Exigências nutricionais de treonina e triptofano digestível para poedeiras semipesadas de 79 a 95 semanas de idade

Abstract

The objective was to determine the nutritional requirements of different relation with threonine: lysine for laying hens in the third production cycle. The experiment was conducted at the Center for Agricultural Sciences of Paraiba Federal University, Brazil. Were used 240 laying hens of brown-egg lineage Dekalb Brown, a period from 74 to 90 weeks of age, distributed in a completely randomized design with five increasing levels of threonine ( 0.447, 0.466, 0.486, 0.505, 0.523 % ), with six replicates and eight hens/replicate. The treatments consisted of level 0.648 % of digestible lysine. After to estimate the lysine, the diets were formulated keeping relations amino acids: lysine, except for threonine, which had growing relations in 69 72, 75, 78 and 81 %. It was evaluated: feed intake ( g / bird / day ), production (% ), weight ( g ), egg mass ( g / bird / day ), egg mass conversions( kg / kg ), egg dozen conversions( kg / dz ), weight (g) and percentage (%) of yolk, albumen and shell , shell thickness (mm ), specific gravity, nitrogen intake (g), nitrogen excretion (g), nitrogen balance (g), coefficient of metabolizable nitrogen (%) and serum uric acid (mg / dL). It was observed a quadratic effect of threonine levels the egg production and linear effect on egg mass conversions, egg dozen conversions and percentage of shell. Recommended level off 0.495% digestible threonine, which corresponds to threonine: digestible lysine and 76.5% which provided optimum results.