Carcass characteristics, chemical and fatty acid composition of Longissimus muscle of Purunã bulls slaughtered at 18 or 24 months of age

Abstract

This study was carried out to evaluate carcass characteristics, chemical and fatty acid composition of the Longissimus muscle of 78 Purunã bulls (39 bulls/treatment) slaughtered at 18 or 24 months old. The experimental design was completely randomized. The bulls were distributed 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 < 0.05) conformation (12.46 vs. 13.41 points), higher (p < 0.05) subcutaneous fat thickness (3.82 vs. 3.11 mm), lower (p < 0.05) Longissimus area (66.17 vs. 70.87 cm2), lower (p < 0.05) muscle percentage (60.64 vs. 64.26%) and higher (p < 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 < 0.05) between both slaughter ages. The total lipid percentage was higher (p < 0.05) for the T18 system (1.61 vs. 1.33%). Longissimus muscle fatty acid composition was not influenced (p < 0.05), with exception of C18:1 n-9 and C18:3 n-3, which were lower (p < 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 < 0.05) according to slaughter age.