Ednardo Rodrigues Freitas

Estudo do crescimento, desempenho, rendimento de carcaça e qualidade de carne de três linhagens de frango de corte

This is study aimed to compare growth performance, meat quality, and carcass yield of three broiler chicken strains: Cobb, Paraiso Pedres and ISA Label. The experiment was analyzed according to a randomized design, with five replicates of 29 birds per treatment. Weight gain, feed intake, and feed conversion were evaluated weekly. Adjustments performed according to Gompertz model to describe the birds growth were based on mean weight gain. The birds growth rate was obtained by the Gompertz derivative model. When the males of each strain reached body weight of 2.5 kg, three broilers of replicate were slaughtered for carcass analyses. Samples of breast samples of two birds were taken for physical-chemical characteristics analyses. Cobb birds had higher weight gain and feed intake, followed by Paraiso Pedres and ISA Label. Cobb birds exhibited higher values of growth potential, according to Gompertz equation. Cobb birds showed higher values of carcass yield, breast, drumstick, liver, intestines, and proventricule than the other strains, that did not differ between them. Cobb birds presented higher values of pH and water retention capacity of breast meat. Paraiso Pedres and ISA Label exhibited stronger red color intensity. Sex did not influence meat quality but influenced feet, drumisticks + upper drumstick, and heart, that were higher in males. Females exhibited higher values of breast, abdominal fat, liver, gizzard, and proventricule yield. Therefore, Cobb strain showed greater capacity to reach higher growth rates and meat quality, and Paraiso Pedres and ISA Label birds exhibited colors that satisfy consumers demand.

Curvas de crescimento e de deposição dos componentes corporais em aves de postura de diferentes linhagens

The growth curves of egg pullets of semi heavy: Hy Line Brown (HLB) and Hisex Brown (HSB) and light strains: Hy Line W36 (HLW36) and Hisex White (HSW) were evaluated. Three hundred birds of each strain were assigned to a completely randomized design with four replicates of 75 birds. Body weight (BW), feather weight (FW) and body depositions of protein, fat, ash and water were weekly measured. The growth curves were determined by Gompertz function with data collections. The semi heavy birds were later than the light ones for BW, with greater body growth rates and weights at maturity. The HLW36 were 64.23 g lighter at maturity than the HSW. Data obtained for feather growth and protein deposition were similar, but the semi heavy birds showed greater weight at maturity (WM) than the light ones. However, for these components, the birds Hy Line had larger depositions than Hisex. HLW36 strain had smaller feather rate at maturity, making it three days later than HSW. The lowest protein deposition in the end of growth period caused the deviation of energy ingested for fat deposition in HSB birds and overestimated the WM in relation to HLB birds. Hy Line birds had later body ash composition and showed greater WM than Hisex. Among the studied variables, Hy Line birds had always heavier WM, however, the body water content of Hisex birds was greater and the maximum rates at maturity were later. This fact explains the similarity in the weight gain among the studied strains, once other body components were greater for Hy Line birds.

Efeito da Idade dos Frangos de Corte sobre a Atividade Enzimática e Digestibilidade dos Nutrientes do Farelo de Soja e da Soja Integral

This work aimed to investigate the effect of broilers age in the digestibility of nutrients in extruded and toasted full fat soybean (EFFS and TFFS) and soybean meal plus oil (SMO), and in the production of digestive pancreatic enzymes. Five digestibility assays were carried out with broilers of one, two, three, four , and six weeks of age. Total collected excreta methodology was applied. The activities of amylase and pancreatic trypsin enzymes increased linearly with the broilers age, as well as the allometric growth of the pancreas. The highest allometric growth ratio occurred in the second week, coincidentally with the period of increasing activity of the digestive enzymes. However, for lipase activity, distinct age affect was found for each feeds. For birds fed on TFFS, the enzyme activity increased linearly with age, while those fed on EFFS, SMO, and concentrate a quadratic effect was observed. The digestibility coefficients for dry matter and ether extract and the soybeans metabolizable energy (ME) varied at different proportions by age. A positive correlation between ether extract digestibility and lipase activity was also observed. The results of corrected apparent and actual metabolizable energy for EFFS presented a quadratic profile in function of age, increasing ME up to the third week and decreasing after this period. However, ME of TFFS, SMO and concentrate was not affected by chicks age. The nutrient digestibility of feedstuffs varies with chicks age, due to the different enzymatic activities.

