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An experimental sequence with Gliricidia sepium forage was carried out, from a saline and high drought ecosystem of the Cauto river basin, in Granma, Cuba, to determine the chemical composition, in situ effective ruminal degradability (ED) of dry matter (DM) and in vitro apparent and true digestibility of DM, organic matter, neutral detergent fiber and acid detergent fiber using the Daysi @ procedure. For the study of in situ degradability, times of 6, 12, 24, 36, 48 and 72 h were used. In the contents of the chemical composition values of 24.79, 36.32, 19.51, 16.81, 0.16 and 18.74 % were found for crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose, lignin and cellulose, respectively. The kinetic degradation performance was characterized by an increase in the dynamics disappearance of the dry matter with the incubation time in the rumen, while in the effective ruminal degradability of DM values between 63.1 and 67.6 % were obtained for different constants of ruminal replacement. The fit of the in situ ruminal degradability data to the proposed model, P = a + b (1 - e-ct), showed R2 higher to 97.00. The estimates of apparent digestibility of dry matter, organic matter, neutral detergent fiber and acid detergent fiber maintained values of 73.57, 64.25, 26.72 and 14.35 % respectively, much lower than true digestibilities, with 17.88, 67.14, 27.93 and 15.00 % for these same constituents, respectively. The results of the analysis of the chemical composition, in situ ruminal degradability of the dry matter and in vitro apparent and true digestibility of the dry matter, organic matter, neutral detergent fiber and acid detergent fiber of Gliricidia sepium show its high nutritional value for ruminants in the region. However, physiological studies that relates the cut frequency, degree of use of nutrients by the animal and effect of some secondary metabolites on the physiological and productive responses of the animals when intakes the plants in these edaphoclimatic conditions are required. [ABSTRACT FROM AUTHOR]

Two Creole cows, 450 ± 10 kg live weight, cannulated in rumen were used, with the purpose of studying the kinetics of in situ ruminal degradability of dry matter of leaves and stems of new varieties of drought tolerant Cenchrus purpureus (CT-601, CT-603 and CT-605) obtained by tissue culture at different regrowth ages (60, 80, 100 and 120 d).For that, they were introduced in duplicate bags in the rumen for 0, 4, 6, 8, 12, 24, 48 and 72 h. The results of the ruminal fermentation were fitted to the exponential equation (a + b) *(1-eˆ(-c*t)). For ages 60, 80 and 100 d, the CT-603 had the highest degradability of the potentially degradable fraction (a + b) of the leaves dry matter, with 81.2, 97.8 and 77.5 %, respectively. For 120 d, was the CT-605 which showed better performance of this fraction, with 84.7%. For the stems, at 60 d, the CT-605 showed 94.6% degradation of the fraction a + b, while the CT-601 and CT-603, at 80 d, showed values of this fraction of 75.2 and 75.1 %, respectively. For 100 and 120 d, CT-601 and CT-603, with 59.7 and 88.8 %, respectively, were highlighted. The protein tenors began to decrease below 7% from 80 d of regrowth. For DM degradability in leaves and stems, each variety showed values that exceeded 50% degradation. It is recommended using the ages of 80 and 100 d, in both botanical fractions, to supply ruminants. [ABSTRACT FROM AUTHOR]

Se realizó una secuencia experimental con nueve ecotipos de Tithonia diversifolia (3, 5, 6, 10, 13, 17, 23, 24 y 25) para determinar composición química, degradabilidad efectiva ruminal (DE) in situ de la materia seca (MS) y digestibilidad aparente y verdadera in vitro de la MS, MO, FND y FAD. Para el estudio de degradabilidad se utilizaron tiempos de 6, 12, 36, 48 y 72 h. El comportamiento cinético se caracterizó por incremento en la dinámica de desaparición de la MS, mientras que en la degradabilidad ruminal efectiva de MS se encontraron valores entre 26.29 – 86.55 % para constantes diferentes de recambio ruminal. El ajuste de los datos de degradabilidad ruminal in situ al modelo propuesto mostró R2 superiores a 0.89. En los ecotipos estudiados, los estimados de digestibilidad aparente de MS y MO (DAIVMS y DAIVMO) mantuvieron valores inferiores a las digestibilidades verdaderas de ambos constituyentes (DVIVMS y DVIVMO). Los valores de DAIVMS estuvieron en el rango de 72.25 a 79.77 %, y los de DAIVMO de 57.71 a 66.20 % con respecto a las cifras de DVIVMS y DVIVMO, que oscilaron de 81.08 a 85.66 %, y de 65.27 a 70.22 % respectivamente. Existieron diferencias entre cada uno de los materiales vegetales por indicador (P < 0.01, P < 0.001). Los resultados del análisis de la composición química, degradabilidad ruminal in situ de la MS y digestibilidad aparente y verdadera in vitro de la MS, MO, FND y FAD de los ecotipos de T. diversifolia sugieren su valor nutricional. Sin embargo, se necesitan estudios fisiológicos que relacionen la frecuencia de corte, nivel de inclusión de estos ecotipos, grado de utilización de los nutrientes por el animal y efecto de algunos metabolitos secundarios en las respuestas fisiológicas y productivas de la planta. [ABSTRACT FROM AUTHOR]

