Comparative utilization of d- and l-methionine by the white pekin duckling (Anas platyrhynchos)

1. 1. White Pekin ducklings (Anas platyrhynchos) were fed a sulfur amino acid-deficient corn-peanut meal basal diet supplemented with either d- or l-methionine (MET) at levels of 0,0.04, 0.08, or 0.16%. 2. 2. Although liver and kidney d-amino acid oxidase activities were induced in birds fed d-MET, their weight gains were only approximately 78% of those fed l-MET at each level of supplementation. 3. 3. Ducklings fed the basal diet supplemented with 0.08 or 0.16% d-MET had significantly (P<0.05) higher plasma MET levels than birds fed an equimolar amount of l-MET. 4. 4. It was concluded that d-MET was a less efficacious source of dietary MET activity than l-MET for White Pekin ducklings.