80 Effects of dietary standardized ileal digestible lysine level in the nursery period and number of dietary phases in the grow-finish period on wean-to-finish growth performance of pigs

Abstract

Abstract The objective was to determine if feeding differing levels of dietary standardized ileal digestible lysine (SID Lys) during the nursery phase influenced the growth performance response to the number of dietary phases fed in the grow-finish period. A split-plot design was used with a 3×2 factorial arrangement of the following treatments: 1) SID Lys level nursery period: Control (SID Lys at requirement) vs. Restricted (0.2 g/kg SID Lys below Control) vs. Excess (0.1 g/kg SID Lys above Control; 2) Number of Dietary Phases in grow-finish: 3 vs. 5. Diets were formulated to meet NRC (2012) requirements, except for SID Lys during the nursery period. The study was carried out over the nursery [weaning (21±2 d; 5.8 ± 0.05 kg BW) to wk 9 post-weaning] and grow-finish [wk 9 to 19 post-weaning (112 ± 3.7 kg BW)] periods using 4,356 pigs housed in single-sex groups of 44 pigs, at a floor space of 0.30 m2/pig and 0.62 m2/pig in nursery and grow-finish periods, respectively. Data were analyzed using PROC MIXED of SAS; pen was the experimental unit. The model included fixed effects of SID Lys level (main plot), Number of Dietary Phases (split plot), their interaction, and random effects of block and block by SID Lys level interaction. There were no treatment interactions (P > 0.05). The Restricted Lys treatment reduced (P < 0.05) ADG and G:F in the nursery period compared to other treatments, but had no effect on these measurements in the grow-finish or wean-to-finish periods. There was no effect (P > 0.05) of the number of dietary phases on growth performance in grow-finish. In conclusion, feeding low levels of Lys in the nursery reduced nursery but not wean-to-finish growth performance; reducing the number of dietary phases in grow-finish from 5 to 3 had no impact on growth performance.