ABSTRACT Exposure to increasing concentrations of CO2 in the first 10 days of incubation may have effects on the development of bird cardiac and respiratory organs. Moreover, the age of breeders can influence hatching performances. This study aimed to investigate the effect of exposure to increasing concentrations of CO2 in the first 10 days of incubation on the morphophysiological development of the digestive system of embryos and chicks from broiler breeders aged 31 and 41 weeks. A total of 860 fertile eggs from the Cobb strain were distributed in a completely randomized design, in a 2 x 2 factorial arrangement, with 2 different gaseous environments (Control (C) - no increase in CO2 concentration and, Hypercapnia (CO2) - a gradual increase in CO2 concentration until reaching 1% on the 10th day) and 2 different broiler breeder ages (31 and 41 weeks). Half of the eggs were obtained from 31-week-old breeders, and the other half from 41-week-old breeders. Compared to the control group, incubation in an atmosphere with 1% CO2 led to an increase in villus heights in the duodenum, jejunum, and ileum of the embryos, with a reduction in villus density in the same segments. Chicks from 41-week-old broiler breeders showed higher villus heights in the duodenum, jejunum, and ileum at day 1 post-hatching, and lower villus density at 7 days. It was concluded that the incubation of fertile eggs in hypercapnia conditions could positively affect the small intestine of embryos and post-hatch chicks.

ABSTRACT Currently, feed formulations for quail are based on foreign data or data from other species; this undermines productivity with the use of excessive or deficient levels of some nutrients. Therefore, this study aimed to determine the nutritional requirement levels of calcium (Ca) and supplementation vitamin D in meat-type quail from 1 to 14 d of age. The experiment was a 4 × 4 factorial arrangement of treatments (levels of Ca: 0.42, 0.58, 0.74 and 0.90% and levels of vitamin D: 1,000, 2,000, 3,000 and 4,000 IU) with 3 replicate pens and 43 quails per pen. Weight gain increased quadratically with increased levels of Ca and vitamin D; this variable yielded estimated levels of 0.73% Ca and 2,883 IU vitamin D. There was no Ca x vitamin D interaction effect on bone variables. Bone Ca, bone phosphorus, bone ash, femoral bone strength, tibial bone strength and the femoral Seedor index increased quadratically with an increase in Ca levels. These variables yielded estimated values of 0.78, 0.71, 0.78, 0.77, 0.83, and 0.71% Ca, respectively. It is concluded that the requirements of Ca and vitamin D for the maximum weight gain of meat-type quails, in the period from one to 14 days of age, were 0.73% Ca (p=0.001) and 2,883 IU vitamin D (p=0.02), respectively.

RESUMO Durante dois anos consecutivos, a resistência mecânica do solo à penetração (RP) foi avaliada em áreas de produção de milho segunda safra para silagem. A retirada da parte aérea do milho no processo de silagem deixa o solo exposto, sujeito à compactação, o que pode comprometer o sistema plantio direto (SPD). Neste contexto, este trabalho teve por objetivo monitorar a RP sob cultivo de plantas de cobertura, associadas à aplicação de água residuária de suinocultura (ARS), em áreas de silagem de milho sob SPD. O trabalho foi desenvolvido em Matelândia, Paraná com sete sistemas de manejo: soja/silagem/aveia e nabo (SSAN); soja/aveia e nabo (SAN); soja/silagem/escarificão + aveia e nabo (SSEAN); soja/silagem e braquiária (SSB); soja/silagem/aveia (SSA); soja e silagem (SS) e soja e milho (SM), repetidos por dois anos consecutivos. Nos tratamentos com ARS foram aplicados 100 m3 ha-1 ano-1, divididos em duas doses iguais: uma sobre o milho e outra nas plantas de cobertura. O delineamento experimental foi em blocos casualizados (DBC), com quatro repetições por tratamento, com quatro amostras por repetição. O sistema sem utilização de plantas de cobertura apresentou maior RP; a camada do solo com maior RP foi a de 0,10 a 0,15 m; a aplicação de ARS, na dose de 100 m3 ha-1 ano-1 diminuiu a RP do solo.

