Improvement of Ruminal Neutral Detergent Fiber Degradability by Obtaining and Using Exogenous Fibrolytic Enzymes from White-Rot Fungi.

The present review examines the factors and variables that should be considered to obtain, design, and evaluate EFEs that might enhance ruminal NDF degradability. Different combinations of words were introduced in Google Scholar, then scientific articles were examined and included if the reported factors and variables addressed the objective of this review. One-hundred-and-sixteen articles were included. The fungal strains and culture media used to grow white-rot fungi induced the production of specific isoforms of cellulases and xylanases; therefore, EFE products for ruminant feed applications should be obtained in cultures that include the high-fibrous forages used in the diets of those animals. Additionally, the temperature, pH, osmolarity conditions, and EFE synergisms and interactions with ruminal microbiota and endogenous fibrolytic enzymes should be considered. More consistent results have been observed in studies that correlate the cellulase-to-xylanase ratio with ruminant productive behavior. EFE protection (immobilization) allows researchers to obtain enzymatic products that may act under ruminal pH and temperature conditions. It is possible to generate multi-enzyme cocktails that act at different times, re-associate enzymes, and simulate natural protective structures such as cellulosomes. Some EFEs could consistently improve ruminal NDF degradability if we consider fungal cultures and ruminal environmental conditions variables, and include biotechnological tools that might be useful to design novel enzymatic products.

Effects of lignocellulolytic enzymes on the fermentation profile, chemical composition, and in situ ruminal disappearance of whole-plant corn silage.

The objective of this study was to examine the enzyme activities of an enzymatic complex produced by Pleurotus ostreatus in different pH and the effects of adding increased application rates of this enzymatic complex on the fermentation profile, chemical composition, and in situ ruminal disappearance of whole-plant corn silage (WPCS) at the onset of fermentation and 30 d after ensiling. The lignocellulolytic enzymatic complex was obtained through in vitro cultivation of P. ostreatus. In the first experiment, the activities of laccase, lignin peroxidase (LiP), manganese peroxidase, endo- and exo-glucanase, xylanase, and mannanase were determined at pH 3, 4, 5, and 6. In the second experiment, five application rates of enzymatic complex were tested in a randomized complete block design (0, 9, 18, 27, and 36 mg of lignocellulosic enzymes/kg of fresh whole-plant corn [WPC], corresponding to 0, 0.587, 1.156, 1.734, and 2.312 g of enzymatic complex/kg of fresh WPC, respectively). There were four replicates per treatment (vacuum-sealed bags) per opening time. Bags were opened 1, 2, 3, and 7 d after ensiling (onset of fermentation period) and 30 d after ensiling to evaluate the fermentation profile, chemical composition, and in situ dry matter and neutral fiber detergent disappearance of WPCS. Laccase had the greatest activity at pH 5 (P < 0.01), whereas manganese peroxidase and LiP had the greatest activity at pH 4 (P < 0.01; P < 0.01). There was no effect of the rate of application of enzymatic complex, at the onset of fermentation, on the fermentation profile (P > 0.21), and chemical composition (P > 0.36). The concentration of water-soluble carbohydrate quadratically decreased (P < 0.01) over the ensiling time at the onset of fermentation, leading to a quadratic increase of lactic acid (P = 0.02) and a linear increase of acetic acid (P = 0.02) throughout fermentation. Consequently, pH quadratically decreased (P < 0.01). Lignin concentration linearly decreased (P = 0.04) with the enzymatic complex application rates at 30 d of storage; however, other nutrients and fermentation profiles did not change (P > 0.11) with the enzymatic complex application rates. Addition of lignocellulolytic enzymatic complex from P. ostreatus cultivation to WPC at ensiling decreased WPCS lignin concentration 30 d after ensiling; however, it was not sufficient to improve in situ disappearance of fiber and dry matter.

Association of ionophores, yeast, and bacterial probiotics alters the abundance of ruminal microbial species of pasture intensively finished beef cattle.

