Efeito da injeção de vitamina A ao nascimento sobre o desenvolvimento de gordura intramuscular e qualidade da carne em bovinos de corte

Abstract

The objective of the currently study was to evaluate the effects of one dose administration of vitamin A (300,000 IU) at birth on performance, carcass traits, meat quality and gene expression in beef cattle. So 34 calves Montana  Nellore were utilized (14 females and 20 males) in a completely randomized design, since birth until finishing. Were performed biopsies in longissimus thoracis (LT) muscle on day 40 after birth and at weaning, and a sampling at slaughter. Animals were weaning at 270 days and feedlot period lasted 180 days. Performance were not affected by vitamin A. Males presented higher average daily gain, final weight and hot carcass weight. Vitamin A improved fat content of LT. Vitamin A administration increased the expression of angiogenic genes PDFGRA e VEGF4 at day 40 after birth and at weaning. For adipogenic genes, the vitamin A administration increased ZNF423 expression at weaning and slaughter in all animals. In addition, females presented greater expression of PPARG at day 40 after birth and at weaning. The expression of myogenic gene WNT were higher at day 40 after birth and at weaning in animals that received vitamin A. At slaughter, WNT expression were higher in males than females, both from control treatment. Vitamin A administration also increased expression of lipogenic genes FABP4 at day 40 after birth, SREBF1 at day 40 after birth and at weaning, on the other hand, decreased expression of FABP4 at weaning. Also, at weaning males that received vitamin A presented greater expression of FABP4 than females from control treatment. At day 40 after birth, females presented greater expression of PPARA than males. Furthermore, expression of SCD1 were greater at day 40 after birth in males that received vitamin A, whereas at slaughter were greater in females from control treatment. Thus, vitamin A administration in cattle at birth proved to be effective as an alternative to improve marbling content without affect animal performance.