ABSTRACT The mechanical resistance of the soil to penetration (RP) was evaluated over two consecutive years in areas where off-season maize is produced for silage. Removal of the aerial part of the maize during the ensiling process leaves the soil exposed and subject to compaction, which may compromise a no-till system (NTS). The aim of this study therefore, was to monitor the RP of a soil under plant cover associated with the application of wastewater from pig farming (WPF) in areas of maize ensiling under NTS. The study was conducted in Matelândia, in the State of Paraná, employing seven management systems: soybean/silage/oats and turnip (SSOT); soybean/oats and turnip (SOT); soybean/silage/scarification + oats and turnip (SSSOT); soybean/silage and brachiaria (SSB); soybean/silage/oats (SSO); soybean and silage (SS) and soybean and maize (SM), repeated over two consecutive years. In the treatments that included WPF, 100 m3 ha-1 yr-1 were applied, split into two equal doses: one on the maize and the other on the cover crops. The experimental design was of randomised complete blocks (RCB), with four replications per treatment, and four samples per replication. The system with no cover crops had a higher RP; the 0.10 to 0.15 m layer of soil had the highest RP; whereas the application of WPF at a dose of 100 m3 ha-1 yr-1 decreased the RP.

ResumoO siri Callinectes danae é estuarino dependente em seu ciclo de vida, sendo que os estudos que levantam informações sobre os aspectos da sua biologia devem também abranger regiões marinhas. Assim, o presente estudo teve como objetivo investigar a maturidade sexual, bem como a preferência ocupacional por adultos em diferentes estágios gonadais e sua periodicidade reprodutiva fora da região estuarina. Para tanto, três enseadas da porção subtropical do litoral sudeste brasileiro foram amostradas mensalmente, durante dois anos. Para cada enseada, seis transectos foram estabelecidos, quatro deles paralelos à linha de praia (5, 10, 15 e 20m de profundidade), um transecto exposto e outro abrigado à ação de ondas. Os resultados mostraram que o padrão de distribuição espaço-temporal de adultos de C. danae foi similar nas três enseadas, embora uma maior abundância tenha sido encontrada em Ubatumirim. Fêmeas ovígeras e com gônadas desenvolvidas foram encontradas em maior abundância que fêmeas com gônadas rudimentares e em desenvolvimento, principalmente nos transectos mais profundos. Apesar das regiões amostradas possuírem características ambientais diferenciadas, o padrão reprodutivo da espécie não sofreu alterações, apresentando reprodução contínua, com maior abundância de fêmeas reprodutivas na primavera e verão. Machos atingiram maturidade em tamanhos maiores que as fêmeas nas três enseadas.

AbstractThe life cycle of the crab Callinectes danae is estuarine-dependent, and studies on aspects of their biology should also cover marine areas. The present study investigated the sexual maturity, as well as habitat preference by adults in different gonadal stages, and the crabs’ reproductive periodicity outside the estuary. Three bays on the subtropical southeastern coast of Brazil were sampled monthly for two years. For each bay, six transects were established, four of them parallel to the beach line (5, 10, 15 and 20 m depth), as well as one transect in an exposed area, and another sheltered from the action of waves. The results showed that the pattern of spatio-temporal distribution of adults C. danae was similar in three bays, although the highest abundance was found in Ubatumirim. Females with developed gonads/ovigerous females were found in greater abundance than females with rudimentary/developing gonads, mainly in deeper transects. Although the areas sampled have different environmental characteristics, the reproductive pattern of the species did not change, showing continuous reproduction throughout, with more abundance of reproductive females on spring and summer. Males reached maturity at larger sizes than females in all three bays.

