Control of Meloidogyne paranaensis mediated by silicon

The potential of silicon (Si) to control nematodes is often reported in association with the resistance induction mechanism. The objective of this work was to evaluate the hypothesis of resistance induction in plants against nematodes through the application of Si. In vitro experiments were carried out to evaluate the effect of Si and potassium chloride (KCl) on the hatching and mortality of Meloidogyne paranaensis juveniles. For the purpose of a greenhouse experiment, tomato plants were used as a model for bifurcated roots, using the respective control treatments, KCl and distilled water. Ten days after treatment, 2,000 eggs of M. paranaensis were inoculated. At 55 days post-inoculation, the reproduction factor and number of nematodes per gram of root were evaluated. Additionally, the tissue nutrient concentration and gas exchange variables were analyzed. Silicon reduces nematode viability, when in direct contact with the nematode in in vitro experiments and in bifurcated plants. When plants were treated with Si on one side of the root, no nematode control was observed on the opposite corresponding side. Results suggested that Si has a positive effect on the reduction of M. paranaensis population, but probably induced resistance to nematode only through direct action.

Control of Meloidogyne paranaensis mediated by silicon

The potential of silicon (Si) to control nematodes is often reported in association with the resistance induction mechanism. The objective of this work was to evaluate the hypothesis of resistance induction in plants against nematodes through the application of Si. In vitro experiments were carried out to evaluate the effect of Si and potassium chloride (KCl) on the hatching and mortality of Meloidogyne paranaensis juveniles. For the purpose of a greenhouse experiment, tomato plants were used as a model for bifurcated roots, using the respective control treatments, KCl and distilled water. Ten days after treatment, 2,000 eggs of M. paranaensis were inoculated. At 55 days post-inoculation, the reproduction factor and number of nematodes per gram of root were evaluated. Additionally, the tissue nutrient concentration and gas exchange variables were analyzed. Silicon reduces nematode viability, when in direct contact with the nematode in in vitro experiments and in bifurcated plants. When plants were treated with Si on one side of the root, no nematode control was observed on the opposite corresponding side. Results suggested that Si has a positive effect on the reduction of M. paranaensis population, but probably induced resistance to nematode only through direct action.(AU)

Data mining as a hatchery process evaluation tool

The hatchery is one of the most important segments of the poultry chain, and generates an abundance of data, which, when analyzed, allow for identifying critical points of the process . The aim of this study was to evaluate the applicability of the data mining technique to databases of egg incubation of broiler breeders and laying hen breeders. The study uses a database recording egg incubation from broiler breeders housed in pens with shavings used for litters in natural mating, as well as laying hen breeders housed in cages using an artificial insemination mating system. The data mining technique (DM) was applied to analyses in a classification task, using the type of breeder and house system for delineating classes. The database was analyzed in three different ways: original database, attribute selection, and expert analysis. Models were selected on the basis of model precision and class accuracy. The data mining technique allowed for the classification of hatchery fertile eggs from different genetic groups, as well as hatching rates and the percentage of fertile eggs (the attributes with the greatest classification power). Broiler breeders showed higher fertility (> 95 %), but higher embryonic mortality between the third and seventh day post-hatching (> 0.5 %) when compared to laying hen breeders eggs. In conclusion, applying data mining to the hatchery process, selection of attributes and strategies based on the experience of experts can improve model performance.

Data mining as a hatchery process evaluation tool

The hatchery is one of the most important segments of the poultry chain, and generates an abundance of data, which, when analyzed, allow for identifying critical points of the process . The aim of this study was to evaluate the applicability of the data mining technique to databases of egg incubation of broiler breeders and laying hen breeders. The study uses a database recording egg incubation from broiler breeders housed in pens with shavings used for litters in natural mating, as well as laying hen breeders housed in cages using an artificial insemination mating system. The data mining technique (DM) was applied to analyses in a classification task, using the type of breeder and house system for delineating classes. The database was analyzed in three different ways: original database, attribute selection, and expert analysis. Models were selected on the basis of model precision and class accuracy. The data mining technique allowed for the classification of hatchery fertile eggs from different genetic groups, as well as hatching rates and the percentage of fertile eggs (the attributes with the greatest classification power). Broiler breeders showed higher fertility (> 95 %), but higher embryonic mortality between the third and seventh day post-hatching (> 0.5 %) when compared to laying hen breeders eggs. In conclusion, applying data mining to the hatchery process, selection of attributes and strategies based on the experience of experts can improve model performance.(AU)

In ovo feeding: a review / Alimentação in ovo: uma revisão

The poultry industry plays a large role in the Brazilian economy. In fact,Brazil ranks as the worlds leading exporter and second largest producer ofpoultry meat as the result of genetic improvement, animal nutrition,management, and biosecurity. During the development of bird embryos, thenutrients are stored within the egg, but carbohydrate supplementation isunsatisfactory upon hatching. Poor carbohydrate supplementation candamage the embryo development and negatively affect poultry weight. Inovo feeding is a promising technique to improve the quality of newly hatchedchicks as it uses systems for feeding the embryos by inoculating nutrientsinto the egg amniotic fluid. However, further studies are needed in order toimprove this technique and create effective implementations and protocolsthat can be widely used in the industry. This study aims to both review theliterature on the use of in-ovo feeding and understand the perspectives ofits use in the broiler production chain.

A avicultura tem tido papel expressivo na economia brasileira, estando o país classificado como o segundo maior produtor e o maior exportador do mundo. Esse resultado é proveniente de avanços no melhoramento genético, nutrição, manejo e biosseguridade. Nas aves, os nutrientes utilizados durante o desenvolvimento embrionário estão contidos no ovo, sendo escassa a reserva de carboidratos logo após a eclosão do pintainho. Essa restrição pode causar prejuízos ao desenvolvimento embrionário, impactando negativamente no peso das aves. Diante disso, a nutrição in ovo mostra-se como uma técnica promissora, que visa prover nutrientes ao embrião por meio da inoculação de soluções com efeitos benéficos ao seu desenvolvimento. Contudo, são necessários mais estudos no intuito de aprimorar a técnica e criação de protocolos efetivos que possam ser amplamente utilizados pela indústria. Nesse contexto, o objetivo desta revisão de literatura foi abordar e depreender as perspectivas da utilização da técnica nutrição in ovo na cadeia produtiva de frangos de corte.

