This study was conducted to evaluate the effects of digestible lysine levels in diets with and without supplementation of industrial amino acids on performance and fat deposition in the carcass of broilers in the starter phase. One thousand four hundred and forty chickens with initial weight of 168.1±5.0 g were distributed in a completely randomized experimental design, in a 5 × 2 factorial arrangement, composed of five digestible lysine levels (10.0, 11.0, 12.0, 13.0 and 14.0 g/kg) and two types of diet (diet with different proportions of corn and soybean meal and diet supplemented with industrial amino acids to obtain the digestible lysine levels), with eight replications and 18 birds per replication. There was interaction effect only on weight gain and fat deposition in the birds. The lysine levels reduced feed intake linearly in both diets, but caused a linear increase in lysine intake. The lysine levels quadratically affected weight gain and feed conversion, which improved up to the estimated levels of 13.0 and 12.8 g/kg lysine, respectively, when the corn:soybean meal ratio of the diet changed. In the diets supplemented with amino acids, the lysine levels increased weight gain and improved feed conversion linearly. Regardless of the type of diet, protein deposition increased linearly, whereas fat deposition reduced also linearly, as the lysine levels in the diets were increased. The levels of 13.0 and 14.0 g/kg digestible lysine provide, respectively, the best performance in birds fed a diet in which the proportion of corn and soybean meal varies and a diet supplemented with industrial amino acids, in the period from 8 to 21 days of age.

Thermal comfort is of great importance in preserving body temperature homeostasis during thermal stress conditions. Although the thermal comfort of horses has been widely studied, there is no report of its relationship with surface temperature (T S). This study aimed to assess the potential of data mining techniques as a tool to associate surface temperature with thermal comfort of horses. T S was obtained using infrared thermography image processing. Physiological and environmental variables were used to define the predicted class, which classified thermal comfort as "comfort" and "discomfort". The variables of armpit, croup, breast and groin T S of horses and the predicted classes were then subjected to a machine learning process. All variables in the dataset were considered relevant for the classification problem and the decision-tree model yielded an accuracy rate of 74 %. The feature selection methods used to reduce computational cost and simplify predictive learning decreased model accuracy to 70 %; however, the model became simpler with easily interpretable rules. For both these selection methods and for the classification using all attributes, armpit and breast T S had a higher power rating for predicting thermal comfort. Data mining techniques show promise in the discovery of new variables associated with the thermal comfort of horses.

This study was conducted to verify the effects of dietary crude protein reduction on growth and carcass performance of 22-42-day-old broilers reared under different temperatures. Treatments were set up in a five by two factorial arrangement, with five crude protein levels (220, 210, 200, 190 and 184 g/kg) and two temperatures (21.6 and 32.2 ºC). Diets were isocaloric and essential amino acid-to-lysine ratio was maintained constant in all treatments. There was no interaction between crude protein reduction and environmental temperature for any of the parameters evaluated. Crude protein had no influence on feed intake. Nevertheless, weight gain and feed conversion ratio were linearly influenced by crude protein reduction. Worse performance was also observed in birds exposed to heat stress as compared with birds kept under thermoneutral temperature. There was no effect of crude protein reduction on breast and legs. Birds kept under heat stress had lower breast yield and higher leg yield as compared with broilers reared at 21.6 ºC. Any crude protein reduction in the range of 220 to 184 g/kg for 22 to 42-day-old broilers has a negative effect on their performance. Heat stress worsens broiler performance and breast yield.

O experimento foi realizado para avaliar os efeitos da suplementação das vitaminas C ou E na ração sobre o desempenho, as características de carcaça e os parâmetros hematológicos de frangos de corte mantidos em ambiente de alta temperatura. Foram utilizados 450 frangos de corte distribuídos em delineamento inteiramente ao acaso, com cinco tratamentos, cada um com nove repetições de 10 aves (período 1 a 21 dias) ou de 7 aves (período de 22 a 42 dias) por unidade experimental. Os tratamentos foram: ração basal (RB) sem suplementação de vitaminas C e E; RB + 300 ppm de vitamina E; RB + 230 ppm de vitamina C; RB + 300 ppm de vitamina E + 230 ppm de vitamina C; e RB + 150 ppm de vitamina E + 115 ppm de vitamina C. Não houve efeito da suplementação das vitaminas C e E no desempenho zootécnico das aves na fase de 1 a 21 dias de idade. Na fase de 1 a 42 dias, a suplementação das vitaminas C e E influenciou somente a conversão alimentar. Os melhores resultados para os pesos absoluto e relativo de peito foram observados nas aves que receberam a ração basal suplementada com as combinações das vitaminas C e E. A concentração plasmática de triiodotironina, a porcentagem de células sanguíneas, a relação heterófilo/linfócito e os pesos absoluto e relativo do baço aos 21 e 42 dias de idade não foram influenciados pela suplementação vitamínica. A suplementação das vitaminas C e ou E não influi no desempenho zootécnico, no peso do baço e nos parâmetros sanguíneos de frangos de corte mantidos até 42 dias de idade em ambiente de alta temperatura. As combinações das vitaminas C e E promovem melhora nos pesos absoluto e relativo de peito de frangos de corte sob alta temperatura.