O presente trabalho foi desenvolvido junto aos Departamentos de Engenharia Rural e Morfologia e Fisiologia Animal da FCAV/Unesp, Jaboticabal - SP. Objetivou-se verificar a influência da inclinação , exposição e cobertura sobre a temperatura interna de modelos reduzidos de instalações zootécnicas. Para o desenvolvimento da pesquisa, foram utilizados 48 modelos reduzidos e dissimilares nas dimensões de 1,00 × 1,00 × 0,50 metros. A cobertura foi de uma água, dispostos nas exposições norte-sul, sendo 24 modelos na exposição norte e 24 na sul. Foram utilizadas, na cobertura, telha de cerâmica, aço galvanizado e fibrocimento. As inclinações variaram de 20; 30; 40 e 50% para telha de cerâmica e 10; 30; 40 e 50% para as demais. No interior dos modelos, foram realizadas leituras de temperatura, de hora em hora, durante 12 meses. Os resultados obtidos foram avaliados num modelo linear geral, no esquema fatorial aninhado 3 × 4 × 2, em que foram considerados: tipo de telha, grau de inclinação e exposição, onde os efeitos de cobertura e exposição foram aninhados no fator inclinação. As médias obtidas foram comparadas pelo teste de Tukey, a 5% de probabilidade. Após a análise dos dados, observa-se que, com o aumento da inclinação na exposição sul, houve decréscimo da temperatura interna no interior do modelo, nas coordenadas geográficas da cidade de Jaboticabal.

The present study was conducted at the Department of Rural Engineering and the Department of Animal Morphology and Physiology of FCAV/Unesp, Jaboticabal, SP, Brazil. The objective was to verify the influence of roof slope, exposure and roofing material on the internal temperature of reduced models of animal production facilities. For the development of the research, 48 reduced and dissemble models with dimensions 1.00 × 1.00 × 0.50 m were used. The roof was shed-type, and the models faced to the North or South directions, with 24 models for each side of exposure. Ceramic, galvanized-steel and fibro tiles were used to build the roofs. Slopes varied between 20, 30, 40 and 50% for the ceramic tile and 10, 30, 40 and 50% for the other two. Inside the models, temperature readings were performed at every hour, for 12 months. The results were evaluated in a general linear model in a nested 3 × 4 × 2 factorial arrangement, in which the effects of roofing material and exposure were nested on the factor Slope. Means were compared by the Tukey test at 5% of probability. After analyzing the data, we observed that with the increase in the slope and exposure to the South, there was a drop in the internal temperature within the model at the geographic coordinates of Jaboticabal city (SP/Brazil).

The objective of the present study was to evaluate the effects of different dietary energy levels and stocking densities on the thermoregulating parameters, live performance, and carcass traits of broilers reared under tropical winter conditions at different times of the day. In total, 1,312 one-d-old male broilers were used. Birds were allotted to three different stocking densities (10, 14 or 18 birds/m²) and two dietary energy levels (2900 or 3200 kcal ME/kg). The following parameters were evaluated:radiant heat load (RHL), rectal temperature (RT), feed intake (FI), weight gain (WG), feed conversion ratio (FCR), livability (L), production of live weight per area (WA), and carcass yield. Stocking density did not affect sensible heat loss (SRL) or rectal temperature (RT); however, as expected, sensible heat loss (SRL) and RT were influenced by time of the day, with higher values in the morning and in the afternoon, respectively. There was no effect of treatment (p>0.05) on carcass or parts yield. Feed intake was reduced in 3%, whereas weight gain and feed conversion ratio improved in 8 and 10%, respectively, as dietary energy level increased. On the other hand, stocking density did not influence live performance or carcass traits. Based on the present results, it is concluded that sensible heat loss depends on dietary energy levels and particularly on time of the day. Therefore, environmental house management is suggested during tropical winters in order to reduce differences between broiler skin and environmental temperatures in the morning and in the afternoon.