An experimental sequence was performed with nine ecotypes of Tithonia diversifolia (3, 5, 6, 10, 13, 17, 23, 24, and 25) to determine chemical composition, in situ rumen effective degradability (ED) of dry matter (DM), and in vitro apparent and true digestibility of DM, OM, NDF, and ADF. Times of 6, 12, 36, 48, and 72 h were used for the degradability study. The kinetic performance was characterized by rise in the dynamics of DM disappearance, whereas the rumen effective DM degradability had values between 26.29 and 86.55 % for different rumen turnover constants. The fit of the data of in situ rumen degradability to the model proposed showed R² superior to 0.89. In the ecotypes under study, the estimates of DM and OM apparent digestibility (IVDMAD and IVOMAD) kept values inferior to the true digestibility of both constituents (IVDMTD and IVOMTD). The values of IVDMAD were within the range from 72.25 to 79.77 %, and those of IVOMAD were from 57.71 to 66.20 %, as compared with the values of IVDMTD and IVOMTD, which ranged from 81.08 to 85.66 %, and from 65.27 to 70.22 % respectively. There were differences between each of the plant materials per indicator (P < 0.01, P < 0.001). The chemical composition analysis results of the in situ DM rumen degradability and the in vitro apparent and true digestibility of the DM, OM, NDF, and ADF of the ecotypes of T. diversifolia suggest their nutritional value. However, physiological studies are required to link the cut frequency, the level of inclusion of these ecotypes, the degree of utilization of the nutrients by the animal and the effect of some secondary metabolites on the physiological and productive responses of the plant. [ABSTRACT FROM AUTHOR]

Para determinar la degradabilidad de la MS y materia orgánica de la harina de semilla de algodón tratada con calor y humedad, se realizó un experimento in situ en rumen. Se utilizaron cuatro ovinos adultos machos, canulados en rumen. Las muestras se incubaron durante 3, 6, 9, 12, 24, 48, y 72 h en posición ventral del rumen. Los valores de degradabilidad potencial (a+b) variaron desde 56.4 hasta 57.5 y desde 86.59 hasta 81.00 % para MS y PB de semilla normal y tratada, respectivamente. Sin embargo, la fracción c, para la MS como para la PB, tuvo un comportamiento mayor en la semilla normal, con respecto a la tratada con calor y humedad. La dinámica de degradación ruminal evidenció tendencia creciente, desde el primero hasta el último horario de incubación, con diferencias (P < 0.01) en las semillas tratadas y sin tratar. La composición química tuvo concentraciones adecuadas para este alimento, con valores de hasta 23.12 y 22.94 %, para PB en harina sin tratar y tratada, respectivamente. Se concluye que al humedecer la semilla hay menor disponibilidad de PB y MS para los animales rumiantes. Además, se cuenta con una opción eficiente y fácil de utilizar en la alimentación animal, con aporte importante de proteínas de sobrepaso para los diferentes sistemas de alimentación. Se recomienda realizar estudios de metabolismo e indicadores productivos que avalen estos resultados. [ABSTRACT FROM AUTHOR]

An in situ experiment was performed in the rumen to determine the DM and organic matter degradability of cottonseed, both normal and treated with heat and humidity. Four adult male sheep were used and fitted with rumen cannula. The samples were incubated for 3, 6, 9, 12, 24, 48, and 72 h in ventral position in the rumen. The values of potential degradability (a+b) varied from 56.4 up to 57.5, and from 86.59 up to 81.00 % for DM and CP of normal and treated seed, respectively. However, the c fraction, for DM and for CP, had better performance in the normal seed, compared with the treated with heat and humidity. The dynamics of rumen degradation evidenced increasing trend, from the first to the last incubation time, with differences (P < 0.01) in the treated and non-treated seeds. The chemical composition had adequate concentrations in this feed, with values up to 23.12 and 22.94 %, for CP in non-treated and treated seed meal, respectively. It was concluded that by humidifying the seed, there is higher availability of CP and DM for the ruminant animals. Besides, there is an efficient and easy to use alternative in animal feeding, with important contribution of bypassing proteins for the different feeding systems. Further studies on metabolism and productive indicators are recommended to support these results. [ABSTRACT FROM AUTHOR]

