Fontes e níveis de vitaminas e minerais na deposição de gordura intramuscular e qualidade da carne em novilhas Angus x Nelore

Abstract

The experiment aimed to evaluate the effect of premixes containing different sources and levels of trace elements and vitamins on intramuscular fat deposition and meat quality in crossbred Angus x Nelore heifers. Forty-two females weighing approximately 358 kg and aged 13 to 26 months were divided into three experimental groups of 14 animals each: Treatment A (Control) – standard level of vitamins A, D and E; without vitamins in the B and C complex; selenium and zinc in inorganic forms; Treatment B - without vitamin A, vitamin D at a reduced level and vitamin E at a higher level; without vitamins in the B and C complex; zinc (same level as treatment A) and selenium at a reduced level, in organic forms; and Treatment C - without vitamin A, vitamin D at a reduced level and vitamin E at a higher level, with vitamins in the B and C complex; selenium and zinc (level of treatment B) in organic forms. The animals were weighed biweekly and consumption was monitored daily by pen. Ultrasound measurements were performed at the beginning and end of the experiment. Meat quality analyses were performed after slaughter. Overall, weight gain results were similar among the 3 experimental groups. Mean delta marbling was numerically higher for treatment C compared to the others. The highest b* value was observed for treatment C, not significantly different from A, but tending to be different from B. Treatment C had the highest number of carcasses classified as having the highest grades (Treatment A: 38%, Treatment B: 31%, Treatment C: 58%). For animals with low initial levels of marbling measured by ultrasound (<3.35), Treatment C tended to provide a higher mean USDA score at the end compared to Treatment A (+1.4 points), and Treatment C tended to have higher total fat content in the rib eye. The cost of the formula was the highest for treatment C and the lowest for treatment A. However, considering a special carcass grading program for the Angus breed (Brazilian Gold Program) and the extra payment of this program (10% bonus), Treatment C provided the highest number of carcasses that could be graded and receive extra revenue.