Chromium and energy restriction as substitutes for ractopamine in finishing gilts diet

ABSTRACT: This study evaluated chromium supplements and energy restriction as substitutes for ractopamine in the diets of late finishing gilts. Sixty gilts were used, with initial weights of 98.87 ± 0.25 kg and final weights of 122.69 ± 10.97 kg, distributed in a randomized block design with five diets: control; yeast chromium (0.8 ppm); chromium picolinate (0.48 ppm); ractopamine (20 ppm) and energy restriction (reduction of 150 kcal of EM kg-1 of feed), with six replicates and two animals per experimental unit. Feeding diet containing ractopamine enabled better (P<0.05) feed conversion and greater weights of the hot carcass of the gilts. The diet containing ractopamine exhibited a lower (P<0.05) cost of feed per kilogram of gain and higher economic efficiency, when compared to diets containing chromium and energy restriction; these exhibited better outcomes, compared to the control diet. Diets supplemented with chromium and ractopamine resulted in a higher (P<0.05) percentage and quantity of lean meat and a higher rate of carcass bonus, when compared to the control diet and energy restriction. The energy reduction did not harm the gilts’ responses, compared to the control diet. Ractopamine supplementation allowed for a better feed conversion, lower feed cost per kilogram of gain, and a higher economic efficiency index. Supplements of chromium and ractopamine increased the percentage and quantity of lean meat and the bonus index of the carcasses. Therefore, chromium picolinate and chromium yeast are potential substitutes for ractopamine for optimizing the gilts carcass characteristics.

摘要：本研究以莱克多巴胺（Ractopamine）的替代方案为目标，评估了铬补充剂与日粮能量限制在育肥后期青年母猪饲养中的应用效果。试验共纳入60头青年母猪，初始体重为98.87±0.25 kg，终末体重为122.69±10.97 kg；试验采用随机区组设计，设置5组日粮处理：对照组、酵母铬（0.8 ppm）组、吡啶甲酸铬（0.48 ppm）组、莱克多巴胺（20 ppm）组，以及能量限制组（每千克饲料代谢能（Metabolizable Energy，EM）降低150千卡），每组设置6个重复，每个试验单元包含2头试验猪。
饲喂添加莱克多巴胺的日粮可显著改善（P<0.05）青年母猪的饲料转化率，同时提升其热胴体重。相较于添加铬补充剂与实施能量限制的日粮组，添加莱克多巴胺的日粮每千克增重所需饲料成本更低（P<0.05），且具备更高的经济效益；而上述两种处理组的生产性能均优于对照组。
与对照组及能量限制组相比，添加铬补充剂与莱克多巴胺的日粮可显著提升胴体瘦肉率与瘦肉产量（P<0.05），同时提高胴体溢价率。与对照组相比，日粮能量限制并未对青年母猪的生产性能产生负面影响。
莱克多巴胺补充剂可有效改善饲料转化率、降低每千克增重的饲料成本，并提升经济效益指数。铬补充剂与莱克多巴胺均可提升胴体瘦肉率与瘦肉产量，以及胴体溢价指数。综上，吡啶甲酸铬与酵母铬可作为莱克多巴胺的潜在替代品，用于优化育肥后期青年母猪的胴体性状。