Se desarrolló un experimento con diferentes combinaciones de Tithonia diversifolia (control 0, T1, 15 %, T2, 30 % y T3, 100 %) para determinar el efecto del nivel de inclusión en la producción de gas y en la cinética de producción de gas in vitro de Pennisetum purpureum vc. Cuba CT-115. La producción de gas se determinó en cada uno de los tratamientos a las 0, 3, 6, 9, 12, 24, 48 y 72 h de fermentación. Los resultados de la fermentación se ajustaron al modelo exponencial Y= a+b* (1-exp -(c*t) ), con coeficientes de determinación (R²) superiores a 96 y valores potenciales (a+b) de hasta 34.64 mL de gas en el tratamiento T1. La mayor velocidad de producción de gas (c) se obtuvo para 100 % de Tithonia, con 0.06 % h-1 con respecto al CT-115 con 0.035 % h-1. El comportamiento de la producción de gas acumulada se caracterizó por incrementar el tiempo de exposición de las muestras al ataque de microorganismos, con valores de 33.3, 30.1, 28.06 y 30.1 a las 72 h, para 15 y 30 % de inclusión, Tithonia diversifolia y CT-115 solos, respectivamente. El mejor comportamiento se obtuvo para 15 % de inclusión de Tithonia en combinación con el CT-115. Los resultados obtenidos permiten sugerir, por los estudios in vitro, que el nivel de 15 % permite mayor capacidad fermentativa del CT-115 y que la inclusión de esta planta provoca aumento en la eficiencia y velocidad de producción de gas del CT-115. Se necesitan otros estudios para avalar esta hipótesis, donde se consideren pruebas con diferentes niveles de inclusión de este arbusto en dietas para rumiantes y tiempos de incubación superiores a las 72 h. [ABSTRACT FROM AUTHOR]

Two experiments were conducted with Cordia alba to determine the in situ effective ruminal degradability (ERD) of dry matter (DM) and organic matter (OM) and the ruminal fermentative capacity through the technique of in vitro gas production. The constant values of ruminal n turnover (k) of 3, 4, and 5 %/h were assumed in the ERD of DM and OM, with the model: DRE = No + Ε ni=1 [(Nti+1 - Nti )* e-kti + ee-kt ti+1/2], while the results of the fermentation were adjusted to the exponential equation Y = a+b*(1-exp(-c*t). The values of degradability ranged from 31.77 to 43.79, and from 33.71 to 43.37, for DM and OM, respectively, with different constants of ruminal turnover and similar tendencies in respect to the degradation percentage. The OM concentration and its degradation dynamics in the rumen suggested that the inclusion in low-quality diets could improve the utilization efficiency, with a behavior similar to the gas production accumulated (mL) by the in vitro fermentation, which had a stable behavior with adjustments of the data to the exponential model applied of R² = 88.47, related, in part, to the possible influence of anti-nutritional factors. It is suggested to continue assessing this tree species and its combinations with tropical grasses, in ecosystems of high drought, to be used in ruminant supplementation. Thus, through ruminal fermentation, there may be exploitation of its potentialities and the effect of anti-nutritional factors on the degree of nutrients utilization. [ABSTRACT FROM AUTHOR]

Se realizaron dos experimentos con Cordia alba (Uvita) para determinar la degradabilidad ruminal efectiva (DRE) in situ de materia seca (MS) y materia orgánica (MO) y la capacidad fermentativa ruminal, mediante la técnica de producción de gas in vitro. En la degradabilidad ruminal efectiva de MS y MO se asumieron los valores de constante de recambio ruminal (k) de 3, 4 y 5 %/h, con el modelo: DRE = No + Εni=1[(Nti+1 - Nti )* e -kti +e-kti+1 /2], mientras que los resultados de la fermentación se ajustaron a la ecuación exponencial Y= a+b*(1-exp(-c*t). Los valores de degradabilidad oscilaron de 31.77 - 43.79 y de 33.71- 43.37, para MS y MO respectivamente, con diferentes constantes de recambio ruminal y tendencias similares, en cuanto al porcentaje de degradación. La concentración de MO y su dinámica de degradación en el rumen sugieren que la inclusión en dietas de baja calidad podría mejorar la eficiencia de utilización, con comportamientos similares a la producción de gas acumulada (mL) por la fermentación in vitro, la cual tuvo un comportamiento estable con ajuste de los datos al modelo exponencial aplicado de R² = 88.47, relacionado, en parte, con la posible influencia de factores antinutricionales. Se sugiere continuar la evaluación de esta especie de árbol y su combinación con gramíneas tropicales, en ecosistemas de alta sequía, para utilizarse en la suplementación de rumiantes. De este modo, mediante la fermentación ruminal, pueden aprovecharse sus potencialidades y el efecto de factores antinutricionales en el grado de utilización de los nutrientes. [ABSTRACT FROM AUTHOR]

Se desarrolló un experimento con 15 plantas de Pithecellobium dulce (vainas-semillas-arilos y hojas-pecíolos) y Tamarindos indica (hojas- pecíolos), en estado adulto, con más de cuatro años de establecimiento, procedentes de la zona oriental de Cuba, específicamente de ecosistemas salinos con alta sequía. Mediante la técnica de producción de gases, durante 0, 3, 6, 12, 24, 48, 72 y 96 h de fermentación, se determinó la capacidad fermentativa ruminal in vitro. Los resultados de la fermentación se ajustaron al modelo exponencial Y= a+b*(1-exp- c*t)). El comportamiento cinético se caracterizó por una tendencia creciente de la producción de gases con el tiempo de exposición de las muestras al ataque microbiano. Alcanzó valores de hasta 41.37, 23.84 y 30.5 mL de gas a las 96 h, para vainas-semillas-arilos de P. dulce y hojas-pecíolos de P. dulce y T. indica, respectivamente. La producción de gas mostró ajuste de los datos al modelo exponencial aplicado con R2 superior a 85. Los resultados demostraron que las plantas estudiadas pudieran ser una opción para la alimentación animal, en ecosistemas salinos y de alta sequía del oriente de Cuba. Se recomienda evaluar in vivo estas especies de árboles resistentes a la sequía y a la salinidad, para lograr la suplementación proteica-energética de los animales en estos agroecosistemas. [ABSTRACT FROM AUTHOR]