This study was carried out to verify if Saccharomyces cerevisiae cell wall (SCCW) dietary supplementation (0.2%) was capable of protecting the intestinal mucosa of broiler chickens vaccinated against coccidiosis. Body weight gain, feed intake, feed conversion and intestinal mucosa morphometric parameters and epithelial loss were evaluated. In the experiment,400 day-old male chicks were distributed according to a completely randomized design in a 2x2 factorial arrangement. The following treatments were applied: T1 - no vaccination/ no SCCW supplementation; T2 - no vaccination/SCCW supplementation; T3 - vaccination/no SCCW supplementation; and T4 - vaccination/SCCW supplementation to four replicates of 25 birds each. Birds were vaccinated on the first day of age using a spray vaccine (Coccivac B®, Coopers), containing E. acervulina, E. maxima, E. mivati and E. tenella. S. cerevisiae cell wall was supplied from the first day of age. Live performance, intestinal morphometric parameters and epithelial loss were evaluated at 14, 21 and 28 days of age. Performance was affected by vaccination only at 21-days of age, when body weight gain was reduced in the vaccinated birds, but no body weight difference was observed on day 28. Vaccine also increased the crypt depth (p<0.05) in the duodenum and jejunum, suggesting a high cell activity in the crypt:villus transition area to maintain the epithelial cell turnover. Villi number/area (103,269 µm²) was not affected (p>0.05) by vaccine or cell wall supplementation, and epithelial loss was more pronounced in the duodenum and jejunum. In conclusion, the findings of this study suggest that S. cerevisiae cell wall supplementation may be an useful management tool to maintain the intestinal integrity of broilers vaccinated against coccidiosis.

Two experiments were carried out to study the effect of breeder age on incubation parameters (hatchability, eggshell thickness, egg surface temperature and chick weight). In Exp. 1, fertile eggs (30- and 60-wk-old breeders) were incubated at three different temperatures (36.8, 37.8 and 38.8 ºC). Eggshell surface temperature was measured by attaching a thermocouple to the shell and data were collected in a datalogger every ten minutes. This study was conducted according to a 3 x 2 factorial design (three temperatures and two breeder ages). Data revealed that eggshell surface temperature changed according to incubation temperature, with the main increase occurring between 10 and 13 days of incubation, and that the maximum increase in eggshell surface temperature was not higher than +0.6 ºC, irrespective of incubator temperature. The incubator temperature affected total incubation period and hatchability (%) at 38.8 ºC, independent of breeder age. Heavier eggs resulted in heavier chicks, irrespective of incubator temperature. In Exp 2, the eggs (30- and 60-wk-old breeders) were incubated at 37.8 ºC and eggs characteristics (weight, specific gravity, total hatchability and chicks weight) were evaluated according to a randomized experimental design. The data showed that breeder age affected eggshell thickness and chick weight (heavier eggs resulted in heavier chicks), but not specific gravity, eggshell surface temperature or hatchability. The findings of this study revealed that hatchability can be influenced by incubation temperature, but not by the breeder age. Breeder age can affect eggshell thickness, egg weight and eggshell surface temperature, but not specific gravity.

Estudos morfométricos e socioambientais foram realizados na bacia hidrográfica do rio Monte Sinai, em Carlinda, MT, visando à criação de subsídios para a sua sustentabilidade ambiental. Para tanto, foram utilizados dados SRTM 90 m, reamostrados para 30 m, para a geração do modelo digital de elevação e dados SPOT (10 m), para a avaliação do uso e cobertura da terra, através de técnicas de SIG. Além disso, foram feitas entrevistas semiestruturadas com os moradores locais e visitas de campo. Os resultados apontaram que a bacia apresenta padrão dentrítico de quarta ordem. A razão altimétrica, declividade, densidade de drenagem e fator de forma indicaram forte controle estrutural da drenagem da bacia hidrográfica. Entretanto, o atual uso e cobertura da terra, dominada por pastagens e mata ciliar degradada, favorecem os processos erosivos e, consequentemente, a perda da ferlitiladade do solo e o assoreamento dos cursos d'água. Foram apontados indicadores de degradação, assim como estratégias de manejo adequadas à melhoria ambiental que venham contribuir e garantir a sustentabilidade ambiental da bacia.

