摘要
This study was carried out to evaluate carcass characteristics, chemical and fatty acid composition of the Longissimus muscle of 78 Purun bulls (39 bulls/treatment) slaughtered at 18 or 24 months old. The experimental design was completely randomized. The bulls weredistributed into two systems: 1) Finished in feedlot 13 to 18 months old (T18), or 2) Finished in feedlot from 21 to 24 months old (T24). The diet, roughage:concentrate ratio of 52:48 (dry matter basis), contained 12% crude protein and 72% total digestible nutrients. The T18 system showed lower (p %26lt; 0.05) conformation (12.46 vs. 13.41 points), higher (p %26lt; 0.05) subcutaneous fat thickness (3.82 vs. 3.11 mm), lower (p %26lt; 0.05) Longissimus area (66.17 vs. 70.87 cm2), lower(p %26lt; 0.05) muscle percentage (60.64 vs. 64.26%) and higher (p %26lt; 0.05) fat percentage (23.56 vs. 20.00%). Moisture (73.27%), ash (1.05%), crude protein percentages (22.56%) and total cholesterol content (36.47 mg/100 g of muscle) were similar (p %26lt; 0.05) between both slaughter ages. The total lipid percentage was higher (p %26lt; 0.05) for the T18 system (1.61 vs. 1.33%). Longissimus muscle fatty acid composition was not influenced (p %26lt; 0.05), with exception of C18:1 n-9 and C18:3 n-3, which were lower (p %26lt; 0.05) for the T18 system. Saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, n-6, n-3 percentage and PUFA/SFA and n-6/n-3 ratio did not change (p %26lt; 0.05) according to slaughter age. Este trabalho teve como objetivo avaliar as caracter赤sticas da carca a e composi o qu赤mica do m迆sculo Longissimus de 78 bovinos Purun (39/tratamento) abatidos no sistema super precoce (SUP) e precoce (PRE). Os bovinos foram distribu赤dos em dois sistemas: 1. Termina o em confinamento dos 13 aos 18 meses de idade (SUP) ou 2. Termina o em confinamento dos 21 aos 24 meses de idade (PRE). Os animais receberam uma dieta com 12% de prote赤na bruta e 72% de NDT compropor o volumoso:concentrado de 52:48. Animais do sistema SUP apresentaram menor (p %26lt; 0,05) conforma o (12,46 vs. 13,41 pontos), maior (p %26lt; 0,05) espessura de gordura de cobertura (3,82 vs. 3,11 mm), menor (p %26lt; 0,05) 芍rea do Longissimus (66,17 vs. 70,87 cm2), menor(p %26lt; 0,05) percentagem de m迆sculo (60,64 vs. 64,26%) e maior (p %26lt; 0,05) percentagem de gordura (23,56 vs. 20,00%). A percentagem de umidade (73,27%), cinzas (1,05%), prote赤na bruta (22,56%) e teor de colesterol total (36,47 mg 100 g-1 de m迆sculo) foi similar (p %26lt; 0,05) entre o peso de abate. A maior (p %26lt; 0,05) percentagem de lip赤deos totais foi para o SUP (1,61 vs. 1,33%). A composi o de 芍cidos graxos n o