The objective of this work is to determine the nutritional requirement of digestible threonine for brown-egg laying hens between 79 to 95 weeks of age. For this experiment, 180 commercial Lohmann Brown laying hens were used, distributed in five digestible threonine levels (0.380; 0.413; 0.446; 0.479 and 0.512%), each one with six replicates and six hens/replicate. It was observed a quadratic effect of threonine levels on the feed intake, egg mass conversions, egg dozen conversions, egg production, egg weight, and egg mass. The digestible threonine intake increased linearly in function of diet threonine levels. It was not observed effect of diet threonine levels for weight gain, yolk index, albumen index, shell percentage, yolk percentage and albumen percentage, except for the Haugh units, which increased in a quadratic way according to digestible threonine levels in the feed. Regarded to the food conversion per egg dozen, the requirement of digestible threonine for commercial hens in the period between 79 to 95 weeks of age is 0.467%, which corresponds to an intake of 462 mg threonine/hen/day.
amino acids; egg production; egg quality
