Correlation of the muscle proteome with meat quality from Angus x Nellore cattle finished in different finishing systems, weight gain rates, and slaughter criteria

Abstract

The aim of this work was to correlate the muscle proteome with the post-mortem metabolism and the meat quality from Angus x Nellore cattle finished in different finishing systems, weight gain rates and slaughter criteria. The experiment will be carried out using a randomized block design (initial live weight) in a 2 x 2 x 2 factorial arrangement, with two finishing systems (pasture and feedlot), two weight gain rates (high and low) and two slaughter criteria (slaughter weight and time of feeding). Seventy-five Angus x Nellore cattle, with initial mean weight of 390 ± 30 kg and 20 months of age will be used. At the beginning of the experiment, three animals will be randomly separated to be slaughtered as reference animals. Of the remaining 72 animals, 36 animals will be housed in an experimental feedlot and 36 animals will be allocated in pens of Brachiaria brizantha cv. Marandu grass. In each finishing system (pasture and feedlot), two distinct weight gain rates will be defined with 18 animals per treatment: 1) feedlot with high rate of weight gain; 2) feedlot with low rate of weight gain; 3) pasture with high rate of weight gain; 4) pasture with low rate of daily weight gain. In addition, of the 18 animals from each finishing system mentioned above, nine animals will be slaughtered at 540 kg live weight and nine animals will be slaughtered after 140 days of feeding. After slaughter, the post-mortem metabolism will be evaluated, as well as the meat quality traits at different ageing times, which will be correlated with the muscle proteome. The muscle proteome will be extracted, its concentration will be determined and the muscle proteins will be identified and correlated with the meat quality traits. It is expected, with this study, to determine that changes in post-mortem metabolism and in the meat quality attributes of finished animals to pasture x feedlot are given by the finishing system or rate of weight gain of the animal. In addition, it is expected to characterize the muscle proteome of animals from different finishing systems, weight gain rates and slaughter criteria, and to identify protein markers for postmortem metabolism, meat color and tenderness.