Stressful conditions are predisposing factors for disease development. Heat stress is one of the most important stressors in poultry production. The reemergence of some previously controlled diseases [e.g., avian necrotic enteritis (NE)] has been extensively reported. The combination of bacterial infection and certain environmental factors have been reported to trigger the disease. The aim of this study was to analyze the effects of long-term heat stress (35 ± 1°C) on the development of NE in broiler chickens. For this purpose, 60 male broiler chickens were divided into the following 6 groups: control group (C), heat stressed control group (C/HS35), thioglycolate group (T), thioglycolate heat-stressed group (T/HS35), infected group (I), and infected heat-stressed group (I/HS35). The poultry of groups I and I/HS35 were experimentally infected with Clostridium perfringens via their feed from 15 to 21 d of life. Heat stress (35 ± 1°C) was constantly applied to the birds of the stressed groups from 14 to 21 d of life. The infected and heat-stressed broiler chickens presented a trend toward a decrease in gross lesion scores and significantly lower microscopic scores of necrosis in the duodenum and jejunum (P < 0.05), lower fusion of villi in the duodenum (P < 0.05), and lower congestion scores in the jejunum and ileum (P < 0.05) in relation to infected and non-heat-stressed chickens. Broilers of I/HS35 group also exhibited small number of heterophils in the duodenum and jejunum compared with those of the I group (P < 0.05). Furthermore, the duodenum and jejunum of infected and heat-stressed broilers showed lower number of clostridia on the intestinal mucosa (P < 0.05). Data were discussed in light of a heat stress induced reduction on intestinal inflammation via a decrease in heterophil migration to the intestinal mucosa, which in turn might have reduced tissue damage during inflammation, hence preventing the development of a more severe form of NE.

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RESUMO -Em dois ensaios experimentais, avaliaram-se níveis de lisina digestível (0,90; 1,00; 1,10; 1,20 e 1,40%) combinados a zinco quelado (43 e 253 ppm) para frangos de corte machos. Os períodos considerados foram: 1 a 11 dias de idade (desempenho) e 1 a 7 dias de idade (balanço de nitrogênio). O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 5 × 2. No ensaio de desempenho, utilizaram-se 7 repetições e 15 aves por unidade experimental e, no ensaio de digestibilidade, 6 repetições e 6 aves por unidade experimental. As dietas continham 2.960 de EM/kg e 21% de proteína bruta. Na fase de 1 a 11 dias de idade, não houve efeito de interação lisina digestível × zinco quelado no desempenho, mas verificou-se efeito quadrático dos níveis de lisina digestível sobre o peso final, o ganho de peso e o ganho de peso relativo e efeito linear crescente no consumo de ração. A conversão alimentar não diferiu com as variações dos níveis de lisina digestível e zinco na dieta. Nas condições de avaliação do desempenho, o nível ótimo de lisina digestível para frangos de corte machos mantidos em piso de concreto é de 1,19%. Na fase de 1 a 7 dias de idade, não houve influência da relação entre níveis de lisina digestível e zinco quelado no balanço de nitrogênio. A retenção de nitrogênio aumentou de forma linear crescente com o aumento da concentração de lisina digestível na dieta, o que está de acordo com o aumento linear do ganho de peso e da eficiência alimentar. A exigência de lisina digestível para frangos de corte machos de 1 a 7 dias de idade é igual ou superior a 1,40%.Palavras-chave: aminoácidos, deposição de nutrientes, micronutrientes, nutrição Digestible lysine and zinc chelate to male broiler: Performance in the preinitial phase and nitrogen retention ABSTRACT -Two experiments were carried out to evaluate different levels of digestible lysine (0.90; 1.00; 1.10; 1.20; e 1.40%) combined with zinc chelate (43 and 253 ppm) to male broiler. The considered periods were: initial phase -performance(1 to 11 days old) and nitrogen retention (1 to 7 days old). A randomized block experimental design in a 5 × 2 factorial arrangement was used. In performance assay, 7 replications and 15 birds per experimental unit was used. In the digestibility essay, 6 replications 6 birds for experimental unit were used. The diets contained 2.960 kcal/kg ME and 21.0% crude protein.In the initial phase, there was no digestible lysine × zinc chelate interaction on performance study, however a quadratic effect of digestible lysine on final weight, weight gain, relative weight gain and crescent linear effect in feed intake was observed.In feed: gain ratio did not differ with digestible lysine level and zinc chelate in the diet. In the performance, the better digestible lysine level for broiler raised in concrete floor is 1.19%. From 1 at 7 days old, there was no influence of the combinations of digestible lysine and zinc chelate on nitrogen balance. The nitrogen retention linearly increased as digestible lysine increased in...

