Three experiments, an essay of digestibility, other of morphometrical intestinal evaluation and of performance were carried out to evaluate the effects of inclusion of Calsporin® (0,03%), fumaric acid (1,5%) and zinc bacitracin with 15% of activity (0,10%) in diets, separated or combined, on utilization of dry matter, crude protein, neutral detergent fiber, gross energy and the morphometrical jejunal analysis and the essay performed of growing rabbits. For the digestibility essay 64 White New Zealand rabbits were used, half of each sex, 50 days old, distributed on a completly randomized design with eight treatments and eight replicates. There was no difference for the digestibility coefficients of dry matter, organic matter, crude protein, neutral detergent fiber and gross energy among the treatments. For the morphometrical jejunal analysis, 100 White New Zealand rabbits were slaughtered, four in the begining of the experiment, with 35 days old, and four animals per treatment at 50, 60, and 75 days old. The inclusion of the additives in the diet, separated or combined, had no effect on the jejunal wall , muscularis external tunica and the total wall morphometry of the growing rabbits. However the thickness of mucosal tunic decreased linearly with the age of rabbits. For the performed essay, 176 White New Zealand rabbits were used, half of each sex, from 35 to 75 days old, allocated in a completely randomized design, with eight treatments, 11 replicates and two animals for each replicate. The inclusion of the additives, separated or combined, had no effect on the performance from 35 to 50 days old. In the total experimental period, the best performance was observed in the animals fed with diets containing fumaric acid, fumaric acid + zinc bacitracin and the diets containing the three additives. The weight and yield carcass, were higher to the animals fed with the addition of fumaric acid or fumaric acid + zinc bacitracin in their diets. There were no effects of the treatments on the liver, kidneys and heart weight.
calsporin®; digestibility; fumaric acid; intestinal morphometry; jejunun; performance; zinc bacitracin