The foliage of six legumes in their vegetative stage: glycine, (Neonotonia wightii), centro (Centrosema pubescens), dolicho (Lablab purpureus), mucuna (Stizolobium aterrium), siratro (Macroptilium atrpurpureum) and arachis (Arachis pintoi) was collected to determine the ruminal degradability of the cell wall (NDF) and the chemical composition of tropical forage species. The plants were established on red ferralitic soil and they were randomly selected, simulating the animal selection. The in situ ruminal degradability was determined through the nylon bag technique in two Holstein bulls, cannulated in the rumen and in stalls. The concentration of CP in DM surpassed 18 % in all foliages, except dolicho and arachis, which had values of 14 %. The total degradability of the NDF (A + B), 72 h after its incubation in rumen, was of 57.8 %. Arachis with 75 % was oustanding. The results showed that the legumes analyzed have levels of protein higher than 14 % and low concentrations of fiber. More than 50 % of the NDF in all the plants was degraded in the rumen. This corroborated its use as diet supplement for ruminant animals fed low-quality forages. [ABSTRACT FROM AUTHOR]

Para determinar la degradabilidad ruminal de la pared celular (FND) y la composición química de especies forrajeras tropicales, se recolectó el follaje de seis leguminosas en su estado vegetativo: glicine, (Neonotonia wightii), centrosema (Centrosema pubescens), dólico (Lablad purpureus), mucuna (Stizolobium aterrimum), siratro (Macroptilium atropurpureum) y arachis (Arachis pintoi). Las plantas estaban establecidas en suelo ferralítico rojo y se escogieron al azar, simulando la selección animal. Se determinó la degradabilidad ruminal in situ, mediante la técnica de la bolsa de nailon en dos toros Holstein, canulados en rumen y estabulados. La concentración de proteína cruda (PB) en la materia seca (MS) superó el 18 % en todos los follajes, excepto dólico y arachis, los que tuvieron valores de 14 %. La degradabilidad total de la fibra neutro detergente (FND) (A+B), 72 h después de su incubación en el rumen fue de 57.8 %. Se destacó el arachis con 75 %. Los resultados indicaron que las leguminosas analizadas contienen niveles de proteína superiores al 14 % y bajas concentraciones de fibra. Más del 50 % de la FND en todas las plantas se degradó en el rumen. Esto corrobora su uso como suplemento dietético para rumiantes alimentados con forrajes de baja calidad. [ABSTRACT FROM AUTHOR]

Samples of mucuna (Stizolobium aterrimum) in vegetative stage were taken to study the chemical composition, protein fractions and the rumen digestion of nutrients (DM, OM and CP) through the method of nylon bags in situ. Different solvents were used for the fractioning of the proteins: albumin (H2O), globulins (NaCl 5%), prolamins (ethanol 80%) and glutelins (NaOH 0.2%). The nutrients degradability values were adjusted to the model: P = a + b [1-e(-c*t)]. The following equation was used for the rumen effective degradability (ED): ED = a + (b*c)/(c + k), with different rates of rumen turnover (0.03, 0.04, 0.05) and different incubation times (6, 8, 12 and 48 h). The protein fractioning of this legume indicated that glutelin was the most represented, with almost the double of albumin and the triple of globulin and prolamin. The effective degradability of DM, OM and CP (N x 6.25) reached values between 37.55-49.9, 41.7-53.41 and 36.74-48.19%, for different rates of rumen turnover (0.03 and 0.05), respectively. The dynamics of the in situ rumen degradation of the indicators increased progressively in time up to the last schedule of incubation established in the experiment and for all the components, in decreasing order (OM, DM and CP). Results showed a correspondence between the protein fractioning and the rumen degradability of the proteins, in regards to the amount of protein of low degradability such as glutelins. [ABSTRACT FROM AUTHOR]

The variability of three indicators of the chemical composition (ash, neutral detergent fiber and total nitrogen) and the effective rumen degradability (ERD) in situ of nutrients (DM, OM and Nt) were studied in six tropical legumes: jackbean (Canavalia ensiformis), dolicho (Lablab purpureus), mucuna (Stizolobium aterrimum), centro (Centrosema pubescens), siratro (Macroptilium atropurpureum) and glycine (Neonotonia wightii). In the chemical composition, the highest variations were found in the contents of Nt. However, in the ERD, the coefficients of variation (CV) were higher than 12% in the indicators studied. Jackbean was the legume with the highest value of rumen degradability for the constituents analyzed, while mucuna had lower performance in DM and OM, and centro, in Nt. The results showed that the legumes under study had, generally, high protein contents. This turns them into a favourable alternative as supplement of the diets based on tropical grasses. The highest variations are related to the nitrogen indicators, both in the chemical composition and in the physiological studies of the animal. It is necessary to further study the factors affecting the variability of these indicators, as well as the role played by some secondary metabolites in the optimum use of the nutrients by the animal. [ABSTRACT FROM AUTHOR]

