Effects of vitamin A supplementation on growth performance, carcass characteristics and meat quality in Limosin × Luxi crossbreed steers fed a wheat straw-based diet

Three experiments were conducted to examine the effects of dietary vitamin A supplementation on performance and carcass parameters in Limosin × Luxi crossbreed finishing steers fed a wheat straw-based diet. Sixteen 12-month old (301 ± 22 kg) steers, 16 12-month old (309 ± 15 kg) steers and 16 24-month old (411 ± 20 kg) steers were used in experiment 1 for 6 months feeding period, in experiment 2 for three months feeding period and in experiment 3 for three months feeding period, respectively. Sixteen steers of each experiment were randomly divided into the four groups of four animals. Treatments consisted of four vitamin A supplementation levels (0, 1100, 2200 and 4400IU/kg DM). The growth rate was affected by dietary vitamin A level in experiment 1 and 2, revealing that the suitable amount of vitamin A supplementation increased the growth rate; excessive vitamin A in the ration decreased the growth rate of 12-month-old finishing steers. The marbling deposition decreased with the increment of vitamin A supplementation level, but possibly associated with vitamin A supplementing duration. Furthermore, the suitable dietary vitamin A level probably decreased lipid and pigment oxidation, and increased the tenderness of beef meat. Vitamin A supplementation had no significant effect on chemical composition of gluteus medius muscle and longissimus dorsi muscle.