The chemical composition and meat quality of 48 feedlot finished Charolais-Nellore steers, fed ad libitum with a 52% corn silage and 48% concentrate, diet that included 0, 100 or 200mg/day of sodium monensin, were evaluated in a completely randomized design. Diets contained 12.3% of crude protein and 58.3% of neutral detergent fibre. Monensin was mixed with the concentrate. Monensin addition did not alter the Longissimus dorsi muscle content of dry matter, crude protein and ether extract (P>0.05), nor influenced meat thawing or cooking losses, shear force, tenderness, color and marbling (P>0.05). However, the palatability and juiciness decreased linearly with monensin addition (P<0.05). On the other hand, meat texture varied in a quadratic way as monensin level increased (P<0,05). Ionophore inclusion did not influence saturated to unsaturated fatty acids ratio (P>0.05), but increased linearly the content of oleate cis and trans isomers (C18:1 n9c e C18:1 n9t). Although the proportion of these specific fatty acids increased, monensin addition reduced meat quality, mainly by decreasing palatability and juiciness.
saturated fatty acids; unsaturated fatty acids; ionophore; palatability; juiciness