Samples of siratro (Macroptilium atropurpureum) in vegetative stage were taken to study the protein fractions and the rumen digestion of nutrients (DM, OM and CP) through the method of nylon bags in rumen. Different solvents were used for the fractioning of the proteins: H2O, NaCl 5%, ethanol 80% and NaOH 0.2% for albumin, globulin, prolamin and glutenin. The nutrients degradability values were adjusted to the model: P = a + b [1-e(-c*t)]. The following equation was used for the rumen effective degradability (ED): ED = a + (b*c)/(c + k), with different rates of rumen turnover (0.03, 0.04, 0.05) and different incubation times (6, 8, 12, 24 and 48 h). The protein fractioning of this legume indicated that glutenin was presented followed by albumin, globulin and prolamin. The effective degradability of DM, OM and CP (N x 6.25) reached mean values of different rates of rumen turnover (47.56, 47.69 and 46.99, respectively). The dynamics of in situ rumen degradation of the indicators increased progressively in time up to the last schedule of incubation established in the experiment and for all the components, in decreasing order CP, DM and OM. Results showed a correspondence between the protein fractioning and the rumen degradability of the proteins, with values of nitrogen and degradable organic matter that may be beneficial for the rumen microorganisms. Further studies on the concentration and type of antinutritional factors are suggested in order to know its effect on the nutrients utilization. [ABSTRACT FROM AUTHOR]

Se tomaron muestras de mucuna (Stizolobium aterrimum), en estado vegetativo, para estudiar la composición química, las fracciones proteicas y la digestión ruminal de nutrientes (MS, MO y PB) por el método de las bolsas in situ. Para el fraccionamiento de las proteínas se usaron diferentes solventes: albúminas (H2O), globulinas (NaCl 5 %), Prolaminas (etanol 80 %) y Glutelinas (NaOH 0.2 %)). Los valores para la degradabilidad de los nutrientes se ajustaron al modelo: P = a+b*[1-e(-c*t)] y para la efectiva ruminal (DE) se utilizó la ecuación DE = a + (b*c) / (c+k), con diferentes constantes de recambio ruminal (0.03, 0.04, 0.05) y tiempos de incubación (6, 8, 12 y 48 h) . El fraccionamiento de las proteínas en esta leguminosa indicó que las glutelinas fueron las más representadas, con casi el doble de las albúminas y el triple de las globulinas y prolaminas. Los resultados de la degradabilidad efectiva de MS, MO y PB (N x 6.25) alcanzaron valores entre 37.55 - 49.9, 41.7-53.41 y 36.74-48.19 %, para diferentes tasas de recambio ruminal (0.03 y 0.05), respectivamente. La evolución de la dinámica de degradación ruminal in situ de los indicadores estudiados, mostró un aumento progresivo con el tiempo de incubación hasta el último horario que se estableció en este experimento y para todos los componentes estudiados, en orden descendente (MO, MS y PB). Los resultados indicaron una correspondencia entre el fraccionamiento proteico y la degradabilidad ruminal de proteínas, en cuanto a la cantidad de proteínas de baja degradabilidad, como lo son las glutelinas. [ABSTRACT FROM AUTHOR]

Se estudió la variabilidad en tres indicadores de la composición química (C, FDN y Nt) y la degradabilidad efectiva ruminal (DER) in situ de nutrientes (MS, MO y Nt) de seis leguminosas tropicales: canavalia (Canavalia ensiformis), dólico (Labblab purpureus), mucuna (Stizolobium aterrimum), centrosema (Centrosema pubescen), siratro (Macroptilium atropurpureum) y glicine (Neonotonia wightii)). Para la composición química, las mayores variaciones se encontraron en los contenidos de Nt. Sin embargo, en la DER, los coeficientes de variación (CV) fueron superiores al 12 % en los indicadores estudiados. Canavalia resultó ser la leguminosa con mayor valor de degradabilidad ruminal en los constituyentes analizados, mientras mucuna tuvo un comportamiento más bajo para MS y MO y centrosema, para Nt. Los resultados mostraron que las leguminosas estudiadas presentan, por lo general, altos contenidos en proteína. Esto las convierte en una opción favorable como complemento de las dietas que se basan en gramíneas tropicales. Las mayores variaciones están relacionadas con los indicadores nitrogenados, tanto en la composición química como en los estudios fisiológicos del animal. Es necesario profundizar en el estudio de los factores que influyen en la variabilidad de estos indicadores, así como en el papel que desempeñan algunos metabolitos secundarios en el aprovechamiento óptimo de los nutrientes por el animal. [ABSTRACT FROM AUTHOR]

