An exogenous protease increases enzymic activities, microbial numbers and fiber degraation by mixed ruminal microorganisms in continuous culture

Contributed to: Conference on Gastrointestinal Function (Chicago, Illinois, Mar 10-12, 2003).The effects of pH and addition of a protease mixture on the fermentation characteristics of a total mixed ration (TMR) were investigated in a dual-flow continuous culture apparatus, using a 4 x 4 Latin Square design with a 2 x 2 factorial arrangement of treatments. The diet (DM basis) consisted of 30% alfalfa hay, 30% corn silage and 40% rolled corn. The silage and the grain were milled fresh, mixed with the alfalfa and treated with the enzyme (1.5 μL/g feed) daily. Ruminal fluid was collected 2 h post-feeding from 3 lactating dairy cows fed a TMR. Fermenters were fed 80 g DM/d in equal portions every 12 h. Treatments were control (C) and enzymetreated (T) TMR at either high pH (HC and HT) or low pH (LC and LT). The pH was altered by diluting the artificial saliva to 60% of its original composition. Enzymic activities and total and cellulolytic bacterial numbers were determined on the liquid phase of the fermenter contents, 6 h post-feeding. Fiber degradation was determined from the outflow residues. Enzyme addition increased (P < 0.05) xylanase, xylosidase, endoglucanase, and protease activities (608 vs. 750; 0.48 vs. 0.80; 82 vs. 112; and 1.2 vs. 7.5 units for C and T, respectively), whereas it tended (P < 0.12) to increase exoglucanase and glucosidase activities (0.8 vs. 1.4; and 4.7 vs. 5.9 units). However, enzyme did not affect (P = 0.18) arabinofuranosidase activity (5.2 vs. 6.8). Total microbial numbers (expressed as Log10) were increased (P < 0.05) at low pH (9.13 vs. 9.36) but enzyme had no effect (P = 0.13). Cellulolytic bacteria were reduced (P < 0.02) at low pH (3.91 vs. 2.79), with no effect (P = 0.88) of enzyme. Low pH reduced (P < 0.001) NDF, ADF, and cellulose degradation. NDF degradation was increased (P < 0.01) by enzyme addition (20% vs. 27%) but ADF was unaffected (P < 0.20), resulting in an increase (P < 0.001) in hemicellulose degradation. It is speculated that the enzyme removed structural barriers present in the feed, allowing a more rapid colonization of the fiber by ruminal microorganisms.Peer reviewe

Evaluación de un modelo de producción de pasturas mediante pruebas empíricas

En el presente trabajo se utilizó un modelo de crecimiento de pasturas desarrollado por McCall y BishopHurley. El objetivo fue evaluar si el modelo es capaz de simular las variaciones en producción primaria neta aérea en la estación húmeda utilizando pruebas empíricas. Se trabajó con una gramínea megatérmica, Chloris gayana. La evaluación empírica se realizó con datos de experimentos realizados en el Instituto de Investigación Animal del Chaco Semiárido (INTA), que incluyeron biomasa seca aérea acumulada durante la estación de crecimiento, y biomasa seca aérea producida entre dos pastoreos. Los estadísticos utilizados fueron raíz cuadrada del cuadrado medio del error, relación RMSE/Media observada, error medio y los coeficientes de la desigualdad de Theil. Los coeficientes de desigualdad de Theil para la producción primaria neta aérea acumulada (Um=0,35, Us=0,1, Uc=0,64) y por cortes (Um=0,08, Us=0,08, Uc=0,84) mostraron que el modelo no presentó errores sistemáticos. El patrón de crecimiento de la producción primaria neta aérea simulado fue 7% oct-nov, 64% dic-ene-feb, 29% mar-abr-may. El trabajo muestra el potencial del modelo de pasturas para simular la dinámica de la producción de Chloris gayana en ambientes del subtrópico argentino, siendo capaz de captar variaciones en el ambiente. En este sentido puede ser útil para estudiar interacciones entre el manejo y la dinámica de las pasturas en climas de alta variabilidad temporal.For this work, a pasture growth model developed by McCall and Bishop-Hurley, was used. The objective was to evaluate the model, using empirical tests. A tropical pasture named Chloris gayana, was used. For the empirical evaluation a database from the Animal Research Institute of Semiarid Chaco (INTA), was used, including information of herbage accumulated during the growing season, and cutting trials based on the difference between pre- and post-grazing herbage. The statistics calculated were root mean square error, relative root mean square error, mean error and Theil coefficients. The Theil coefficients for accumulated herbage (Um = 0.35, Us = 0.1, Uc = 0.64) and cutting trials (Um = 0.08, Us = 0.08, Uc = 0, 84), showed that the model did not present systematic errors. The growth pattern of simulated herbage was 7% Oct-Nov, 64% Dec-Jan-Feb, 29% Mar-Apr-May. The work shows the potential of the pasture model to simulate the forage production of Chloris gayana in subtropical environments, capturing variations in the environment. In this sense, it can be useful for studying interactions between management strategies and dynamics responses of pastures in highly variable climates.Instituto de Investigación Animal del Chaco SemiáridoFil: Nasca, Jose Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido; ArgentinaFil: Berone, German Dario. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Arroquy, Jose Ignacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cesáreo Naredo ArgentinaFil: Feldkamp, C.R. Asociación Argentina de Consorcios Regionales de Experimentación Agrícola; Argentina.Fil: Colombatto, Dario. Universidad de Buenos Aires. Facultad de Agronomia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Essential oils from Argentinean native species reduce in vitro methane production

