Feedstuffs and additives with immunomodulatory characteristics were investigated to reduce losses caused by disease and to optimize the production potential of the bird. Therefore, the objective of this study was to assess the influence of yeast extract and prebiotics on broilers fed a prestarter diet, and the impact of ambient temperature on maternal and postvaccinal humoral immune responses. The birds were fed diets supplemented with yeast extract, prebiotics, or both in the prestarter phase (1 to 7 d), and from d 8 on, all birds received the same diet. The birds were vaccinated against Newcastle disease virus and infectious bursal disease at 8 and 18 d of age. The addition of yeast extract and prebiotic in the prestarter phase did not change the humoral immune response against Newcastle disease virus or infectious bursal disease throughout the production cycle of the broilers. The higher temperature increased IgG levels, especially maternal antibody titers, despite the immunomodulating effect of heat stress until the second week of life. DESCRIPTION OF PROBLEMThe immune system of the newly hatched chick is prepared to fight pathogens in a nonspecific manner through innate immunity, and can develop specific modes of defense through cellular and humoral immunity, which requires contact with antigens [1]. Acquired immunity differs from the innate responses by possessing specificity in recognition of foreign invaders (antigens) and the development of memory; therefore, it results in a more rapid response than was elicited during the primary exposure when the bird is reexposed to an antigen [2].

(1 a 7 dias), de modo que, a partir do oitavo dia, todas as aves receberam a mesma ração. Adotou-se o delineamento experimental inteiramente casualizado, em arranjo fatorial 3 × 2 × 2, composto de 3 temperaturas de criação (alta 34 ± 1 o C; controle 32 ± 2 o C; e baixa 27 ± 2 o C), 2 níveis de extrato de levedura (com ou sem) e 2 níveis de prebiótico (com ou sem).As temperaturas ambiente alta e baixa prejudicaram o desempenho das aves aos 7 e aos 21 dias de idade. A inclusão de prebiótico na ração pré-inicial melhora o ganho de peso das aves criadas sob baixa temperatura aos 21 dias de idade e aumenta a viabilidade até os 21 dias de idade. A adição do extrato de leveduras melhora a conversão alimentar aos 21 dias de idade. Palavras-chave: estresse térmico, mananoligossacarídeos, ração pré-inicial, Saccharomyces cerevisiae Performance of broilers from 1 to 21 days old fed diets with yeast extract and prebiotic, reared at different temperaturesABSTRACT -The performance of broilers reared at different temperatures and fed diet with or without yeast extract and/or prebiotic in the starter phase was evaluated. One thousand, four hundred and forty 1-d male Cobb-500® were reared at different climatic chambers. The diets with or without yeast extract or prebiotic were fed only in the starter phase(1 to 7 days), and from the 8 th day on all broiler were fed the same commercial diet. It was used a complete randomized experimental design, as a 3 × 2 × 2 factorial arrangement, with 3 rearing temperatures (high 34 ± 1 o C, control 32 ± 2 o C and low 27 ± 2 o C), 2 yeast extract level (with or without) and 2 prebiotic level (with or without). High and low temperatures decreased the performance of brids at 7 and 21 days old. The inclusion of prebiotic in the pre-starter phase increased weight gain of birds under low temperature at 21 days old and the viability until 21 days old. The inclusion of yeast extract increase feed conversion at 21 days old.

The objective of this study was to evaluate the performance, carcass and parts yield, and blood changes in broilers fed different protein, carbohydrate, and lipid levels. Birds were fed a commercial diet until seven days of age. On day 8, birds were distributed according to a completely randomized experimental design in a 4 x 2 factorial arrangement (control diet, low protein diet, low carbohydrate diet or low lipid diet vs. supplementation of 0 or 0.3ppm organic selenium) with four replicates of 15 birds each. Broilers fed low protein presented lower body weight, feed intake, and worse feed conversion ratio on day 42, as well as lower carcass and breast yields, higher leg and abdominal fat yields, higher triglyceride and lower uric acid blood levels. Broilers fed the low carbohydrate diets presented low glucose levels on days 14 and 42.Creatine-kinase (CK) levels increased as birds aged. The livability of broilers fed the low protein diets improved and of those fed low carbohydrate diets worsened with dietary selenium addition on days 35 and 42. Selenium supplementation increased glucose levels in 42-d-old broilers. Changes in dietary protein caused more impact on broiler performance compared with carbohydrates and lipids. Changes in macronutrients caused metabolic changes in broilers. Selenium affected broiler livability as measured on days 35 and 42, and glucose blood levels.

