This experiment aimed at evaluating the influence of the supplementation of digestible lysine and digestible arginine at different ratios in the diet fed to layers between 24 to 44 weeks of age on egg quality. In total,320 Lohmann LSL laying hens were allotted according to a completely randomized design in a 2 x 4factorial arrangement, consisting of two digestible lysine levels (700 or 900 mg/kg of diet) and four digestible arginine levels (700, 800, 900,or 1000 mg/kg of diet). Diets contained, therefore, digestible Lys:Arg ratios of 100, 114, 128, and 142 when the diet contained 700 mg digestible lysine per kg of diet, and 78, 89, 100, and 111 when 900 mg digestible lysine per kg was supplemented. The data obtained with digestible arginine levels were fitted to polynomial regression equations, and with digestible lysine, the F test (5% probability) was used to compare the means. The following variables were evaluated: egg weight; internal egg quality (yolk percentage and index, albumen percentage, Haugh units), eggshell quality (specific gravity andeggshell percentage); and whole egg, albumen, and yolk solids content. Digestible lysine and arginine interaction did not affect egg quality. Increasing levels of digestible lysine and arginine reduced eggshell quality and albumen solids, respectively. The levels of these amino acids suggested to improveegg quality are 700 mg digestible lysine and 700 mg digestible arginine/kg of feed at a Dig Lys: Dig Arg ratio of 100.

The objective of this study was to evaluate the effect of the dietary supplementation of phytogenic additives (PAs) and glutamine plus glutamic acid (Gln/Glu), associated or not, in replacement of antibiotic growth promoters and anticoccidials (AGP/AC) on the performance and carcass yield of broilers. Five hundred male Cobb broilers were housed in an experimental house and randomly distributed into five treatments, with four replicates of 25 birds each. Treatments consisted of a control diet (CD); CD+AGP/AC; CD+Gln/Glu; CD+PAs; CD+Gln/ Glu+PAs. Diets were formulated only with plant feedstuffs, i.e., they did not contain any animal byproducts. Performance data were collected for the accumulated periods of 1-7, 1-21, and 1-42 days of age. Carcass yield and parts yield were determined at 42 days of age. Treatments did not influence performance during none of the evaluated periods. The greatest carcass yield (p<0.05) was obtained in birds in the treatments CD+Gln/Glu and CD+Gln/Glu+PAs relative to CD, but not different from birds in the AGP+AC and PAs treatments, which were not different from the CD treatment. Birds fed the CD+Gln/Glu diet presented greater breast yield (p<0.05) compared with those in the CD and AGP/AC treatments, but there was no difference in comparison with the other treatments. Under the conditions of the present experiment, the dietary supplementation with phytogenic additives and with glutamine plus glutamic acid does not affect the performance, but improves carcass yield and breast yield of broilers.