In ovo feeding: a review / Alimentação in ovo: uma revisão

The poultry industry plays a large role in the Brazilian economy. In fact,Brazil ranks as the worlds leading exporter and second largest producer ofpoultry meat as the result of genetic improvement, animal nutrition,management, and biosecurity. During the development of bird embryos, thenutrients are stored within the egg, but carbohydrate supplementation isunsatisfactory upon hatching. Poor carbohydrate supplementation candamage the embryo development and negatively affect poultry weight. Inovo feeding is a promising technique to improve the quality of newly hatchedchicks as it uses systems for feeding the embryos by inoculating nutrientsinto the egg amniotic fluid. However, further studies are needed in order toimprove this technique and create effective implementations and protocolsthat can be widely used in the industry. This study aims to both review theliterature on the use of in-ovo feeding and understand the perspectives ofits use in the broiler production chain.(AU)

A avicultura tem tido papel expressivo na economia brasileira, estando o país classificado como o segundo maior produtor e o maior exportador do mundo. Esse resultado é proveniente de avanços no melhoramento genético, nutrição, manejo e biosseguridade. Nas aves, os nutrientes utilizados durante o desenvolvimento embrionário estão contidos no ovo, sendo escassa a reserva de carboidratos logo após a eclosão do pintainho. Essa restrição pode causar prejuízos ao desenvolvimento embrionário, impactando negativamente no peso das aves. Diante disso, a nutrição in ovo mostra-se como uma técnica promissora, que visa prover nutrientes ao embrião por meio da inoculação de soluções com efeitos benéficos ao seu desenvolvimento. Contudo, são necessários mais estudos no intuito de aprimorar a técnica e criação de protocolos efetivos que possam ser amplamente utilizados pela indústria. Nesse contexto, o objetivo desta revisão de literatura foi abordar e depreender as perspectivas da utilização da técnica nutrição in ovo na cadeia produtiva de frangos de corte.(AU)

Aspectos técnicos e econômicos da engorda de lagostas: a experiência do vietnam e perspectiva de desenvolvimento da atividade no nordeste brasileiro / Technical and economic aspects of spiny lobster growout: the viatnamese experience and development perspective for the activity in northeastern Brazil / Aspectos técnicos y económicos del engorde de langosta: la experiencia de vietnan y perspectiva de desarrollo de la actividad en nordeste brasileño

A proposta desta revisão é resumir as informações sobre os estudos da engorda de lagostas em gaiolas no Vietnam. Esta sinopse demonstra que os juvenis podem ser cultivados sob regime de confinamento e se adapta bem as condições artificiais com alimentação. Na aquicultura, na engorda de juvenis de lagostas capturadas na natureza (Palinuridae) até o tamanho comercial está emergindo no Vietnam. No Vietnam o cultivo de lagostas em gaiolas no mar começou na década de 1990. Nesse contexto tradicionalmente a Panulirus ornatus e outras espécies são alimentadas com rejeito de pesca e pescado de baixo valor. O objetivo global da engorda pode ser o alívio da pobreza, e neste respeito para os criadores de lagostas é em particular uma oportunidade atrativa para brasileiros devido à captura de pós-larvas de lagostas (com autorização dos órgãos competentes) e sua engorda envolve tecnologia simples, mínimo de capital, e é apropriado como uma atividade alternativa de renda para pescadores.(AU)

The purpose of this review is to sumarize the studies on spiny lobster cage farming in Vietnam. The review showed that spiny lobster juveniles can be held in communal culture systems, since they adapt well to the artificial feeding conditions. In aquaculture, the growout phase of wild-caught juvenile spiny lobsters (Palinuridae) to market size is an emerging sector in Vietnam. Spiny lobster farming in sea cages commenced in the 1990s in Vietnam. Traditionally, Panulirus ornatus lobster and other species are fed with bycatch and cheap fish. The main purpose of the growout phase can be the decrease in poverty, and in this respect lobster farming is a particularly attractive opportunity for Brazil, since the capture of post-hatching lobsters (with authorization of the competent organs) and their growout involves simple technology, minimal capital and is ideally suited as an alternative activity for income generation for fisherman.(AU)

La propuesta de esta revisión es resumir las informaciones sobre los estudios de engorde de langostas en jaulas en Vietnan. Esta sinopsis demuestra que los juveniles pueden cultivarse en régimen de confinamiento y se adapta bien a las condiciones artificiales de alimentación. En la acuicultura, el engorde de juveniles de langostas capturadas en la naturaleza (Palinuridae) hasta el tamaño comercial, está emergiendo en Vietnan. Allá el cultivo de langostas en jaula en el mar empezó en la década de 1990. En ese contexto tradicionalmente la Panulirus ornatus y otras espécies son alimentadas con desechos de pesca y pescado de bajo valor. El objetivo global de engorde puede ser el alivio de la pobreza, y con relación a los creadores de langostas es en particular una atractiva oportunidade para brasileños, debido a la captura poslarvas de langostas (con autorización de los órganos competentes), y su engorde involucra tecnologia simple, mínimo de capital, y es apropriado como uma actividad alternativa de renta para los pescadores.(AU)

Aspectos técnicos e econômicos da engorda de lagostas: a experiência do vietnam e perspectiva de desenvolvimento da atividade no nordeste brasileiro / Technical and economic aspects of spiny lobster growout: the viatnamese experience and development perspective for the activity in northeastern Brazil / Aspectos técnicos y económicos del engorde de langosta: la experiencia de vietnan y perspectiva de desarrollo de la actividad en nordeste brasileño

A proposta desta revisão é resumir as informações sobre os estudos da engorda de lagostas em gaiolas no Vietnam. Esta sinopse demonstra que os juvenis podem ser cultivados sob regime de confinamento e se adapta bem as condições artificiais com alimentação. Na aquicultura, na engorda de juvenis de lagostas capturadas na natureza (Palinuridae) até o tamanho comercial está emergindo no Vietnam. No Vietnam o cultivo de lagostas em gaiolas no mar começou na década de 1990. Nesse contexto tradicionalmente a Panulirus ornatus e outras espécies são alimentadas com rejeito de pesca e pescado de baixo valor. O objetivo global da engorda pode ser o alívio da pobreza, e neste respeito para os criadores de lagostas é em particular uma oportunidade atrativa para brasileiros devido à captura de pós-larvas de lagostas (com autorização dos órgãos competentes) e sua engorda envolve tecnologia simples, mínimo de capital, e é apropriado como uma atividade alternativa de renda para pescadores.(AU)

