RESUMO -Objetivou-se avaliar o fornecimento de misturas de extratos vegetais nas dietas de frangos de corte.Utilizaram-se 1.350 aves distribuídas em blocos casualizados, com seis repetições e cinco dietas, uma sem aditivos e outras quatro, cada uma contendo um dos aditivos: 10 ppm de avilamicina; 200 ppm de um produto contendo óleos essenciais de cravo, tomilho, canela e pimenta; 100 ppm de um produto comercial composto de óleos essenciais sintéticos de orégano e canela e óleo-resina de pimenta microencapsulados; 500 ppm de um produto comercial constituído de óleo de eucalipto, óleo essencial de canela-da-china, folhas de boldo-do-chile e sementes de feno-grego na fase inicial e 1.200 ppm nas fases de crescimento e final. Aos 21 e 42 dias, foram avaliadas as variáveis de desempenho e aos 44 dias de idade, as características de carcaça. Dos 27 aos 30 dias de idade, foi realizado o ensaio de metabolismo pelo método de coleta total de excretas e determinadas a energia metabolizável e a digestibilidade da proteína bruta das dietas. As dietas com misturas de extratos vegetais não tiveram efeito significativo sobre o desempenho se comparadas à dieta sem aditivo e à dieta com antibiótico. A ausência de desafio na criação e a utilização de dietas com ingredientes de alta digestibilidade podem ter contribuído para que as aves expressassem todo o seu potencial, tornando indetectável a melhora ocasionada pela inclusão de qualquer dos aditivos. Dietas contendo misturas de extratos vegetais promovem desempenho semelhante ao obtido com dietas contendo antibiótico.Palavras-chaves: aditivos, características de carcaça, desempenho, ensaio de metabolismo Plant extracts in diets for broilersABSTRACT -The trial was carried out to evaluate different blends of plants extracts in broilers diets. It was used 1,350 broilers distributed in a randomized block design with six replicates and five diets, one without additive and the four others, each containing one of the following additives: 10 ppm of avilamycin; 200 ppm of a product containing essential oils of carnation, thyme, cinnamon and microencapsulated capsicum; 100 ppm of a product containing essential oils of synthetic cinnamaldehyde and carvacrol and capsicum oleoresin microencapsulated; 500 ppm of a commercial product containing eucalypt oil, essential oil of Chinese cinnamon, leaves of Chilene boldo and seeds of fenu-Greek at the initial phase and 1200 ppm in the grower and finisher phases. Performance parameters were evaluated at 21 and 42 days of age and the carcass characteristics at 44 days of age. From 27 to 30 days of age, it was carried out the metabolism trial trough total excreta collection method and metabolizable energy and the crude protein digestibility of the diets were determined. The diets with plant extract blends had no significant effect on the performance when compared to diet without additives or diet with avilamycin. The lack of challenge in the experimental facilities and the use of diets with high digestibility ingredients might have contributed to broil...

RESUMO Evaluation of corn with different densities for broilersABSTRACT -The objective of this work was to determine the nutritional value of corn of four different qualities, obtained by stratification in densimetric table, for broilers at different ages. The corns were designed as: MDA -high density corn; MDI -medium density corn; MDB -low density corn and MDO -original density corn, composed of 25% MDA, 50% MDI and 25% MDB. Three biological assays were carried out by using the traditional total excreta collection method for determination of nitrogen corrected apparent metabolizable energy (AMEn). The first metabolism assay was carried out with Cobb chicks at 14 to 17 days of age, the second assay with chicks at 25 to 28 days of age and the third with chicks at 38 to 41 days of age. Chemical analyses were made for determination of the nutritional profile, classification of the grains according to density and comparison by estimates of energy value prediction equations. The values of AMEn of corns of different qualities (MDA, MDI, MDB and MDO) determined in broilers in initial phase were: 3562, 3382, 3198 and 3357 kcal/kg for growth phase and for final phase they were 3576, 3555, 3229 and 3416 kcal/kg and for the finish phase they were 3610, 3554, 3354 and 3585 kcal/kg, respectively. These results prove that significant energy losses of the lowest quality corns and the efficiency of the densimetric Zootec., v.40, n.7, p.1554-1561, 2011