Níveis protéicos na ração de frangos de corte na fase de crescimento

O objetivo deste trabalho foi determinar o nivel minimo de proteina bruta para atender as exigencias nutricionais de frangos de corte Hubbard, machos e femeas, na fase de crescimento. Oitocentos e oitenta pintos machos e femeas de 22 a 42 dias de idade foram distribuidos ao acaso em esquema fatorial 5x2 (niveis de proteina bruta x sexos), com quatro repeticoes de 22 aves. Os niveis de proteina testados foram 15%, 17%, 19%, 21% e 23%. Houve efeito quadratico dos niveis de proteina no ganho de peso e na conversao alimentar dos machos. Em relacao as femeas, o efeito foi quadratico no ganho de peso e linear na conversao. A relacao entre o rendimento de carcaca e o nivel de proteina bruta da racao foi linear e independente do sexo. O consumo de racao, a gordura abdominal e o rendimento de peito foram influenciados apenas pelo sexo. Recomenda-se 21,70% de proteina bruta para os machos e 19,00% para as femeas, na fase de crescimento.

Níveis de energia metabolizável para machos de corte de crescimento lento criados em semiconfinamento

Foram conduzidos tres ensaios para avaliar os niveis de energia metabolizavel (EM) e a melhor relacao energia:proteina (E:P) para aves de corte machos de crescimento lento criadas em semiconfinamento nas fases inicial (1 a 21), de crescimento (22 a 49) e de terminacao (50 a 70 dias de idade). Em cada ensaio, 400 machos da linhagem ISA Label na fase de criacao foram alojados em instalacao experimental constituida de 20 piquetes com area coberta de 3,13 m²para alimentacao e recolhimento das aves e uma area de pastejo de 72,87 m². O delineamento experimental foi o inteiramente casualizado com cinco tratamentos e quatro repeticoes de 20 aves. Os niveis de energia metabolizavel fornecidos na racao na fase inicial variaram de 2.600 a 3.200 kcal/kg; na fase de crescimento de 2.700 a 3.300 kcal/kg; e na fase final de 2.800 a 3.400 kcal/kg. A proteina bruta e os demais nutrientes foram mantidos constantes em todas as racoes, de acordo com recomendacoes do NRC (1994) para cada fase. A relacao energia:proteina e o nivel de energia metabolizavel que melhoraram o desempenho e as caracteristicas da carcaca de frangos de corte ISA Label machos criados em sistema semiconfinado em cada fase estudada foram 128 e 2.750; 147 e 2.850 e 172 e 3.100 kcal de EM/kg nas fases inicial, de crescimento e de terminacao, respectivamente.

Modelling energy utilization for laying type Pullets

Three trials were carried out to determine energy metabolized (EM) requirement model for starting and growing pullets from different strains, at five ambient temperatures and different percentage feather coverage. In Trial I, metabolizable energy requirements for maintenance (MEm) and efficiency of energy utilization were estimated using 64 birds of two different strains, Hy-Line W36 (HLW36) and Hy-Line Semi-heavy (HLSH), from 9 to 13 weeks of age. The effects of ambient temperature (12, 18, 24, 30 and 36”C) and percentage feather coverage (0, 50 and 100%) on MEm were assessed in the second trial, using 48 birds per temperature per strain (HLSH and HLW36) from 9 to 13 weeks of age. Trial III evaluated ME requirements for weight gain (MEg) using 1,200 birds from two light strains (HLW36 and Hisex Light, HL) and two semiheavy strains (HLSH and Hisex Semi-heavy, HSH) reared until 18 weeks of age. According to the prediction models, MEm changed as a function of temperature and feather coverage, whereas MEg changed as a function of age and bird strain. Thus, two models were developed for birds aged 1 to 6 weeks, one model for the light strain and one for the semi-heavy strain. Energy requirements (ER) were different among strains from 7 to 12 weeks, and therefore 4 models were elaborated. From 13 to 18 weeks, one single model was produced for semi-heavy birds, since ER between semi-heavy strains were not different, whereas two different models were elaborated for the light layers. MEg of light birds was higher than MEg of semi-heavy birds, independent of age.