The effect of the association of non-protein nitrogen, yeast, and bacterial probiotics on the ruminal microbiome of beef cattle intensively finished on pasture was evaluated. The experiment was carried out in a completely randomized design with five treatments and four replications. The treatments consisted of a group of animals kept on pasture that received low consumption supplementation (LS) and four groups that received for 98 days, 17.5 g concentrate kg-1 body weight. The supplements were composed of the association of additives: urea (U), slow-release non-protein nitrogen (U+SRN), yeast (Saccharomyces cerevisiae; U+SRN+Y), and bacterial probiotics (live strains of bacteria; U+SRN+Y+BP). All supplements also contained salinomycin and virginiamycin. After slaughtering the animals, samples of ruminal content were collected to quantify groups of fibrolytic bacteria (Ruminococcus albus and Fibrobacter succinogenes), non-fibrolytic (Prevotella ruminicola, Selenomonas ruminantium, and Streptococcus bovis), Archaea, and ciliate protozoa, using the qPCR technique. The abundance of F. succinogenes was the same for the LS animals and those that received the supplement U+SRN+Y (1.42×108 copies mL-1) but higher than the other treatments. Supplementation reduced by 90% the abundance of S. bovis compared to the LS. The inclusion of yeast increased the abundance of fibrolytic bacteria by 2.2-fold. For animals that received the supplement U+SRN+Y+BP and the LS, there was no difference for non-fibrolytic bacteria (3.07×109 copies mL-1). The use of yeasts and sources of non-protein nitrogen in high-concentrate diets for beef cattle stimulates the growth of fibrolytic bacteria, which can contribute to the reduction of digestive disorders and metabolic diseases in animals that receive diets with high concentrate in pasture intensive termination systems.

Exogenous enzyme on in vitro gas production and ruminal fermentation of diet containing high level of concentrate / Enzimas exógenas sobre produção de gás e fermentação ruminal in vitro de dieta contendo alta nível de concentrado

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.(AU)

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.(AU)

Exogenous enzyme on in vitro gas production and ruminal fermentation of diet containing high level of concentrate / Enzimas exógenas sobre produção de gás e fermentação ruminal in vitro de dieta contendo alta nível de concentrado

Exogenous enzyme preparations (fibrolytic activity (FIB), 0, 0.6, 1.2, 1.8, and 2.4 mg/ml liquid volume incubated; amylolytic activity (AMZ), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated; proteolytic activity (PRO), 0, 0.05, 0.10, 0.15, and 0.20 mg/ml liquid volume incubated) were incubated in vitro. Their fermentation effects were assessed based on accumulated gas production, kinetic parameters, and fermentation profile using the technique of gas fermentation. Ruminal liquid was obtained from two rumen cannulated Santa Inês sheep, fed a diet with roughage-to-concentrate ratio of 20:80. Accumulated gas production was during 96 h of incubation, measured at 18 different times. After incubation, pH, dry matter degradability (DMD), organic matter in vitro digestibility (OMD), metabolisable energy (ME), partitioning factor (PF96), gas yield (GY24), short chain fatty acids (SCFA), and microbial protein production (MCP) were evaluated. Increasing FIB dose linearly decreased (P 0.05) lag time without affecting others kinetic parameters. However, FIB increased the accumulated gas production, resulting in improved DMD, OMD, ME, GY24 and SCFA. The addition of AMZ decreased linearly (P 0.05) lag time and increased (P 0.05) gas production on initial times of incubation without altering the fermentation profile. The inclusion of PRO did not affect (P>0.05) the evaluated parameters. The addition of these exogenous enzyme preparations with fibrolytic activity altered ruminal fermentation in vitro of diets containing high levels of concentrates.

Preparações de enzimas exógenas (atividade fibrolítica (FIB); 0,0; 0,6; 1,2; 1,8 e 2,4 mg/ml do volume de líquido incubado; atividade amilolítica (AMZ); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado; atividade proteolítica (PRO); 0,0; 0,05; 0,10; 0,15 e 0,20 mg/ml do volume de líquido incubado) incubado in vitro. Os efeitos de fermentação foram avaliados com base na produção de gás acumulado, parâmetros cinéticos e, perfil de fermentação usando a técnica de fermentação in vitro. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, alimentados com dieta relação volumoso:concentrado de 20:80. A produção de gás acumulada foi durante 96 h de incubação, mensurados em 18 tempos diferentes. Após a incubação foi avaliado pH, digestibilidade da material seca (DMS), digestibilidade da material orgânica (DMO), energia metabolizável (EM), fator de partição (FP96), rendimento de gás (RG24), ácidos graxos de cadeia curta (AGCC), e produção de proteína microbiana (PPM). O incremento de doses linear de FIB diminuiu (P 0,05) o lag time sem afetar outros parâmetros cinéticos. No entanto, adição de FIB aumentou a produção de gás acumulado, resultando em incremento na DMS, DMO, EM, RG24 e AGCC. A adição de AMZ diminuiu linearmente (P 0,05) lag time e incrementou (P 0,05) produção de gás nos tempos iniciais de incubação sem alterar o perfil de fermentação. A inclusão de PRO não afetou (P>0,05) os parâmetros avaliados. As adições de preparações enzimáticas exógenas com atividades fibrolíticas alteram fermentação ruminal in vitro de dieta de alta níveis de concentrado.

