The optimal true ileal digestible lysine and total sulfur amino acid requirement for nursery pigs between 20 and 50 lb

Swine research, 2005 is known as Swine day, 2005An experiment involving 360 pigs (PIC, avg. BW = 22.0 lb) was conducted to determine the appropriate true ileal digestible (TID) lysine and total sulfur amino acid (TSAA) requirement of nursery pigs and, consequently, to determine the optimal TSAA:lysine ratio. This trial was organized as a combination of two simultaneous experiments, with one set of diets consisting of five increasing TID lysine concentrations (1.05, 1.15, 1.25, 1.35, and 1.45%) and the second set of diets consisting of five increasing TID TSAA concentrations (0.61, 0.69, 0.76, 0.83, and 0.90%). The highest concentrations of both lysine and TSAA (1.45% and 0.90%, respectively) were combined as one diet and used in both the lysine and TSAA titrations, to give a total of 10 treatments. Pigs were randomly allotted to eight replications, with five pigs per pen, on the basis of initial BW. Average daily gain and F/G improved (quadratic, P<0.01) with increasing TID lysine. The largest improvement in growth rate and feed efficiency for PIC pigs in these facilities occurred as the TID lysine increased to 1.25 and 1.35%, respectively; there was little improvement in performance thereafter. Increasing TID TSAA increased (quadratic, P<0.01) ADG and improved (quadratic, P