Production and quality of tropical grasses at different regrowth intervals in the Brazilian semiarid

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.(AU)

Production and quality of tropical grasses at different regrowth intervals in the Brazilian semiarid

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.

Morphogenic and structural characteristics of tropical forage grasses managed under different regrowth periods in the Brazilian semi-arid region / Características morfogênicas e estruturais de gramíneas forrageiras tropicais manejadas com diferentes períodos de rebrotação no semiárido brasileiro

The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.(AU)

Objetivou-se avaliar as características morfogênicas e estruturais de gramíneas tropicais manejadas sob diferentes períodos de rebrotação. O experimento foi conduzido no Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Norte, localizado no município de Apodi-RN. O delineamento foi em blocos ao acaso e os tratamentos foram alocados em arranjo fatorial 3x4, sendo três cultivares (Andropogon, Buffel e Massai) em quatro períodos de rebrotação (21, 35, 49 e 63 dias). A interação entre cultivar e idade foi significativa para todas as variáveis estudadas, com exceção da largura da lâmina foliar e da taxa de acúmulo. As maiores taxas de aparecimento de folhas foram observadas no capim-buffel, independentemente da idade de rebrotação. Apenas no capim-andropogon, essa característica não foi influenciada pela idade. As maiores taxas de alongamento de colmo foram observadas no capim-buffel e as menores no capim-massai até os 35 dias de rebrotação, atribuído a presença de inflorescências. As alturas do dossel dos capim-massai e capim-andropogon foram maiores que a do capim-buffel até os 35 dias rebrotação, a partir dos 35 dias de rebrotação o capim-andropogon apresentou maior altura que os demais. O capim-andropogon obteve maior taxa de acúmulo que o capim-massai apenas aos 21 dias de rebrotação. O capim-buffel deve ser desfolhado aos 21 dias, enquanto que os capins andropogon e massai podem ser manejados sem prejuízos entre 21 e 63 dias de rebrotação.(AU)

Fractionation of nitrogen compounds and carbohydrates in forages of different ages / Fracionamento de compostos nitrogenados e carboidratos em forragens de diferentes idades

Here we tested how feeding with exogenous enzymes affects the performance, carcass yield, and ilealdigestibility in broilers from 21- to 42-days-old. The study included 1008 male broilers randomlydistributed into six diets: positive control (PC), corn and soybean meal containing all the nutritionalrequirements; negative control (NC), with a 120 kcal.kg-1 reduction in metabolizable energy relative tothe PC; enzyme complex one (NC + 100 ppm of endo-1,4-beta-xylanase); enzyme complex two (NC+ 200 ppm of xylanase, amylase and protease); enzyme blend one (NC + 100 FXU kg-1 of xylanaseand 200 FXU kg-1 of amylase); and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXUkg-1 of amylase). The enzyme complex two (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase)and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXU kg-1 of amylase) had greaterweight gain, feed conversion, carcass yield, and digestibility of nutrients than the NC (P < 0,05). Wefound that enzyme complex two and enzyme blend two valued their nutritional matrix promoting betterperformance and digestibility of broilers.

O trabalho foi realizado para avaliar o uso de enzimas sobre o desempenho, rendimento de carcaça edigestibilidade ileal em frangos de corte no período de 21 a 42 dias de idade. Foram utilizados 1008frangos de corte, machos, distribuídos em seis dietas: controle positivo (CP) a base de milho e farelo desoja, contendo todas as exigências nutricionais, controle negativo (CN) com redução de 120 kcal.kg-1deenergia metabolizável, complexo enzimático um (CN + 100 ppm de endo-1,4-beta-xilanase); complexoenzimático dois ( CN + 200 ppm de xilanase, amilase e protease); blend enzimático um (CN + 100 FXU.kg de xilanase e 200 FXU.kg de amilase e blend enzimático dois (CN + 100 FXU.kg de xilanase e 300FXU.kg de amilase). O complexo enzimático dois (CN + 200 ppm de xilanase, amilase e protease) eblend enzimático dois (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase) proporcionaram ganhode peso, conversão alimentar, rendimento de carcaça e digestibilidade de nutrientes superior ao controlenegativo (P < 0,05). Concluiu-se que o complexo enzimático dois e blend enzimático dois valorizaramsua matriz nutricional promovendo melhor desempenho e digestibilidade em frangos de corte.