The aim of this study was to evaluate the effect of Argentinean essential oils (EO) on methane production during in vitro fermentation compared to EO with proven effects as rumen fermentation modifiers. A complete randomized block design was used and the treatments included EO from Aloysia gratissima (50, 100, 150 and 300 mg/L), Eucalyptus globulus (5, 50, 150 and 300 mg/L), Lippia turbinata (30, 60, 120 and 240 mg/L), Mentha x piperita var. vulgaris (50, 100, 200 and 400 mg/L), Origanum vulgare ssp. hirtum cv. Compacto (0.5, 5, 50 and 250 mg/L) and cv. Mendocino (50, 150, 250 and 350 mg/L), Rosmarinus officinalis (100, 300, 500 and 700 mg/L), Schinus molle (75, 150, 300 and 600 mg/L), Tagetes minuta (5, 50, 125 and 250 mg/L), and Thymus vulgaris (5, 50, 150 and 300 mg/L). Two controls were included: control (not containing EO) and monensin (1.87 mg/L). Variables measured were: digestibility of neutral detergent fiber, gas and methane production. Compared to the control, monensin reduced methane production by 44%, but with a 15% reduction in fiber digestibility. Except for E. globulus and L. turbinata, each variable measured was significantly reduced with the higher level of inclusion compared to the control, representing that overall microbial activity was affected. L. turbinata (60.8% limonene) reduced methane by half compared to control, and by 35 to 85% when compared to monensin, without affecting digestibility of the fiber. Some essential oils from native Argentinean plants exhibited great potential to reduce enteric methane production without affecting digestibility, of which L. turbinata was the most promising alternative.El objetivo de este estudio fue evaluar el efecto de aceites esenciales (AE) de plantas nativas de Argentina en la producción de metano durante la fermentación in vitro, en comparación con AE con efectos comprobados como modificadores de la fermentación ruminal. Se realizó un diseño en bloque completos al azar y los AE y dosis evaluados fueron: Aloysia gratissima (0,5, 5, 50 y 250 mg/L) , Eucalyptus globulus (5, 50, 150 y 300 mg/L), Lippia turbinata (30, 60, 120 y 240 mg/L), Mentha x piperita var. vulgaris (50, 100, 200 y 400 mg/L), Origanum vulgare ssp. hirtum cv. Compacto (0,5, 5, 50 y 250 mg/L) y cv. Mendocino (50, 150, 250 y 350 mg/L), Rosmarinus officinalis (100, 300, 500 y 700 mg/L), Schinus molle (75, 150, 300 y 600 mg/L), Tagetes minuta (5, 50, 125 y 250 mg/L), y Thymus vulgaris (5, 50, 150 y 300 mg/L). Se incluyeron dos controles: control (sin AE) y monensina (1,87 mg/L). Las variables evaluadas fueron: digestibilidad in vitro de la fibra en detergente neutro, producción de gas y metano. En comparación al control, la monensina redujo la producción de metano en un 44%, pero con una reducción de un 15% en la digestibilidad de la fibra. Con excepción a E. globulus y L. turbinata, todas las variables fueron reducidas significativamente con el mayor nivel de inclusión comparado con el control, lo cual representa que la actividad microbiana se vio afectada. L. turbinata (60,8% limoneno) redujo la producción de metano a la mitad comparado al control, y entre un 35 y 85% en comparación a la monensina, sin que la digestibilidad de la fibra se vea afectada. Algunos aceites esenciales de plantas nativas de Argentina demostraron gran potencial para reducir la producción de metano entérico sin afectar la digestibilidad, de los cuales L. turbinata fue la alternativa más promisoria.EEA ManfrediFil: García, F. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Brunetti, Maria Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Lucini, Enrique I. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias,; ArgentinaFil: Scorcione Turcato, M.C. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Moreno, Maria Valeria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Frossasco, Georgina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Colombatto, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia; Argentina.Fil: Martinez, Maria Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; ArgentinaFil: Martinez Ferrer, Jorge. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Manfredi; Argentin

