ABSTRACT The objective of this study was to evaluate the performance, carcass yield and growth curves of different commercial strains of broiler chicken. 2400 day-old chicks, males and females of the Cobb500, RossAp95, Hubbard Flex and a new Francesa line were used. The birds were distributed in a completely randomized design in a factorial arrangement 4x2 (line x sex), forming eight treatments with 10 replicates each. The birds were fed with the same diet. Feed intake, weight gain and feed conversion were determined. At 42 days, it was determined at the request of carcass and cuts of each lineage. The Gompertz model was applied to a growth curve for each line. The RossAP95 line shows the best performance results. Growth curves showed lower sexual dimorphism in the Hubbard Flex line. The Hubbard Flex strain presented higher thigh yield and a Cobb500 genetics the higher breast yield. Based on the results found it was observed that the RossAP95 performed better. Hubbard Flex line exhibits the least sexual dimorphism. The Cobb500 have better yield for breast and as Hubbard Flex birds greater thigh yield.

ABSTRACT This study aimed to evaluate the effect of different reductions in digestible amino acids content (lysine, methionine, and threonine), according to two nutritional requirements in corn, soybean meal, and meat and bone meal based diets, with protease supplementation, on performance parameters and carcass characteristics. A total of 1080 day-old chicks, male, Cobb 500, were allotted to a completely randomized design, in a factorial arrangement 3 x 2, three reductions in digestible amino acids content (lysine, methionine, and threonine) and two nutritional requirements (Rostagno et al. 2005 and Cobb-Vantress Guidelines 2008), and all diets were supplemented with protease (200 ppm) with 6 replicates of 30 birds per pen. There was no significant interaction (p<0.05) between digestible amino acid reductions and both nutritional requirements for the performance variables and carcass yield and cuts. There was an effect of amino acid reduction and protease supplementation only on slaughter weight (p<0.05). Broilers fed according to the nutritional requirements of Rostagno et al. (2005) showed better (p<0.05) performance when compared to broilers fed as specified by the nutritional requirements of Cobb-Vantress (2008) with no significant differences in carcass characteristics. Protease supplementation of corn, soybean meal, and meat and bone meal based diets allows a reduction in the inclusion of crystalline amino acids (lysine, methionine, and threonine).

The activity of three commercial microbial phytase (Aspergillus oryzae, A. niger, and Saccharomyces cerevisae) products used in broiler nutrition was determined at different pH (2.0 to 9.0) and temperature (20 to 90°C) values. Enzymatic activity was determined according to the reaction of the phytase with its substrate (sodium phytate), in four replicates, and was expressed in units of phytase activity (FTU). A. oryzae phytase exhibited optimal activity at pH 4.0 and 40°C, but its absolute activity was the lowest of the three phytases evaluated. A. niger phytase exhibited maximal activity close to pH 5.0 and 45ºC, whereas S. cerevisae phytase presented its highest activity at pH close to 4.5 and temperatures ranging between 50 and 60°C. It was concluded that A. niger and S. cerevisae phytase products exhibited the highest absolute activities in vitro at pH and temperature values (pH lower than 5.0 and 41ºC) corresponding to the ideal physiological conditions of broilers, which would theoretically allow high hydrolysis rate of the phytate contained in the feed.

Three experiments were carrie out to evaluate the influence of cage density on the performance of 25- to 84-week-old laying hens. Forty hundred Lohmann-LSL layers were distributed in cages (100x40x 45x50cm) according to a completely randomized experimental design with split plot in time.Three treatments (10, 12, or 14 hens per cage, corresponding, to 450, 375, and 321cm²/bird, respectively), with 15 assessment periods (four weeks each), and eight replicates per treatment were applied. Considering that layer's production cycle is affected by age, three experimental trials (25 to 44; 45 to 64 and 65 to 84 weeks of age) were carried out, and the data collected in each trial was individually analyzed. Increasing cage density significantly reduced feed intake in all phases studied. Increasing birds/cm² significantly decreased feed intake and improved feed conversion at all stages of study, and egg production was only affected in 45-week-old birds. The number of birds per cage should be reduced as birds age in order not to affect their performance. Birds with more cage space in the presented higher feed intake; however, this did not result in higher egg production or lower mortality. These results suggest that up to 45 weeks of age, 375 cm² per layer results in the best performance, and from then on, 450 cm² per bird is required to maintain egg production and to reduce hen mortality.

