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. RESUMO Objetivou-se avaliar os efeitos do ganho compensatório associado ao uso de 10ppm de ractopamina após um período de restrição alimentar, em suínos em terminação, sobre características de desempenho, carcaça e qualidade de carne. Foram utilizados 20 machos castrados e 20 fêmeas, com 110 dias de idade e 66,137±6,13kg de peso vivo, submetidos a quatro tratamentos, fatorial 2 x 2 (alimentação à vontade ou com 20% de restrição entre zero e 21 dias de experimentação; e alimentação à vontade, sem ou com 10ppm de ractopamina, durante 22 a 42 dias de experimentação), com 10 repetições, sendo o animal a repetição. Não houve interação entre os fatores para nenhum dos parâmetros avaliados. Animais tratados com ractopamina apresentaram melhor ganho de peso (1,083 versus 1,259kg), conversão alimentar (2,910 versus 2,577), peso da carcaça quente e fria (86,08 versus 89,00 e 83,46 versus 87,20kg, respectivamente), profundidade do lombo (63,02 versus 68,40mm), área de olho de lombo (41,43 versus 46,59mm2) e diâmetro de fibras musculares (27,48 versus 35,85µm). Animais submetidos à restrição alimentar seguida de arraçoamento