Efeito da temperatura ambiente e do empenamento sobre o desempenho de frangas leves e semipesadas

Este trabalho foi conduzido para determinar os efeitos da temperatura ambiente e do empenamento das aves sobre o desempenho de duas linhagens de postura na fase de crescimento (10a a 13a semana de idade). Foram alojadas 480 aves de reposicao da marca Hy-line, sendo 240 aves de cada linhagem W-36 (leve) e Brown (semipesada), em 5 câmaras climaticas com temperaturas de 12, 18, 24, 30 e 36oC. Em cada temperatura foram avaliadas 3 coberturas de pena; 100% (nao depenada), 50% (depenada em 50% do corpo) e 0% (totalmente depenada). A analise estatistica dos dados foi realizada segundo um esquema fatorial (5 x 3 x 2) sendo: 5 temperaturas, 3 porcentagens de cobertura de pena e 2 linhagens. Os dados foram submetidos a uma analise de regressao para a obtencao das curvas respostas com os melhores ajustes. A linhagem semipesada apresentou maior consumo de racao em relacao a linhagem leve em todas as temperaturas. Houve diminuicao do ganho de peso em funcao da reducao no consumo de racao e aumento da temperatura. A linhagem leve apresentou uma maior amplitude nas faixas de conforto termico (18,33oC a 32,00oC) do que a linhagem semipesada (23,75oC a 29,50oC).

Desempenho, eficiência de utilização dos nutrientes e estrutura do trato digestório de pintos de corte alimentados na fase pré-inicial com rações de diferentes formas físicas

This experiment was conducted to evaluate the effect of different physical form of pre-starter diet on performance, nutrient utilization and development of gastrointestinal tract of broiler chicks during the first week of age. A total of 150-day-old male broiler chicks was allotted to a completely randomized design with three treatments and five replicates of 10 birds each. Treatments consisted of three physical forms of a commercial pre-starter diet: mashed, crumbled and pressed into pellets. Except for gizzard, the other organs of the digestive tract and morphologic structures of the small intestine were not affected by the physical form of the diet. The highest N digestibility was observed in birds fed pellet diet, while crumbled diet showed the highest digestibility of EE. The metabolizable energy determined for mashed diet was lower than those determined for the other physical forms of the diet. Birds fed mashed diet had the lowest feed intake and body weight gain and the worse feed conversion. These birds also showed lower intake of energy and less protein, fat and energy retention in the body. They used a higher proportion of the energy consumed for heat production. Pre-starter diets prepared as pellets or crumbles allow better nutrient utilization and improve chick performance.

Programas de alimentação para matrizes pesadas após o pico de postura, com base em modelos para predizer a exigência energética

This research was carried out to evaluate the performance of broiler breeder hens submitted to different feeding programs applying models to predict the metabolizable energy requirements after peak production. The experiment was conducted during 84 days (three periods of 28 days), at the Sao Paulo State University - Jaboticabal. Seven hundred and forty female broiler breeders Hubbard Hy-Yield, and eighty males Petterson 55-week old were assigned to a randomized design with four treatments and five replicates of 37 birds (box), and a factorial model 4´3 (four treatments and three periods). The feeding programs evaluated were: T1 - feeding according to the lineage recommendation (428 kcal/bird/day from 55 to 66-weeks old); T2 - energy reduction (2 kcal/bird/day for each week); T3 - feeding according to UNESP (2000) model; T4 - feeding according to NRC (1994) Model. The feeding program with weekly energy reduction was suitable to maintain the productive and reproductive performance of the birds, indicating the possibility of reducing 2 kcal/bird/day, at each week, in broiler breeders fed after 55 weeks of age. The UNESP and NRC models promoted higher energy intakes than the lineage recommendation, probably due to the body weight of breeders, that were above the recommended for lineage, providing higher energy requirements of maintenance.