DIETARY SALBUTAMOL AND LEVEL OF PROTEIN - EFFECTS ON THE ACUTE STRESS-RESPONSE IN PIGS

Effect on the acute stress response of dietary inclusion of 3 ppm salb utamol (beta-2-adrenergic agonist) at two levels of protein were inves tigated in growing pigs (from 25 kg live weight). The trial comprised six litters (blocks) of four females allocated randomly to four treatm ent groups in accordance with a 2 X 2 factorial arrangement. The respo nse to an open-field test and to an intruder were measured at 50 kg li ve weight. Salbutamol increased immobility and looking, reduced total exploration, and increased plasma ACTH after test. At high dietary lev els of protein, salbutamol also increased the latency to attack. High dietary levels of protein reduced standing still, latency to contact a novel object and an intruder, and level of plasma cortisol before tes t. Moreover, high protein without salbutamol seemed to reduce the late ncy to attack an intruder. In conclusion, chronic treatment with salbu tamol shifted the acute stress response in pigs toward a passive respo nse, whereas high dietary level of protein provoked an active response , which may have consequences in pig production.