LAUSR

A total of 912 pigs (PIC TR4 × (Fast LW × PIC L02)) were used in a 43-d trial to evaluate the influence of feed grade amino acid levels in late nursery and grower diets containing 30% dried distillers grains with solubles (DDGS) on growth performance. Pigs were randomly assigned to pens (19 pigs per pen) and pens were randomly allotted in weight blocks to 1 of 4 dietary treatments with 12 pens per treatment. Treatment diets were fed in 2 phases from 10 to 19.5 kg and 19.5 to 35 kg with digestible lysine at 1.31 and 1.15%, respectively). Predetermined orthogonal contrasts were used to evaluate linear or quadratic effects based on percentage of digestible lysine from intact protein versus feed grade lysine. Dietary treatments contained low, medium, high, or very high levels of feed grade amino acids with L-lysine added at 0.25, 0.40, 0.55, and 0.70% of the diet, respectively, with all other amino acids added as needed to meet minimum ratios relative to lysine (60% Ile; 58% Met and Cys; 65% Thr; 19% Trp; 72% Val). Overall, from d 0 to 43, there was an increase (quadratic, P< 0.020) in average daily gain (ADG) and average daily feed intake (ADFI) with pigs fed increasing levels of feed grade amino acids having the greatest gain and feed intake at the medium and high inclusion of feed grade amino acids, respectively. For overall gain:feed (G:F), pigs fed the medium level of feed grade amino acids had improved G:F (P=0.002) compared to pigs fed the high and very high feed grade amino acids with the pigs fed the low feed grade amino acids intermediate. In summary, feeding pigs medium levels of feed grade amino acids resulted in increased ADG and G:F during the late nursery and grower period.