Dunshea F R, King R H, Campbell R G, Sainz R D, Kim Y S
Department of Agriculture, Victorian Institute of Animal Science, Werribee, Australia.
J Anim Sci. 1993 Nov;71(11):2919-30. doi: 10.2527/1993.71112919x.
Sixty pigs were used to investigate the effects of two levels of dietary ractopamine (RAC; 0 and 20 mg/kg) and three sex types (SEX; boars, gilts, and barrows) on performance over the live weight range 60 to 90 kg. Pigs were housed in individual pens and allowed ad libitum access to a diet containing 3.466 Mcal of DE and 10.7 g of lysine/kg. Control boars exhibited faster and more efficient growth and deposited more protein and less fat than gilts or barrows. The RAC increased ADG by 17 and 21% in gilts and barrows but not in boars. Feed intake was not altered by dietary RAC. Dietary RAC increased the rate of protein deposition by 15, 42, and 41% in boars, gilts, and barrows, respectively. Nevertheless, the daily rate of protein deposition was greatest in RAC-treated boars. The RAC tended to reduce the daily rate of fat deposition by 21% in boars but not in gilts or barrows. Carcass protein content increased by 5% and fat content decreased by 8% in response to RAC. These improvements in carcass composition occurred without compromising meat quality. Results show that RAC is a potent stimulator of protein deposition in finishing pigs. However, increased protein deposition is not necessarily at the expense of fat deposition.
选用60头猪来研究两种水平的日粮莱克多巴胺（RAC；0和20毫克/千克）以及三种性别类型（SEX；公猪、后备母猪和去势公猪）对60至90千克体重范围内生长性能的影响。猪单独饲养在栏舍中，自由采食含3.466兆卡消化能和10.7克赖氨酸/千克的日粮。对照公猪比后备母猪或去势公猪生长更快、更高效，沉积的蛋白质更多而脂肪更少。RAC使后备母猪和去势公猪的平均日增重分别提高了17%和21%，但对公猪没有影响。日粮RAC未改变采食量。日粮RAC分别使公猪、后备母猪和去势公猪的蛋白质沉积率提高了15%、42%和41%。然而，经RAC处理的公猪每日蛋白质沉积率最高。RAC倾向于使公猪的每日脂肪沉积率降低21%，但对后备母猪或去势公猪没有影响。胴体蛋白质含量因RAC而增加了5%，脂肪含量降低了8%。胴体组成的这些改善并未损害肉质。结果表明，RAC是育肥猪蛋白质沉积的有效刺激剂。然而，蛋白质沉积增加不一定以脂肪沉积为代价。
