RESUMO Avaliou-se o efeito dos níveis de energia metabolizável incrementados com glicerina ou óleo de soja sobre o desempenho de frangos de corte em quatro fases (1 a 7; 8 a 21; 22 a 33 e 34 a 42 dias), e o rendimento de carcaça e cortes. Foram utilizadas 2400 aves com delineamento inteiramente casualizado, em esquema fatorial (duas fontes x quatro níveis de energia), com cinco repetições. Os tratamentos foram estabelecidos por meio da inclusão da glicerina ou do óleo de soja, em intervalos de 75 kcal/kg de energia metabolizável da dieta, o primeiro nível com 75 kcal abaixo da exigência, o segundo corresponde à exigência de cada fase (2925, 2980, 3050 e 3100 Kcal) o terceiro e o quarto nível com 75 kcal e 150 kcal, acima do valor da exigência para a fase avaliada. A exigência de energia metabolizável para frangos de corte, independente da fonte de incremento energético (glicerina ou óleo de soja), foi estimada em 3.075; 3.130; 3.200 e 3.250 kcal de EM/kg de ração, para as fases de 1 a 7; 8 a 21; 22 a 33; 34 a 42 dias, respectivamente. Entretanto, a utilização de glicerina como fonte de incremento energético, promoveu melhor eficiência no desempenho nas duas primeiras fases (1 a 7 e 8 a 21 dias de idades).

ABSTRACT The effect of increased levels of metabolisable energy with glycerine or soybean oil was evaluated in the performance of broilers at four growth stages (1 to 7, 8 to 21, 22 to 33 and 34 to 42 days), in addition to the carcass and cut yield. A total of 2,400 birds were used in a completely randomised design in a 2 x 4 factorial scheme (two sources x four energy levels), with five replications. The treatments were determined by including glycerine or soybean oil at intervals of 75 kcal/kg of metabolisable energy in the diet: the first level with 75 kcal less than the requirement, the second corresponding to the requirement for each stage (2925, 2980, 3050 and 3100 Kcal), and the third and fourth levels with 75 kcal and 150 kcal more than the required value for the stage under evaluation. The metabolisable energy requirement for broilers, irrespective of the energy source (glycerine or soybean oil), was estimated at 3,075, 3.130, 3,200 and 3,250 kcal ME/kg feed, for stages 1 to 7, 8 to 21, 22 to 33 and 34 to 42 days respectively. However, the use of glycerine as a source of increased energy promoted better performance efficiency during the first two stages (1 to 7 and 8 to 21 days of age).

A pesquisa foi conduzida para avaliar o desempenho, metabolizabilidade dos nutrientes e rendimento de carcaça e dos principais cortes comerciais de frangos de cortes alimentados com dietas contendo aditivos alternativos a antibióticos promotores de crescimento, no período de 22 a 42 dias. Os tratamentos foram constituídos de uma ração controle padrão para atender as exigências das aves em cada fase e os demais adicionados de antibiótico; probióticos, prebióticos e simbióticos, com quatro repetições. O uso de probiótico (Lactobacillus acidophilus, Streptococcus faecium e Bifidumbacterium bifidum), do prebiótico (mananoligossacarídeo - MOS) e simbióticos, em ração de frangos de corte, proporciona resultado semelhante ao uso do antibiótico avilamicina 12% para desempenho, rendimento de carcaça e cortes comerciais (peito, dorso, coxa, sobrecoxa, asas, entreasas), coeficiente de metabolizabilidade da matéria seca, da proteína bruta e da energia bruta, no período de 22 a 42 dias de idade, constituindo esses aditivos em alternativa importante na substituição dos antibióticos promotores de crescimento.

