Interaction Between Feeding Techniques and Ambient Temperature on Growing Pigs Performance and Body Composition

Pigs maintained in hot environments voluntarily reduce feed intake, and thus growth performance, to lower the heat dissipation burden. Feeding pigs with low protein diets has been proposed to attenuate the negative effects of heat stress in pigs reared in hot climate areas. The aim of this study was to evaluate the performance and body composition of pigs fed in conventional group-phase feeding systems (CONV) or fed individually with daily tailored diets (PREC: precision feeding) under two thermal conditions (TN: thermoneutral, 23°C; and HT: high temperature, 30°C). Forty-eight 41-kg (± 0.98) BW barrow pigs were assigned to treatments (12 animals per treatment) in a 2×2 factorial arrangement. The experiment lasted 55 days (phase 1 from d 0 to 27 and phase 2 from d 28 to 55). CONV fed pigs received within each phase a constant blend of diets A (high nutrient density) and B (low nutrient density) supplying the estimated nutrient requirements of the group, while PREC pigs received daily a personalized blend providing the estimated amount of nutrients. Body mineral, and lean and fat masses were assessed by dual-energy X-ray absorptiometry at the beginning and at the end of each phase. Data were analyzed using the MIXED procedure of SAS including the fixed effects of feeding system (FS), ambient temperature (AT) and their interactions. Initial BW was included as a covariate. ADFI, ADG, net energy intake (NEI) and lysine intake (LI) were lower at 30°C than at 23°C (P < 0.01) but were similar within FS. LI was lower in PREC than in CONV pigs at both 23°C and 30°C (-16.9% and - 14.1%, respectively) but had similar growth performance. The means of protein (PG) and lipid (LG) gain, body protein (BPC) and lipid (BLC) content were different (P < 0.01) for AT independently of FS. In the PREC, bone mineral content was lower (P = 0.01) than CONV (1.16 and 1.26 kg) at 23°C. The results of this study indicate that precision feeding may be an efficient strategy for high as well as thermoneutral temperatures, reducing the excessive nutrient intake of pigs, without impairing the performance and body composition.