Kinetic parameters of ruminal degradation in vitro with combinations of exogenous enzymes in diets of production systems simulated / Parâmetros cinéticos de degradação ruminal in vitro com combinações de enzimas exógenas em dietas de sistemas de produção simulados

This study evaluated the effects of eight combinations of three exogenous enzymes with fibrolytic activity (FIB), amylolytic activity (AMZ), and proteolytic activity (PRO) on the accumulated gas production (PG) and kinetic parameters in simulated fermentations in two diet production systems using the in vitro gas production technique. In experiment 1, ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, kept in a feedlot and fed a diet containing a roughage:concentrate ratio of 20:80. In experiment 2, the ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, and kept on pasture (Brachiaria brizantha cv. Marandu). The accumulated gas production was measured during a 96-hour incubation, measured at 18 different time points. After incubation, the pH, dry matter degradability, organic matter in vitro digestibility, digestibility of neutral detergent insoluble fiber, metabolizable energy, partitioning factor, gas yield, short chain fatty acids and microbial protein production were determined. In the in vitro fermentation using the feedlot diet, the increased use of fibrolytic enzymes increased PG and improved the profile characteristics and kinetic parameters of the fermentation, regardless of the combination with other enzymes. In the in vitro fermentation using the forage diet, increased fibrolytic enzymes also increased PG, with improvements in the kinetic parameters and the profile of the fermentation, independent of the use of the other enzymes. The addition only of fibrolytic enzymes has major potential to optimize the use of feedlot diets as well of forage in ruminant feed.(AU)

Objetivou-se avaliar oito combinações entre três enzimas exógenas fibrolíticas (FIB), amilolíticas (AMZ), e proteolíticas (PRO), sobre a produção acumulada de gás (PG), parâmetros cinéticos e perfil da fermentação simulando dietas de dois sistemas de produção através da técnica de produção de gás in vitro. No experimento 1, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos em confinamento, alimentados com dieta com relação volumoso:concentrado 20:80. No experimento 2, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos no pasto (Brachiaria brizantha cv. Marandu). A produção de gás acumulada foi obtida em 96 h de incubação, mensurada em 18 horários. Ao final da incubação determinaramse o pH, degradabilidade da matéria seca, digestibilidade in vitro da matéria orgânica, desaparecimento da fibra insolúvel de detergente neutro, energia metabolizável, fator de partição, rendimento de gás, ácidos graxos de cadeia curta, produção de biomassa de proteína microbiana. A fermentação in vitro simulando dietas de confinamento, determinou-se que a participação de enzimas fibrolíticas aumentou PG, e melhorou as características dos parâmetros cinéticos e perfil da fermentação, independente da combinação ou/não com outras enzimas. A fermentação in vitro simulando dietas de forragem, a participação de enzimas fibrolíticas aumentou PG, com melhorias nos parâmetros cinéticos e perfil da fermentação, com ou sem a combinação de outras enzimas. A inclusão apenas de enzimas fibrolíticas tem o maior potencial de otimizar a utilização de dieta de confinamento como também em forragens na alimentação de ruminantes.(AU)

Kinetic parameters of ruminal degradation in vitro with combinations of exogenous enzymes in diets of production systems simulated / Parâmetros cinéticos de degradação ruminal in vitro com combinações de enzimas exógenas em dietas de sistemas de produção simulados

