Department of Animal Sciences and Industry, College of Agriculture, Kansas State University, Manhattan, KS 66506-0201, USA.
J Anim Sci. 2013 Jul;91(7):3265-71. doi: 10.2527/jas.2011-4286. Epub 2013 May 8.
A total of 2,152 pigs (C22 × 336 PIC) were used in 4 experiments to determine the interactive effects of dietary l-carnitine and ractopamine HCl (RAC) on finishing pig growth performance. All trials were arranged as factorial arrangements with main effects of l-carnitine (0, 25, or 50 mg/kg in Exp. 1 and 2 and 0 or 50 mg/kg in Exp. 3 and 4) and RAC (0, 5, or 10 mg/kg in Exp. 1 and 0 or 10 mg/kg in Exp. 2, 3, and 4). Dietary carnitine was fed from 38 to 109 kg (Exp. 1 and 3) or for the last 4 or 3 wk before slaughter (118 kg; Exp. 2 and 4, respectively). Ractopamine HCl was fed for 4 wk (Exp. 1, 2, and 3) or 3 wk (Exp. 4) before slaughter. Experiments 1 and 2 were conducted in university research facilities, and Exp. 3 and 4 were conducted in a commercial research facility. All diets were formulated to contain 1.00% total Lys during the last phase of each experiment. In all experiments, pigs fed RAC had increased (P < 0.05) ADG and G:F compared with pigs fed no RAC. Feeding l-carnitine before the RAC feeding period did not affect pig growth performance. In Exp. 1 and 2, l-carnitine did not affect ADG during the last 4 wk; however, in Exp. 2, G:F tended (quadratic; P = 0.07) to improve with increasing l-carnitine. In Exp. 3, l-carnitine × RAC interactions were observed (P < 0.04) for ADG and G:F. Both added l-carnitine and RAC improved performance, but the response was not additive. In Exp. 4, pigs fed l-carnitine had increased (P < 0.04) ADG (0.88 vs. 0.84 kg) and G:F (0.36 vs. 0.35) compared with pigs fed no l-carnitine, and the response was additive to that of RAC. Analysis of treatments common to all experiments showed that pigs fed RAC had increased (P < 0.01) ADG (1.03 vs. 0.93 kg) and G:F (0.40 vs. 0.35) compared with pigs fed no RAC. Pigs fed l-carnitine tended to have increased (P = 0.07) ADG (1.00 vs. 0.96 kg) and improved (P < 0.01) G:F (0.38 vs. 0.37) compared with pigs not fed l-carnitine. These results confirm that RAC improves growth performance of finishing pigs. Added l-carnitine improved growth performance of finishing pigs, and the greatest response was observed in Exp. 3 and 4, which were conducted in commercial research environments. These experiments imply that adding l-carnitine to a finishing diet does not enhance the growth effects of RAC and that effects of RAC and l-carnitine on ADG and G:F are independent.
本研究共使用了 2152 头猪（C22 × 336 PIC），进行了 4 个试验，以确定日粮左旋肉碱和盐酸莱克多巴胺（RAC）对育肥猪生长性能的互作效应。所有试验均采用主效应设计，包括左旋肉碱（试验 1 和 2 中添加 0、25 或 50mg/kg，试验 3 和 4 中添加 0 或 50mg/kg）和 RAC（试验 1 和 2 中添加 0、5 或 10mg/kg，试验 3 和 4 中添加 0 或 10mg/kg）的主效应。从 38kg 到 109kg（试验 1 和 3）或宰前最后 4 或 3 周（118kg；试验 2 和 4）添加左旋肉碱。RAC 连续添加 4 周（试验 1、2 和 3）或 3 周（试验 4）。试验 1 和 2 在大学研究设施中进行，试验 3 和 4 在商业研究设施中进行。在每个试验的最后阶段，所有日粮均以含有 1.00%总赖氨酸进行配制。在所有试验中，与未添加 RAC 的猪相比，添加 RAC 的猪 ADG 和 G:F 增加（P<0.05）。在 RAC 喂养期之前添加左旋肉碱不会影响猪的生长性能。在试验 1 和 2 中，在最后 4 周内，左旋肉碱对 ADG 没有影响；然而，在试验 2 中，随着左旋肉碱添加量的增加，G:F 呈（二次；P=0.07）改善趋势。在试验 3 中，观察到了左旋肉碱和 RAC 的互作效应（P<0.04）对 ADG 和 G:F 的影响。添加左旋肉碱和 RAC 都提高了性能，但反应不是累加的。在试验 4 中，与未添加左旋肉碱的猪相比，添加左旋肉碱的猪 ADG（0.88 比 0.84kg）和 G:F（0.36 比 0.35）增加（P<0.04），且对 RAC 的反应是累加的。对所有试验共有的处理进行分析表明，与未添加 RAC 的猪相比，添加 RAC 的猪 ADG（1.03 比 0.93kg）和 G:F（0.40 比 0.35）增加（P<0.01）。与未添加左旋肉碱的猪相比，添加左旋肉碱的猪 ADG 呈（P=0.07）增加趋势（1.00 比 0.96kg），G:F 改善（P<0.01）（0.38 比 0.37）。这些结果证实 RAC 可改善育肥猪的生长性能。添加左旋肉碱可改善育肥猪的生长性能，且在试验 3 和 4 中观察到最大的反应，这两个试验是在商业研究环境中进行的。这些试验表明，在育肥日粮中添加左旋肉碱不会增强 RAC 的生长效果，且 RAC 和左旋肉碱对 ADG 和 G:F 的影响是独立的。
