This study evaluated the level and length of time of vitamin A supplementation and its effects on carcass and cuts yield, meat quality, and myopathies in 42-day-old broilers. A total of 1,920 birds were divided into 6 groups, and each group received a different level of vitamin A: 0; 6,000; 16,000; 26,000; 36,000 and 46,000 IU/ kg. From d 1 to 21, the treatments were distributed among 16 replicates with 20 birds. From the 22nd d on, 8 repetitions remained with the initial treatment and the others received diets with no vitamin A supplementation. Twelve birds were slaughtered per treatment to evaluate carcass and cuts yield, shear force, cooking loss, water holding capacity, and the presence of substances reactive to thiobarbituric acid. The remaining birds were slaughtered and evaluated in loco for Wooden Breast ( WB ) and White Striping ( WS ). Wings weight was affected by vitamin A levels. The duration of the vitamin A supplementation process had effects on the weight of breast, legs with a dorsal portion, and meat color in the yellow intensity (b*). Incidence of WB had higher scores in birds supplemented until 42 d of age. WS showed a quadratic response and a lower response with supplementation of 29,700 IU/ kg. Even for WS, a higher occurrence of the normal score was found in birds supplemented until 21 d of age. Minimal quadratic responses were obtained for normal, moderate, and severe scores, in supplementations of 29,301; 29,959, and 29,827 IU/ kg, respectively. WB had lower occurrence rates in birds supplemented until 21 d of age. Consequently, the severe score was more frequent when supplementation was provided until 42 d of age. The level of vitamin A and the length of time during which this supplementation was provided had influence on cuts yield, meat color and the incidence of WB and WS of the 42-day-old birds.

0.132, 0.173, 0.215, in order to provide 0.588, 0.628, 0.669, 0.709 and 0.750% methionine + cystine in the diet. The inclusion of methionine + cystine followed, respectively, the proportions of 67, 72, 77, 81 and 86% with

The objective of this study was to determine the requirement of digestible methionine + cystine of brown-eggs laying hens from 50 to 66 weeks age at the end of the first production cycle. The design was completely randomized, with 150 Brown Shaver hens, which were distributed in five treatments with six replications of five birds each. Birds received a basal diet with 2857 kcal/kg metabolizable energy and 15.97% crude protein, supplemented with 0.132; 0.174, 0.215, 0.256 and 0.298% DL-methionine (98%), in order to provide 0.572, 0.613, 0.653, 0.693 and 0.734% digestible methionine + cystine. The levels of digestible methionine + digestible cystine followed, respectively, the relations of 67, 72, 77, 81 and 86% with lysine fixed at 0.851%. Feed intake, methionine + cystine intake, feed conversion per dozen eggs, egg weigth and mass, percentage of egg components, internal egg quality and weight gain were evaluated. Methionine + cystine levels showed a quadratic effect on feed conversion per dozen eggs and egg weight, a linear effect on feed conversion per kilogram of eggs and percentage of albumen. There was also a positive linear effect on yolk percentage. The methionine + cystine requirement was estimated at 0.572%, corresponding to 682 mg of digestible methionine + cystine/bird/day

A total of 2622 male broilers were distributed in a 2 × 5 factorial design, using 2 lipid sources (soybean oil and palm fat), 5 levels of vitamin A supplementation (0, 3,000, 6,000, 12,000, and 24,000 IU kg −1 ), with 10 replicates, and also 1 control diet ( CD ) for each lipid source used (7 replicates), each experimental unit being composed of 23 birds. During the first 21 d (how were the birds fed) and from 22 to 42 d of age, a redistribution of the treatments was carried out in a 2 × 2 × 5 factorial design: half of the repetitions of each treatment received the diet of the initial treatment, and the others received the CD with its type of lipid source. In the phase from 1 to 21 d of age, the effect of lipid source on feed intake ( FI ) and feed conversion ratio ( FCR ), and the effect of vitamin supplementation on FI and weight gain ( WG ) were observed, with a quadratic response for both variables. At 42 d of age, the lipid source and vitamin A level influenced the FI, whereas the WG and FCR showed interactions between period and the level of vitamin A supplementation. Neither lipid source resulted in blood parameters out of the typical pattern for birds, and the same was observed in relation to dietary vitamin A supplementation. From 1 to 21 d of age, a vitamin A supplementation of 15,585 IU kg −1 was estimated, and at 42 d, 15,527 IU kg −1 and 15,148 IU kg −1 were estimated for the periods 1 to 21 d and 1 to 42 d, respectively.

An experiment was conducted in the Department of Experimental Stations of the Universidade Tecnológica Federal do Parana -UTFPR campus Dois Vizinhos -PR, with the objective of determining the nutritional levels of threonine for laying hens aged 75 to 90 weeks. One hundred fifty laying Shaver Brown pullets were used in a completely randomized design (CRD) submitted to a basal diet containing 2.85 kcal ME/g and 148.7 g/kg CP, supplemented with 4.6; 4.9; 5.2; 5.5 or 5.8 g/kg of digestible Lthreonine (98 %), which provided 0.000, 0.027, 0.058, 0.089 or 0.120% threonine, respectively. The feed conversion, egg production, egg weight, egg mass and internal egg quality were not affected (P> 0.05) by the threonine in the diet. The Haugh unit showed a linear effect with threonine consumption in that it increased levels of digestible amino acids in the diet. The variables percent albumin and shell showed quadratic effects, so the recommended dietary digestible threonine level was 5.20 g/kg, which corresponds to 0.648 g threonine/hen/day, and 5.25 g/kg, which is equivalent to 0.654 g threonine/hen/ day, respectively. The specific gravity was affected by the level of threonine; the indicated level is 5.22 g/kg, equivalent to 0.651 g of threonine/hen/day obtained by the quadratic effect. Key words: Digestible amino acid, egg quality, performance ResumoConduziu-se um experimento no Núcleo de Unidades de Ensino e Pesquisa da Universidade Tecnológica Federal do Paraná -UTFPR, Campus de Dois Vizinhos -PR, com o objetivo de determinar os níveis nutricionais de treonina digestível para poedeiras comerciais, no período de 75 a 90 semanas de idade. Foram utilizadas 150 poedeiras Shaver Brown semipesadas num delineamento inteiramente casualizado (DIC), submetidas à uma ração basal contendo 2,85 Kcal EM/g, 148,7g/kg de PB, suplementada com 4,6; 4,9; 5,2; 5,5 e 5,8g/kg de L-treonina digestível (98%), que forneceu 0,000; 0,027; 0,058; 0,089 e 0,120% de treonina digestível, respectivamente. A conversão alimentar, a produção de ovos, o peso do ovo, massa de ovos e a qualidade interna dos ovos não foram influenciados (P>0,05) pelos níveis de treonina na dieta. A unidade Haugh e o consumo de treonina apresentaram efeito linear à medida em que aumentavam os níveis do aminoácido digestível na dieta. As variáveis porcentagem de albúmen e casca apresentaram efeito quadrático e os níveis nutricionais de treonina digestível recomendados foram de 5,20g/kg, o que corresponde a 0,648 g de treonina/ave/dia e, 5,25g/kg que equivale a 0,654 g de treonina/ave/dia, respectivamente. A gravidade específica foi afetada pelos níveis de treonina digestível, e o nível indicado é de 5,22g/kg, que equivale a 0,651 g de treonina/ave/dia obtido por meio de efeito quadrático. Palavras-chave: Aminoácido digestível, desempenho, qualidade do ovo