Two experiments were carried out to determine which factor influences weight at hatch of broiler chicks: breeder age or incubated egg weight. In Experiment 1, 2340 eggs produced by 29-and 55-weekold Ross ® broiler breeders were incubated. The eggs selected for incubation weighed one standard deviation below and above average egg weight. In Experiment 2, 2160 eggs weighing 62 g produced by breeders of both ages were incubated. In both experiments, 50 additional eggs within the weight interval determined for each breeder age were weighed, broken, and their components were separated and weighed. At hatch, hatchlings were sexed and weighed, determining the average initial weight of the progeny of each breeder age. Data were analyzed using the Analyst program of SAS ® software package. In Experiment 1, the weight difference between eggs produced by young and mature breeders was 10.92 g, and the component that mostly influenced this difference was the yolk (7.51 g heavier in mature breeders, compared with 4.23 g difference in albumen and 0.8 g in eggshell weights). Hatchling weight difference was 9.4 g higher in eggs from mature breeders. In Experiment 2, egg weight difference was only 0.74 g, but yolk weight was 4.59 g higher in the eggs of mature breeders. The results obtained in the present study indicate that hatchling weight is influenced by egg weight, and not by breeder age. INTRODUCTIONA chicken egg generally consists of 58.5% albumen, 31% yolk, and 10.5% shell, but this composition varies according to genetic strain and breeder age (Vieira & Moran, 1999).Chick weight at hatch is directly related to egg weight, corresponding to 62 to 76% of egg weight. This correlation between increases after the 11th day of incubation and may remain the same during the entire rearing period (Wilson, 1991).Breeder age strongly influences egg weight, as well as egg quality and composition. Young breeders tend to produce lighter eggs, and consequently, lighter day-old chicks (Dalanezi et al., 2004); however, egg with the same weight can be produced by breeders of different ages as well breeders of the same age can produce eggs with different weights. Some studies showed that chick weight is independent of breeder age and it is only influenced by egg weight (Pinchasov, 1991).Egg weight increases with breeder age due to the increase in yolk size, whereas the variation in the weight of the eggs produced by breeders of the same age results from an increase in albumen proportion (Lima et al., 2001). It must be mentioned that eggs with the same weight, independently of breeder age, produce day-old chicks with the same weight and quality. Mail Adress

RESUMO -O objetivo neste estudo foi avaliar os efeitos de um complexo enzimático, composto por protease, xilanase e amilase, associado ou não a betaína em dietas para frangos de corte sobre o desempenho das aves e a análise econômica. Pintos machos da linhagem Cobb 500 (924), com peso médio inicial de 45,8 g, foram alimentados com quatro dietas, cada uma com sete repetições, em um delineamento inteiramente casualizado. Cada unidade experimental continha 33 aves. As dietas foram:controle -rações à base de milho e farelo de soja; enzimas -rações acrescidas de enzimas (protease, xilanase e amilase); betaína -rações acrescidas de betaína natural; enzimas + betaína -rações acrescidas de enzimas e betaína. Evaluation of an enzymatic complex and natural betaine in rations for broilers chickens raised in a commercial poultry houseABSTRACT -The objective of this study was to evaluate the effects of an enzymatic complex composed of protease, xylanase and amylase, associated or not to betaine in diets for broiler chickens on the performance of birds and economical analysis. It was used Cobb 500 male broiler chicks (924) at average initial weight of 45.8 g fed four diets, each one with seven replicates, in a completely randomized design. Each experimental unit had 33 birds. The diets were: control -corn and soybean meal-based rations; enzymes -rations added with enzymes (protease, xylanase and amylase); betaine -rations added with natural betaine; enzymes + betaine -rations added with enzymes and betaine. In the period from 1 to 7 days, the addition of enzymes or betaine into the rations did not influence performance traits. In the period from 1 to 21 days of age, birds fed diets with enzymes + betaine showed lower average feed intake when compared to those diets only with enzymes. However, average weight gain and feed conversion were similar. Diets with enzyme or betaine did not influence performance of the birds compared to control diet. Likewise, in the period from 1 to 35 days, performance of the birds fed diets with enzymes and betaine was similar to the control group. At 41 days of age, broilers fed diets with enzyme or betaine showed performance similar to the control group, so, the additives used had the expected effects. However, combination of the additives did not show the same efficiency. There was no significant influence of diets in the feed cost. Among the evaluated additives, only enzyme and betaine do not affect performance of the birds.

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