This study evaluated the effects of eight combinations of three exogenous enzymes with fibrolytic activity (FIB), amylolytic activity (AMZ), and proteolytic activity (PRO) on the accumulated gas production (PG) and kinetic parameters in simulated fermentations in two diet production systems using the in vitro gas production technique. In experiment 1, ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, kept in a feedlot and fed a diet containing a roughage:concentrate ratio of 20:80. In experiment 2, the ruminal fluid was obtained from two Santa Ines sheep, cannulated in the rumen, and kept on pasture (Brachiaria brizantha cv. Marandu). The accumulated gas production was measured during a 96-hour incubation, measured at 18 different time points. After incubation, the pH, dry matter degradability, organic matter in vitro digestibility, digestibility of neutral detergent insoluble fiber, metabolizable energy, partitioning factor, gas yield, short chain fatty acids and microbial protein production were determined. In the in vitro fermentation using the feedlot diet, the increased use of fibrolytic enzymes increased PG and improved the profile characteristics and kinetic parameters of the fermentation, regardless of the combination with other enzymes. In the in vitro fermentation using the forage diet, increased fibrolytic enzymes also increased PG, with improvements in the kinetic parameters and the profile of the fermentation, independent of the use of the other enzymes. The addition only of fibrolytic enzymes has major potential to optimize the use of feedlot diets as well of forage in ruminant feed.

Objetivou-se avaliar oito combinações entre três enzimas exógenas fibrolíticas (FIB), amilolíticas (AMZ), e proteolíticas (PRO), sobre a produção acumulada de gás (PG), parâmetros cinéticos e perfil da fermentação simulando dietas de dois sistemas de produção através da técnica de produção de gás in vitro. No experimento 1, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos em confinamento, alimentados com dieta com relação volumoso:concentrado 20:80. No experimento 2, o líquido ruminal foi obtido de dois ovinos da raça Santa Inês, canulados no rúmen, mantidos no pasto (Brachiaria brizantha cv. Marandu). A produção de gás acumulada foi obtida em 96 h de incubação, mensurada em 18 horários. Ao final da incubação determinaramse o pH, degradabilidade da matéria seca, digestibilidade in vitro da matéria orgânica, desaparecimento da fibra insolúvel de detergente neutro, energia metabolizável, fator de partição, rendimento de gás, ácidos graxos de cadeia curta, produção de biomassa de proteína microbiana. A fermentação in vitro simulando dietas de confinamento, determinou-se que a participação de enzimas fibrolíticas aumentou PG, e melhorou as características dos parâmetros cinéticos e perfil da fermentação, independente da combinação ou/não com outras enzimas. A fermentação in vitro simulando dietas de forragem, a participação de enzimas fibrolíticas aumentou PG, com melhorias nos parâmetros cinéticos e perfil da fermentação, com ou sem a combinação de outras enzimas. A inclusão apenas de enzimas fibrolíticas tem o maior potencial de otimizar a utilização de dieta de confinamento como também em forragens na alimentação de ruminantes.

In vitro evaluation of palm fronds as feedstuff on ruminal digestibility and gas production / Avaliação in vitro das folhas de palmeiras como alimento de digestibilidade de ruminais e produção de gás

This study was carried out to evaluate using palm fronds only or supplemented with fibrolytic enzymes as alternative roughage on the ruminal nutrients digestibility and gas production. Treatments were: clover hay (Trifolium alexandrinum), palm fronds only and palm fronds plus fibrolytic enzymes (enzymes were mixed with palm fronds in rate of 4 g kg-1 of dry matter (DM). The results showed a reduction (p < 0.05) in gas production, ammoniac nitrogen (NH3-N, DM and organic matter (OM) digestibility in palm fronds compared with clover hay. While supplementing palm fronds with fibrolytic enzymes improved DM and OM digestibility compared with palm fronds only without (p < 0.05) differences with clover hay. Also, supplementing palm fronds with fibrolytic enzymes reduced (p < 0.05) gas production compared with other treatments. It could be concluded that adding fibrolytic enzymes improved the utilization of palm fronds as alternative roughage without negative effect on nutrients digestibility and reduced gas production which improve the environmental aspects of feeding ruminant animals.

