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：本研究评估了铬补充剂与能量限制作为莱克多巴胺（ractopamine）替代品，应用于育肥后期小母猪日粮的效果。试验共使用60头初始体重为98.87±0.25 kg、终末体重为122.69±10.97 kg的小母猪，采用随机区组设计，设置5种试验日粮：对照组、酵母铬（yeast chromium）组（添加量0.8 ppm）、吡啶甲酸铬（chromium picolinate）组（添加量0.48 ppm）、莱克多巴胺（ractopamine）组（添加量20 ppm）以及能量限制组（每千克饲料代谢能（EM）降低150 kcal），共设置6个重复，每个重复单元包含2头试验动物。饲喂添加莱克多巴胺的日粮，可使育肥后期小母猪获得更优的饲料转化率（P<0.05）与更高的热胴体重。与添加铬制剂及能量限制的日粮组相比，莱克多巴胺组的每千克增重饲料成本更低（P<0.05），经济效益更佳；且该两组的试验效果均优于对照组。与对照组及能量限制组相比，添加铬制剂与莱克多巴胺的日粮可显著提升瘦肉率与瘦肉产量（P<0.05），同时提高胴体奖励率。与对照组相比，能量限制未对小母猪的生长性能产生不良影响。补充莱克多巴胺可改善饲料转化率、降低每千克增重饲料成本，并提升经济效益指数。添加铬制剂与莱克多巴胺均可提高胴体的瘦肉率、瘦肉产量及胴体奖励指数。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，用于优化育肥后期小母猪的胴体性能指标。