摘要
The objective of this study was to evaluate growth performance, carcass characteristics, and plasma amino acid profiles of feedlot steers fed rumen-protected Lys. Forty-two Angus-cross steers (304 ± 25 kg) were blocked by weight and fed treatment diets for 180 d (growing days 0 to 55; finishing days 56 to 180): 1) Lys-deficient diet (CON; n = 12 steers), 2) Lys-adequate diet containing soybean meal (POS; n = 12 steers), or 3) Lys-deficient diet plus supplemental rumen-protected Lys (RPL; AjiPro-L; Ajinomoto Animal Nutrition North America, Eddyville, IA; n = 18 steers). Consecutive day bodyweights (BWs) were recorded to begin and end growing and finishing. Individual steer dry matter intake (DMI) was recorded. Blood was collected on days 0, 56, and 179 for analysis of physiological free amino acids. Steers were harvested on day 180 and carcass characteristics were recorded. Data were analyzed using Proc Mixed of SAS 9.4. Steer was the experimental unit and treatment was the fixed effect for all parameters. Block was a fixed effect for growth performance, feed intake, and carcass data. The day 0 value for each parameter of physiological free amino acids was used as a covariate during analysis. The CON steers had greater BW, average daily gain (ADG), and gain to feed (G:F) at the end of growing (day 56; P ≤ 0.05) vs. POS and RPL. The CON steers also had greater final BW (P = 0.04) and overall ADG (P = 0.04) than RPL, while POS was intermediate. Carcass characteristics were not different across treatments [hot carcass weight, dressing percent, ribeye area, back fat, kidney/pelvic/heart (KPH) percent, marbling, or calculated yield grade; P ≥ 0.13]. Plasma urea N was greater in POS steers on days 56 and 179 (P ≤ 0.04). Plasma Lys and Arg concentrations were greater in POS at day 56 (P ≤ 0.02); however, there was no difference among treatments for these two variables at day 179 (P ≥ 0.44). Steers in all treatments had greater DMI than predicted, causing a negative metabolizable Lys balance for all treatments during growing. Though the metabolizable Lys balance was positive for POS and RPL-fed steers during finishing, the increased metabolizable Lys in these treatments may have decreased performance if other amino acids were imbalanced due to increased intakes.
摘要译文
本研究的目的是评估饲喂瘤胃液体的饲养液体的生长性能，胴体特性和血浆氨基酸谱。四十二个Angus-Cross Steers（304±25 kg）被重量和喂养的治疗饮食堵塞180d（生长日为0至55;完成第56至180天）：1）缺乏缺乏饮食（CON; n = 12个阉牛），2）Lys-andequate饮食含豆粕（POS; n = 12个阉牛），或3）Lys缺陷饮食加上补充瘤胃保护的Lys（RPL; ajipro-l; Ajinomoto动物营养北美，伊迪维尔，IA; n = 18个阉牛。录制了连续的一天体重（BWS）开始和结束生长和整理。记录单个转向干物质摄入（DMI）。在第0,56和179天收集血液，用于分析生理游离氨基酸。在第180天收获Steers，并记录胴体特性。使用SAS 9.4的PROC分析数据。转向是实验装置，治疗是所有参数的固定效果。块是对生长性能，进料摄入和胴体数据的固定效果。在分析期间使用生理游离氨基酸的每种参数的第0天值作为调节剂。 CON Steers具有更大的BW，平均每日增益（ADG），并在生长结束时获得（G：F）（第56天; p≤0.05）与POS和RPL。 POS中，CON Steers还具有更大的最终BW（P = 0.04）和总体ADG（P = 0.04），而POS是中间体。治疗中的胴体特性没有差别[热胴体重量，敷料百分比，ribeye区域，背脂肪，肾/盆腔/心脏（kPh）百分比，大理石结构或计算的产量等级; P≥013]。在第56和179天（P≤0.04）的POS操舵中血浆尿素N更大。在第56天的POS中血浆液体和Arg浓度更大（p≤0.02）;然而，在第179天的这两个变量的治疗中没有差异（p≥0.44）。所有治疗中的阉牛比预测更大的DMI，导致在生长期间对所有治疗产生负面代谢的Lys平衡。尽管在整理过程中，代谢型Lys平衡对于POS和RPL喂养的带状器是阳性的，但是如果由于摄入量增加，则这些治疗中的可代谢液体增加可能会降低。
Katie J Heiderscheit [1]; Stephanie L Hansen[1]. Effect of rumen-protected lysine on growth performance, carcass characteristics, and plasma amino acid profile in feedlot steers[J]. Translational Animal Science, 2020,4(3)