Interrelationships between dietary ractopamine, energy intake, and sex in pigs

Abstract

A major constraint to protein deposition in the pig is energy intake. Ractopamine (RAC) is a β-agonist which has been shown to increase protein deposition under both ad libitum and restrictive feeding regimes. To assess the interactions between energy intake, sex, and dietary RAC, 104 crossbred pigs (52 boars and 52 gilts) were used in a slaughter-balance experiment conducted over the growth phase of 60-90 kg liveweight. To obtain initial body composition, 4 pigs of each sex were slaughtered at 60 kg. The remaining 96 pigs were allocated to a 2x6x2 factorial experiment. The respective factors were sex (boar or gilt), dietary digestible energy (DE) intake (21-2, 24.7, 28.2, 32.7, 36.7 MJ DE/d..