This experiment was carried out to evaluate the effect of supplementation of vitamins C or E in the diet on performance, carcass characteristics and hematological parameters of broilers kept under high environmental temperature. Four hundred and fifty broilers were distributed in a completely randomized design with five treatments and nine replications, with 10 and 7 birds per experimental unit, respectively, according to the periods from 1 to 21 and 22 to 42 days old. Treatments consisted of a basal diet (RB) without supplementation of vitamins C and E; RB + 300 ppm of vitamin E; RB + 230 ppm of vitamin C; RB + 300 ppm of vitamin E + 230 of vitamin C, and RB + 150 ppm of vitamin E + 115 of vitamin C. Treatments did not influence performance of birds in the phase of 1 to 21 days of age. At 1 to 42 days of age, supplementation of vitamins C and E only influenced feed conversion. The best results for the absolute and relative weights of breast were observed in birds fed the basal diet supplemented with different combinations of vitamins C and E. Plasma concentration of triiodothyronine, percentage of blood cells, the heterophil/lymphocyte ratio and absolute and relative weights of the spleen at 21 and 42 days of age were not influenced by vitamin supplementation. Supplementation of vitamins C and/or E did not influence performance, weight of the spleen or blood parameters of chickens maintained until 42 days of age in a high temperature environment. The combination of vitamins C and E promotes improvement in absolute and relative weights of breast of broilers reared under high temperature

O experimento foi realizado para avaliar o efeito da redução do nível de proteína bruta (PB) da ração formulada de acordo com o conceito de proteína ideal e suplementada com aminoácidos industriais, sobre o desempenho e rendimento de cortes de frangos de corte machos de 22 a 42 dias de idade mantidos em ambiente termoneutro. Foram utilizados 280 frangos de corte machos "Cobb" com peso inicial de 856 ± 6,48 g, distribuídos em delineamento experimental inteiramente casualizado, com cinco tratamentos (21,6; 20,6; 19,6; 18,6 e 17,6% de PB), oito repetições de sete aves por unidade experimental. A temperatura no interior da sala foi mantida em 21,6 ± 0,7ºC, a umidade relativa em 74 ± 4,0% e a temperatura de globo negro em 22,5 ± 0,7ºC. O índice de temperatura de globo e umidade (ITGU) calculado para o período foi de 70 ± 0,9. Não houve efeito da redução dos níveis de PB sobre o ganho de peso e o consumo de ração, entretanto, a conversão alimentar foi influenciada pela redução dos níveis de PB sendo que as aves alimentadas com a ração que continha 22,0% de PB apresentaram o melhor resultado. A redução dos níveis de PB não influenciou o peso absoluto de carcaça e os pesos absoluto e relativo de peito, coxa e sobrecoxa. A redução do nível de PB da ração, de 21,6 para 17,6%, e formulada de acordo com o conceito de proteína ideal piora a conversão alimentar dos frangos de corte mantidos em ambiente termoneutro, não influenciando as demais variáveis estudadas.

The objective of this experiment was to evaluate the effects of dietary crude protein (CP) level reduction of ration formulated according to ideal protein concept and with supplementation of industrial amino acids on the performance and yield of noble cuts of broilers from 22 to 42 days of age kept under thermoneutral conditions. It was used 280 "Cobb" male broilers with initial weight of 856 ± 6.48 g, distributed in a completely randomized experimental design, with five treatments (21.6; 20.6; 19.6; 18.6 and 17.6% CP) and eight replications with seven birds per experimental unit. Temperatures inside the rooms were maintained at 21.6 ± 0.7°C, relative humidity at 74.4.0% and black globe temperature of 22.5 ± 0.7°C. Black globe temperature and humidity index (BGHTI) calculated for a period of 70 ± 0.9. There was no effect of the reduction of the levels of CP on weight gain and on feed intake but feed conversion was influenced by the reduction of the CP levels, and the birds fed diet with 22.0% of CP presented a better result. The reduction of the levels of CP did not influence absolute carcass weight and absolute and relative weights of breast, thigh and drumstick. Reduction of the level of dietary CP from 21.6 to 17.6% and formulated according to ideal protein concept worsens feed conversion of broilers kept in thermoneutral environment, not influencing the other studied variables.

Para manter a posição de maior exportador de carne de frango, o Brasil deve se adequar às exigências internacionais dos padrões de qualidade, procurando sempre recursos alternativos de melhoria, sem grande incremento no custo de produção, incluindo a qualidade da cama, requisitos de bem-estar animal e as questões ambientais, como o uso e a reutilização das camas de frango. Para isso são necessárias pesquisas nas áreas de bem-estar animal, ambiência, comportamento animal e uso de tecnologias de climatização modernas que aperfeiçoem a qualidade do ambiente gerado para criação dos frangos, visando, além deste fator, menor emissão de gases com potencial efeito estufa para o ambiente, tornando-se um sistema de produção sustentável. De acordo com o exposto, realizou-se uma ampla revisão bibliográfica deste assunto, buscando mostrar o estado da arte dos principais fatores relacionados aos novos conceitos de ambiência e bem-estar de frangos de corte.

To keep the position in being a world-wide exporter of chicken meat, Brazil must meet international quality standards, always seeking alternative resources of improvement, without increasing production costs, including litter quality, requirements of animal welfare and environment affairs, such as the use and reuse of broiler litter. Researches are performed in the areas of animal welfare, environment, animal behavior and use of modern climatization technology improving the quality of the environment created to raise broilers, also trying to reduce the greenhouse gas emissions and global warming in the environment, becoming a sustainable production system. This paper has a bibliographic revision of the subject mentioned above, intending to show a state-of-art key factors related to a new concept of broiler environment and welfare.