RESUMO

The influence of fasting and vaccination against infectious bronchitis (IB) on growth, gastrointestinal development, and morphometric parameters of the small intestine of newborn broiler breeders was investigated. Weight gain (WG), feed conversion ratio (FCR), gastrointestinal visceral growth, residual yolk sac, and morphometric parameters of the small intestine were measured in chicks aged up to 21 d. We showed that WG was lowest in chicks exposed to longer fasting periods (72 h), although compensatory gains with increasing age were also observed. Unvaccinated chicks performed better at seven days; however, at 21 d of age, a compensatory response led to better FCR in vaccinated birds. Allometric growth of the gastrointestinal tract was affected following longer fasting periods, but this effect occurred predominantly in younger birds (three days). Compared with non-fasted, birds fasted for 72 h had lower villus height and crypt depth along the small intestine at three days and lower villus height in the duodenum and jejunum at seven days. However, at 14 and 21 days of age, the previous changes in intestinal morphology imposed by fasting had been offset. The IB vaccine, applied in the first day of life, does not affect the allometric growth of the gastrointestinal organs, but causes momentary loss in the intestinal morphometry, which contributes to the reduction of WG at seven days. Our results suggest that long fasting periods after hatching (48 and 72 h) should be avoided in broiler breeders due to the resulting delay in gastrointestinal organ development and growth impairment up to 21 d of life.(AU)

Assuntos

RESUMO

This research was conducted aiming to evaluate the thermal behavior of metallic and fiber cement tiles installed in simple and double layers. The experiment was performed on prototypes of roofing in single layers and double-spaced from 1.0 to 5.0 cm. It was used temperature sensors, installed on the inner surface of the roofing and in the center of the model for data collection. Data were analyzed using Skott-Knott test, considering the time of day, and roof type. The results showed that the spacing between tiles has an important influence on temperature gradient inside the prototype, been observed that double-spaced roofs, with 5.0 cm, showed the best results for metallic and fiber cement tiles.

Assuntos

RESUMO

This research was conducted aiming to evaluate the thermal behavior of metallic and fiber cement tiles installed in simple and double layers. The experiment was performed on prototypes of roofing in single layers and double-spaced from 1.0 to 5.0 cm. It was used temperature sensors, installed on the inner surface of the roofing and in the center of the model for data collection. Data were analyzed using Skott-Knott test, considering the time of day, and roof type. The results showed that the spacing between tiles has an important influence on temperature gradient inside the prototype, been observed that double-spaced roofs, with 5.0 cm, showed the best results for metallic and fiber cement tiles.(AU)

Assuntos

RESUMO

The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL) and the goodness of fit on the models: quadratic polynomial (QP), exponential (EXP), linear response plateau (LRP) and quadratic response plateau (QRP). It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj), coefficient of variation (CV) and the sum of the squares of deviations (SSD).It was verified in QP and EXP models that small changes on the placement and distribution of the levels caused great changes in the estimation of the OL. The LRP model was deeply influenced by the absence or presence of the level between the response and stabilization phases (change in the straight to plateau). The QRP needed more levels on the response phase and the last level on stabilization phase to estimate correctly the plateau. It was concluded that the OL and the adjust of the models are dependent on the positioning and the number of the levels and the specific characteristics of each model, but levels defined near to the true requirement and not so spaced are better to estimate the OL.

O objetivo deste trabalho foi avaliar a influência do número e posição de níveis nutricionais utilizados em ensaios dose-resposta na estimativa do nível-ótimo (OL) e ajuste dos modelos polinomial quadrático (QP), exponencial (EXP), linear response plateau (LRP) e quadratic respose plateau (QRP). Utilizaram-se dados provenientes de ensaios dose-resposta realizados na FCAV-Unesp Jaboticabal, atendendo as pressuposições de homocedasticidade e normalidade. O ajuste dos modelos foi avaliado considerando as seguintes estatísticas: coeficiente de determinação ajustado (R²adj), coeficiente de variação (CV) e soma dos quadrados dos desvios (SSD).Verificou-se que, nos modelos QP e EXP, pequenas mudanças na localização e distribuição dos níveis ocasionam grandes alterações na estimativa do OL. O modelo LRP foi influenciado pela ausência ou presença do nível intermediário às fases de resposta e estabilização (mudança da reta crescente para platô). O modelo QRP precisou de um número maior de níveis na fase de resposta e o último nível da fase de estabilização para estimar corretamente o platô. Pôde-se concluir que a determinação do OL e o ajuste dos modelos dependem da posição e quantidade de níveis, além das características específicas de cada modelo, mas níveis definidos próximos do verdadeiro requerimento e não muito espaçados são melhores para estimar corretamente o OL.

RESUMO

The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL) and the goodness of fit on the models: quadratic polynomial (QP), exponential (EXP), linear response plateau (LRP) and quadratic response plateau (QRP). It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj), coefficient of variation (CV) and the sum of the squares of deviations (SSD).It was verified in QP and EXP models that small changes on the placement and distribution of the levels caused great changes in the estimation of the OL. The LRP model was deeply influenced by the absence or presence of the level between the response and stabilization phases (change in the straight to plateau). The QRP needed more levels on the response phase and the last level on stabilization phase to estimate correctly the plateau. It was concluded that the OL and the adjust of the models are dependent on the positioning and the number of the levels and the specific characteristics of each model, but levels defined near to the true requirement and not so spaced are better to estimate the OL.(AU)

O objetivo deste trabalho foi avaliar a influência do número e posição de níveis nutricionais utilizados em ensaios dose-resposta na estimativa do nível-ótimo (OL) e ajuste dos modelos polinomial quadrático (QP), exponencial (EXP), linear response plateau (LRP) e quadratic respose plateau (QRP). Utilizaram-se dados provenientes de ensaios dose-resposta realizados na FCAV-Unesp Jaboticabal, atendendo as pressuposições de homocedasticidade e normalidade. O ajuste dos modelos foi avaliado considerando as seguintes estatísticas: coeficiente de determinação ajustado (R²adj), coeficiente de variação (CV) e soma dos quadrados dos desvios (SSD).Verificou-se que, nos modelos QP e EXP, pequenas mudanças na localização e distribuição dos níveis ocasionam grandes alterações na estimativa do OL. O modelo LRP foi influenciado pela ausência ou presença do nível intermediário às fases de resposta e estabilização (mudança da reta crescente para platô). O modelo QRP precisou de um número maior de níveis na fase de resposta e o último nível da fase de estabilização para estimar corretamente o platô. Pôde-se concluir que a determinação do OL e o ajuste dos modelos dependem da posição e quantidade de níveis, além das características específicas de cada modelo, mas níveis definidos próximos do verdadeiro requerimento e não muito espaçados são melhores para estimar corretamente o OL.(AU)

Assuntos