Dexamethasone (DEX) is a corticoid hormone that is experimentally used to mimic the effects of increased levels of endogenous corticosterone observed during the stress response. Currently, stress is considered one of the major predisposing factors for diseases in the poultry industry. The aim of this study was to analyze the effects of DEX and/or of a 20-fold coccidial vaccine dose on leukocyte phenotypes in the spleen and cecal tonsils of chickens. Twenty specific-pathogen-free (SPF) Leghorn chickens were divided into four groups: a non-treated group (NT), a DEX-treated group (Dex), a vaccinated group (V) and a DEX-treated+vaccinated group (Dex+V). On experimental day (ED) 42, each bird in the vaccinated groups received a anti-coccidial vaccine. DEX was injected in the birds of the Dex and Dex+V groups (0.9 mg/kg) onED42 and ED45. + cells in the spleen of birds of the V group was higher than those measured in the other experimental groups. Our data suggest that CD4 + CD25 + cells and macrophages might be influenced by DEX treatment in spleen, but not in the cecal tonsils of chickens inoculated with Eimeria.

Lactating female rats presented less intense allergic lung inflammation. Our findings suggest that lactation may protect females from asthmatic crises.

Os efeitos dietéticos de lisina digestível e zinco quelato para frangos de corte machos entre 22 e 42 dias de idade foram avaliados em dois ensaios experimentais. Adotou-se o delineamento inteiramente casualizado em arranjo fatorial 5 × 2, com cinco níveis de lisina (0,841; 0,876; 0,997; 1,022 e 1,030%) e dois de zinco (43 e 243 ppm). No primeiro ensaio, utilizaram-se 900 aves com peso médio inicial de 957,4 g distribuídas em parcelas experimentais de 30 aves e três repetições e, no segundo ensaio, 180 frangos com peso médio inicial de 866,22 g, divididos em parcelas de três aves e seis repetições. As características avaliadas foram desempenho, rendimento de cortes e composição corporal (1º ensaio), balanço de nitrogênio e digestibilidade aparente das dietas (2º ensaio). Houve interação entre os níveis de lisina e zinco para o ganho de peso, a conversão alimentar, a matéria seca ingerida e o balanço energético. Os rendimentos de peito, coxa e sobrecoxa tiveram aumentos lineares em resposta ao acréscimo no nível de lisina digestível na dieta. O melhor desempenho foi obtido com o nível de 0,997% de lisina digestível (ou 1,134% lisina total) e de 43 ppm de zinco. Para maior rendimento dos cortes, o nível de lisina digestível recomendável deve ser no mínimo 1,002% (ou 1,139% de lisina total), independentemente dos níveis de zinco quelato. A maior inclusão de zinco em dietas para frangos de corte dos 22 aos 42 dias de idade não melhora a utilização da lisina na dieta e aumenta a deposição de gordura corporal.