Este estudo teve como objetivo avaliar as folhas de palmeiras sozinhas ou suplementadas com enzimas fibrolíticas, como uma alternativa de degradação da fibra na digestibilidade de nutrientes de ruminantes e produção de gás. Os tratamentos foram: Feno (Trifolium alexandrinum), folhas de palmeiras, e folhas de palmeiras com adição de enzimas fibrolíticas (as enzimas foram misturadas com a folha com taxa de 4g kg-1 matéria seca (MS). Os resultados mostraram uma redução da produção de gás (p < 0.05), nitrogênio amoniacal (NH3-N), MS e matéria orgânica (MO) na digestibilidade das folhas da palmeira comparadas com o feno. Enquanto a suplementação de folhas com as enzimas fibrolíticas, aumentou a digestibilidade DM e OM comparado com as folhas de palmeira, que não teve diferenças com o feno (p < 0.05). Também, suplementando as folhas de palmeiras com as enzimas fibrolíticas reduziram em (p < 0.05) a produção de gás comparado com os outros tratamentos. Pode ser concluído que a adição das enzimas fibrolíticas aumenta a utilização da folha da palmeira como uma alternativa de forragem a qual não possui efeitos negativos na digestibilidade de nutrientes e reduz a produção de gás, a qual melhora os aspectos dos meios da alimentação de animais ruminantes.

In vitro evaluation of palm fronds as feedstuff on ruminal digestibility and gas production / Avaliação in vitro das folhas de palmeiras como alimento de digestibilidade de ruminais e produção de gás

This study was carried out to evaluate using palm fronds only or supplemented with fibrolytic enzymes as alternative roughage on the ruminal nutrients digestibility and gas production. Treatments were: clover hay (Trifolium alexandrinum), palm fronds only and palm fronds plus fibrolytic enzymes (enzymes were mixed with palm fronds in rate of 4 g kg-1 of dry matter (DM). The results showed a reduction (p < 0.05) in gas production, ammoniac nitrogen (NH3-N, DM and organic matter (OM) digestibility in palm fronds compared with clover hay. While supplementing palm fronds with fibrolytic enzymes improved DM and OM digestibility compared with palm fronds only without (p < 0.05) differences with clover hay. Also, supplementing palm fronds with fibrolytic enzymes reduced (p < 0.05) gas production compared with other treatments. It could be concluded that adding fibrolytic enzymes improved the utilization of palm fronds as alternative roughage without negative effect on nutrients digestibility and reduced gas production which improve the environmental aspects of feeding ruminant animals.(AU)

Este estudo teve como objetivo avaliar as folhas de palmeiras sozinhas ou suplementadas com enzimas fibrolíticas, como uma alternativa de degradação da fibra na digestibilidade de nutrientes de ruminantes e produção de gás. Os tratamentos foram: Feno (Trifolium alexandrinum), folhas de palmeiras, e folhas de palmeiras com adição de enzimas fibrolíticas (as enzimas foram misturadas com a folha com taxa de 4g kg-1 matéria seca (MS). Os resultados mostraram uma redução da produção de gás (p < 0.05), nitrogênio amoniacal (NH3-N), MS e matéria orgânica (MO) na digestibilidade das folhas da palmeira comparadas com o feno. Enquanto a suplementação de folhas com as enzimas fibrolíticas, aumentou a digestibilidade DM e OM comparado com as folhas de palmeira, que não teve diferenças com o feno (p < 0.05). Também, suplementando as folhas de palmeiras com as enzimas fibrolíticas reduziram em (p < 0.05) a produção de gás comparado com os outros tratamentos. Pode ser concluído que a adição das enzimas fibrolíticas aumenta a utilização da folha da palmeira como uma alternativa de forragem a qual não possui efeitos negativos na digestibilidade de nutrientes e reduz a produção de gás, a qual melhora os aspectos dos meios da alimentação de animais ruminantes.(AU)

Fribrinolytic activity and gas production by Pleurotus ostreatus-IE8 and Fomes fomentarius - EUM1 in bagasse cane / Actividad fibrolítica y producción de gas por Pleurotus ostreatus-IE8 y Fomes fomentarius-EUM1 en bagazo de caña