-The objective of this research was to evaluate the performance, carcass yield and intestinal morphometry of broiler chickens raised under different temperatures that received feed with or without yeast extract and prebiotic in the pre-initial phase. One thousand four hundred and forty one-day old male chicks were used, raised in different climate chambers.Feed with or without the addition of yeast extract and prebiotic was offered only in the pre-initial phase (1 to 7 days). From the eighth day on, every chick received the same feed, readjusted according to usual recommendations. A randomized complete experimental design was used in a 3 × 2 × 2 factorial arrangement, consisting of three environmental temperatures (hot, comfort and cold) and two levels of yeast extract (with or without) and prebiotic (with or without). The performance of the birds was evaluated considering weight gain, feed intake, food conversion and viability at 42 days of age. Carcass yield and intestinal morphometry were also evaluated. Environmental heat impaired performance and carcass yield. Prebiotic inclusion in the pre-initial feed increased weight gain and enhanced food conversion of birds raised under hot conditions. The inclusion of products in the feed of broiler chickens raised in hot and cold environments has beneficial effects on chicken intestinal villi.Key Words: carcass yield, heat stress, intestinal morphometry, mannanoligosaccharides, performance, Saccharomyces cervisiae Extrato de leveduras e prebiótico na dieta pré-inicial de frangos de corte criados em diferentes temperaturasRESUMO -Objetivou-se nesta pesquisa avaliar o desempenho, o rendimento de carcaça e a morfometria intestinal de frangos de corte criados em diferentes temperaturas e que receberam na fase pré-inicial ração contendo ou não extrato de leveduras e prebiótico. Foram utilizados 1.440 pintos machos de 1 dia de idade, criados em diferentes câmaras climáticas. As rações, acrescidas ou não de extrato de leveduras e prebiótico, foram oferecidas somente na fase pré-inicial (1 a 7 dias). A partir do oitavo dia, todas as aves receberam a mesma ração, reajustada de acordo com as recomendações usuais. Adotou-se o delineamento experimental inteiramente casualizado em arranjo fatorial 3 × 2 × 2, composto de três temperaturas de criação (calor, conforto e frio) e dois níveis de extrato de leveduras (com ou sem) e prebiótico (com ou sem). O desempenho das aves foi avaliado considerando o ganho de peso, o consumo de ração, a conversão alimentar e a viabilidade aos 42 dias de idade.Também foram avaliados o rendimento de carcaça e a morfometria intestinal. O calor ambiente prejudicou o desempenho e o rendimento de carcaça. A inclusão de prebiótico na ração pré-inicial aumentou o ganho de peso e melhorou a conversão alimentar das aves criadas no calor. A inclusão dos produtos na ração de frangos de corte criados em ambiente de calor e no frio tem efeito benéfico sobre as vilosidades das aves.

-The objective of this study was to assess the effect of the inclusion of passionflower (Passiflora alata) in diets on performance, behavior, heterophil/lymphocyte ratio (H/L), corticosterone plasma levels (CPL) and immune response of quails. The study was carried out using 192 birds, distributed in randomized blocks with 4 diets (0, 125, 250 and 375 and 0, 250, 500 and 750 mg of passionflower/kg of feed for the rearing and laying period, respectively), 8 replicates and 6 birds per experimental unit. The rearing period began when birds were 28 days of age and it lasted for 15 days. In this phase, it was evaluated daily feed intake, daily weight gain, feed conversion, viability, tonic immobility time, intensity of injuries, behavior, heterophil/lymphocyte ratio, and corticosterone plasma levels. Laying phase started when birds were 43 days of age and it finished when they were 140 days of age; it was compesed of six 14-day cycles in which it evaluated feed intake, feed conversion, egg production and quality, viability, tonic immobility time, intensity of injuries, behavior, heterophil/ lymphocyte ratio, corticosterone plasma levels and immune response. In the rearing period, the use of passionflower in the diet of quails influenced the behavioral parameters, and the birds became calmer, mainly at the dosage of 375 mg/kg of ration.However, in the laying period, passionflower was efficient in reducing stress in the quails, and the most promising results are observed when higher dosages of the phytotherapic were applied. Nevertheless, the dose of 750 mg/kg of feeeding reduces egg production, though it does not influence quality of eggs neither immune response of the quails.Key Words: behavior, corticosterone, heterophil/lymphocyte ratio, immune response, stress, tonic immobility Efeitos da utilização de passiflora em rações de codornas japonesas nas fases de recria e postura