Boron supplementation in broiler feed is not a routine practice. However, some reports suggest a positive effect of boron on performance. This study assessed the effects of boron supplementation on broiler performance. Diets were based on maize and soybean meal, using boric acid P.A. as boron source. Six supplementation levels (0, 30, 60, 90, 120 and 150 ppm) were evaluated using 1,440 one-day old males housed at a density of 30 chickens in each of 48 experimental plots of 3m². A completely randomized block design was used with 8 replicates. Feed intake, weight gain and feed conversion were assessed in the periods from 1 to 7 days, 1 to 21 days and 1 to 42 days of age, and viability was evaluated for the total 42-day rearing period. No performance variable was affected by boron supplementation (p>0.05) in the period from 1 to 7 days. The regression analysis indicated an ideal level of 37.4 ppm of boron for weight gain from 1 to 21 days (p<0.05) without affecting feed conversion (p>0.05), although feed intake was reduced linearly with increased boron levels (p<0.05). In the total rearing period (1 to 42 days), the level of 57 ppm boron was adequate for weight gain (p<0.01) without affecting feed conversion (p>0.05). Ash and calcium percentages in the tibias of broilers and viability in the total rearing period were not affected by boron supplementation (p>0.05).

The present study investigated the chemical composition and metabolizable energy levels of ten meat and bone meals (MBM) produced in Minas Gerais state (Experiment I) and evaluated the growth performance of broilers fed with diets containing those MBM (Experiment II). In the first experiment, energy values (apparent metabolizable energy [AME] and corrected apparent metabolizable energy [AMEn]) of ten different MBM were determined using the traditional method with total collection of excreta. Four hundred forty 21 day-old Hubbard broilers were used. A reference corn and soybean meal-based diet was replaced in 20% by the feed containing MBM to be tested. A completely randomized experimental design was used with eleven treatments (one reference diet and ten MBM), four repetitions per treatment and 10 birds per repetition (5 males and 5 females). In the second experiment, five MBMs from the ten analyzed in Experiment 1 were used as phosphorus source and compared to a diet containing bicalcium phosphate. The growth performance of the broilers fed with these diets was analyzed, considering two ages of the onset of MBM inclusion in the diet (1 or 7 days of age). One-day-old Hubbard broilers (1,320 birds) were housed in 44 plots with 30 birds per experimental unit. The experiment consisted of 11 treatments in a 5x2 factorial arrangement, with five sources of MBM, two ages for the onset of inclusion, and a reference treatment without addition of MBM. The results obtained showed a great variation in the chemical composition and apparent metabolizable energy of the evaluated meals. No significant differences were found on the performance of broilers fed diets with different MBM or the diet with bicalcium phosphate as phosphorus source. The performance of broilers was not significantly influenced by the onset of MBM inclusion in the diets.

The supplementation of cobalt and vitamin B12 in diets for commercial laying hens on the second production cycle was studied. Four hundred and eighty light commercial laying hens, Lohmann LSL, were used at initial phase of forced molting laying period. The trial was conducted in a randomized design. The plots were the treatments which were constituted by combination of five cobalt levels (0.00; 0.30; 0.60; 0.90 and 1.20ppm) and two vitamin B12 levels (without and with 10µ/kg), and the split-plots were four periods (21, 42, 63 and 84 days) during the second period of production, with 4 repetitions and 12 hens per experimental unit. Food and water were provided ad libitum and eggs were collected twice daily. Performance and egg quality parameters were evaluated. At the end of experimental period, two layers from each treatment were slaughtered, and liver and blood samples were taken for analysis. Performance and egg quality were not different (p>0.05) among cobalt supplementation levels, although egg damage data were different (p<0.05). Supplementation with vitamin B12 decreased egg weight. No influence of cobalt or vitamin B12 supplementation was seen on the concentration of cobalt in the liver and yolk as well as on blood analysis (hematrocrit, hemoglobin, erythrocytes, and leukocytes). The results revealed that vitamin B12 supplementation was important for commercial laying hens on the second cycle of production, but not cobalt supplementation.

