An experiment was conducted to determine the optimal standardize ileal digestible (SID) Lys level for growth performance of nursery pigs. A total of 980 pigs (PIC 337 × Camborough; initial BW = 5.4 kg), placed in pens with 28 pigs each, were used in a 42-d trial. There were 5 treatments consisting of 1.15, 1.25, 1.35, 1.45, or 1.55% SID Lys. Experimental diets were fed from d 0 to 21 followed by a common corn-soybean meal based diet (1.30% SID Lys) from d 21 to 42. Pigs were weighed weekly to calculate ADG, ADFI, and G:F. Data was analyzed with SAS MIXED procedure. From d 0 to 21, increasing the SID Lys level resulted in a linear (P < 0.01) ADG, G:F, and BW improvement. Because of the linear nature of the response, the breakpoint could not be determined. From d 21 to 42, when pigs were fed a common diet, linear (P < 0.05) ADG and G:F responses were observed; pigs previously fed the lower SID Lys levels had improved performance. This compensatory response resulted in no evidence for differences (P > 0.10) in overall (d 0 to 42) ADG and final BW, although there was a linear (P = 0.004) G:F improvement.

In conclusion, increasing SID Lys level linearly improved performance; however, pigs fed low SID Lys levels presented compensatory growth and obtained similar performance in the overall nursery period.

Cemin, H., L. Swalla, S. Hansen and E. Hansen. 2022. Effects of Digestible Lysine Level on Growth Performance of Nursery Pigs. 2022 American Society of Animal Science Midwest Section Meeting, Abstract PSIV-12.