RESUMO: Avaliou-se o efeito de programas de iluminação contínuo e intermitentes com diferentes fotofases sobre o desempenho produtivo e a qualidade de ovos de poedeiras aplicados ao início da fase de postura. Foram utilizadas 420 poedeiras da linhagem Hy line Brown com 21 semanas de idade, criadas sobre cama, submetidas durante seis períodos de 28 dias, entre o solstício de verão e de inverno, a três programas de iluminação: contínuo (PIC) de 16h de luz; programa intermitente com fotofases inicial e final de 15min (PII15); e programa intermitente com fotofases inicial e final de 30min (PII30). Utilizou-se um delineamento inteiramente casualisado, com dez repetições de 14 aves. Os resultados das médias foram submetidos à análise de variância e analisadas pelo teste de Tukey (5%). O programa PIC apresentou maior consumo de ração e massa de ovos em relação ao PII15, a produção de ovos das aves no PIC foi 1,8% superior aos fotoperíodos intermitentes. Os programas de luz não alteraram a qualidade de ovo. Programas intermitentes para poedeiras semipesadas, criadas sobre cama em galpão aberto, aplicados no início da fase de postura reduzem o desempenho produtivo das aves sem afetar a qualidade de ovos.

ABSTRACT: It was possible to evaluate the effect of continuous and intermittent lighting programs with different photophases on the performance and eggs quality of laying hens, applied to the beginning of the laying phase. The authors used 420 Hy-line Brown laying hens with 21 weeks of age, bred on bedding and submitted for six periods of 28 days between the solstice of summer and winter. The three lighting programs were: (PIC) 16 hours of continuos light, intermittent program with initial and final photophases of 15 minutes (PII15) and an intermittent program with initial and final photophases of 30 minutes (PII30). A completely randomized design with ten repetitions of 14 birds was used. The mean values were subjected analysis of variance and analyzed by the Tukey test (5%). The PIC program showed higher feed intake and eggs' mass about the PII15, and the eggs production of birds, in the PIC, was 1.8% greater than the intermittent photoperiods. Programs of light did not change the egg quality. The intermittent programs for semi-heavy laying hens bred on bedding in an open shed, applied at the beginning of the laying phase, reduced the productive performance of the birds without affecting the eggs quality.

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.

Este estudo teve como objetivo avaliar os valores bioquímicos e atividade enzimática hepática e renal em frangos de corte submetidos à intoxicação experimental com aflatoxina B1 com e sem a adição de montmorilonita sódica na dieta. Foram utilizados 528 frangos de corte, da linhagem Cobb, subtimetidos a seis tratamentos entre 1° ao 42° dia de vida: (T1) Controle: dieta normal; (T2) dieta com 5 ppm de aflatoxina; (T3) dieta com 0,25% montmorilonita sódica; (T4) dieta com 5ppm de aflatoxina + 0,25% montmorilonita sódica; (T5) dieta com 0,5% montmorilonita sódica; (T6) dieta com 5ppm de aflatoxina + 0,5% montmorilonita sódica. O tratamento (T2) com aflatoxina demonstrou significante (P<0,01) diminuição dos níveis de ácido úrico, albumina, colesterol, creatinina, triglicerídeos, globulinas e proteína total. Houve aumento significativo da alamino amino transferase (ALT) enquanto que a enzima aspartato amino transferase (AST) não foi significantemente diferente entre os tratamentos. Nos tratamentos T3 e T5, não houve alteração nas dosagens bioquímicas em relação ao tratamento controle (T1). A adição 0,5% de montmorilonita sódica na dieta (T6) apresentou melhores resultados na redução da adsorção da aflatoxina em relação à adição de 0,25% de montmorilonita sódica (T4). Os resultados obtidos, nas condições em que foi realizado este experimento, sugerem que altos níveis de aflatoxina (5ppm) na dieta causam alterações bioquímicas significativas na atividade enzimática de frangos de corte e que o tratamento preventivo com a montmorilonita sódica pode ser usado para se evitar o risco causado pela contaminação alimentar com aflatoxinas.

The aim of this research was to evaluate the hepatic biochemical profile and the renal enzymatic activity of broiler chicken experimentally intoxicated with aflatoxin and supplemented with sodic montmorilonite on the diet. 528 Cobb’s broiler chickens were used divided in 6 treatments (from 1st to the 42th day of life) as described: (T1) control: normal diet; (T2) diet with 5ppm of aflatoxin; (T3) diet with 0.25% sodic montmorilonite; (T4) diet with 5 ppm of aflatoxin + 0.25% sodic montmorilonite; (T5) diet with 0.5% sodic montmorilonite; (T6) diet with 5 ppm of aflatoxin + 0.5% sodic montmorilonite. The treatment T2 showed significantly decreased levels of uric acid, albumin, cholesterol, creatinine, triglycerides, globulins and total serum proteins and an increase of serum alanine aminotransferase (ALT) activity. Aspartate aminotransferase (AST) did not showed important differences among treatments. In treatments T3 and T5, there were no variations on the biochemical values, when compared to treatment T1. Addition of 0.5% of montmorilonite in the diet (T6), presented better results on the increase of the adsorption of aflatoxin when compared to 0.25% sodic montmorilonite (T4). Clearly, the results showed that high levels of aflatoxin in the diet (5ppm) causes important changes in the serum enzymatic activity of broiler chickens. Also, it was demonstrated that using sodic montmorilonite may be used to avoid risks caused by food contaminated by aflatoxins.