J.S.R. Rocha

Efeito da classificação dos ovos sobre o rendimento de incubação e os pesos do pinto e do saco vitelino

Two experiments were carried out to study the effects of broiler breeder age on weight uniformity of 1,080 eggs and yolks, and the effects of 9,216 eggs classified prior to setting on hatchability, embryonic mortality, and the relationship between chick and yolk sac weights. In the first study, the three treatments were eggs from broiler breeders on 31st (M31), 38th (M38), and 43th (M43)-week of age. In the second study, eggs produced by three broiler breeders flocks (31st, 38th, and 43th wk of age) were divided in six treatments; A: eggs weighting from 66 to 72g, 33,3% of them produced by broiler breeders of different ages; B: eggs weighting from 58 to 65g, 33,3% of them produced by broiler breeders of different ages; C: eggs weighting from 52 to 57g, 33,3% of them produced by broiler breeders of different ages; D: eggs from 31-wk-old broiler breeders, weighting from 52 to 72g; E: eggs from 38-wk-old broiler breeders, weighting from 52 to 72g; F: eggs from 43-wk- old broiler breeders weighting from 52 to 72g. Eggs produced by M31 had egg and yolk weights more uniform than the eggs collected from M43. Treatment A had the worst hatchability, higher embryonic mortality after 15 days of incubation, and produced heavier hatched chicks with superior absolute and relative weights of yolk sac.

Influência da forma física da ração e da linhagem sobre o desempenho e rendimento de cortes de frangos de corte

Avaliou-se o efeito da forma fisica da racao sobre o desempenho e o rendimento de cortes de duas linhagens de frangos de corte, Cobb e Ross. Foram utilizados 900 frangos machos, criados em galpao experimental, com idades entre um a 45 dias. Os tratamentos foram definidos pela linhagem e forma fisica da racao da seguinte forma: (T1) racao farelada a vontade, (T2) racao peletizada a vontade e (T3) racao peletizada controlada. Para avaliacao do desempenho, o delineamento experimental foi o inteiramente ao acaso, em arranjo fatorial 3 x 2 (tres dietas e duas linhagens) e cinco repeticoes, sendo cada repeticao composta de 30 aves. Para a avaliacao do rendimento de cortes da carcaca, o delineamento foi o mesmo, com excecao do numero de repeticoes, que foi de 30, sendo cada ave considerada como uma repeticao. A racao peletizada controlada reduziu o ganho de peso em relacao a peletizada a vontade em 4,7% e melhorou a viabilidade da linhagem Cobb em 10%. Independentemente da linhagem, maiores ganhos de peso foram obtidos quando as aves foram alimentadas com racao peletizada a vontade. A restricao alimentar favoreceu a conversao alimentar das aves em 2%. A linhagem nao influenciou os parâmetros de rendimento de cortes e porcentagens de orgaos digestivos avaliados. A peletizacao favorece o desempenho de frangos de corte.

Antioxidant properties of vitamins in nutrition of broiler breeders and laying hens

The reaction of free radicals with polyunsaturated fatty acids (PUFAs) initiates a chain-reaction process known as lipid peroxidation in living systems and oxidative rancidity in foods. PUFAs are more susceptible to oxidation, resulting in the formation of toxic products. As embryonic tissues are characterised by high concentration of PUFAs, the use of antioxidants in broiler breeder diets improves chick oxidative status. Eggs ‘in shell’ are considered resistant to oxidative rancidity, however studies showed that yolk lipids within table eggs oxidise during storage and this oxidation is influenced by time and temperature of storage and the degree of unsaturation of yolk fatty acids. Thus, experiments into supplementing laying hen diet with antioxidants have been conducted to preserve the table eggs nutritional value. The literature shows that vitamin E has antioxidant activity in the egg yolk, protecting embryonic tissues efficiently during incubation and in the first days of a chicks life. However, these studies have not considered the effect of this vitamin on incubation yield. Without this economic variable, the positive results observed in the embryo and for chick oxidative status have little value for application in the field, mainly because the concentrations recommended in studies are much higher than those used in practice. Other antioxidants, e.g. canthaxanthin, act in synergy with vitamin E, however, the high cost of these ingredients could prevent its use for broiler breeders. This review discusses the effect of vitamins (especially vitamin E) in broiler breeders and laying hens nutrition on oxidative stability of embryonic tissues and table egg yolk lipids, respectively.

Avaliação da qualidade da casca dos ovos provenientes de matrizes pesadas com diferentes idades

We conducted a study on eggshell quality from Cobb® broiler breeders at different ages by assessing the relationship between eggshell weight and egg weight and analysis of specific weight, thickness, porosity, strength and electron microscopy. Both treatments were defined by broiler breeder age, considering eggs from young breeders (33 weeks) and eggs from old breeders (63 weeks). It was observed that eggs from breeders at 33 weeks have lower weight and number of pores per cm2 compared with eggs from older birds. 63 weeks broiler breeders had lower percentage of eggshell in relation to egg weight, lower specific weight, strength and thickness, when compared with eggs from young breeders. The proportion of shell membranes in relation to its total thickness was significantly higher in young breeders. It was concluded that eggs from older broiler breeders have lower eggshell quality than the young breeders. The shell membranes in young breeders eggs play a significant role in its structure, making it necessary to focus on this layer in future studies on eggshell quality and their relationship between breeder age and incubation yield.

