Bioavailability of lysine from a liquid lysine source in chicks

Two experiments were conducted to assess the bioavailability of lysine from a liquid lysine product (LLP; 60% lysine) relative to crystalline L-lysine . HCl. Ln the first experiment, four groups of five chicks were fed a lysine-deficient basal diet containing corn, soybean meal, and feather meal or the basal diet supplemented with 0.1 or 0.2% lysine from L-lysine . HCl or UP from Day 8 to 22 posthatching. Weight gain and feed efficiency responded linearly (P < 0.01) to increasing levels of lysine from either lysine source, and multiple linear regression analysis of weight gain regressed on supplemental lysine intake indicated no difference (P > 0.05) in the response to lysine from L-lysine . HCl or LLP. Experiment 2 was conducted using a lysine-deficient basal diet containing corn, peanut meal, and feather meal, and all diets were fed to five groups of five Chicks from Day 8 to 21 posthatching. Treatment additions again consisted of 0.1 or 0.2% lysine from L-lysine . HCl or UP. Weight gain and feed efficiency responded linearly (P < 0.01) to increasing levels of lysine from L-lysine . HCl and LLP, and multiple linear regression analysis of weight gain regressed on supplemental lysine intake indicated no difference (P > 0.05) in the response to lysine from L-lysine . HCl or UP. These data indicate that lysine from UP is fully bioavailable relative to lysine from crystalline L-lysine . HCl, and could therefore be used as a source of lysine in practical poultry diets.