Resumen

AGOSTINI, P.S. et al. Effects of ractopamine on performance and physiology of pigs. Arch. zootec. [online]. 2011, vol.60, n.231, pp.659-670. ISSN 1885-4494.  https://dx.doi.org/10.4321/S0004-05922011000300054.

The goal of this work was to evaluate the inclusion of different levels of ractopamine to finishing rations for swine, during 21 days before the slaughter, on the performance, carcass and meat quality parameters and on physiologic and serum characteristics related with behavior. Thirty six pigs (Large White x Landrace), 18 barrows and 18 females, weighting 87.0±5.02 kg, fed ad libitum with isonutrient rations, with 0, 10 and 20 ppm of ractopamine, were used. The experimental design was randomized blocks, factorial 3 x 2 (3 levels of ractopamine and 2 genders), with 6 repetitions for the performance parameters and 12 repetitions for the other characteristics. There were a positive linear effect (p<0.05) to the weigh gain and to the feed conversion rate and a quadratic effect to the feed consumption (been the minimal point to 9.4 ppm of ractopamine). To the carcass parameters there was a quadratic effect to the carcass yield (been the minimal point to 9.5ppm of ractopamine). The parameters a^*(red-blue component) and c^*values (saturation index) and marbling presented a negative linear effect according to the levels of ractopamine. The fiber diameter of the L. dorsi muscle and the tonality angle index (h^*) showed a positive linear effect to the levels of ractopamine. There were no effects on the other meat quality characteristics, resulting meats without PSE and DFD. The ractopamine can be used until 20 ppm with positive effects on the performance and carcass parameters, without effects on the behavior and on meat quality.

Palabras clave : Beta adrenergic; Stress; Fat.

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