Standardized Ileal Digestible Lysine Requirement of 6- to 10-kg Weanling Pigs

The objective of the experiment was to determine the Standardized Ileal Digestible (SID) lysine requirement for weanling pigs from 6 to 10 kg of Body Weight (BW). A total of 216 weanling pigs with an initial BW of 6.23±0.93 kg were assigned to six diets in a randomized complete block design with five blocks based on BW. Six corn-dried whey-soybean meal-based diets were formulated to contain 6 concentrations of SID lysine from 1.17 to 1.62% with an increment of 0.09% at the expense of corn. Pigs were fed experimental diets during 14 days of trial and BW of pigs and feed intake were recorded on day 7 and 14. During the first 7 days, average daily gain, Average Daily Feed Intake (ADFI) and Gain:Feed (G:F) of pigs were not affected by the dietary SID lysine concentration. However, the ADFI of pigs linearly decreased (p=0.002) as the SID lysine concentration increased during the following 7 days. During the overall period, the addition of dietary SID lysine linearly decreased (p=0.007) ADFI whereas linearly increased (p=0.011) G:F. The SID lysine requirement was determined by four different statistical analyses including linear broken-line model, quadratic broken-line model, 95% of the upper asymptotic value of quadratic model and the former intercept between plateau of the linear broken-line model and quadratic model. Mean value for the SID lysine requirement was 1.43% (4.07 g/Mcal metabolizable energy), ranged from 1.39 to 1.49% (from 3.95 to 4.24 g/Mcal metabolizable energy) based on G:F of pigs from 6 to 10 kg of BW.