-This study evaluated levels of digestible lysine and organic zinc for male Ross strain broilers from 1 to 11 days of age. It was used 1,050 chicks distributed in randomized block design, in 5 × 2 factorial scheme, with seven repetitions of 15 birds per experimental unit. The dietary concentrations of digestible lysine were 0.90; 1.00; 1.10; 1.20; and 1.40% combined with 43 and 253 ppm zinc chelate. The diets contained 2,965 ± 18 kcal/kg of apparent metabolizable energy (AME) and 21.48 ± 0.18% of CP. It was determined chemical composition, protein, lipid, mineral and water depositions on carcass and empty body. There was no interaction among the factors digestible lysine and organic zinc. Effect of zinc concentration increase was observed on greatest deposition of body fat, indicating that there is interference in lipid metabolism of the birds in the studied phase. The most pronounced effects resulted from the dietary inclusion of lysine.There was a linear effect on reconstituted body weight as a response to the increase of dietary lysine, which suggests equal or superior requirement to the greatest studied level. However, the deposition of water and protein on the carcass had a quadratic increase, characterizing higher muscle mass accumulation up to the levels 1.25 and 1.27 of this amino acid in the diet. Considering the studied strain, broiler chickens from the first to the 11th days of age require 1.28 ± 0.01% of digestible lysine, according to the deposition of muscle mass.Key Words: amino acid, nutrient deposition, nutrition, requirement, zincLisina digestível e zinco orgânico para frangos de corte machos de 1 a 11 dias de idade: composição química e taxas de deposição corporal RESUMO -Neste estudo foram avaliados níveis de lisina digestível e zinco orgânico para frangos de corte machos da linhagem Ross, na fase de 1 a 11 dias de idade. Utilizaram-se 1.050 pintos distribuídos em delineamento de blocos ao acaso, em esquema fatorial 5 × 2, com sete repetições de 15 aves por unidade experimental. As concentrações dietéticas de lisina digestível foram 0,90; 1,00; 1,10; 1,20; e 1,40% em combinação com 43 e 253 ppm de zinco quelato. As dietas continham 2965 ± 18 kcal/kg de energia metabolizável aparente (EMA) e 21,48 ± 0,18% de PB. Foram determinadas a composição química, deposição proteica, lipídica, mineral e de água na carcaça e no corpo vazio. Não houve interação dos fatores lisina digestível e zinco orgânico. Efeito do aumento da concentração de zinco foi observado na maior deposição corporal de gordura, indicando haver interferência no metabolismo lipídico das aves na fase estudada. Os efeitos mais pronunciados decorreram da inclusão dietética da lisina. Observou-se efeito linear no peso vivo reconstituído, como resposta ao acréscimo de lisina na dieta, o que sugere exigência igual ou superior ao maior nível estudado. Contudo, a deposição de proteína e água na carcaça teve aumento quadrático, caracterizando maior acúmulo de massa muscular até os níveis 1,25 e 1,27 desse aminoácido na dieta. Conside...

Purpose: We have previously shown that domperidone-induced short-term hyperprolactinemia reduces the lung’s allergic inflammatory response in an ovalbumin antigenic challenge model. Since purinergic receptor P2X7R activity leads to proinflammatory cytokine release and is possibly related to the pathogenesis of allergic respiratory conditions, the present study was designed to investigate a possible involvement of purinergic and prolactin receptors in this phenomenon. Methods: To induce hyperprolactinemia, domperidone was injected intraperitoneally in rats at a dose of 5.1 mg × kg^–1 per day for 5 days. P2X7 expression was evaluated by lung immunohistochemistry while prolactin receptor expression in bronchoalveolar lavage leukocytes was analyzed through flow cytometry. Results: Previous reports demonstrated that rats subjected to short-term hyperprolactinemia exhibited a decrease in leukocyte counts in bronchoalveolar lavage, especially granulocytes. Here, it is revealed that hyperprolactinemia promotes an increased expression of prolactin receptors in granulocytes. Also, increased expression of purinergic P2X7R observed in allergic animals was significantly reduced by hyperprolactinemia. Conclusions: Both purinergic and prolactin receptor expression changes occur during the anti-asthmatic effect of hyperprolactinemia.