215 Compensatory Growth Following One or Two Weeks of Lysine Restriction at Weaning

Abstract

Abstract At weaning it is increasingly common to feed low crude protein (CP) and low standardized ileal digestible (SID) lysine (LYS) diets for improved health outcomes. This nutrient restriction often leads to decreased growth. Compensatory growth in this discussion is a period of enhanced growth that occurs after a period of nutrient restriction. This experiment was conducted to determine if compensatory growth occurs after one or two-weeks restriction of SID LYS at weaning. For the experiment, pigs (n = 252; ~23.5 days of age, 7.24 ± 1.02 kg BW, 8 reps/treatmentt, 5 or 6 pigs/pen) were randomly allotted to one of six treatments in a randomized complete block design with a 2 x 3 factorial arrangement of treatments. Treatment main effects were SID LYS/CP (0.07 or 0.065) or duration of SID LYS restriction (1.2% SID LYS for 0, 1, or 2 weeks). When not restricted, pigs were fed a diet with 1.5% SID LYS. After the first 14 days, all pigs consumed a common diet for 24 days with 1.35% SID LYS. Body weight, feed disappearance, visual fecal scores, and visual piglet scores were measured. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Pairwise comparisons with Tukey adjustment were used for treatment LSmean separation. No effect of SID LYS/CP or interaction of SID LYS/CP and SID LYS program was detected. Results for the main effect of SID LYS program is presented in Table 1. Restricting SID LYS for the first week resulted in decreased ADG and gain:feed (P < 0.05; Table 1). This same effect was observed in week 2. However, those pigs that moved from 1.2% SID LYS in week 1 to 1.5% SID LYS in week 2 had the similar ADG and gain:feed during week 2 as the pigs that consumed 1.5% SID LYS for both weeks. Pigs that had two weeks of SID LYS restriction had lower body weight at d 38 (P< 0.05), whereas pigs with one week of SID LYS restriction had similar body weight at d 38 to unrestricted LYS fed pigs. In addition to performance, unrestricted LYS decreased stool quality (P<0.05) but improved the visual appearance of pigs (P < 0.10) at d 14 and d 38. In conclusion, pigs can have compensatory growth when SID LYS is restricted from 1.5% to 1.2% for one week, but not two weeks.