The purpose of this review is to sumarize the studies on spiny lobster cage farming in Vietnam. The review showed that spiny lobster juveniles can be held in communal culture systems, since they adapt well to the artificial feeding conditions. In aquaculture, the growout phase of wild-caught juvenile spiny lobsters (Palinuridae) to market size is an emerging sector in Vietnam. Spiny lobster farming in sea cages commenced in the 1990s in Vietnam. Traditionally, Panulirus ornatus lobster and other species are fed with bycatch and cheap fish. The main purpose of the growout phase can be the decrease in poverty, and in this respect lobster farming is a particularly attractive opportunity for Brazil, since the capture of post-hatching lobsters (with authorization of the competent organs) and their growout involves simple technology, minimal capital and is ideally suited as an alternative activity for income generation for fisherman.(AU)

La propuesta de esta revisión es resumir las informaciones sobre los estudios de engorde de langostas en jaulas en Vietnan. Esta sinopsis demuestra que los juveniles pueden cultivarse en régimen de confinamiento y se adapta bien a las condiciones artificiales de alimentación. En la acuicultura, el engorde de juveniles de langostas capturadas en la naturaleza (Palinuridae) hasta el tamaño comercial, está emergiendo en Vietnan. Allá el cultivo de langostas en jaula en el mar empezó en la década de 1990. En ese contexto tradicionalmente la Panulirus ornatus y otras espécies son alimentadas con desechos de pesca y pescado de bajo valor. El objetivo global de engorde puede ser el alivio de la pobreza, y con relación a los creadores de langostas es en particular una atractiva oportunidade para brasileños, debido a la captura poslarvas de langostas (con autorización de los órganos competentes), y su engorde involucra tecnologia simple, mínimo de capital, y es apropriado como uma actividad alternativa de renta para los pescadores.(AU)

Embryonic and larval development of the topmouth gudgeon, Pseudorasbora parva (Teleostei: Cyprinidae)

The topmouth gudgeon, Pseudorasbora parva (Temminck & Schlegel, 1842), is a small cyprinid fish that inhabits the littoral zones of freshwater habitats throughout Asia and Europe. It is regarded as an invasive species in Europe, but in its native range, in China, as food and as an environmental bio-indicator. In this study, the embryonic and larval development of P. parva was investigated for the first time. The eggs of P. parva are transparent, adhesive and elliptical. The mean size of fertilized eggs was (1.63×1.31) ± 0.04 mm. From fertilization to hatching, embryonic development could be divided into eight stages and 34 phases, and the incubation period lasted for 109.25 hours at 24 ± 1 °C. Newly hatched larvae were 4.1 ± 3 mm in length, and the yolk absorption was completed within six days after hatching. The first and second swim bladders formed at the third and ninth day, respectively. The pectoral fin formed before the hatching stage, followed by the caudal, dorsal, anal and ventral fin formation after hatching. About 20 days after hatching, the morphology of the fry was similar to the adult fish. These findings provide a basis for determining the complete ontogeny of P. parva, as well as facilitate the management and utilization of this fish.(AU)

Embryonic and larval development of the topmouth gudgeon, Pseudorasbora parva (Teleostei: Cyprinidae)

The topmouth gudgeon, Pseudorasbora parva (Temminck & Schlegel, 1842), is a small cyprinid fish that inhabits the littoral zones of freshwater habitats throughout Asia and Europe. It is regarded as an invasive species in Europe, but in its native range, in China, as food and as an environmental bio-indicator. In this study, the embryonic and larval development of P. parva was investigated for the first time. The eggs of P. parva are transparent, adhesive and elliptical. The mean size of fertilized eggs was (1.63×1.31) ± 0.04 mm. From fertilization to hatching, embryonic development could be divided into eight stages and 34 phases, and the incubation period lasted for 109.25 hours at 24 ± 1 °C. Newly hatched larvae were 4.1 ± 3 mm in length, and the yolk absorption was completed within six days after hatching. The first and second swim bladders formed at the third and ninth day, respectively. The pectoral fin formed before the hatching stage, followed by the caudal, dorsal, anal and ventral fin formation after hatching. About 20 days after hatching, the morphology of the fry was similar to the adult fish. These findings provide a basis for determining the complete ontogeny of P. parva, as well as facilitate the management and utilization of this fish.

Reprodução de peixes reofílicos nativos do Brasil: fertilização artificial e qualidade da água / Reproduction of brazilian reofilic fish: artificial fertilization and water quality

A demanda de pescado tem aumentado, sendo impulsionada pelo crescimento populacional e a busca por alimentos saudáveis indicado para o consumo humano. No entanto, a pesca predatória e a degradação do ambiente natural estão levando ao declínio das populações naturais de peixes. Nesse contexto, a expansão da piscicultura mostra-se como uma boa alternativa para contornar tais problemas. Para isso, é importante conhecer as principais técnicas reprodutivas adotadas e determinar o protocolo adequado para cada espécie. Alguns aspectos importantes devem ser considerados, como a técnica de indução à reprodução, o tipo de desova, a taxa de fertilização e eclosão dos ovos, bem como o acompanhamento do desenvolvimento embrionário e larval, além de normalidade e sobrevivência das larvas. Outros pontos importantes são o monitoramento e o controle da qualidade da água, observando parâmetros físicos e químicos, pois afetam diretamente o desenvolvimento dos organismos aquáticos. O objetivo da presente revisão foi apresentar os principais protocolos de manejo reprodutivo e parâmetros de qualidade de água na rotina de fertilização artificial de peixes reofílicos nativos do Brasil.(AU)

