RESUMO

To gain insights into the forage morphological and anatomical characteristics in a silvopastoral system (SPS) with Bolsa de Pastor (Zeyheria tuberculosa) and palisadegrass 'Marandu' (Urochloa brizantha) monoculture (MONO). The SPS was established through natural regeneration of the tree species. Treatments were a SPS and MONO distributed in a completely randomized design with six replicates and repeated measures were the harvest periods. Response variables were morpho-physiological and anatomical characteristicss: green: dead material ratio, leaf blade: stem+sheath ratio, leaf area index, chlorophyll and carotenoid concentrations, proportions of non-lignified and achlorophyllous areas, lignified areas in stems, proportions of non-lignified and achlorophyllous areas, lignified and chlorophyllous areas in leaves, as well as cell length in longitudinal section of stem. Morpho-physiological patterns were altered (p < 0.05) under natural shading conditions due to higher photosynthetic efficiency in the SPS. There was no effect (p > 0.05) of the systems on anatomical patterns, proportions of non-lignified and achlorophyllous, lignified and chlorophyllous tissues, these proportions were influenced only by the periods of the year, both for stems and leaves. Cells of the internodes of the grasses of the studied systems had the same length. The SPS alters morpho-physiological characteristics of palisadegrass and increases the concentration of chlorophyll a and b.(AU)

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RESUMO

The aim was to evaluate if the inclusion of exogenous amylolytic enzyme affect the nutrient intake and digestibility in ewes fed high-concentrate diets containing flint corn. Five Santa Inês × Dorper crossbred ewes (54.04 ± 4.5 kg and aged 8 months) were used in a 5 x 5 Latin square design. All animals were housed in individual metabolic cages for 60 days. The treatments consisted of a control diet (without amylolytic enzyme) and four inclusion levels of an amylolytic enzyme (3,000, 6,000, 9,000, and 12,000 α-amylase dextrinizing units [DU] kg-1 dry matter [DM]). The enzyme was mixed into the feed at the time of supply to the animals. Data were analyzed by ANOVA, and orthogonal polynomial contrasts were used. Nutrient intake was not influenced by amylolytic enzyme inclusion. The digestibility of DM, organic matter, neutral detergent fiber, total carbohydrates, non-fibrous carbohydrates, and gross energy showed a quadratic increase with enzyme inclusion (P<0.05), with maximum values at levels of 7,600, 7,500, 6,300, 7,500, 7,400, and 7,800 DU kg-1 DM, respectively. Total digestible nutrients of diets also showed a quadratic increase, with a maximum value of 894 g kg-1 at a level of α-amylase activity of 7,786 DU kg-1 DM. The inclusion of the exogenous amylolytic enzyme from 6,300 to 7,800 DU kg-1 DM doesn't alter nutrient intake and improves the digestibility in ewes fed high-concentrate diets.(AU)

Objetivou-se avaliar se a inclusão de enzima amilolítica exógena afeta a ingestão e a digestibilidade dos nutrientes em ovelhas alimentadas com dietas de alto teor de concentrado contendo milho flint. Foram usadas cinco ovelhas mestiças Santa Inês × Dorper (54,04 ± 4,5 kg e 8 meses de idade) em um quadrado latino 5x5. Todos os animais foram alojados em gaiolas metabólicas individuais por 60 dias. Os tratamentos consistiram em uma dieta controle (sem enzima amilolítica) e quatro níveis de enzima amilolítica (3.000; 6.000; 9.000 e 12.000 unidades de dextrinização [UD] de α-amilase kg-1 de matéria seca [MS]). A enzima foi misturada com o alimento no momento do fornecimento aos animais. Os dados foram analisados por ANOVA e contrates ortogonais polinomiais. O consumo de nutrientes não foi influenciado pela inclusão da enzima amilolítica. A digestibilidade da MS, matéria orgânica, fibra em detergente neutro, carboidratos totais, carboidratos não fibrosos e energia bruta apresentaram efeito quadrático com a inclusão de enzima (P<0,05), com valores máximos nos níveis de inclusão da enzima 7.600; 7.500; 6.300; 7.500; 7.400 e 7.800 UD kg-1 MS, respectivamente. Os nutrientes digestíveis totais também apresentaram efeito quadrático, com máximo valor de 894 g kg-1 no nível de atividade de α-amilase de 7.786 UD kg-1 MS. A inclusão da enzima amilolítica exógena entre 6.300 e 7.800 UD kg-1 MS não modifica o consumo de nutrientes e melhora a digestibilidade de ovelhas alimentadas com dietas de alto teor de concentrado.(AU)

Assuntos