Suplementação de colina em dietas para frangos de corte machos na fase inicial de criação

The effects of supplemental levels of choline on performance, carcass composition and gross and histopatology characteristics of the livers in the initial phase in diets for broiler chickens were evaluated. The treatments were defined by the levels of choline supplementation (zero, 100, 200, 300 and 400mg choline/kg diet). The period of creation was one to 21 days-old. Diets formulated based on corn, soybean meal and meat meal are constituted by isonutrient except the levels of choline. The experimental design was completely randomized and the estimation of choline supplementation was evaluated by regression models. The levels of choline supplementation showed a significant linear effect for the F test (P 0.05). The supplementation of 400 mg choline/kg diet improves feed conversion of broilers at 21 days old.

Efeito da classificação dos ovos sobre a uniformidade, o desempenho e o rendimento de abate de frangos de corte

The effect of egg classification on uniformity, performance, and meat yield of broiler chicks was evaluated using 140 males and 140 females hatched from one of each of the following treatments: A - eggs weighting from 66 to 72g, 33,3% of them produced by broiler breeders of different ages; B - eggs weighting from 58 to 65g, 33,3% of them produced by broiler breeders of different ages; C - eggs weighting from 52 to 57g, 33,3% of them produced by broiler breeders of different ages; D - eggs from 31-wk-old broiler breeders, weighting from 52 to 72g; E - eggs from 38-wk-old broiler breeders, weighting from 52 to 72g; and F - eggs from 43-wk-old broiler breeders, weighting from 52 to 72g. It was used a completely randomized design, in a 6x2 factorial (six categories of egg classification x two genders) with four replicates of 35 bird each. The chicks were raised from one to 44-day-old and slaughtered at 45-day-old. Sorting eggs by weight prior to incubation was not efficient to keep the better broiler chickens uniformity until they were 44-day-old. A significant and positive relationship between 7-day-old chick weight and broiler weight at slaughtering age was observed, except in chicks from treatment D. Broiler performance and meat yield were not affected by egg classification.

Desempenho de frangos de corte alimentados com diferentes níveis de suplementação de vitamina E

This study aimed to evaluate the effect of vitamin E supplementation on the performance of broiler chickens in the initial and growth phase, from one to 21 and 21 to 39 days of age, respectively. Five increasing levels of DL-α tocopherol supplementation (10, 30, 50, 75 and 100mg to each kg of diet) were added to the diet. In the initial phase (experiment I), the lowest vitamin E level was superior by presenting significant effect (P≤0.05) on body weight at 21 days of age and weight gain from one to 21 days old. In the growth phase (experiment II), there was no significant effect (P>0.05) of vitamin E supplementation on the variables studied. The minimum level of vitamin E supplementation tested is sufficient to attend the requirements of male broiler chickens.

Efeitos de planos nutricionais e de fontes de metionina sobre o desempenho, rendimento e composição de carcaças de frangos de corte

Para avaliar os efeitos de dois diferentes planos nutricionais de aminoacidos sulfurados totais (AAST) e de duas fontes de metionina nas racoes de frangos de corte, foi realizado um experimento com 840 frangos machos, da linhagem agRoss 308. Os tratamentos foram definidos pelos planos nutricionais de AAST (normal e reduzido) e pelas fontes de metionina (DL-metionina e metionina hidroxianaloga - MHA) usadas nas racoes. O delineamento experimental foi o inteiramente ao acaso, em arranjo fatorial 2x2, (duas fontes de metionina x dois planos nutricionais de AAST). Nao foram encontradas diferencas entre os tratamentos para o consumo de racao, ganho de peso, viabilidade, rendimento de carcaca, porcentagem de peito e composicao das carcacas e visceras. As aves que receberam as racoes com o plano normal de AAST apresentaram melhor conversao alimentar, e as que receberam racao contendo DL-metionina tiveram menor porcentagem de gordura abdominal. Concluiu-se que a substituicao da DL-metionina pela MHA nao afetou o desempenho, que o plano nutricional normal melhorou a conversao alimentar dos frangos de corte e que as fontes de metionina e os planos nutricionais de AAST nao influenciaram o rendimento e a composicao da carcaca e visceras de frangos de corte.

In ovo feeding and its effects on performance of newly-hatched chicks

The broiler chicks gastrointestinal tract undergoes significant morphological and physiological changes during the first days after hatch. These changes occur mostly because birds switch from a diet based on fatty acids from the yolk sac to a diet based on carbohydrates, provided by commercial feeds, often formulated with corn and soya bean meal. In ovo feeding techniques enable the study of the early adaptation of the avian gastrointestinal tract, such as supplementation with carbohydrates during embryonic development. This procedure consists of inoculation into the amniotic fluid through a hole in the egg shell near the air-chamber during late embryonic growth. The hatching process requires large supply of energy to the muscles, and in ovo feeding has the objective of providing extra energy in order to avoid glycogen store reductions, which are needed during the first days after hatch. However, published reports have shown that in ovo manipulation can reduce incubation yield, mostly when applied during the beginning of embryonic development. The best results of in ovo feeding were found when supplementation was with carbohydrates.

The effects of relative humidity and turning in incubators machines on the incubation yield and chick performance

Due to the high demands and production costs of the poultry industry it is imperative to study alternatives to modify the practice of incubation in order to maximise productivity by ensuring the conditions necessary for the development of embryos of current strains. Such changes in the management of incubation cannot affect the quality of chicks and broiler performance during early growth. To achieve these goals, several factors that work together during artificial incubation should be considered, for example, the relative humidity and turning machine incubators. Some research has already been conducted to define the optimum for these factors. This article reviews the results of studies where relative humidity and use of turning systems in incubators and their impact on incubation yield and chick performance were examined.