The fish has increased demand driven by population growth and the search for healthful foods suitable for human consumption. However, overfishing and degradation of the natural environment are leading to the decline of natural fish populations. Within context, the expansion of fish farming is a good alternative to overcome such problems. Therefore, it is important to understand the main reproductive techniques used and determine the proper protocol for each species. Some important aspects should be considered such as fish induced breeding techniques, spawning type, fertilization and hatching rate, as well as monitoring the embryonic and larval development, besides the normality and larvae survival. Other important points are the monitoring and control of water quality, observing the physical and chemical variables, as they directly affect the development of aquatic organisms. The aim of this review was to present the main protocols of reproductive management and water quality parameters in the routine of artificial fertilization of brazilian native reofilic fish.(AU)

Reprodução de peixes reofílicos nativos do Brasil: fertilização artificial e qualidade da água / Reproduction of brazilian reofilic fish: artificial fertilization and water quality

A demanda de pescado tem aumentado, sendo impulsionada pelo crescimento populacional e a busca por alimentos saudáveis indicado para o consumo humano. No entanto, a pesca predatória e a degradação do ambiente natural estão levando ao declínio das populações naturais de peixes. Nesse contexto, a expansão da piscicultura mostra-se como uma boa alternativa para contornar tais problemas. Para isso, é importante conhecer as principais técnicas reprodutivas adotadas e determinar o protocolo adequado para cada espécie. Alguns aspectos importantes devem ser considerados, como a técnica de indução à reprodução, o tipo de desova, a taxa de fertilização e eclosão dos ovos, bem como o acompanhamento do desenvolvimento embrionário e larval, além de normalidade e sobrevivência das larvas. Outros pontos importantes são o monitoramento e o controle da qualidade da água, observando parâmetros físicos e químicos, pois afetam diretamente o desenvolvimento dos organismos aquáticos. O objetivo da presente revisão foi apresentar os principais protocolos de manejo reprodutivo e parâmetros de qualidade de água na rotina de fertilização artificial de peixes reofílicos nativos do Brasil.

The fish has increased demand driven by population growth and the search for healthful foods suitable for human consumption. However, overfishing and degradation of the natural environment are leading to the decline of natural fish populations. Within context, the expansion of fish farming is a good alternative to overcome such problems. Therefore, it is important to understand the main reproductive techniques used and determine the proper protocol for each species. Some important aspects should be considered such as fish induced breeding techniques, spawning type, fertilization and hatching rate, as well as monitoring the embryonic and larval development, besides the normality and larvae survival. Other important points are the monitoring and control of water quality, observing the physical and chemical variables, as they directly affect the development of aquatic organisms. The aim of this review was to present the main protocols of reproductive management and water quality parameters in the routine of artificial fertilization of brazilian native reofilic fish.

EFFECT OF TEMPERATURE AND DIET (STARCH AND FIBER) ON EMBRYONIC DEVELOPMENT, ENERGY METABOLISM AND GROWTH OF RED-FOOTED TORTOISE (Chelonoidis carbonaria).