Morphometric and environmental studies were performed in Monte Sinai River Watershed, Carlinda, state of Mato Grosso, Brazil, to create subsidies for its environmental sustainability. Thus, it was used SRTM 90 m data, resampled to 30 m, for the generation of digital elevation model data, and SPOT data (10 m) to evaluate the land use/cover, using GIS techniques. In addition, semi-structure interviews with local residents and field visits were conducted. The results showed that the watershed has dendritic drainage pattern of fourth order. The relief ratio, slope, drainage density and shape aspects demonstrate the strong structural control of drainage watershed. However, the current land use/cover, dominated by pastures and degraded riparian vegetation, favored erosion and loss of soil fertility and sedimentation of waterways. Degradation indicators were pointed out, as well as suitable management strategies for environmental improvement that would contribute and ensure the environmental sustainability of the watershed.

Após acidente ambiental em empresa produtora de ácido sulfúrico, realizou-se estudo transversal para investigação de sintomas respiratórios e irritativos na população. Aplicou-se questionário em amostra aleatória simples, em pessoas presentes no local no dia da ocorrência, no raio de 900 m do estabelecimento, considerando a direção dos ventos. Foi calculada a prevalência de sintomas segundo gradientes de 300 m e realizado teste de Chi-Quadrado para sintomas isolados e agregados. Os dados foram georreferenciados, e foi ponderada a densidade de sintomas por área. Nas 451 pessoas estudadas, o teste de Chi-Quadrado foi significativo para todos os sintomas, exceto chiado comparando gradientes de distância. Os sintomas agregados apresentaram as seguintes ODDS Ratio (OR): respiratórios altos (OR: 6,18; 2,10; 1,00); irritativos (OR: 6,06; 2,09; 1,00); respiratórios baixos (OR: 4,93; 2,08; 1,00); náuseas e dor de cabeça (OR: 4,66; 2,02; 1,00). Os autores encontraram maior densidade de sintomas nas proximidades da fonte emissora. O estudo contribuiu para desencadear medidas mitigadoras na empresa.

Following an environmental accident in a sulfuric acid production plant, a transversal study was made to investigate respiratory and irritative symptoms on the population. A questionnaire was applied to a simple random sample from people present until 900 meters from the plant by the time of the event, considering the winds' directions. The prevalence of symptoms and Chi-square test was made according to gradients of 300 meters. The density of symptoms per area, geo-referenced, was pondered. The Chi-square test was significant on the 451 people studied for all symptoms, except by wheezing, comparing gradients of distance. The grouped symptoms presented the following ODDS Ratio (OR): high respiratory (OR: 6.18; 2.10; 1.00); irritative (OR: 6.06; 2.09; 1.00); low respiratory (OR: 4.93; 2.08; 1.00); nausea and headache (OR: 4.66; 2.02; 1.00). The authors have found a major density of symptoms in the vicinities of the source. The study contributed to instigate mitigating measures in the company.

The aspects involved in broiler water intake are not well known, despite the importance of water in animal nutrition and physiology. Water intake behavior should be taken into account when deciding on different types of drinkers. Bell and nipple drinkers are the most commonly used in commercial broiler production. Broilers were housed in cages equipped with two different drinker types and raised at two different environmental temperatures (25 and 34 ºC) to evaluate water intake behavior and volume. Broiler water intake behavior was influenced by drinker type. Birds visited bell drinkers less often, but presented higher total water intake per visit to the drinker as compared to those drinking from nipple drinkers. The results of this study suggest that both broilers drinking behavior and water intake volume should be taken into account when deciding on drinker type to equip broiler houses.