This research was conducted to evaluate the performance, metabolizability of nutrients and yield of carcass and the most commercial cuts of broiler chickens fed with diets containing antibiotic growth promoter, probiotics, prebiotic and symbiotics, in the period from 22 to 42 days of age. The experimental treatments were constituted of the basal diet to attempt the nutritional requirements of birds in each phase and others treatments were added of antibiotic; probiotics; prebiotic and symbiotics. The use of probiotic (Lactobacillus acidophilus, Streptococcus faecium and Bifidumbacterium bifidum), and prebiotic (mananoligossacarídeo-MOS) and symbiotics in ration of broiler chicken feed, produce performance, carcass yield and yield of most of the commercial cuts (breast, back, thigh, drumstick, wings and wing drumette), as well as metabolizability coefficient of dry matter, crude protein and gross energy, similar to that achieved with the use of the antibiotic Avilamycin 12%, during the period from 22 to 42 days of age. This way, these additives are important alternative in the substitution of antibiotics.

Objetivou-se avaliar métodos de análise da cinza insolúvel em ácido como indicador na determinação da energia metabolizável do milho para aves em relação ao procedimento padrão de coleta total de excretas. Foi formulada uma dieta referência a base de milho e farelo de soja e uma dieta teste com inclusão de 40% de milho à dieta referência. Foi adicionado 1% de celite™ às dietas, como fonte de cinza insolúvel em ácido. Foram utilizados 60 pintos de corte, da linhagem Cobb500, dos 12 aos 21 dias de idade, distribuídos em um delineamento experimental inteiramente casualizado com duas dietas e seis repetições de cinco aves cada. A energia metabolizável da dieta referência e dieta teste foram determinadas utilizando quatros métodos de análise de cinza insolúvel em ácido (indicador) e também utilizando as fórmulas preconizadas pelo procedimento de coleta total de excretas. Não houve diferença significativa na energia metabolizável do milho determinada com a cinza insolúvel em ácido como indicador quando comparada ao procedimento de coleta total de excretas. Entretanto, observou-se que os métodos de análise da cinza insolúvel em ácido proporcionaram grande variabilidade nos resultados de energia metabolizável do milho, que apresentaram desvio padrão oscilando entre 88 a 229kcal/kg. A cinza insolúvel em ácido pode ser determinada por vários métodos e utilizada como indicador para estimar a energia metabolizável do milho.

The objective was to evaluate methods of analysis of acid-insoluble ash (AIA) as an indicator for the measurement of apparent metabolisable energy (AME) on corn for poultry compared with the standard technique of total collection of excreta. Was formulated reference diet (RD) based on corn and soybean meal and a test diet (DT) with inclusion of 40% corn to the RD. It was added 1% of Celite™ to the diets as a source of acid-insoluble ash. We used a total of 60 chicks, Cobb500, from 12 to 21 days of age, distributed in a completely randomized design, with two treatments and six repetitions with five birds each. The AME of the RD and DT were determined using four methods of analysis of AIA (indicator) and using the formulas recommended by the method of total excreta collection. There wasn`t significant difference in AME of corn determined using the AIA as an indicator when compared to the method of total excreta collection. However, it was observed that the methods of analysis gave the AIA great variability in results AME of corn that had standard deviations ranging from 88-229kcal/kg. The acid insoluble ash (AIA) can be determined for most techniques and used to estimate the AME of corn.

The objective of this study was to analyze the effect of whole cassava root scrapings at different levels in diets for broilers in the period of 22 to 42 days of age in high-temperature environments on performance, as well as to evaluate the metabolizability of dry matter (DM), crude protein (CP) and gross energy (GE) and nitrogen balance. A total of 400 male Ross broilers were used for evaluation of performance and 80 birds of the same strain were used in the metabolism experiment. The design was of randomized block with five treatments and four replications. The experimental unit was represented by twenty birds on the performance evaluation and four birds were housed in metabolic cages for the metabolism evaluation. The treatments consisted of diets containing inclusion levels of cassava root scrapings (0, 50, 100, 150 and 200 g/kg), formulated to meet the nutritional requirements accordingly to each phase of the birds. Whole cassava root scrapings can be included in diets for 22 to 42 day-old broiler chickens, at a level between 118.75 and 200 k/kg, in environments of high temperatures, with positive interference on weight gain and feed conversion, without affecting the coefficient of metabolizability of dry matter, crude protein, gross energy and nitrogen balance, or carcass characteristics, such as yields of main cuts and metabolically active organs of the birds.