Existe pouca informação sobre as condições de incubação dos ovos, necessidades nutricionais e de manejo em cativeiro de jabutis piranga (Chelonoidis carbonaria) para a conservação. No primeiro estudo desta dissertação considerou-se que embriões de répteis respondem às mudanças da temperatura com ajustes metabólicos e fisiológicos que influenciam o sucesso de eclosão, fenótipo, e taxa de crescimento. As mudanças climáticas e o aquecimento global podem afetar as populações de répteis e a incubação artificial tem sido proposta como uma estratégia potencial para estudar e mitigar esses efeitos. Foram coletados ovos de jabuti piranga e incubados artificialmente às temperaturas constantes de 27,5°C e 29,5°C para determinar o efeito da temperatura no desenvolvimento embrionário mediante ovoscopia; a morfologia e a taxa de crescimento inicial do filhote. Os efeitos diretos da temperatura no período de incubação, massa perdida de ovos, índice de eclosão, tamanho e peso do filhote foram avaliados na eclosão e aos três meses de idade. Filhotes produzidos à 29,5°C apresentaram períodos de incubação mais curtos (141 dias) do que os de 27,5°C (201 dias; p <0,05). A perda de massa de ovo, o peso e tamanho do filhote na eclosão não foram diferentes entre as temperaturas de incubação (P> 0,05). No entanto, o índice de incubação (taxa de sobrevivência) foi menor (64,5% versus 100%) em ovos incubados a 29,5°C, mas o peso e a largura do plastrão dos filhotes foram maiores aos 3 meses de idade do que para os filhotes dos ovos incubados a 27,5°C (p <0,05). Esses resultados indicam claramente que a temperatura de incubação tem uma influência importante no sucesso eclosão e no tamanho e peso dos filhotes nos primeiros meses, influenciando a taxa de crescimento inicial. O segundo objeto de estudo considerou que alterações da carapaça são um problema importante, observado em muitos zoológicos e criatórios ao redor do mundo. O objetivo do estudo foi determinar o efeito de dois alimentos, um com elevado teor de fibra e outro com elevado teor de amido, sobre o metabolismo energético, digestibilidade dos nutrientes e crescimento do jabuti piranga. Seguindo um delineamento inteiramente casualizado, com 20 filhotes recém eclodidos, aleatoriamente divididos em duas rações experimentais (10 filhotes por ração). O estudo teve uma duração de 18 meses, período no qual os filhotes receberam apenas sua respectiva dieta experimental, e água ad libitum. As avaliações realizadas nos animais incluíram: determinação dos coeficientes de digestibilidade aparente dos nutrientes e tempo de trânsito gastrointestinal aos 5 e 11 meses; determinação da taxa metabólica em repouso e pós-prandial, com cálculo do incremento calórico em câmaras de respirometría por calorimetria indireta aos 6 e 12 meses; avaliação do crescimento e características da carapaça, com especial atenção à formação de piramidismo; e determinação da composição corporal por absorciometria de raio-X de dupla energia (DXA) quando os animais atingiram 250 g de peso vivo. Valores de P<0,05 foram considerados significativos. As análises foram conduzidas pelo R Studio Software (versão 3.2.3, AT). Os animais alimentados com a dieta alto amido apresentaram maiores consumos massa-específicos de matéria seca (12,75±3,11mg) em comparação aos animais da dieta alta fibra (10,20±3,37mg) (P<0,05). Apresentaram, ainda, menores tempos de trânsito e retenção gastrointestinal dos alimentos, de 2,95±1,01 e 8,09±2,05 dias, respectivamente (P<0,05), em comparação aos animais alimentados com dieta alta fibra (4,23±1,40 e 10,05±2,41 dias, respectivamente). Maiores eficiências digestivas dos nutrientes avaliados foram observadas em animais alimentados com a dieta com alto amido, com coeficiente de digestibilidade aparente da energia de 75,73±2,68% em comparação a 68,10±2,35% para a dieta alta fibra (P<0,05). A digestibilidade aparente da proteína bruta, no entanto, foi maior na dieta com alta fibra (P<0,05). Em relação à produção de calor em repouso e pós prandial na temperatura de preferência, estas não foram afetadas pela dieta (P>0,05). Foram observados incrementos calóricos de 43,85±14,92 e 41,33±14,66 kJ/kg/dia para as dietas alto amido e alta fibra, respectivamente (P>0,05). Os animais alimentados com a dieta de alto amido apresentaram aos 13 meses maiores larguras do plastrão e da carapaça, resultando em maiores taxas de crescimento da largura da carapaça do que os filhotes alimentados com a ração alta fibra (P<0,05). Sob as duas dietas animais desenvolveram carapaças com aparência piramidal, mas os alimentados com alto amido desenvolveram alterações de piramidismo com maior intensidade (P<0,05). Adicionalmente, os filhotes alimentados com alto amido apresentaram menor conteúdo mineral (1,88±0,15% versus 2,15±0,19%) e menor densidade óssea (0,13±0,01g/mm2 versus 0,15±0,02g/mm2) do que os alimentados com alta fibra (P<0,05), reforçando a piora na formação da carapaça. No terceiro estudo, filhotes alimentados com a dieta alta em fibra foram mantidos à duas temperaturas (18°C e 28°C), para avaliar o efeito da temperatura no consumo de energia bruta e digestível, taxa metabólica em repouso e pós-prandial aos 6 e 12 meses, e a temperatura corporal superficial. Maior consumo massa específico de energia bruta e ganho de peso foram obtidos na primavera e verão. A maior e menor taxa metabólica em repouso à 28°C foram obtidas na primavera e inverno, respectivamente. À 28°C, os animais apresentaram maior consumo diário de energia bruta e digestível, consumo de oxigênio, produção de CO2, e taxa metabólica em repouso e pós-prandial, sendo a produção de calor em repouso de 30,56±4,07kJ/kg/dia à 28°C e de apenas 7,71±1,26kJ/kg/dia à 18°C (P<0,05). Coeficiente do incremento calórico específico foi também afetado pela temperatura, sendo a digestão menos dispendiosa energeticamente à 28°C do que a 18°C (P<0,05). Coeficientes respiratórios atípicos foram observados à 18°C (0,30-0,50). Adicionalmente uma forte influência da massa corporal foi descrita na taxa metabólica em repouso com exponente alométrico de 0,62 e 0,92 à 28°C e 18°C, respectivamente. E observou-se a prioridade de termorregular a temperatura superficial da cabeça sob temperatura baixa, e os animais apresentaram temperaturas corporais superficiais maiores pós alimentação. Como conclusão, o presente trabalho indica a importância de se considerar o efeito da temperatura e da composição da dieta no metabolismo energético e crescimento de jabuti piranga. Alimentos com maior energia digestível, como elevado amido pode induzir crescimento mais acelerado da carapaça com menor mineralização. Adicionalmente a importância de considerar a diferencia dos requerimentos de energia em diferentes regimes térmicos.