O crisântemo (Dendranthema grandiflora, Tzevelev.) é uma das principais flores comercializadas no Brasil e no mundo. Apesar de sua importância, no Brasil o manejo da irrigação em crisântemo é caracterizado pelo empirismo, necessitando-se de maiores estudos quanto ao uso de água pela cultura. Este trabalho teve como objetivo estudar os efeitos de níveis de irrigação sobre o crisântemo cultivado em ambiente protegido. O experimento foi conduzido, de 06/08-27/10/03, na Fazenda Venezuela, no município de Guaramiranga-CE, em ambiente protegido de 9 x 30 m. O delineamento experimental foi blocos ao acaso, com quatro tratamentos (níveis de irrigação correspondentes a 50; 75; 100 e 125% da evaporação no tanque classe "A", ECA), e quatro repetições, totalizando dezesseis parcelas. O ciclo da cultura foi de 82 dias e as lâminas totais aplicadas foram: 192,2; 246,4; 300,9 e 355,4 mm para os tratamentos 50, 75, 100 e 125% da ECA, respectivamente. Não houve diferença significativa para número de hastes por pacote e de pacotes por m² e, tampouco, para produtividade (Tabela 1). Entre tratamentos, o número de hastes por pacote variou de 21 (75, 100 e 125% ECA) a 22 (50% ECA), o número de pacotes por m², entre 3,63 (100% ECA) e 4,28 (75% ECA) e, a produtividade, entre 3,94 (125% ECA) e 4,36 kg m-2 (75% ECA). À medida que se aumentou a lâmina d'água, diminuiu-se linearmente a eficiência do uso da água. A irrigação utilizando-se lâmina de água correspondente a 125% da ECA apresentou significativamente a menor eficiência no uso da água (0,0107 pacotes m-2 mm-1), enquanto os tratamentos em que a irrigação correspondeu a 50 e 75% da ECA foram os mais eficientes (0,0210 e 0,0174 pacotes m-2 mm-1, respectivamente).

Chrysanthemum (Dendranthema grandiflora, Tzevelev.) is one of the most important flowers traded both in Brazil and in the world. In spite of that, chrysanthemum irrigation management in Brazil is characterized by empiricism, therefore deeper studies related to the plant water use are needed. This work aimed to study the effects of irrigation depths on chrysanthemum grown in protected cultivation. The experiment was conducted from August 6 to the October 27 of 2003, in Guaramiranga, Ceará State, Brazil, under a 9 x 30 m protected cultivation structure. The experimental design was completely randomized blocks, with four treatments (irrigation depths corresponding to 50; 75; 100, and 125% of the evaporation of the class "A" evaporation pan, ECA), and four replications. The crop cycle lasted for 82 days and the total water amounts applied were: 192.2; 246.4; 300.9, and 355.4 mm for the 50, 75, 100 and 125% of ECA treatments, respectively. No significant differences were found in the number of stems per pack, in packages per m², and even in productivity (Table 1). Among treatments, the number of stems per package varied from 21 (75, 100 e 125% ECA) to 22 (50% ECA), the number of packages per m² from 3,63 (100% ECA) to 4,28 (75% ECA), and the productivity from 3,94 (125% ECA) to 4,36 kg m-2 (75% ECA). As the amount of water used increased, the efficiency of water use decreased. Irrigation using the water amount corresponding to 125% of ECA presented the lowest (significant) water use efficiency (0,0107 pacotes m-2 mm-1), while treatments with irrigation corresponding to 50 and 75% of ECA were the most efficient ones (0,0210 e 0,0174 packages m-2 mm-1, respectively).