Foram utilizados 240 frangos machos, Hubbard, com peso médio inicial de 1204g, em DIC, com os tratamentos em esquema fatorial 2 x 3 x 2, sendo 2 níveis de KCl (0,0% e 1,2%) x 3 níveis de NH4Cl (0,0%; 0,2% e 0,4%) x 2 níveis de energia (3000 e 3200 kcal EM/kg de ração), com 4 repetições de 5 aves por parcela. Os parâmetros avaliados foram: peso médio (PM), consumo de ração (CR), ganho de peso (GP), conversão alimentar (CA), rendimento de carcaça (RC) e gordura abdominal (GA). Os dados foram analisados pelo programa estatístico Statistical Analyses System (SAS, 1996). As temperaturas máxima e mínima foram de 32,7° e 22,8°C, e o índice de temperatura do globo negro e umidade (ITGU) observado às 9:00 e 15:00 horas foi de 76 e 83, respectivamente. A análise de variância revelou interação (p<0,05) apenas entre o KCl e o nível energético da ração sobre o CR. Não se verificou efeito (p>0,05) dos fatores estudados sobre o PM e GP. Para a CA houve efeito (p<0,05) do NH4Cl e do nível energético da ração. Para o rendimento de carcaça, não se observou efeito (p>0,05) dos fatores estudados. Os frangos que receberam ração suplementada com 1,2% KCl apresentaram menor teor de gordura abdominal (p<0,05) em relação aos que não receberam a suplementação (1,16% vs 1,40%, respectivamente) e o nível energético alto elevou significativamente (p<0,01) a gordura abdominal em relação ao nível baixo (1,42% vs 1,14%, respectivamente). Com os resultados obtidos, concluiu-se que a elevação do nível energético da ração melhorou a conversão alimentar e aumentou a gordura abdominal; o KCl não afetou o desempenho, mas reduziu (p<0,05) a gordura abdominal independente do nível de energia da dieta; e a suplementação com 0,4% de NH4Cl piorou a conversão alimentar de frangos de corte criados no verão.

Two hundred and forty male broiler chickens with initial average weight of 1,204g, were utilized; in CRD with the treatments in 2 x 3 x 2 factorial design, 2 levels of KCl (0.0%; 1.2 %) x 3 levels of NH4Cl (0.0%; 0.2% and 0.4%) and 2 levels of energy (3,000 and 3,200 kcal ME/kg of ration) with 4 replications of 5 birds per plot. The evaluated parameters were: average weight (AW), feed consumption (FC), weight gain (WG) feed conversion (FC), carcass yield (CY) and abdominal fat (AF). The data were analyzed through the statistical program Statistical Analysis System (SAS, 1996). The maximum and minimum temperatures and black globe-humidity index (BGHI), recorded at 9:00 and 15:00 were (32.7 and 22.8; 76 and 83). The KCl significantly reduced (p<0.05) abdominal fat (AF). Metabolizable energy affected (p<0.05) FC (2.12 vs 2.30) and AF (1.42% vs 1.14%) for the high and low levels, respectively. For the other parameters, no significant effects of the factors studied (p>0.05) were found. Energy level of the ration improved feed conversion and increased abdominal fat; KCl did not affect performance and reduced abdominal fat regardless of the energy level in the diet; and the supplementation with 0.4% NH4Cl reduced feed conversion of broiler chickens raised in summer.