There is very little information about egg incubation conditions, nutrient requirements, and captive management of the red-footed tortoise (Chelonoidis carbonaria) for conservation purposes. In the first study of this thesis, it was considered that reptile embryos respond to temperature changes with metabolic and physiological adjustments that influence hatchling success, phenotype, behaviour, and growth rate. Climate change and global warming can affect the reptile population by altering the frequencies of hatchling survival and phenotypes. Therefore, previous studies proposed artificial incubation as a potential strategy for mitigating these effects. Red footed tortoise eggs were collected and incubated at constant temperatures of 27.5°C and 29.5°C to investigate the physiological effects of temperature on embryo development, hatchling morphology and early growth rate. The direct effects of temperature on the incubation period, lost egg mass, hatching index, hatchling size, and mass were evaluated at hatching and at three months of age. Hatchlings from 29.5°C presented shorter incubation times (141 says) than those from 27.5°C (201 days; P<0.05). Egg mass loss, hatchling mass, and size at hatching were not different between the incubation temperatures (P>0.05). However, the hatching index (survival rate) was lower (64.5% versus 100%) in eggs incubated at 29.5°C, but the hatchling mass and straight plastron width were higher at 3 months of age than those for eggs incubated at 27.5°C (P<0.05). These results clearly indicate that incubation temperature has an important influence on hatchling success and hatchling size and mass in the first months by influencing the early growth rate. The second objective of the thesis considered that changes in the carapace are an important problem, observed in many zoos around the world. The objective was to determine the effect of two diets, one with a high fiber content and the other with a high starch content, on energy metabolism, nutrient digestibility, and growth of the red footed tortoise. Following a completely randomized design, with 20 hatchlings, randomly divided into two experimental diets (10 hatchlings per feed). The study lasted 18 months, during which the animals received only their respective experimental diet, and water ad libitum. The evaluations performed on the animals included: determination of the apparent digestibility coefficients of the nutrients and gastrointestinal transit time at 5 and 11 months; determination of the metabolic rate at rest and postprandial, with calculation of the heat increment in respirometry chambers by indirect calorimetry at 6 and 12 months; evaluation of the growth and characteristics of the carapace, with special attention to the formation of pyramiding; and determination of body composition by dual energy X-ray absorptiometry (DXA) when the animals reached 250 g of body mass. Values of P <0.05 were considered significant. The analyzes were conducted by R Studio Software (version 3.2.3, AT). Animals fed with the high starch diet showed higher mass-specific dry matter intake (12.75±3.11mg) compared to animals fed with the high fiber diet (10.20±3.37mg) (P<0.05). They also presented shorter transit times and gastrointestinal retention of food, of 2.95±1.01 and 8.09±2.05 days, respectively (P<0.05), compared to animals fed a high fiber diet. (4.23±1.40 and 10.05±2.41 days, respectively). Higher digestive efficiencies of the evaluated nutrients were observed in animals fed with the high starch diet, with an apparent energy digestibility coefficient of 75.73±2.68% compared to 68.10±2.35% for the high fiber diet. (P<0.05). The apparent digestibility of crude protein, however, was higher in the high fiber diet (P<0.05). Regarding the production of heat production at rest and post-prandial at the preferred temperature, these were not affected by the diet (P>0.05). Heat increments of 43.85 ± 14.92 and 41.33 ± 14.66 kJ/kg/day were observed for the high starch and high fiber diet, respectively (P>0.05). The animals fed with the high starch diet presented, at 13 months, wider plastrons and carapaces, resulting in higher growth rates of the carapace width than the hatchlings fed with the high fiber diet (P<0.05). Under the two animal diets, they developed pyramiding growth, but those fed with the high starch diet developed this doming with greater intensity (P<0.05). Additionally, hatchlings fed with the high starch diet had lower mineral content (1.88±0.15% versus 2.15±0.19%) and lower bone density (0.13±0.01g/mm2 versus 0.15±0.02g/mm2) than those fed with the high fiber diet (P<0.05). In the third study, hatchlings fed with the high fiber diet were kept at two temperatures (18 ° C and 28 ° C), to assess the effect of temperature on the consumption of gross and digestible energy, resting and post-prandial metabolic rate at 6 and 12 months old, and surface body temperature. Higher mass-specific consumption of gross energy and body mass gain were obtained in the spring and summer. The highest and lowest resting metabolic rate at 28°C were obtained in spring and winter, respectively. At 28°C, the animals showed higher daily consumption of gross and digestible energy, oxygen consumption, CO2 production, and rest and post prandial metabolic rate, with a heat production at rest of 30.56±4.07kJ/kg/day at 28 °C and only 7.71±1.26 kJ/kg/day at 18°C (P<0.05). Specific heat increment coefficient was also affected by temperature, with digestion being less energy-intensive at 28°C than at 18°C (P<0.05). Atypical respiratory coefficients were observed at 18°C (0.30- 0.50). In addition, a strong influence of body mass has been described on the resting metabolic rate with an allometric exponent of 0.62 and 0.92 at 28°C and 18°C, respectively. In addition, it was observed the priority of thermoregulating the surface temperature of the head under low temperature, and animals presented higher surface body temperatures after feeding. In conclusion, the present work indicates the importance of considering the effect of temperature and the composition of the diet on energy metabolism and growth of red-footed tortoise. Feeds with higher digestible energy, such as high starch, can induce accelerated carapace growth with less mineralization. In addition, the importance of considering the difference in energy requirements in different thermal regimes.

Performance of broilers submitted to high CO2 levels during incubation combined with temperature fluctuations at late post-hatch

Incubation represents around 1/3 of the life cycle of broilers of modern strains; therefore, the appropriate management of this period is crucial to ensure the quality of the neonate. An experiment evaluated the effect of carbon dioxide concentrations during incubation on the live performance, heart morphology, and differential leukocyte count in the blood of broilers submitted to fluctuating temperatures between 35 and 42 days of age. In total, 2,520 fertile eggs were distributed according to a completely randomized design with four CO2 concentrations (4,000; 6,000; 8,000 and 10,000 ppm) during the first ten days of incubation, after which all eggs were incubated at the same CO2 level (4,000 ppm). After hatching, male chicks were placed in the experimental broiler houses, and at 35 days of age, 25 birds from each level of CO2 were separated and placed in cages to study the effect of cyclic temperature variations up to 42 days of age on their live performance, heterophil:lymphocyte ratio, and heart morphology. At 42 days of age, blood was collected for hematology and two birds per replicate were sacrificed and evaluated for ascites score and heart and liver relative weights. Heart morphology was assessed by analyzing digital images. In this experiment, hypercapnia during incubation and fluctuating temperatures during the growout did not affect mortality, ascites score, heart and liver relative weights, or heart characteristics (p>0.05). However, heterophill:lymphocyte ratio increased (p 0.05) with increasing carbon dioxide concentrations during incubation. It was concluded that high CO2 levels during incubation did not influence the resistance of broilers to fluctuating temperatures during the last week of age.

Performance of broilers submitted to high CO2 levels during incubation combined with temperature fluctuations at late post-hatch

Incubation represents around 1/3 of the life cycle of broilers of modern strains; therefore, the appropriate management of this period is crucial to ensure the quality of the neonate. An experiment evaluated the effect of carbon dioxide concentrations during incubation on the live performance, heart morphology, and differential leukocyte count in the blood of broilers submitted to fluctuating temperatures between 35 and 42 days of age. In total, 2,520 fertile eggs were distributed according to a completely randomized design with four CO2 concentrations (4,000; 6,000; 8,000 and 10,000 ppm) during the first ten days of incubation, after which all eggs were incubated at the same CO2 level (4,000 ppm). After hatching, male chicks were placed in the experimental broiler houses, and at 35 days of age, 25 birds from each level of CO2 were separated and placed in cages to study the effect of cyclic temperature variations up to 42 days of age on their live performance, heterophil:lymphocyte ratio, and heart morphology. At 42 days of age, blood was collected for hematology and two birds per replicate were sacrificed and evaluated for ascites score and heart and liver relative weights. Heart morphology was assessed by analyzing digital images. In this experiment, hypercapnia during incubation and fluctuating temperatures during the growout did not affect mortality, ascites score, heart and liver relative weights, or heart characteristics (p>0.05). However, heterophill:lymphocyte ratio increased (p 0.05) with increasing carbon dioxide concentrations during incubation. It was concluded that high CO2 levels during incubation did not influence the resistance of broilers to fluctuating temperatures during the last week of age.