Se tomaron muestras de siratro (Macroptilium atropurpureum) en estado vegetativo para estudiar las fracciones proteicas y la digestión ruminal de nutrientes (MS, MO y PB) por el método de las bolsas en rumen. Para el fraccionamiento de las proteínas, se usaron diferentes solventes: H2O, NaCl 5 %, etanol 80 % y NaOH 0.2 %, para albúminas, globulinas, prolaminas y glutelinas. Los valores de degradabilidad de nutrientes se ajustaron al modelo: P = a + b*[1-e(-c*t)]. Para la degradabilidad efectiva ruminal (DE) se utilizó la ecuación DE = a + (b*c) / (c+k), con diferentes constantes de velocidad de recambio ruminal (0.03, 0.04, 0.05) y tiempos de incubación (6, 8, 12, 24 y 48 h). El fraccionamiento de las proteínas en esta leguminosa indicó que las glutelinas se presentaron seguidas de las albúminas, globulinas y prolaminas. Los resultados de la degradabilidad efectiva de MS, MO y PB (N x 6.25) alcanzaron valores promedio de diferentes constantes de velocidad de recambio ruminal (47.56, 47.69 y 46.99), respectivamente. La evolución de la dinámica de degradación ruminal in situ de los indicadores estudiados mostró aumento progresivo con el tiempo, hasta el último horario de incubación establecido en el experimento y para todos los componentes estudiados, en orden descendente PB, MS y MO. Los resultados indicaron una correspondencia entre el fraccionamiento proteico y la degradabilidad ruminal de proteínas, con valores de nitrógeno y materia orgánica degradable, que pueden ser beneficiosos para los microorganismos del rumen. Se sugiere realizar estudios acerca de la concentración y tipo de factores antinutricionales, en función de ver su efecto en el grado de utilización de los nutrientes. [ABSTRACT FROM AUTHOR]

The in situ effective rumen degradability of dry matter (DM) and total nitrogen (Nt) of leucaena (Leucaena leucocephala), Nicaraguan cocoashade (Gliricidia sepium) and star grass (Cynodon nlemfuensis) was determined in three cows fitted with cannula in rumen. They were subject to a grazing system of grasses (Cynodon nlemfuensis) and legumes in the form of protein banks (Leucaena leucocephala and Gliricidia sepium), in a ratio 50:50. The values of effective rumen degradability varied between 41.53-51.70%, 37.92-47.66% and 36.97-47.41%, in each of the feeds, respectively, using different constants of rumen turnover. However, values of effective rumen degradability of Nt up to 60.56% were found in Nicaraguan cocoashade, followed by leucaena (49.60) and star grass (46.91), with levels of degradable nitrogen that decreased with the constant increase of rumen turnover. It was found that the legumes studied had higher DM and Nt degradability than star grass and a high nutritional potential. The high protein concentration and its dynamics of degradation in rumen suggest that the inclusion in low-quality diets may improve the efficiency of utilization and keep adequate production levels. The evaluation of the use of these legume species should be continued for ruminant supplementation, combined with tropical grasses. Thus, the potential of the legumes may be used to provide peptides and amino acids to the rumen microorganisms and bypassing nutrients. Besides, an optimum use of the lignocellulosic compound may be made as energy source for the animal through rumen fermentation. [ABSTRACT FROM AUTHOR]

A random block design with three replicates and two treatments (clone with 60 and 95 d of resting) was used in order to study the effect of the resting time on the in situ rumen degradability of the lignocellulosic compound and on the fermentative potential of the clone Pennisetum Cuba CT-115. The experiment was developed at the Institute of Animal Science using a cultivar of the clone fertilized with 100 kg of N/ha and without irrigation. After a cut for having the plants at the same height, samplings were conducted at 60 and 95 d, respectively, and 100 plants were collected at random per treatment and replicate. They were dried in an oven of air circulation at 60 °C for 48 h and ground at a particle size of 1 mm to determine the chemical composition and the in vitro gas production and at 1.5 mm for determining the in situ rumen degradability of dry matter and the lignocellulosic compound. The performance of the kinetics of degradation of dry matter and the lignocellulosic compound was quite similar for both resting times. There was a rapid increase in time for the degradation up to 24 h, for later manifest a slower increase, almost constant up to 72 h. The rumen effective degradability of DM and NDF did not differ for both ages, whereas that of ADF was lower for Cuba CT-115, with 95 d of resting (23.3% vs 38.6%), with a lag phase or latency period higher than that of the clone with 60 d (10.7 h vs 6.3 h). The soluble fraction (46% vs 19%), the potential degradability (84.22% vs 68.62%) and the effective degradability in rumen (62.2% vs 44.7%) of the hemicellulose were higher in Cuba CT-115 with 60 d. The production of gas accumulated (mL) by the fermentation of the clone during the in vitro incubation had a quite similar performance for both ages, with good fitness (R² = 0.99) to the exponential model applied. The results prove that for both resting times, both the rumen degradation of the lignocellulosic compound and the fermentative potential of the Pennisetum Cuba CT-115, had a very similar performance. There was only influence of the resting time on the rumen degradability of the ADF and the hemicellulose. [ABSTRACT FROM AUTHOR]

