Short communication: Effects of breeder age and pre-placement feed on IgY concentration in egg yolk and chick serum.

Breeder age and pre-placement feed are factors that can affect broiler performance during grow out. This study evaluated the effects of breeder age (29 and 55 weeks old) on IgY transference to egg yolk in addition to the effects of breeder age (29 and 55 weeks old) and pre-placement feed (with or without), in a factorial arrangement, on IgY concentration in chick serum. Forty-eight eggs were collected from a breeder flock and considered the experimental units. Eighteen chicks from each breeder age were randomly selected to determine IgY at pulling. After 48 h of placement, old breeders had greater egg weight and yolk weight (p ≤ 0.05) than the young ones. Breeder age (p > 0.05) had no effect on IgY concentration of egg yolk. Breeder age (p > 0.05) had no effect on IgY concentration of chick serum at pulling. There was no interaction (p > 0.05) between breeder age and pre-placement feed for IgY concentration of chick serum at housing. There was also no effect of breeder age or pre-placement feed during placement time (48 h) on IgY concentration of chick serum at housing (p > 0.05). In conclusion, 48 h of fasting had no effect on IgY concentration in chick serum despite breeder age. It appears that the immunoglobulins from the residual yolk sac are not used as a protein source during the period between hatching and housing.

Effects of placement time on performance and gastrointestinal tract growth of male broiler chickens

The main objective of this study was to evaluate the effect of placement time on the performance of broiler chickens and the development of their gastrointestinal tract. Two methodologies for measuring broiler performance were compared, one considering day of pulling as the first day, the other considering day of placement as the first day. A total of 1,056 one-day old male Cobb® 500 broiler chicks were subjected to treatments of different placement times after pulling from the hatchery: 3, 24, 48, and 72 h. The studied traits were: feed intake, body weight, feed conversion, viability, and gastrointestinal tract development. When day of pulling was considered the first day, feed intake and body weight at 39 days decreased as placement time increased. However, when day of placement was considered the first day, fasting up to 72 h did not have any negative effect on broiler performance at 39 days post-placement. Placement time did not affect yolk sac utilization or liver weight. At nine days post-placement, weights of gizzard + proventriculus, pancreas, and small intestine increased with increasing placement time. At seven days of age, there was no effect of placement time on villus height or crypt depth. It is possible to place broiler chicks up to 72 h post-hatching with no negative effects when day of placement is considered the first day for evaluating broiler performance.(AU)

Pelleting of feed for broiler chickens: factors affecting pellet quality / Peletização de ração para frangos de corte: fatores que interferem na qualidade do pélete

The efficiency of the pellet can be translated by the quality of the pellet which is defined as the proportion of intact pellets that come to feeders for chickens, i.e., its resistance to breakage between the feed mill and farms. The use of diets with a higher percentage of intact pellets results in better performance of birds when compared with the feed rations. The main factors that affect pellet quality are: characteristics of pelleting, the feed composition, particle size, pelleting temperature, moisture and steam injection. From a nutritional standpoint, one can consider that the smaller the particle size of food increased their contact with the digestive juices, which aids digestion and absorption of nutrients. However, finely ground lead to less stimulation and growth of intestinal ephitellium. But from the standpoint of production of feed, the larger the particle size of ingredients largest economy with energy and greater efficiency (tons / hour) milling. Because of this, it is suggested that the particle sizes used vary between 500 and 700 ìm to not to cause loss of performance of the birds, nor the income from the factory. Increased energy, through the addition of oils and fats, have much influence on performance parameters of broilers and the quality of the pellet produced. The presence of oils and / or fat, depending on the amount, on its hydrophoby characteristic, causing damage to the particles aggregation acting as a lubricant between food particles and the matrix of pelleting, decreasing the pelleting pressure and itsgelatinization, resulting into poor quality pellets.

A eficácia do processo de peletização pode ser traduzida pela qualidade do pélete no qual é definida pela proporção de péletes íntegros que chegam aos comedouros dos frangos, ou seja, sua resistência à quebra entre a fábrica de rações e as granjas. A utilização de rações com um maior percentual de péletes íntegros resulta em melhor desempenho das aves quando comparadas com as rações fareladas. Os principais fatores que interferem na qualidade do pélete são: características da peletizadora, composição da ração, tamanho da partícula, temperatura da peletização, umidade e injeção de vapor. Do ponto de vista nutricional, pode-se considerar que quanto menor o tamanho das partículas do alimento, maior seu contato com os sucos digestivos, o que favorece a digestão e a absorção dos nutrientes. Entretanto, partículas finamente moídas prejudicam a estimulação e o crescimento das vilosidades intestinais. Já do ponto de vista de produção de rações, quanto maior o tamanho das partículas dos ingredientes maior a economia com a energia e maior a eficiência (toneladas/hora) de moagem. Devido a isso, sugere-se que a granulometria utilizada varie entre 500 e 700 ìm para não ocasionar perda do desempenho das aves, nem do rendimento da fábrica. O aumento da energia, por meio da inclusão de óleos e gorduras, tem influência tanto nos parâmetros de desempenho de frangos de corte quanto na qualidade do pélete produzido. A presença de óleos e/ou gorduras, dependendo da quantidade,por sua característica hidrofóbica, pode prejudicar a agregação das partículas, agindo como lubrificante entre as partículas do alimento e a matriz da peletizadora, reduzindo a pressão de peletizacão,diminuindo a gelatinização do amido e resultando em péletes de baixa qualidade.

Use of exogenous enzymes for poultry: a critical view / Uso de enzimas exógenas na avicultura: uma visão crítica

The search for alternatives that enable the reduction of production costs, especially in the poultry industry goes against the performance of products such as exogenous enzymes. However, efficient use of such products depends on meaningfull and concrete results on its potential benefits. Thus, much research has been conducted in attempt to elucidate the enzymes potential on improving the digestibility of ingredients and consequently on the performance of birds. Until then, the results presented, especially about the group of enzymes understood by carbohydrases and proteases are still very contradictory. Several methods and surface analysis adopted by researchers led to a series of inaccurate and biased conclusions. It is necessary to adopt specific assessments that glimpse the pratical potential and enzymes objective concerned to raw materials used in Brazil, aiming to achieve clear and timely results.

A busca por alternativas que possibilitem a redução dos custos produtivos, em especial na avicultura, vai ao encontro à atuação de produtos como as enzimas exógenas. No entanto, a utilização eficiente de tais produtos depende de resultados expressivos e concretos sobre seus possíveis benefícios. Desta forma, inúmeras pesquisas têm sido conduzidas na tentativa de elucidar melhor o poder das enzimas sobre a melhoria da digestibilidade de ingredientes e consequentemente, sobre o desempenho das aves. Até então, os resultados apresentados, principalmente sobre o grupo de enzimas compreendidas pelas carboidrases e proteases ainda são bastante contraditórios. Diversas metodologias e análises superficiais adotadas pelos pesquisadores levam a uma série de conclusões imprecisas e tendenciosas. Faz-se necessário a adoção de avaliações específicas que vislumbre o potencial prático e objetivo de complexos enzimáticos, sobre tudo que levem em consideração as matérias-primas usadas no Brasil, com vistas à obtenção de resultados claros e pontuais.