Performance of broilers submitted to high CO2 levels during incubation combined with temperature fluctuations at late post-hatch

Incubation represents around 1/3 of the life cycle of broilers of modern strains; therefore, the appropriate management of this period is crucial to ensure the quality of the neonate. An experiment evaluated the effect of carbon dioxide concentrations during incubation on the live performance, heart morphology, and differential leukocyte count in the blood of broilers submitted to fluctuating temperatures between 35 and 42 days of age. In total, 2,520 fertile eggs were distributed according to a completely randomized design with four CO2 concentrations (4,000; 6,000; 8,000 and 10,000 ppm) during the first ten days of incubation, after which all eggs were incubated at the same CO2 level (4,000 ppm). After hatching, male chicks were placed in the experimental broiler houses, and at 35 days of age, 25 birds from each level of CO2 were separated and placed in cages to study the effect of cyclic temperature variations up to 42 days of age on their live performance, heterophil:lymphocyte ratio, and heart morphology. At 42 days of age, blood was collected for hematology and two birds per replicate were sacrificed and evaluated for ascites score and heart and liver relative weights. Heart morphology was assessed by analyzing digital images. In this experiment, hypercapnia during incubation and fluctuating temperatures during the growout did not affect mortality, ascites score, heart and liver relative weights, or heart characteristics (p>0.05). However, heterophill:lymphocyte ratio increased (p 0.05) with increasing carbon dioxide concentrations during incubation. It was concluded that high CO2 levels during incubation did not influence the resistance of broilers to fluctuating temperatures during the last week of age.(AU)

AVALIAÇÃO DOS EFEITOS DE PRINCÍPIOS FITOTERÁPICOS E HOMEOPÁTICOS NO CONTROLE DE Rhipicephalus (Boophilus) microplus E COMPARAÇÃO DE TÉCNICAS PARA ESTIMATIVA DE ECLOSÃO DE LARVAS in vitro

O parasitismo por Rhipicephalus (Boophilus) microplus ocasiona grandes perdas econômicas nos rebanhos bovinos, e seu controle por meio de carrapaticidas sintéticos enfrenta problemas de resistência, além do risco de resíduos nos alimentos e ambiente. Com o objetivo de contribuir com informações relevantes para o controle desse parasita, o presente estudo teve três objetivos: 1) avaliar in vitro o efeito do óleo essencial de Ocotea elegans canela-sassafrás sobre larvas e fêmeas ingurgitadas de R. (B.) microplus; 2) avaliar medicamento homeopático no controle de infestações naturais; 3) comparar as técnicas de estimativa visual e de quantificação por amostragem de larvas eclodidas no teste de imersão de fêmeas adultas, visto a importância dessas no levantamento de substâncias com ação carrapaticida. No primeiro experimento Efeito acaricida e repelente in vitro do óleo essencial de Ocotea elegans (canela-sassafrás) sobre Rhipicephalus (Boophilus) microplus, foram adotados os testes: contato de larvas em papel impregnado (LPI), teste de repelência larvar (TR) e imersão de fêmeas adultas (AIT). A fim de verificar a eficácia, O. elegans foi avaliada nas concentrações de 0,78 mg/mL a 100 mg/mL. No AIT, a partir da concentração de 25 mg/mL, a eficácia foi superior a 90%. Os LPI (48h) a 100 mg/mL resultaram em taxas de mortalidade acima de 70%. Já o TR obteve repelência superior a 80% a partir da menor concentração avaliada. Em relação às concentrações letais (CL), a menor CL50 obtida no LPI foi de 25,59 mg/mL 48h pós tratamento. As CL50 e CL90 no AIT foram de 4,96 e 17,37 mg/mL e no TR de 0,04 e 1,24 mg/mL, respectivamente. Foi possível concluir que O. elegans demonstrou efeito significativo sobre fêmeas ingurgitadas e de repelência das larvas, e possivelmente pode ser um adjuvante no controle do carrapato bovino, devendo-se priorizar testes in vivo. No segundo experimento, Estudo da homeopatia no controle de infestações naturais por R. (B.) microplus em bovinos de leite, 24 fêmeas da raça Holandesa e Jersey x Holandesa foram divididas nos grupos controle (placebo) (n=12) e tratado (bioterápico 30 CH + Sulphur 30 CH) (n=12), administrado no concentrado (2kg/animal/dia) por 12 meses. De cada grupo coletou-se fêmeas ingurgitadas, a fim de comparar os parâmetros reprodutivos, e semi-ingurgitadas para avaliações morfo-histológicas dos ovários. Mensurou-se o peso vivo (PV), volume globular (VG) e realizou-se contagens de fêmeas ingurgitadas no corpo dos animais. Os resultados médios de PV, VG e n° de carrapatos não foram diferentes estatisticamente para os grupos controle e homeopatia: 616,5 kg e 618,6 kg, 27,9% e 27,3%, 12,19 e 13,58 carrapatos, respectivamente. Nas análises in vitro, as médias do peso das fêmeas (0,18 e 0,17 g), peso dos ovos (0,07 e 0,06 g), % de eclosão de larvas (70,1 e 76,6%) e índice de eficiência reprodutiva (54,3 e 60,6%), para os grupos controle e homeopatia, respectivamente, também não tiveram diferença estatística. Além disso, nenhuma alteração nos ovários foi observada nos estudos em foto-microscopia. Portanto, o medicamento homeopático avaliado não foi eficaz no controle de R. (B.) microplus e não interferiu nos parâmetros reprodutivos das fêmeas ingurgitadas. Finalmente, no estudo Alternative methods for egg hatch evaluation of Rhipicephalus (Boophilus) microplus em que comparou-se duas técnicas de estimativa de eclosão de ovos, fêmeas ingurgitadas coletadas de bovinos foram submetidas ao AIT com extratos vegetais e mantidas em incubadora para realizar a oviposição. Os ovos foram transferidos para seringas e incubados por 15 dias. A eclosão dos ovos foi avaliada em 210 seringas por estimativa visual (%) e também contadas até 100, em três repetições. Foram encontradas diferenças significativas entre os dois testes. Na estimativa visual (56,8%) a porcentagem de eclosão média foi maior do que na quantificação por amostragem (48,0%). Na quantificação por amostragem, não foram observadas diferenças estatísticas nas contagens das três amostras (48,1, 47,8 e 48,1%) e a correlação entre as repetições foi de 0,96, sugerindo que a contagem de uma amostra é suficiente e o resultado independente do avaliador. O presente estudo contribuiu com informações inéditas sobre o potencial acaricida e repelente de O. elegans. Discutiu-se que apesar do medicamento homeopático não ter tido efeito, tal conclusão não pode ser estendida a outras formulações homeopáticas, vias de aplicação e condições de manejo adversas às do presente estudo. Por fim, os resultados do estudo comparativo contribuem para o aperfeiçoamento do AIT e podem estimular os pesquisadores a optar por técnicas mais confiáveis na avaliação da eclosão de ovos.

