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Performance and nitrogen balance of laying hens fed increasing levels of digestible lysine and arginine

The objective of this experiment was to evaluate the effect of two digestible lysine levels and four digestible arginine levels on laying hens from 24 to 48 weeks of age. Three hundred and twenty Lohmann LSL laying hens were allotted in a completely randomized design in a 2 × 4 factorial arrangement, with two levels of digestible lysine (700 and 900 mg/kg of diet) and four digestible arginine levels (700, 800, 900 and 1000 mg/kg of diet). Results indicated requirement of 884 and 830 mg of digestible arginine/kg of diet, considering an average feed intake of 95 g/hen/day and an average hen weight of 1.5 kg, aiming at lesser feed intake and better nutritional balance of nitrogen, respectively. High digestible lysine levels in the diet require higher digestible arginine supplementation for a better performance of hens.

Níveis de lisina digestível para poedeiras Hy-Line W-36 em produção

In this experiment it was aimed to determine the best levels of digestible lysine for laying hens in production period. Performance, nutrients intake, metabolism, egg quality, blood parameters and development of reproductive tract for 160 Hy-Line W-36 hens at 25 weeks of age. Hens were distributed in a completely randomized design with four levels of digestible lysine (600, 700, 800 or 900 mg of Lys/kg) and four replicates by using a split spot scheme was used at evaluation of nitrogen balance, blood parameters and reproductive tract. Lysine levels in the diet affected food, protein and energy intakes whose maximum point was noted at the level of 720 mg of Lysine. For egg production, food conversion, and nitrogen balance, the best levels of lysine was 800 mg, 900 mg, and 700 mg, respectively. The digestibility of ethereal extract, egg quality, development of reproductive tract and blood parameters were not affected by levels of digestible lysine in the diet. It is suggested 700 and 800 mg of digestible lysine for metabolism and performance, respectively, and 600 mg for egg quality and better development of the reproductive trait.

Níveis de lisina digestível para poedeiras Lohmann LSL na fase de 16 a 25 semanas de idade

In this experiment, the effects of digestible lysine levels on performance, nitrogen balance and fat digestibility in Lohmann LSL hens 16 to 25 weeks of age were evaluated. Four levels of digestible lysine (0.6, 0.7, 0.8 and 0.9% in ration) were assessed by utilizing 160 16-year-old laying hens 16 to 25 weeks of age. The diets were isonutritive with 17% CP and 2800 (pre laying) and 2750 (pre peak) kcal/kg. A completely randomized design was used with four lysine levels assessed in four replicates. The lysine levels did not influence weight gain, feed intake, protein and energy intake, age at first egg laying, egg production, egg weight, feed conversion indexes, egg mass, nitrogen balance or crude fat. There was positive linear increase on lysine intake according to the dietary levels of digestible lysine. Lysine levels do not influence the performance or the nutrients balance, and 0.6% of lysine per kilogram of feed is recommended.

Effect of Incubator Type and Broiler Breeder Age on Hatchability and Chick Quality

Two experiments were conducted to evaluate the effect of broiler breeder age and incubator type on hatching parameters, hatch window, embryo diagnosis results, and hatchling physical quality. The treatments consisted of a combination of three broiler breeder ages (29, 35 and 59 weeks of age) and two incubator types (single stage, SS; or and multiple stage, MS). A completely randomized design in a 3x2 factorial arrangement was applied. In Experiment I, 1,896 eggs were used and 360 eggs in Experiment II. There was an interaction between breeder age and incubator type only for hatchling physical quality score. Independently of incubator type, hatchability rate, late embryo mortality, and egg contamination were higher in the eggs laid by older breeders (59-wk-old). Early mortality (0-4 days) was higher in the embryos from young breeders (29-wk-old). A shorter hatch window birth was obtained in the SS incubator, resulting in higher hatchling body weight relative to egg weight, and better hatchling physical quality score. Both types of incubators provide good conditions for embryo development; however, the physical quality of chicks derived from eggs from intermediate-aged breeders (35-wk-old) is better when eggs are incubated in SS incubators.

