Níveis de lisina e treonina digestíveis na ração de poedeiras comerciais sobre a qualidade de ovos

This research had the objective of evaluating the influence of different levels of digestible lysine and threonine in the ration of commercial laying hens (Lohmann LSL) aged between 25 and 44 weeks on the quality of eggs. Three-hundred sixty laying hens were fed rations containing different levels of digestible lysine (0.700; 0.800 and 0.900%) combined with threonine (0.500; 0.550 and 0.600%). The rations contained 16% crude protein. The experimental set up was in a completely randomized design in a 3x3 factorial scheme (three levels of lysine and three levels of theronine), resulting in nine treatments with five replicates. The experiment unit consisted of a cage with eight hens each. The data on specific gravity, weight of eggs, total solids of yolk, Haugh unit, percentage of yolk, albumin and shell were submitted to analysis of variance and polynomial regression using the SAS statistical software. No regression effect was observed for either lysine or threonine intake for the studied parameters, except for albumin percentage. Interaction was verified between the levels of lysine and theronine (p < 0.05) in the rations regarding specific gravity. The levels of 900 and 550 mg of digestible lysine and threonine, respectively, enhanced the specific gravity, whereas for the other parameters of egg quality, the recommendation is 700 mg of digestible lysine and 500 mg of digestible threonine in the ration.