The parasitism by Rhipicephalus (Boophilus) microplus causes large economic loss in cattle herds and its control through chemical acaricides faces problems of resistance and residues in food and in the environment. Aiming to contribute with relevant information for the control of this parasite, the present study had three objectives: 1) evaluate the effect in vitro of Ocotea elegans essential oil on larvae and engorged females of R. (B.) microplus, 2) evaluate homeopathic medicine to control R. (B.) microplus natural infestations, and 3) compare visual estimation and quantification by sampling techniques of larvae hatching in the engorged females immersion test, due to the importance of this technique in the screening of substances with antiparasitic action. In the first experiment, "In vitro acaricidal and repellent effect of Ocotea elegans essential oil on R. (B.) microplus", were adopted the tests: larval packet test (LPT), the larval repellency test (RT) and the adult immersion test (AIT). In order to verify efficacy, O. elegans was evaluated at concentrations of 0.78 mg/mL to 100 mg/mL. In the AIT, from the concentration of 25 mg/ml, the efficacies were higher than 90%. LPT (48h) at 100 mg/mL resulted in mortality rates higher than 70%. The RT obtained repellency higher than 80% sice the lowest concentration evaluated. In relation to the lethal concentrations, the lowest LC50 obtained in the LPT was 25.59 mg/mL, 48 hours post treatment. The LC50 and LC90 in the AIT were 4.96 and 17.37 mg/mL and in TR were 0.04 and 1.24 mg/mL, respectively. It was possible to conclude that O. elegans had significant effect in engorged females and larvae repellency and may be in the future an adjuvant for tick control, prioritizing in vivo tests. In the second experiment, Study of homeopathy in the control of natural infestation of R. (B.) microplus in dairy cattle, 24 females of the Dutch and Jersey x Dutch breed were divided in the control group (placebo) and treated (biotherapic 30 CH + Sulphur 30 CH) (n=12), administered in the concentrate at 2 kg/animal/day for 12 months. It was collected in each group engorged females to compare the reproductive parameters, and semi-engorged females for the ovaries histologic evaluation. The live weight (LW), packed cell volume (PCV) and counts of engorged females in the animals body were held. The average results of LW, PCV and ticks were not statistically different in the control and homeopathic groups: 616.5 kg and 618.6 kg, 27.9% and 27.3%, 12.19 and 13.58 ticks, respectively. In the in vitro analyzes, the average weight of females (0.18 and 0.17 g), egg weight (0.07 and 0.06 g), larvae hatching % (70.1 and 76.6%) and reproductive efficiency index (54.3 and 60.6%), to control and homeopatic groups, respectively, had no statistical difference as well. In addition, no changes in the ovaries were observed in microscopy. Therefore, the homeopathic medicine assessed didnt present efficacy in the R. (B.) microplus control, and didnt interfere in the reproductive parameters of engorged females. Finally, in the study "Alternative methods for egg hatch evaluation of Rhipicephalus (Boophilus) microplus" in which two techniques of egg hatching estimation were compared, engorged females collected from cattle were subject to the AIT with plant extracts and kept in an incubator to perform oviposition. Eggs were transferred to syringes and incubated for 15 days. Egg hatching was evaluated in 210 syringes by visual estimation (%) and also counted until 100 in three repetitions. Significant differences were found between the two tests. In the visual estimation (56.8%) the hatching percentage average was higher than in the quantification by sampling (48.0%). In quantification by sampling, no statistical differences were observed in the pairwise counts between the three samples (48.1, 47.8 and 48.1%) and, the correlation of repetitions was 0.96, suggesting that the count of one sample is sufficient and the result should not differ much, regardless of the evaluator. The present study contributed with unreleased information about the acaricide and repellent effect of O. elegans. It was discussed that despite the homeopathic medicine had not effect, such conclusion cannot be extended to other homeopathic formulations, process of application and management conditions adverse to the present study. Finally, the results of the comparative study contribute for the improvement of the AIT and may encourage researchers to choose more reliable techniques in the assessment of the egg hatching.

Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages

This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.

Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages

This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.

Broiler adaptation to post-hatching period

In the latest years more attention has been given to mechanisms for bird adaptation at post-hatching period by management of environmental conditions and formulations of diets offered during this period when digestive, immune, and thermo-regulating systems suffer slight changes. In post-hatching period, digestive system is anatomically complete, but its functionality is still immature in relation to adult birds. The chick immunity depends on maternal antibodies transferred to egg just before laying. In addition, variations within thermal comfort zone might affect initial development of chick. For example, high temperatures may induce hyperthermia with dehydration, while low temperatures may lead to hypothermia responsible by pulmonary hypertension syndrome. In conclusion, productivity might be enhanced when good conditions are offered to chicks during the period from last embryo development to first days after hatching.

Nos últimos anos, os processos adaptativos que ocorrem no período pós-eclosão têm recebido atenção especial através de controle de condições ambientais e manipulação de dietas específicas para este período, uma vez que os sistemas digestório, imunológico e termorregulador sofrem sensíveis alterações. No período de pós-eclosão, o sistema digestório está anatomicamente completo, mas sua capacidade funcional ainda está imatura se comparado à de aves adultas. Nesta fase, a imunidade é dependente dos anticorpos maternais que foram depositados no ovo antes mesmo da oviposição. Além disso, oscilações na zona de conforto térmica também podem influenciar o desenvolvimento inicial das aves. Por exemplo, temperaturas altas podem induzir a hipertermia com desidratação enquanto temperaturas baixas podem desencadeiar quadros hipotérmicos que levam à síndrome de hipertensão pulmonar. Concluindo, melhores índices produtivos podem ser alcançados quando boas condições são oferecidas aos animais no período que compreende o final do desenvolvimento embrionário e os primeiros dias após a eclosão.