Níveis de proteína e de arginina digestível na ração pré-inicial de frangos de corte

This experiment was carried out to evaluate levels of crude protein and digestible arginine in pre-starter broiler ration and their effects on the performance of the broilers from 7 to 21 days of age. A total of 600 Cobb chicks was assigned to a block randomized design in a 4 × 2 factorial arrangement consisting of 4 levels of digestible arginine (1.363; 1.463; 1.563 and 1.663%) and two levels of crude protein (20 and 22%) with eight treatments, each one with five replicates of 15 broilers each. For the experiment, weight gain, feed intake, feed conversion ratio, gastrointestinal biometry, digestibility and retention of dry matter and nitrogen were evaluated. The highest weight gain from 1 to 14 days old was obtained with the 22% crude protein feed. The levels of digestible arginine had a quadratic effect in feed conversion from 1 to 10 days old. The esophagus and crop weights were higher for broilers fed 20% crude protein based diet; however, there was a quadratic effect of the digestible arginine levels on the intestine length at the age of 10 days and on the esophagus + crop weight at 3 days of age. At 14 days of age, there was interaction among crude protein and digestible arginine levels for liver relative weight, which showed quadratic response to 20% of crude protein, and for intestine length, whose highest value was obtained with 22% of crude protein and 1.603% of digestible arginine. Nitrogen balance and retention were the highest for levels of 22% of crude protein. The level of 1.363% of digestible arginine meets nutritional requirements of pre-starter broilers.

Poultry viscera and bone meal in broiler pre-starter and starter diets

The use of viscera and bone meal in poultry pre-starter and starter diets and its effects on performance, digestive organ development and digestibility and nutrient retention were evaluated. In the first assay, 280-day-old Avian Cobb® chicks were allotted in four experimental groups with five replicates of 14 birds each, in the pre-starter phase; in the second assay, 280 eight-day-old Avian Cobb 48® chicks were allotted in four experimental groups with five replicates of 12 birds each. The experimental diet consisted of increasing levels of viscera and bone meal: 0% (control diet), 3%, 6% and 9% in pre-starter (Assay 1) and starter (Assay 2) diets, to meet nutritional requirements and feed composition proposed by the Brazilian Tables, all of them isonutritive and isoenergetic. A metabolic assay was developed and the total excreta collection was performed from the 4th to the 7th days in Assay 1 and from the 14th to the 17th days in Assay 2. On these days, one chick per experimental unit, representing the mean body weight of the parcel, was euthanized to perform digestive organ morphometry. Mean body weight was 45.4±0.4 on the 1st day in Assay 1 and 179.5±0.8 at 8 days of age in Assay 2. In Assay 1, a negative linear effect was observed for weight gain. Levels of viscera and bone meal influenced quadratically nitrogen digestibility index (Y = 66.0101 + 0.482425X - 0.0481086X2) and linearly the digestibility of dry matter (Y = 71.7775 - 0.615792X) and ether extract (Y = 78.3678 - 0.309136X). Morphometric measures of digestive organs were not influenced by viscera and bone meal levels. For Assay 2, negative and linear effect was observed for viscera and bone meal levels on weight gain (Y = 551.667 - 5.08341X) and feed intake (Y = 955.961 - 7.48435X). Quadratic effect was observed for ether extract digestibility (Y = 82.557 + 1.12021X - 0.150117X2) and maximum point was obtained at 3.7% viscera and bone meal inclusion for ether extract retention. Mortality was not affected by treatments in either of the assays. Viscera and bone meal can be used at 3 or 4% inclusion in broiler pre-starter and starter diets.

SELÊNIO E VITAMINA EM DIETAS PARA TILÁPIAS Oreochromis niloticus

Dentre as especies de peixes que demonstram potencial para o cultivo no Brasil, a tilapia do Nilo (Oreochromis niloticus) e considerada a especie mais produtiva. Essa especie apresenta diversas vantagens, entre elas: rapido crescimento, maior rendimento de file, resistencia a baixa qualidade de agua e boa aceitacao no mercado consumidor. Na nutricao de peixes varios sao os aspectos a serem avaliados em uma racao. O selenio e a vitamina E fazem parte de um sistema de defesa antioxidante multicomponente. Este sistema protege as celulas contra os efeitos adversos das especies reativas de oxigenio e outros radicais livres que iniciam a oxidacao. Alem disso a suplementacao de Vitamina E na dieta proporciona um maior desempenho produtivo, efeitos positivos nos parâmetros imunologicos dos peixes e resistencia ao estresse. O selenio e um elemento que possui margem estreita entre os niveis de exigencia e toxidez. As exigencias sao baixas, mas se nao atingida, podem comprometer o sistema antioxidante e causar graves consequencias para o metabolismo do animal. A capacidade do peixe em acumular selenio nos tecidos pode tornar a carne de pescado um interessante alimento funcional para a nutricao humana, especialmente como boa fonte de selenio. A especie tilapia do Nilo tem um nivel de exigencia especifica de selenio e vitamina E que nao pode ser satisfeito somente pelo ambiente aquatico. Desta forma uma correta suplementacao na dieta de minerais e vitaminas podera garantir um maior desempenho, proporcionando uma melhor qualidade de carne e melhor aceitacao no mercado.