O cultivo de flores no estado do Ceará vem se ampliando nos últimos anos, principalmente nas regiões serranas que proporcionam clima favorável ao desenvolvimento de diversas culturas. Entretanto, poucos são os trabalhos desenvolvidos nessa área, fazendo com que os produtores se utilizem do empirismo no desenvolvimento dos cultivos. Por conseguinte, esse trabalho teve como objetivo avaliar os efeitos do número de plantas (2, 3 e 4) e da quantidade de drenos (1 e 8) por vaso no número de hastes por vaso da roseira, em ambiente protegido. O experimento foi conduzido na Empresa Reijers, no município de São Benedito-CE, sendo o delineamento experimental em blocos casualizados em arranjo fatorial 3 x 2, com quatro repetições. Avaliou-se o número de hastes com 35, 40, 50 e 60 cm e, o número total de hastes por vasos de 12,0 L. As maiores quantidades de plantas por vaso proporcionaram um maior número de hastes por área, mas com predomínio de hastes de menor valor comercial. A utilização de um menor número de plantas por vaso resultou em um menor número de hastes por área, mas em maior número de hastes com maior valor comercial. A utilização de vasos com maior número de drenos reduziu o número total de hastes por vaso.

The cultivation of flowers in Ceará State has expanded during the last years, especially in highland areas with a favorable climate for several crops. However, there exist only limited research in this area, so that producers work empirically with those crops. Consequently, this research aimed to evaluate the effects of the number of plants (2, 3 and 4) and the amount of drains (1 and 8) per pot on the number of stems per pot, in a protected environment. The experiment was carried out in São Benedito, Ceará State, Brazil, following a 3 x 2 factorial randomized block design with four repetitions. The number of stems with 35, 40, 50, 60 cm and, the total number of stems per pots of 12.0 L were evaluated. The highest number of plants per pot provided the greatest number of stems per pot, but with a predominance of lower commercial value. On the other hand, the least number of plants per pot resulted in few stems per area which were better evaluated commercially. The use of pots having more drains reduced the total number of stems per pot.

A study was carried out to elaborate response surface models using broiler performance data recovered from literature in order to predict performance and elaborate economic analyses. Nineteen studies published between 1995 and 2005 were retrieved using the systematic literature review method. Weight gain and feed conversion data were collected from eight studies that fulfilled the pre-established inclusion criteria, and a response surface model was adjusted using crude protein, environmental temperature, and age as independent variables. The models produced for weight gain (r² = 0.93) and feed conversion (r² = 0.85) were accurate, precise, and not biased. Protein levels, environmental temperature and age showed linear and quadratic effects on weight gain and feed conversion. There was no interaction between protein level and environmental temperature. Age and crude protein showed interaction for weight gain and feed conversion, whereas interaction between age and temperature was detected only for weight gain. It was possible to perform economic analyses to determine maximum profit as a function of the variables that were included in the model. It was concluded that the response surface models are effective to predict the performance of broiler chickens and allow the elaboration of economic analyses to optimize profit.

In order to evaluate the effects of broiler genotype and of heat exposure on performance, carcass characteristics, and protein and fat accretion, six hundred one-day-old male broilers were randomly assigned in a 2 x 3 factorial arrangement, according to the following factors: genetic group (selected and non-selected broilers) and pair-feeding scheme (Ad32 - reared under heat stress and fed ad libitum; Ad23 - reared at thermoneutrality and fed ad libitum; Pf23 - reared at thermoneutrality and pair fed with Ad32), with a total of six treatments with four replicates of 25 birds each. Independent of pair-feeding scheme, selected broilers showed better feed conversion, higher carcass yield, and lower abdominal fat deposition rate. However, as compared to non-selected broilers, they reduced more intensively feed intake when heat exposed, which promoted significant breast-yield decrease, and more pronounced changes on carcass chemical composition. These findings allows concluding that, in both genetic groups, both environmental temperature and feed-intake restriction influence abdominal fat deposition rate and other carcass characteristics; however, the impact of heat exposure on broiler performance is more noticeable on the selected line.