Se determinó la degradabilidad ruminal efectiva in situ de materia seca (MS) y nitrógeno total (Nt) de leucaena (Leucaena leucocephala), gliricidia (Gliricidia sepium) y pasto estrella (Cynodon nlenfuensis), en tres vacas canuladas en rumen. Estas se sometieron a un sistema de pastoreo de gramíneas (Cynodon nlenfuensis) y leguminosas, en forma de bancos de proteína (Leucaena leucocephala y Gliricidia sepium), en una relación 50:50. Los valores de la degradabilidad ruminal efectiva de MS en gliricidia, leucaena y pasto estrella, oscilaron entre 41.53-51.70 %, 37.92-47.66 % y 36.97-47.41 %, en cada uno de los alimentos, respectivamente, al utilizar diferentes constantes de recambio ruminal. Sin embargo, se encontraron valores de degradabilidad ruminal efectiva de Nt de hasta 60.56 % de degradabilidad en gliricidia, a los que siguieron leucaena (49.60) y pasto estrella (46.91), con niveles de nitrógeno degradable que disminuyeron con el aumento de la constante de recambio ruminal. Se encontró que las leguminosas estudiadas presentaron mayor degradabilidad de MS y Nt que el pasto estrella y un alto potencial nutricional. La alta concentración de proteína y su dinámica de degradación en el rumen sugieren que su inclusión en dietas de baja calidad podría mejorar la eficiencia de utilización y mantener niveles adecuados de producción. Debe continuarse la evaluación del uso de estas especies de leguminosas en la suplementación de rumiantes, combinadas con gramíneas tropicales. De esta manera, puede aprovecharse el potencial de las leguminosas para proveer de péptidos y aminoácidos a los microorganismos ruminales y nutrientes sobrepasantes. Además, puede hacerse un uso óptimo del complejo lignocelulósico como fuente energética para el animal, mediante su fermentación ruminal. [ABSTRACT FROM AUTHOR]

Para estudiar el efecto del tiempo de reposo en la degradabilidad ruminal in situ del complejo lignocelulósico y en el potencial fermentativo del clon Pennisetum Cuba CT-115, se utilizó un diseño de bloques al azar con tres réplicas y dos tratamientos (clon con 60 y 95 d de reposo), en el Instituto de Ciencia Animal, en un cultivar del clon fertilizado con 100 kg de N/ha y sin riego. Después de un corte de emparejamiento, se realizaron muestreos a los 60 y 95 d, respectivamente, y se tomaron 100 plantas al azar por tratamiento y réplica. Se secaron en estufa de circulación de aire a 60 °C durante 48 h y se molieron a un tamaño de partícula de 1 mm para determinar la composición química y la producción de gas in vitro y a 1.5 mm para determinar la degradabilidad ruminal in situ de la materia seca y del complejo lignocelulósico. El comportamiento de la cinética de degradación de la materia seca y el complejo lignocelulósico fue muy similar para los dos tiempos de reposo. Con el tiempo, hubo un rápido incremento de la degradación hasta las 24 h, para luego manifestarse un incremento más lento, casi constante hasta las 72 h. La degradabilidad efectiva ruminal de la MS y la FDN no difirió para ambas edades, mientras que de la FDA fue menor para el Cuba CT-115, con 95 d de reposo (23.3 % vs. 38.6 %), con una fase lag o período de latencia superior al clon con 60 d (10.7 h vs. 6.3 h).Tanto la fracción soluble (46 % vs. 19 %) como la degradabilidad potencial (84.22 % vs. 68.62 %) y la degradabilidad efectiva ruminal (62.2 % vs. 44.7 %) de la hemicelulosa, fue mayor en el Cuba CT-115 con 60 d. La producción de gas acumulada (ml) por la fermentación del clon durante el período de incubación in vitro tuvo un comportamiento muy similar para ambas edades, con un buen ajuste (R² = 0.99) al modelo exponencial aplicado. Los resultados demuestran que para ambos tiempos de reposo, tanto la degradación ruminal del complejo lignocelulósico como el potencial fermentativo del Pennisetum Cuba CT-115, tuvieron un comportamiento muy similar. Solo se observó la influencia del tiempo de reposo en la degradabilidad ruminal de la FDA y la hemicelulosa. [ABSTRACT FROM AUTHOR]

The article presents a study which determined the in situ ruminal degradability of nutrients in the rumen in the ecotype, as well as the in vitro intestinal digestibility of the non-degraded nitrogen. The materials and methods used are described. Results showed that there is a high nitrogen contribution from leucaena in the rumen.

The article provides information on a study which determined the possible influence of condensed tannins on the in situ ruminal degradability of leucaena nutrients using polyethylene glycol (PEG). The study also determined the in vitro ruminal digestibility of nitrogen in leucaena by the in situ and in vitro three-step method using pepsin-pancreatin. Used in the study was a random block design with three replications per treatment. The effect of the PEG level on the in vitro digestibility of nitrogen was identified, as well.

The article presents research on the possible differences in the chemical indicators of different Leucaena leucocephala ecotypes in both seasons in Cuba. The chemical indicators were dry matter (DM), crude protein (CP), ash, organic matter (OM), organic matter digestibility (OMD), acid detergent fiber (ADF), lignin, cellulose and hemicellulose and secondary metabolites. The findings demonstrated that the ecotypes have high quality in the seasons observed.

The article highlights the results of a study which assessed the chemical composition of six ecotypes of Leucaena leucocephala. Dry matter, crude protein, true protein, ash and neutral detergent fiber and the anti-nutritional factors mimosine and DHP were analyzed during the dry and rainy seasons. In the dry season, the chemical indicators averaged 24, 29.4, 22.59, 7.92 and 46.50 percent, respectively. In the rainy season, they averaged 25.74, 25.39, 22.74, 8.53 and 43.42 percent, respectively.

