Use of ractopamine during compensatory gain of finishing pigs on carcass and meat performance and quality

ABSTRACT The objective of this study was to evaluate the effects of compensatory gain associated with the use of 10ppm ractopamine after a period of feed restriction in finishing pigs on performance, carcass and meat quality. Twenty castrated males and 20 females, at 110 days of age and 66.137±6.13kg live weight, were submitted to four treatments using a 2 x 2 factorial design (fed ad libitum or with 20% restriction between 0(21 days of age and fed with or without 10ppm ractopamine for 22(42 days of experimentation), with 10 replicates (animals). There was no interaction between the factors for any of the evaluated parameters. Animals treated with ractopamine presented better weight gain (1.083 versus 1.259kg), feed conversion (2.910 versus 2.577), warm and cold carcass weight (86.08 versus 89.00 and 83.46 versus 87.20kg, respectively), loin depth (63.02 versus 68.40mm), loin eye area (41.43 versus 46.59mm2) and muscle fiber diameter (27.48 versus 35.85μm). Animals submitted to feed restriction followed by ad libitum feed presented compensatory gain without losses to carcass and meat characteristics, but with a reduction in the ethereal extract (2.19 versus 1.64%) and lower water loss due to thawing in the meat (11.35 versus 9.42%). The effects of compensatory gain after food restriction and ractopamine are independent of the parameters evaluated.

摘要
本研究旨在评估育肥猪在经历一段期限饲后，添加10ppm莱克多巴胺（ractopamine）所带来的补偿生长（compensatory gain）对其生产性能、胴体品质及肉品品质的影响。试验选取40头生猪，含20头去势公猪与20头母猪，均为110日龄，初始活重为66.137±6.13kg，采用2×2因子设计设置4个处理组：分别于21日龄起至试验第22~42天期间，实施自由采食或20%限饲，并分别添加或不添加10ppm莱克多巴胺，每个处理设置10个重复（每重复1头试验动物）。
各评估参数均未观测到因子间存在交互作用。饲喂莱克多巴胺的试验猪表现出更优的生产性能：平均日增重更高（1.083 vs 1.259kg）、饲料转化率更佳（2.910 vs 2.577）、热胴体重与冷胴体重更高（分别为86.08 vs 89.00kg、83.46 vs 87.20kg）、背膘厚度更大（63.02 vs 68.40mm）、眼肌面积更广（41.43 vs 46.59mm²）且肌纤维直径更粗（27.48 vs 35.85μm）。
经限饲后转为自由采食的试验猪呈现出补偿生长现象，其胴体与肉品特性未出现不良损失，但乙醚浸出物含量降低（2.19% vs 1.64%），且肉品解冻失水率更低（11.35% vs 9.42%）。
限饲后补偿生长与莱克多巴胺的使用效果，对于所有评估参数而言均相互独立。