Realizou-se um experimento com o objetivo de estudar a suplementação de sódio para poedeiras comerciais no segundo ciclo de produção. Foram utilizadas 360 aves Lohmann - LSL, distribuídas em gaiolas convencionais, onde receberam 5 tratamentos experimentais (níveis de sódio suplementar de 0,05; 0,10; 0,15; 0,20 e 0,25%), com 6 repetições de 12 aves cada, avaliados em 3 períodos de 21dias. O delineamento experimental foi o inteiramente casualizado em esquema de parcelas subdivididas, sendo os tratamentos designados nas parcelas e as avaliações nos períodos, nas subparcelas. As rações foram isonutritivas à base de milho e farelo de soja e fornecidas à vontade. O sódio suplementar foi adicionado às dietas usando o NaCl contendo 39,7% desse elemento. Ao final de cada período experimental, foram avaliadas as características de desempenho, qualidade de casca dos ovos e percentagem de umidade das excretas. No final do experimento, foi realizada análise de sódio e potássio no plasma e o peso vivo das aves. Os níveis de sódio estudados influenciaram o desempenho das poedeiras, com redução no consumo de ração, peso vivo e produção de ovos nos níveis mais baixos de sódio e a umidade das excretas foi mais alta à medida que se elevou o nível de sódio fornecido na ração. Conclui-se que, para melhor desempenho das poedeiras no segundo ciclo de produção, a suplementação de sódio deve ser de 0,185% ou 0,219% de sódio total nas rações.

One experiment was conducted aiming to study the sodium supplementation for commercial laying hens on second cycle of production. A total of 360 Lohmann - LSL layers were randomly assigned to 30 conventional cages during 3 periods of 21 days, where 6 cages were placed on each of the 5 dietary treatments (sodium supplemental levels of 0.05, 0.10, 0.15, 0.20 and 0.25%) with 12 layers per cage. A completely randomized design was used in a split-plot schedule. The dietary treatments represented the parcels and the periods represented the split plot. The corn-soybean meal diets were isonutrient and were provided for "ad libitum" consumption. The supplemental sodium was added to the diets in the form of NaCl, with 39.7% of sodium. Performance, eggshell quality and excreta moisture traits were evaluated at the end of each 21 day period, whereas live weight and plasma sodium and potassium were measured at the end of the experiment. Sodium levels influenced the layers performance, which was characterized by reduction on feed consumption, live weight and egg production on the lower sodium levels and by the increase on excreta moisture on the higher sodium level. It follows that in order to achieve the best performance of the laying hens on the second cycle of production, the dietary sodium supplementation must be of 0.185% or 0.219% of total sodium.

O objetivo deste trabalho foi avaliar os efeitos da suplementação de ferro, proveniente do sulfato ferroso (26% de ferro), em ração à base de milho e farelo de soja, sobre o desempenho, qualidade do ovo, deposição de ferro na gema e parâmetros sangüíneos de poedeiras comerciais no segundo ciclo de produção. Foram utilizadas 240 poedeiras comerciais Lohmann-LSL, oriundas de plantel comercial e submetidas a muda forçada com 72 semanas de idade, alojadas em galpão convencional de postura, em uma densidade de três aves por gaiola (25 x 45 x 40 cm). O delineamento experimental foi inteiramente casualizado, com os tratamentos constando níveis de 0, 20, 40, 60 e 80 ppm de ferro suplementar, com quatro repetições de 12 aves, e três períodos de avaliações de 28 dias cada. A ração utilizada foi à base de milho e farelo de soja, contendo 127 ppm de ferro analisado. A suplementação de ferro não interferiu no desempenho, na qualidade interna e externa dos ovos e nos parâmetros sangüíneos das poedeiras. O conteúdo de ferro na gema (mg/100g) elevou-se linearmente quando houve aumento da suplementação deste até o nível de 80 ppm, utilizado no presente trabalho.

The objective of this work was to evaluate the effects of the supplementation of iron in ration based on corn and soybean meal, on the productive performance, egg quality , egg yolk iron deposition and blood parameters of commercial laying hens in second production cycle. 240 commercial Lohmann-LSL laying hens with 72 weeks of age were submitted to the forced molt. The hens were raised in the conventional cage by using three hens by cage (25 x 45 x 40cm). A completely randomized design was utilized, with treatments based on five iron supplementation levels (0, 20, 40 60 and 80ppm) in the ration, with four replications and three evaluations periods of 28 days each. The corn/soybean meal based diet were used, containing 127 ppm of analysed iron. The iron supplementation did not affect the productive performance and internal and external eggs quality and analysed blood parameters . The content of iron egg yolk (mg/100g) increased linearly when iron supplementation increased in the diet at the level of 80 ppm, used in this research.