Non-additivity of feedstuffs examined in vitro and the influence of incubation medium pH.

Contributed to: Proceedings of the British Society of Animal Science 2001, p.133. (York, Reino Unido, April 9-11, 2001)Non-additivity occurs when the nutritive value of a mixture of feedstuffs differs from that of the sum of its components. It is most commonly observed when one dietary constituent influences, either positively or negatively, the apparent digestibility of another under conditions where components such as nitrogen and sulphur are non-limiting. In general negative effects occur due to the depression of rumen pH or substrate competition, while positive effects have been identified when readily fermentable fibre sources such as sugar beet pulp have been included in rations containing poorly fermented forages such as cereal straw. With the increasing use of in vitro systems, not just to examine feed degradation characteristics but to derive parameters such as microbial protein yield, the following study was conducted to determine whether such interactions could be identified in vitro.Peer reviewe

Efecto de la adición de enzimas exógenas y del pH sobre la fermentación ruminal de dietas mixtas en un sistema de cultivos continuos

Ponencia presentada a las X Jornadas sobre Producción Animal AIDA (Zaragoza, 14 a 16 de mayo del 2003). Publicada en un volumen extra de la revista ITEAPosteriormente, ha sido publicado como artículo en: Journal of Animal Science 81(10): 2617-2627 (2003). https://digital.csic.es/handle/10261/5385Para la realización de este trabajo, Gonzalo Hervás disfrutó de una ayuda para estancias breves en el extranjero del Plan Nacional de Formación de Personal Investigador del Ministerio de Ciencia y Tecnología (MCyT).Peer reviewe

Efficiency and stability in subtropical beef cattle grazing systems in the northwest of Argentina

The objective of this work was to evaluate the efficiency and stability of cow–calf, fattening and whole cycle beef cattle agro-ecosystems from the subtropical region of Argentina. For this purpose, an agro-ecosystem model consisting of a production and a management system was developed. Flexible management rules were incorporated. This simulation-based study compared potential trends of different agro-ecosystems under different animal body sizes and several management options traditionally applied in the region. The experiment aimed at estimating productive, energetic and economic efficiency and stability. The results showed that whole cycle and cow–calf systems were more stable but less productive than fattening systems. Within each agro-ecosystem, as body size increased, energetic and economic efficiency and stability decreased. Systems dynamics and multi-criteria approaches allowed recognizing tradeoffs among indicators, and main differences between agro-ecosystems. Further investigation is required to generalize these findings to other system structures, particularly when economic aspects are taken into account in decision making processes.Instituto de Investigación Animal del Chaco SemiáridoFil: Nasca, Jose Andres. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Animal del Chaco Semiárido; ArgentinaFil: Feldkamp, C.R. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Asociación Argentina de Consorcios Regionales de Experimentación Agrícola; Argentina. Universidad de Concepción del Uruguay. Facultad de Ciencias Agrarias; ArgentinaFil: Arroquy, Jose Ignacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Santiago del Estero.Facultad de Agronomía y Agroindustrias; ArgentinaFil: Colombatto, Dario. Universidad de Buenos Aires. Facultad de Agronomia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effects of enzyme supplementation of a total mixed ration on microbial fermentation in continuous culture, maintained at high and low pH

