PSVI-15 Effects of Dietary SID Lysine Restriction in the Growing Period and Number of Dietary Phases on Growth Performance of Growing-finishing Pigs

Abstract

Abstract This study evaluated the effects of dietary SID lysine restriction in the growing period and number of dietary phases in the growing-finishing (GF) period on growth performance of GF pigs (32.7 ± 9.43 kg to 115.5 ± 8.18 kg BW). A RCBD (block = gender and start day) was used with a 3 × 2 factorial arrangement of treatments: 1) Dietary SID Lysine Level {Control [NRC (2012) recommendation]; Moderate Restriction [0.15% lower than Control]; Aggressive Restriction [0.30% lower than Control]} and 2) Number of Dietary Phases in GF (4 vs. 2). Lysine level treatments were applied from 32 to 64 kg BW. Diets were based on corn-soybean meal and corn coproducts, formulated to be isocaloric, and to meet or exceed recommendations of NRC (2012) for each phase, with the exception of SID lysine levels which were according to treatment. A total of 4,488 pigs were housed in single-sex groups of 34 pigs (22 replicates) with floor space of 0.63 m2/ pig. Pigs had ad libitum access to feed and water throughout and were weighed at start and end of the study; feeder additions were recorded. Pen was the experimental unit and data were analyzed using R version 3.6.2. The model accounted for the fixed effect of treatments, the interaction, and random effect of block. There were no treatment interactions (P > 0.05) and no effect (P > 0.05) of Number of Dietary Phases on overall growth performance. Decreasing dietary SID lysine linearly reduced (P < 0.05) overall ADG and ADFI with no effect (P > 0.05) on G:F. Restricting dietary SID lysine level to the extent used in this study reduced overall growth rate with no impact on feed efficiency.