Objective. To characterize the fibrolytic enzymatic activity of Pleurotus ostreatus-IE8 and Fomes fomentarius-EUM1 in sugarcane bagasse (BCA); to evaluation of the kinetics of in vitro production of BCA treated by solid fermentation (FS), crude enzyme extract (ECE) of P. ostreatus-IE8 and Fibrozyme®. Materials and methods. In fungi measured radial growth rate ( Vcr ) and biomass production in two culture media (with or without nitrogen source); activity of xylanases, cellulases and FS on BCA at 0, 7 and 15 d. The chemical analysis and kinetic analysis of in vitro gas production in 4 treatments (ECE adding enzymes obtained from the direct addition FS or FS ), witness (Fibrozyme®) and a control without addition and analyzed by a was completely randomized design. Results. Xylanases (7 d ) showed 6.32 and 5.50 UI g-1 initial substrate dry weight (SSi) for fungi P. ostreatus-IE8 and F. fomentarius-EUM1 , respectively ; P. ostreatus-IE8 scored higher activity of laccases (10.65 g-1 UI SSi) and F. fomentarius-EUM1 (1.90 UI g-1 SSi) cellulases. The ECE of P. ostreatus-IE8 and commercial enzyme did not differences (p>0.05). In the chemical composition or the gas production kinetics. The 4 treatments evaluated decreased values of the variables measured in the kinetics of gas production compared to the control (p≤0.05). Conclusions. The ECE of P. ostreatus-IE8 was similar to commercial enzyme degradation in vitro, so it is feasible to use pre-digest high fiber products.

Objetivos. Caracterizar la actividad enzimática fibrolítica de Pleurotus ostreatus-IE8 y Fomes fomentarius-EUM1 en bagazo de caña de azúcar (BCA) y evaluar la cinética de producción de gas in vitro del BCA por fermentación sólida (FS) o con extractos crudos enzimáticos (ECE) de P. ostreatus-IE8 o Fibrozyme®. Materiales y métodos. En los hongos de estudio se evaluó la velocidad de crecimiento radial (Vcr) y producción de biomasa en dos medios de cultivo (con o sin fuente de nitrógeno); actividad de xilanasas, celulasas y lacasas de la FS sobre BCA a 0, 7 y 15 d. El análisis químico y cinética de producción de gas in vitro en 4 tratamientos (proceso de FS o adición de enzimas obtenidas de ECE de la FS), un testigo (Fibrozyme®) y un control sin adición de enzimas, todo ello se analizó en un diseño completamente al azar. Resultados. Las xilanasas (7 d) mostraron 6.32 y 5.50 UI g-1 sustrato seco inicial (SSi) en P. ostreatus-IE8 y F. fomentarius-EUM1, respectivamente. P. ostreatus-IE8 mostró mayor actividad lacasa (10.65 UI g-1 SSi) y F. fomentarius-EUM1 (1.90 UI g-1 SSi) de celulasas. El ECE de P. ostreatus-IE8 y Fibrozyme® no presentaron diferencias (p>0.05) en la composición química ni en la cinética de producción de gas. Los 4 tratamientos evaluados disminuyeron los valores de las variables medidas en la cinética de producción de gas in vitro respecto al testigo (p≤0.05). Conclusiones. El ECE de P. ostreatus-IE8 fue similar a Fibrozyme® en la degradación in vitro, indicando su viabilidad y uso para pre-digerir subproductos altos en fibra.

Effect of fibrolytic enzymes added to a Andropogon gayanus grass silage-concentrate diet on rumen fermentation in batch cultures and the artificial rumen (Rusitec).

In vitro batch cultures were used to screen four fibrolytic enzyme mixtures at two dosages added to a 60 : 40 silage : concentrate diet containing the C(4) tropical grass Andropogon gayanus grass ensiled at two maturities - vegetative stage (VS) and flowering stage (FS). Based on these studies, one enzyme mixture was selected to treat the same diets and evaluate its impact on fermentation using an artificial rumen (Rusitec). In vitro batch cultures were conducted as a completely randomized design with two runs, four replicates per run and 12 treatments in a factorial arrangement (four enzyme mixtures×three doses). Enzyme additives (E1, E2, E3 and E4) were commercial products and contained a range of endoglucanase, exoglucanase and xylanase activities. Enzymes were added to the complete diet 2 h before incubation at 0, 2 and 4 µl/g of dry matter (DM). Gas production (GP) was measured after 3, 6, 12, 24 and 48 h of incubation. Disappearance of DM (DMD), NDF (NDFD) and ADF (ADFD) were determined after 24 and 48 h. For all four enzyme mixtures, a dosage effect (P>0.05) DM, N, NDF or ADF disappearance after 48 h of incubation nor daily ammonia-N, volatile fatty acids or CH(4) production. However, enzyme application increased (P<0.05) microbial N production in feed particle-associated (loosely-associated) and silage feed particle-bound (firmly associated) fractions. With A. gayanus silage diets, degradation may not be limited by microbial colonization, but rather by the ability of fibrolytic enzymes to degrade plant cell walls within this recalcitrant forage.