The present study was conducted to evaluate the performance, carcass yield, and histomorphometry of the small intestine of broilers fed yeast sugarcane supplemented with enzymatic blend from 22 to 42 days of age. Seven hundred broiler chicks were distributed in a completely randomized design in a factorial design (2x3+1), two levels of the enzyme blend (0 and 200 g/ton), three protein levels (0%, 6% and 12%) and a control diet. The level of 6% yeast showed higher feed intake and weight gain after 33 days. From 22 to 42 days there was no significant effect (p<0.05) to the use of yeast in animal performance, carcass yield and cuts. At 42 days an interaction between the factors for width and crypt depth in the duodenum and jejunum, respectively, was observed. The inclusion of yeast in the diets for broilers from 22 to 42 days did not affect the performance and yield of the carcass. Yeast increased the muscle wall of the jejunum. The use of the enzymatic blend did not influence performance but affected the integrity of the intestinal mucosa.

SUMMARY This study aimed at evaluating the use of exogenous enzymes in diets with Saccharomyces cerevisiae and their impact on zootechnical performance, carcass yield, intestinal histomorphometry and of broiler diets in the initial phase. A completely randomized design was used in a 2×3 + 1 factorial arrangement, with two levels of enzyme complex (EC), (0 and 200g / ton), three yeast levels (0, 6 and 12%) and a control diet, making up seven treatments, with five replicates of 20 broilers per experimental unit. We evaluated the performance (feed intake, weight gain and feed conversion ratio), carcass yield and cuts, histomorphometry of the small intestine (height, circumference and width of villi, height and width of the crypt, thickness of the intestinal muscle wall and villi/crypt relationship). From 1 to 7 and 1 to 21 days, the inclusion of yeast led to reduced broiler performance. At 21 days, the addition of EC resulted in an increase of (p <0.05) in the thickness of the muscular wall of the duodenum and decreased the width of the crypt in the ileum. The 12% level of yeast without the EC provided a thicker jejunum intestinal muscle wall when compared to the positive control. There was no significant effect on carcass yield and cuts between treatments. In conclusion, the inclusion of yeast reduces performance from 1-21 days. The enzyme complex and yeast does not change the performance or carcass yield, however, it does bring benefits to the intestinal mucosa.

Objetivou-se avaliar o efeito da suplementação da enzima β-mananase com e sem levedura de cana de açúcar (Saccharomyces cerevisiae) para frangos de corte 1 a 21 dias de idade. Utilizou-se 720 pintos de corte de um dia de idade, machos, da linhagem Cobb, distribuídos em delineamento inteiramente casualizado com seis tratamentos e, seis repetições de 20 aves cada. Os tratamentos foram: Dieta basal (DB); DB + β-mananase (100 g/t); DB + 7% de levedura de cana-de-açúcar (DL); DL + β-mananase (80 g/t); DL + β-mananase (100 g/t); DL + β-mananase (120 g/t). Avaliou-se o desempenho zootécnico na fase pré-inicial (1 a 7) e na fase inicial (1 a 21 dias de idade), a morfometria do intestino delgado (duodeno, jejuno e íleo) e, a viabilidade econômica da ração. Os dados foram submetidos à análise da variância do programa SAS e as médias foram comparadas pelo teste de Student Newmann Keuls (SNK). Na fase pré-inicial, os tratamentos com DL + β-mananase (80, 100 e 120 g/t) apresentaram as melhores médias de conversão alimentar. Na fase inicial, aos frangos que consumiram à dieta basal (DB) e DB + β-mananase apresentaram peso médio, ganho de peso e conversão alimentar melhores. Para a morfometria intestinal, criptas ileais mais rasas foram observadas no tratamento com DL+ β-mananase (120 g/t) em relação a dieta basal e vilos ileais mais largos foram observados no tratamento com DL+ β-mananase (100 g/t) em relação a dieta com DL+ β-mananase (80 g/t). A espessura da parede muscular, no duodeno, foi menor nos frangos que consumiram a DB em relação a DB + β-mananase (100 g/t), no jejuno, foi maior na DL e na suplementação com 100 g/t em relação a 80 e 120 g/t e no íleo, foi maior nas dietas com suplementação de β-mananase em relação a DB e DL. Para a viabilidade econômica, a adição de 7% de levedura de cana-de-açúcar, com ou sem enzima proporcionaram aumento do custo médio de ração e índice de custo, e redução do índice de eficiência econômica. Com base nos resultados zootécnicos recomenda-se DL + β-mananase (120g/t) para a fase pré-inicial e inicial. Contudo, o uso de levedura de cana-de-açúcar com e sem suplementação da enzima β-mananase não é economicamente viável no período de 1 a 21 dias.

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The objective of the study was to evaluate the effect of inclusion of enzyme complex in diets of corn and soybean meal upon the metabolizable energy, heat production, zootechnical performance, intestinal morphometry, carcass yield and commercial cuts of broilers, in the period of 21 to 42 days. Metabolism and performance test were performed in a completely randomized design with 4 treatments (Positive Control (CP) and Negative Control (CN), with enzyme complex and without enzyme complex, respectively), 8 repetitions of 4 birds (metabolism) and 15 birds (performance)). Metabolizable energy, heat production, intestinal histomorphometry, zootechnical performance, carcass yield and economic evaluation were analyzed. No effects were observed for metabolizable energy and heat production when enzymes to the diets were added. There was no effect of the treatments upon the performance and the carcass yield. The enzymes caused an increase in the width of the crypt in the duodenum. The others variables (villus height and width, crypt height, wall thickness) of the duodenum, jejunum and ileum were not influenced. Enzymes in diets without energy reduction are not economically viable in the period of 21 to 42 days of age.