EFFECT OF AVILAMYCIN AND TYLOSIN ON THE M ETABOLIZABLE ENERGY IN GROWING AND FINISHING PIGS

In two metabolism trials with growing and finishing pigs the influence of the antibiotic feed additives Avilamycin and Tylosin on the metabo lizable energy was investigated at different levels of dietary protein content. In the first experiment (growing pigs) the antibiotics were supplied al levels of 0 mg/kg, 40 mg/kg Avilamycin and 40 mg/kg Tylosi n to diets containing 18.5%, 17.5%, 16.5% and 14.0% of crude protein. In the second experiment (finishing pigs) 0 mg/kg antibiotics, 20 mg/k g Avilamycin and 20 mg/kg Tylosin were used in diets containing 16.5% and 14.0% of crude protein. The body weight of the animals averaged 46 kg (growing pigs) and 68 kg (finishing pigs). In growing pigs the sup plementation of Tylosin increased the digestibility of dry matter and energy at 1 percentage unit each, while in finishing pigs no effects w ere observed. Since the urinary energy excretion was not affected by a ntibiotics, there was only in Tylosin treated growing pigs a slight ri se in dietary contents of metabolizable energy by 1.6%. The reduction of the dietary protein content resulted in increased digestibility of dry matter and energy, reduced urinary energy excretions and increased dietary contents of metabolizable energy.