The article discusses research which sought to determine the nutritive value of the foliage from tropical forage trees Brosimum alicastrum and Bauhinia galpii. Degradability studies were performed through the in situ bag technique to evaluate the chemical composition of both plants and their degradative characteristics in the rumen for their rational and economic incorporation into cattle production systems. It was found that both plants have nutritive potential for their incorporation into silvopastoral systems.

In order to evaluate the in situ degradability of PREDICAL (bagasse pith of sugar cane treated with calcium hydroxide and steam) as feed for ruminants, and compare it with the degradability of untreated bagasse pith of sugar cane, star grass (43 d of regrowth), sugar cane and Pennisetum purpureum cv. Cuba CT-115, two experiments of in situ digestibility were performed using a completely randomized design. The time of incubation of the first experiment was 48 h. In the second experiment, treatments were similar and time of incubation was extended up to 72 h. The ruminal degradability of PREDICAL in the second experiment was 58.51 % of the dry matter, and it did not differ from the degradability of a variety of forage sugar cane or the one of Pennisetum purpureum cv. CT-115. The estimation of the metabolizable energy contribution of PREDICAL was 8.58 MJ/kg of dry matter. In situ degradability and ME contribution of PREDICAL were approximately similar regarding those of the sugar cane (Saccharum officinarum L, variety Cuba -1616-75), recommended for forage use. After 72 h of incubation, degradability was similar to that of CT-115 and, in all cases, superior to the one of star grass (Cynodon nlemfuensis) under the typical conditions of dry season. [ABSTRACT FROM AUTHOR]

An experiment was undertaken with 15 plants of Pithecellobium dulce (pods-seeds-arils and leaves-petioles) and Tamarindos indica (leaves-petioles) in the adult state and with more than 4 years of establishment. They came from the eastern part of Cuba, specifically from saline ecosystems with high drought. Through the gas production technique, the in vitro ruminal fermentative capacity was determined at 0, 3, 6, 12, 24, 48, 72, and 96 h of fermentation. The results of the fermentation were adjusted to the exponential model Y=a+b*(1-exp(-c*t)). The kinetic performance was characterized by a growing trend in gas production with the time of exposure of the samples to the microbial attack. Values of 41.37, 23.84, and 30.5 mL were reached for the pods-seeds-arils of P. dulce, and leaves-petioles of P. dulce and T. indica, respectively. The gas production showed fit of the data to the exponential model with R higher than 85. The results proved that the plants under study could be an alternative to animal feeding in saline ecosystems or of high drought in the eastern part of Cuba. The in vivo evaluation of these tree species resistant to drought and salinity is recommended to have protein-energy supplementation for the animals in these agroecosystems. [ABSTRACT FROM AUTHOR]

In order to characterize the bromatological composition of three agricultural wastes: maize (Zea mays), sorghum (Sorghum sp.) and chickpea (Cicer arietinum) in Sinaloa state, Mexico, selected for their possibilities of use in ruminants feeding, was determined to the samples (n = 21) of these by-products the percentage of crude protein, neutral detergent fiber, acid detergent fiber, hemicellulose and cellular content. The crude protein, neutral detergent fiber, acid detergent fiber and cellular content showed differences (P ˂ 0.0001) between treatments, while hemicellulose was similar in the three agricultural wastes. The obtained results show that the chickpea waste has a better chemical composition than the rest. They also suggest performing physiological tests on ruminants to determine the inclusion levels and potential use of wastes, in order to determine their nutritional value. [ABSTRACT FROM AUTHOR]

Two hundred samples of Pennisetum purpureum, dried and ground at 1 mm particle size, from a wide range of varieties, physico-chemical characteristics and origin, were used to obtain the equations of calibration and determine the chemical composition of this species through the technique of NIRS. The algorithm to obtain the equations of calibration of each of the indicators used the data bank from the laboratory analyses and the values of wave length from the readings of the samples in the near red reflectance spectrophotometer through crossed validation. The equations of calibration for the DM, CP, NDF, ADF, cellulose, hemicelluloses, lignin, ashes, and in vitro digestibility of DM of the P. purpureum were appropriate, not only for having a low standard error of calibration, but also for the high coefficient of determination. It is recommended to use the NIRS to determine the chemical composition of any variety of this species, having the necessary equations of calibration. [ABSTRACT FROM AUTHOR]

The article discusses a study to determine the nutritive quality and the phytochemical screening of Albizia lebbeck. The study was carried out in a typical dairy unit at the Institute of Animal Science in Cuba. The results suggest that it is possible to know the potential nutritive quality of the Albizia lebbeck foliage to be used in the feeding of ruminants.

The article focuses on a study which examined the phytochemical screening of Erythrina mysorensis and its nutritive potential was determined by in vitro gas production. It has been found that gas production increased with the time of exposition of the samples to the attack of ruminal microbes. Forage fermentation was adjusted based on the Logistic and Monomolecular models which established non-linear relationship between the gas production and the time of exposition of the samples to the fermentative activity.