在实验4中，我们通过在几种饮食疗法中补充补饲以平衡Lys对EE的预测需求量来评估饲喂日粮的转向性能。对照治疗包括阴性对照（NEGCON），其缺乏可吸收的赖氨酸，并且不含瘤胃保护产物。阳性对照（POSCON），其中瘤胃保护的豆粕用于平衡可吸收的AA与EE之比。另外三种饮食疗法包括类似量的瘤胃保护豆粕和递增量的AjiPro，其配方可提供POSCON提供的可吸收Lys的50％（AJ50），100％（AJ100）或150％（AJ150）。从生长研究的第151天开始，每14天连续2天对ste牛皮进行称重，并在不再盈利时（定义为收益成本超过收益价值时）分配最终体重。与AJ150相比，NEGCON，POSCON和AJ100的ers牛皮保持较高的获利能力。食用POSCON的ers牛在早期肥育阶段（第75至112天）的ADG（kg / d）要比所有其他处理的ADG少。然而，饲喂根据Lys需求优化的日粮（POSCON和AJ100），后期肥育期（第112至179天）的日增重（kg / d）要高于所有其他处理。在d 112到179之间，POSCON的G：F比所有其他治疗更高，但与AJ100并无区别。当封装的Lys不足或过量时，补充精制后的ste牛皮的获利会更快。在满足Lys要求的日粮中，后期加工（从112到179天）使用瘤胃保护产品可提高饲料效率，但这不会影响从生长到精加工的整体overall牛性能。对转向AA需求和随后的AA代谢的更准确的了解将使瘤胃保护产品的使用更加精确和有效。
Prestegaard, Jacquelyn. Optimizing Beef Cattle Performance Using Rumen-protected Lysine Supplementation in Diets Balanced for Predicted Amino Acid and Effective Energy Requirement[D]. US: University of Missouri - Columbia, 2017