188 Evaluation of Alternative Summer Feeding Strategies to Optimize Performance in High Lean Genetics Using Energy, Narasin and Phytonutrient Blend Individually, Or, in Combination

Abstract The objective of this study was to determine the effects of feeding medium energy diets together with feed ingredients (Narasin-Skycis, Elanco Animal Health, Greenfield, IN; Phytonutrient blend-LeanFuel, Furst-McNess Company, Freeport, IL) as compared to low and high energy diets in high lean genetics during the summer. A total of 1375 pigs (PIC 337×PIC 1050; average 32.92 kg) were used in the experiment and were randomly assigned within block to 1 of 5 treatments by weight and gender, and 5 diet phases were formulated to meet and exceed NRC 2012 requirements, and formulated to a constant Lysine:NE ratio using corn, soybean meal and fat as low-energy, 3307 kcal/kg ME (L), moderate-energy, 3362 kcal/kg (M) and high-energy, 3417 kcal/kg ME (H) diets, and the trial ran from 32.92 kg to slaughter. Treatments 1) L 2) H 3) M with 1135 g/ton of LeanFuel added from 81.65 kg onwards 4) M with 13.6 g/ton Narasin throughout 5) M with 13.6 g/ton Narasin throughout and LeanFuel added from 81.65 kg onwards. Data were analyzed using the PROC GLIMMIX of SAS with pen serving as the experimental unit and blocks included in random effects. There was no difference in removals (P = 0.934). There was no difference in ADG between L and H, but H improved G:F by 2.5% (P < 0.01) as expected. ADG was intermediate for M+LF and M+Nar, with M+Nar+LF having a significantly greater ADG than both L and H by 4.8% for the overall period (P < 0.01). Feed efficiency was significantly lower for H, M+LF, M+Nar and M+Nar+LF as compared to L, but there was no difference for G:F between H and M+LF, M+Nar and M+Nar+LF. Gain per pig was increased by M+Nar+LF by 5.1 kg and 4.5 kg over L and H, respectively (P < 0.01). The combined use of Nar and LF offer an approach to supporting growth rate during the summer.