29 Effects of using different dietary standardized ileal digestible lysine plans on growth performance and carcass characteristics of PIC 337 or PIC 800 sired grow-finish pigs

Abstract The present study aimed to evaluate the impact of using different dietary standardized ileal digestible (SID) lysine (Lys) plans on growth performance of PIC 337 and PIC 800 sired grow-finish pigs. A total of 2,016 gilts and barrows were placed in 2 separate rooms with 48 single sex pens each (21 pigs/pen; 0.69 m2/pig). Pens were blocked by body weight (BW) and randomly allotted in a 2 × 2 × 2 factorial arrangement with genetic line (PIC 337 or 800), sex (barrows or gilts), and nutrition plan (current SID Lys curve recommendation for PIC 800 as % of PIC 337 SID Lys curve or alternative SID Lys curve) as factors. Pigs (27.4 ± 1.41 kg BW) were followed during the grower-finisher phase until slaughter. Pigs were fed either the current recommendation or an alternative SID Lys curve for PIC 800, in a 5 phase feeding program: phase 1 (23-40 kg; 97 vs 100%, respectively); phase 2 (40-60 kg; 97 vs 95%, respectively); phase 3 (60-80 kg; 97 vs 95%, respectively); phase 4 (80-105 kg; 97 vs 95%, respectively); and phase 5 (105-135 kg; 97 vs 90%, respectively). Pigs were fed isoenergetic diets. Performance and carcass traits, and removals and mortality were recorded. Data were analyzed using mixed models in R, and considering pen as the experimental unit for performance traits and individual carcasses for carcass traits. There was no evidence of interaction between genetic line and nutrition plan factors. Overall, PIC 337 vs 800 pigs did not differ on average daily gain (ADG; P 0.05), but PIC 337 pigs consumed 150 g/d less and were 0.1 more feed efficient than PIC 800 pigs (P 0.05; Table 1). Moreover, PIC 337 pigs had 1.9 kg less of hot carcass weight, but 2.1 mm more of loin depth compared with PIC 800 pigs (P 0.05; Table 1). Regarding nutrition plan, no significant differences were observed for overall performance and carcass traits between pigs fed the current or alternative SID Lys curve (P 0.05; Table 1). Additionally, no significant differences were observed for overall removals and mortality by genetic line or nutrition plan (P 0.05; Table 1). In summary, different genetic sire line (PIC 337 and PIC 800) differed on performance and carcass traits. Further research is needed to continue studying the genetic evolution and nutrition plan for each genetic sire line in the grower-finisher period to understand their nutrient requirements.