Fractionation of nitrogen compounds and carbohydrates in forages of different ages / Fracionamento de compostos nitrogenados e carboidratos em forragens de diferentes idades

Here we tested how feeding with exogenous enzymes affects the performance, carcass yield, and ilealdigestibility in broilers from 21- to 42-days-old. The study included 1008 male broilers randomlydistributed into six diets: positive control (PC), corn and soybean meal containing all the nutritionalrequirements; negative control (NC), with a 120 kcal.kg-1 reduction in metabolizable energy relative tothe PC; enzyme complex one (NC + 100 ppm of endo-1,4-beta-xylanase); enzyme complex two (NC+ 200 ppm of xylanase, amylase and protease); enzyme blend one (NC + 100 FXU kg-1 of xylanaseand 200 FXU kg-1 of amylase); and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXUkg-1 of amylase). The enzyme complex two (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase)and enzyme blend two (NC + 100 FXU kg-1 of xylanase and 300 FXU kg-1 of amylase) had greaterweight gain, feed conversion, carcass yield, and digestibility of nutrients than the NC (P < 0,05). Wefound that enzyme complex two and enzyme blend two valued their nutritional matrix promoting betterperformance and digestibility of broilers.(AU)

O trabalho foi realizado para avaliar o uso de enzimas sobre o desempenho, rendimento de carcaça edigestibilidade ileal em frangos de corte no período de 21 a 42 dias de idade. Foram utilizados 1008frangos de corte, machos, distribuídos em seis dietas: controle positivo (CP) a base de milho e farelo desoja, contendo todas as exigências nutricionais, controle negativo (CN) com redução de 120 kcal.kg-1deenergia metabolizável, complexo enzimático um (CN + 100 ppm de endo-1,4-beta-xilanase); complexoenzimático dois ( CN + 200 ppm de xilanase, amilase e protease); blend enzimático um (CN + 100 FXU.kg de xilanase e 200 FXU.kg de amilase e blend enzimático dois (CN + 100 FXU.kg de xilanase e 300FXU.kg de amilase). O complexo enzimático dois (CN + 200 ppm de xilanase, amilase e protease) eblend enzimático dois (CN + 100 FXU.kg de xilanase e 300 FXU.kg de amilase) proporcionaram ganhode peso, conversão alimentar, rendimento de carcaça e digestibilidade de nutrientes superior ao controlenegativo (P < 0,05). Concluiu-se que o complexo enzimático dois e blend enzimático dois valorizaramsua matriz nutricional promovendo melhor desempenho e digestibilidade em frangos de corte.(AU)

Morphogenic and structural characteristics of tropical forage grasses managed under different regrowth periods in the Brazilian semi-arid region / Características morfogênicas e estruturais de gramíneas forrageiras tropicais manejadas com diferentes períodos de rebrotação no semiárido brasileiro

The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.

Objetivou-se avaliar as características morfogênicas e estruturais de gramíneas tropicais manejadas sob diferentes períodos de rebrotação. O experimento foi conduzido no Instituto Federal de Educação Ciência e Tecnologia do Rio Grande do Norte, localizado no município de Apodi-RN. O delineamento foi em blocos ao acaso e os tratamentos foram alocados em arranjo fatorial 3x4, sendo três cultivares (Andropogon, Buffel e Massai) em quatro períodos de rebrotação (21, 35, 49 e 63 dias). A interação entre cultivar e idade foi significativa para todas as variáveis estudadas, com exceção da largura da lâmina foliar e da taxa de acúmulo. As maiores taxas de aparecimento de folhas foram observadas no capim-buffel, independentemente da idade de rebrotação. Apenas no capim-andropogon, essa característica não foi influenciada pela idade. As maiores taxas de alongamento de colmo foram observadas no capim-buffel e as menores no capim-massai até os 35 dias de rebrotação, atribuído a presença de inflorescências. As alturas do dossel dos capim-massai e capim-andropogon foram maiores que a do capim-buffel até os 35 dias rebrotação, a partir dos 35 dias de rebrotação o capim-andropogon apresentou maior altura que os demais. O capim-andropogon obteve maior taxa de acúmulo que o capim-massai apenas aos 21 dias de rebrotação. O capim-buffel deve ser desfolhado aos 21 dias, enquanto que os capins andropogon e massai podem ser manejados sem prejuízos entre 21 e 63 dias de rebrotação.