PSVII-21 Revision of the model estimating real-time Lys requirements in individual growing-finishing pigs

Abstract

Abstract The objective of this study was to review the calibration of the model estimating real-time Lys requirements individual in growing-finishing pigs. Two 28 d growth experiments were performed with 110 pigs distributed in a complete randomized design with growing (25 kg BW ± 2.1, n = 60; 10 pigs per treatment) and finishing (68 kg BW ± 1.8, n = 60; 10 pigs per treatment) barrows. Pigs were fed with 60, 70, 80, 90, 100, or 110% of the pig’s estimated individual standardized ileal digestible (SID) Lys (SIDLys) requirements. Body composition was measured by dual-energy X-ray densitometry on days 1 and 28 of the trial. Pigs were housed in the same pen but fed individually using computerized feeding stations. The Mixed and NLIN procedures of SAS were used to analyze the data and estimate optimal SIDLys requirements. In the growing and finishing trials protein in gain (17 to 19%; 13 to 16%) and N efficiency (52 to 65%; 40 to 55%) increased linearly (P < 0.01) with the increasing levels of SIDLys. Maximum ADG (0.98 kg/d) and protein deposition (PD; 170 g/d) were observed in growing pigs fed at 100% of the estimated SIDLys requirements (P < 0.001). Finishing pigs had maximal ADG (1.2 kg/d) when fed at 100% of the estimated SIDLys requirements, but PD increased linearly (P < 0.05) with SIDLys levels without reaching a plateau at the higher levels of Lys intake. The proposed model correctly estimates the level of SIDLys that maximizes PD and ADG in growing (25 to 50 kg of BW), and ADG in finishing pigs (65 to 100 kg BW); still, there is an opportunity for increasing PD in older pigs fed using precision feeding techniques.