ABSTRACT An experiment was conducted with the purpose of evaluating enzyme blends on the performance, carcass traits, and bone mineralization of broilers. In total, 928 one-day-old Cobb 500 male chicks of were used. A completely randomized design with four treatments with eight replicates of 29 birds each was adopted. The evaluated treatments were: 1- Positive Control (PC), feed containing the nutritional recommendations of the genetic company's manual; 2- Negative Control (NC), feed with reductions of 75 kcal/kg AME and 0.10 and 0.12 percent points of phosphorus and calcium, respectively; 3 - NC + enzyme blend (amylase + b-glucanase, xylanase, and phytase; 250 g/t of feed) and 4 - NC + enzyme complex (phytase, amylase, xylanase, glucanase, pectinase, cellulase, and protease; 200 g/t of feed). Birds fed the diet with reduced nutrient levels (NC) presented the worst performance (p<0.05). The supplementation of the enzyme blend promoted similar (p<0.05) weight gain and feed conversion ratio as those obtained with the PC diet during the period of 1-21 days of age. During the phase of 22-42 days and the entire experimental period, weight gain and feed conversion ratio improved with the use of the enzyme combinations compared with the NC group, but remained lower than the PC group. Enzymes combinations did not affect (p>0.05) carcass or parts yields. The broilers fed the reduced-nutrient and energy diet presented lower (p<0.05) tibial ash, calcium, and phosphorus contents that the other treatments. The use of enzyme combinations improved the performance of broilers fed diets with reduced nutrient and energy levels.
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).
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.
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.