The definitive version is available at: http://jas.fass.org/cgi/content/full/81/10/2617Previously published as proceeding at the XXXV Jornadas de Estudio (X Jornadas sobre Producción Animal AIDA (Zaragoza, Spain, May 14-16, 2003). https://digital.csic.es/handle/10261/5103A dual-flow continuous culture system was used to investigate the effects of pH and addition of an enzyme mixture to a total mixed ration (TMR) on fermentation, nutrient digestion, and microbial protein synthesis. A 4 × 4 Latin square design with a factorial arrangement of treatments was used, with four 9-d periods consisting of 6 d for adaptation and 3 d for measurements. Treatments were as follows: 1) high pH with control TMR, 2) high pH with TMR treated with enzyme, 3) low pH with control TMR, and 4) low pH with TMR treated with enzyme. Ranges of pH were 6.0 to 6.6 and 5.4 to 6.0 for high and low, respectively. Fermenters were fed twice daily a TMR consisting of 30% alfalfa hay, 30% corn silage, and 40% rolled corn (DM basis). The silage was milled fresh and the TMR was fed to the fermenters in fresh form (64% DM). The enzyme mixture was a commercial product of almost exclusive protease activity; it was applied daily to the fresh TMR and stored at 4°C for at least 12 h before feeding. Degradability of OM, NDF, ADF, and cellulose was decreased (P < 0.05) by low pH. Hemicellulose and protein degradation were not affected by pH. Enzyme addition increased (P < 0.01) NDF degradability (by 43% and 25% at high and low pH, respectively), largely as a result of an increase in hemicellulose degradation (by 79% and 51% at high and low pH, respectively). This improvement was supported by an increase (P < 0.05) in the xylanase and cellulase activities in the liquid phase of the fermenter contents. Total VFA were decreased (P < 0.05) by low pH, but were not affected by enzyme addition. Total bacterial numbers were increased (P < 0.03) at low pH and tended (P < 0.13) to increase with enzyme addition. Cellulolytic bacteria in effluent fluid were decreased (P < 0.02) at low pH but were unaffected by enzyme addition. Despite a large increase (P < 0.001) in protease activity, protein degradation was only numerically increased by enzyme addition. Microbial protein synthesis was higher (P < 0.10) at high pH but was not affected by enzyme addition. Methane production, expressed as a proportion of total gases, was decreased (P < 0.001) at low pH but was not affected by enzyme addition. It is concluded that it is possible to adapt the continuous culture system to use fresh feeds instead of dried feeds. Overall, the results indicate that the enzyme product used in this study has a potential to increase fiber degradability without increasing methane production.Lethbridge Research Centre contribution No. 387 03003. We thank A. F. Furtado, D. D. Vedres, and G. R. Bowman for skilled technical assistance; K. Koenig for helpful suggestions; and T. Entz for help with statistical analysis. Herva´s acknowledges receipt of a fellowship from the Spanish Ministry of Science and Technology (MCyT).Peer reviewe

Effects of pH manipulation and enzyme addition to a total mixed ration on microbial fermentation in continuous culture

Journal of Dairy Science 86, Suppl. 1, p. 151. In: A Joint Meeting of the American Dairy Science Association (ADSA), the American Society of Animal Science (ASAS) & the Mexican Association of Animal Production (MAAP) (Abstract No. 595), p. 151. 22-26 de Junio de 2003. Phoenix, Arizona (Estados Unidos).The effects of pH and enzyme addition were examined in continuous culture using a 4 x 4 Latin square design, with four 9-d periods consisting of 6 d for adaptation and 3 d for measurements. The buffer pH was adjusted to 100% (high) or 60% (low) of the normal concentration of artificial saliva. Fermenters were fed twice daily a diet consisting of 30% alfalfa hay, 30% corn silage, and 40% rolled corn (DM basis). The silage was milled fresh and the TMR was fed fresh to the fermenters (64% DM). The EM was a protease containing no other major activities, and was applied daily to the TMR, at least 12 h before feeding. Treated feed was stored at 4◦C until fed. Ranges of pH were 6.0-6.6, and 5.4-6.0 for high and low, respectively. Degradability of OM, NDF, ADF, and cellulose were reduced (P < 0.05) by low pH, but hemicellulose and protein degradation were not affected. EM addition increased (P < 0.01) NDF degradability (by 43% and 25% at high and low pH, respectively), largely due to an increase in hemicellulose degradation (by 79% and 51%, respectively). Total volatile fatty acids (VFA) and its molar proportions were decreased (P < 0.05) by low pH, but were not affected by EM. Protein degradation was only numerically (P = 0.17) increased by EM. Total N flow tended (P = 0.07) to be reduced with EM, but neither bacterial nor dietary N flow was affected by the treatments. Microbial protein synthesis was not affected by either pH (P = 0.29) or EM (P = 0.86). Methane production, expressed as a proportion of total gases, was decreased (P < 0.001) at low pH, but was not affected by EM. It is concluded that it is possible to adapt the CC system to use fresh feeds instead of dried feeds. Overall, the results indicate that the EM used in this study has significant potential to increase fiber degradability without increasing methane production.Peer reviewe

