Resumen

PEREZ, Aníbal; OBISPO, Néstor E; PALMA, José  y  CHICCO, Claudio F. Effect of ractopamine and lysine levels on the performance of leaning pigs in the finishing phase. Zootecnia Trop. [online]. 2005, vol.23, n.4, pp.429-445. ISSN 0798-7269.

Genetically improved leaning pigs (gilts and barrows) in the finishing phase were used to investigate the effect of two levels of ractopamine (RAC: 0 and 100 ppm) and three levels of lysine (Lys: 0.95, 1.05, and 1.15%) on the average daily gain (ADG), hot (Hw) and cold (Cw: 24 and 48 h) weights, dressing percentage (DP), and drip losses at 24 (DL24) and 48 hours (DL48). There was an interaction between sex and RAC which allowed gilts ADG were similar than those observed for barrows. ADG was higher (P<0.001) for those pigs on Lys 1.15%, with increases of 8.2 and 11.03% for the treatments Lys 0.95 and 1.05%, respectively. Hw was higher (P<0.01) for Lys 095% than Lys 1.05 and 1.15% by 4.9 and 3.5 kg, respectively. DP, Cw 24 and 48h were not affected by the level of this amino acid in the diet. Lys at 1.05% showed higher (P<0.001) drip losses at 24 and 48h, with values of 2.61 and 1.80 kg, respectively. The lower drip losses were observed for Lys 1.15% (1.92 and 1.23 kg, for 24 and 48 h, respectively). RAC10 was 5.85 kg higher (P<0.001) in Hw than control. Similarly, adding RAC showed higher (0.9 percentage units) than RAC0 (P<0.05). Cw at 24 and 48 h were much higher RAC10 with increases of 5.863 and 5.13 kg, respectively, as compared to RAC0. DL 24 were similar between treatments, however DL48 was higher (P<0.001) by 0.709 kg for RAC10 as compared to RAC0.

Palabras clave : Pig; ractopamine; lysine; dressing percentage; average daily gain.