Prediction of the Ym factor for livestock from on-farm accessible data

Methane emission factor (Ym) is directly involved to calculate the worldwide livestock methane inventories, hence it is important to refine the estimation of this parameter for different livestock production systems. The purpose of this work was to generate refined mathematical models to predict CH4 emissions from an extensive compilated database at on-farm level and to compare them with different models already available in the literature. Methane emission predictive models (expressed as Ym, % gross energy intake; and methane production, CH4p, g an−1 d−1) where fitted taken into account the production system, the livestock type and the feed characteristics available at on-farm level within a reasonable uncertainty range. In order to develop the models, only easy available parameters were selected to fit new mathematical models. Hence, the full model included: ruminant types (beef cattle, dairy cattle, and sheep), fibre sources (fresh forage, conserved forage, and straw) and concentrate levels (DM basis) in the diet (Low, 65%). Full models were assessed by the Bayesian Information Criterion (BIC) and terms that did not reach significance level (P≤0.05) were dropped from the model. Furthermore, predicted results were assessed through correlation and regression analyses considering the model significance. Models developed in this study were compared by the degree of adjustment of a simple regression. Additive and technique terms were initially dropped from the full model used to predict Ym because they did not have effect in the prediction (P>0.10). Therefore, the final equation for Model 1 was: Ym(a)=Intercept−0.243(±0.051)×DMI (kg d−1)+5.9×10−3(±1.17×10−3)×NDF (g kg−1 DM−1)+5.7×10−3(±1.63×10−3)×DMD (g kg−1 MS−1) (BIC=559). All terms of this model, intercept factor (type of cattle×source of fibre×level of concentrate), DMI, NDF, and DMD were significant (P<0.0001). DMI was the term with the greatest weight in the model. The predicted Ym value decreased about 0.243 percentage units (P<0.0001) per each additional kg in DMI. When the equation was compared with previous publicated models, our model showed a satisfactory degree of fitting. In conclusion, this new model improved the estimation of the Ym factor from beef and dairy production systems, using different forage quality characteristics from on-farm level to increase precision.EEA Santiago del EsteroFil: Jaurena, Gustavo. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Cantet, Juan Manuel. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Arroquy, Jose Ignacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santiago del Estero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Santiago del Estero.Facultad de Agronomía y Agroindustrias; ArgentinaFil: Palladino, Rafael Alejandro. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wawrzkiewicz, Marisa. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Colombatto, Dario. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Impact of Chestnut and Quebracho Tannins on Rumen Microbiota of Bovines

The use of phytogenic dietary additives is being evaluated as a means to improve animal productivity. The effect of tannins seems to be the influence not only directly on the digestive process through binding of dietary proteins but also indirectly over their effects on gastrointestinal microbiota. High-throughput sequencing of 16S rRNA gene was used to analyze the impact of dietary supplementation with a blend of chestnut and quebracho tannins on the rumen microbiota of Holstein steers. Bacterial richness was lower in tannins treated animals, while the overall population structure of rumen microbiota was not significantly disturbed by tannins. The ratio of the phyla Firmicutes and Bacteroidetes, a parameter associated with energy harvesting function, was increased in tannins supplemented animals, essentially due to the selective growth of Ruminococcaceae over members of genus Prevotella. Fibrolytic, amylolytic, and ureolytic bacterial communities in the rumen were altered by tannins, while methanogenic archaea were reduced. Furthermore, ruminal pH was significantly higher in animals supplemented with tannins than in the control group, while urease activity exhibited the opposite pattern. Further work is necessary to assess the relation between tannins impact on rumen microbiota and alteration of rumen fermentation parameters associated with bovine performance