Resumen Introducción: Los ensilajes del pasto king grass (Cenchrus purpureus (Schumach.) Morrone, syn. Pennisetum purpuphoides) y cáscaras de piña (Ananas comosus) son alternativas de alimento para ganado en condiciones de escasez alimentaria. Objetivo: Describir las dinámicas de la microbiota presente en los ensilajes de king grass y piña durante el proceso de fermentación usando secuenciación de próxima generación (NGS) y evaluar el efecto de protección de Lacticaseibacillus paracasei_6714 como inoculante de ensilaje ante Listeria monocytogenes. Métodos: Usamos un diseño aleatorio no restringido para caracterizar la microbiota presente en ensilajes de king Grass cosechados 70 días después de rebrote y de cáscaras de piña. Inoculamos mezclas de pasto y cáscara con L. paracasei_6714 o L. monocytogenes, o ambos, con un tratamiento control sin inocular. El perfil nutricional y de fermentación fue evaluado luego de 30 días. Después de 15 y 30 días de fermentación, usamos un análisis de para determinar la dinámicas y diversidad de la microbiota en los ensilajes inoculados y control. Resultados: Los contenidos de materia seca y digestibilidad, no difirieron significativamente; sin embargo, hubo diferencias en proteína cruda, pH y ácidos orgánicos. Obtuvimos 4 432 secuencias variantes de amplicon de Proteobacteria, Firmicutes, Bacterioidetes, Actinobacteria, Verrucomicrobia, Planctomycetes y de Patescibacteria. La abundancia relativa de cada filo vario dependiendo del material y periodo de fermentación. Similitudes de filo fueron mayores al 70 % (pero no mayor que 50 % con Bray-Curtis a nivel de especie). Conclusión: Estas comunidades bacterianas parecen cumplir un papel importante durante la fermentación del ensilaje. Un manejo apropiado del proceso de ensilaje puede reducir o eliminar baterías patogénicas.

Abstract Introduction: King grass (Cenchrus purpureus (Schumach.) Morrone, syn. Pennisetum purpuphoides) and pineapple peel (Ananas comosus) silages are food alternatives for livestock in conditions of feed shortage. Objective: To describe the dynamics of the microbiota present in king grass and pineapple silage during the fermentation process using next generation sequencing (NGS) and to evaluate the protective effect of Lacticaseibacillus paracasei_6714 as a silage inoculum against Listeria monocytogenes. Methods: We used an unrestricted randomized design to characterize the microbiota present in silages made from king grass harvested 70 days after regrowth and pineapple peel. We inoculated mixtures of grass and peel with L. paracasei_6714 or L. monocytogenes, or both, with a non-inoculated treatment as control. The nutritional and fermentative profile was evaluated after 30 days. After 15 and 30 days of fermentation, we used 16S rRNA analysis to determine the dynamics and diversity of the microbiota in the inoculated and control silages. Result: Dry matter content and digestibility did not differ significantly; however, there were differences in crude protein, pH and organic acids. We obtained 4432 amplicon sequence variants of Proteobacteria, Firmicutes, Bacterioidetes, Actinobacteria, Verrucomicrobia, Planctomycetes and Patescibacteria. The relative abundance of each phylum varied depending on the material and fermentation period. Phylum similarity was over 70 % (but not greater than 50 % with Bray-Curtis at the species level). Conclusion: These bacterial communities seem to have an important role during silage fermentation. Proper management of silage processing can reduce or eliminate pathogenic bacteria.

RESUMO O objetivo do presente trabalho foi avaliar a composição química, o perfil fermentativo e os parâmetros da degradação da fibra em detergente neutro de três silagens do resíduo da produção do palmito pupunha, sendo estas silagens de folha, bainha foliar e composta (55% de folha e 45% de bainha foliar). O resíduo foi acondicionado em silos experimentais e aberto após sessenta dias de fermentação com retirada de amostras das silagens para a determinação da composição química e dos parâmetros de degradação da fibra em detergente neutro nos tempos de 0, 3, 6, 9, 12, 24, 36, 48, 72 e 96 horas de incubação in vitro. Houve diferença no teor de matéria seca entre os três tipos de silagem, assim como para a proteína bruta, fibra em detergente neutro, fibra em detergente ácido e lignina. A silagem de folhas apresentou maior taxa de degradação fracional e maior fração potencialmente degradável da fibra em detergente neutro ao longo das 96 horas de incubação. Quanto aos parâmetros fermentativos, a silagem feita com a folha apresentou maiores valores de pH (3,79) e ácido lático (1,18%), ácido acético (0,39%) e ácido propiônico (0,24%). O ácido butírico foi maior para a silagem composta (0,012%) e o nitrogênio amoniacal foi maior para a silagem de bainha (0,94%). A silagem de folha apresentou melhores características químicas, parâmetros fermentativos e características de degradabilidade in vitro, demostrando ser a silagem com melhor valor nutricional para alimentação de animais ruminantes.

ABSTRACT The objective of the present work was to evaluate the chemical composition, fermentation profile, and degradation parameters of the neutral detergent fiber of three silages made with the waste from production of heart of peach of palm, which consisted of leaf, leaf sheath, and their compound (55% leaf and 45% leaf sheath). The waste was packed in experimental silos and open after sixty days of fermentation; silage samples were collected for determination of chemical composition and degradation parameters of neutral detergent fiber at 0, 3, 6, 9, 12, 24, 36, 48, 72, and 96 h of incubation in vitro. A difference was detected in the dry matter, crude protein, neutral detergent fiber, acid detergent fiber, and lignin contents between the three types of silage. The leaf silage showed a higher fractional degradation rate and a higher potentially digestible fraction of neutral detergent fiber over the 96 h of incubation. As for the fermentative parameters, silage made with the leaf showed a higher pH (3,79) and lactic acid (1,18%), acetic acid (0,39%) and propionic acid (0,24%). The butyric acid was higher for compound silage (0,012%) and ammoniacal nitrogen was higher for sheath silage (0,94%). The leaf silage displayed better chemical characteristics, fermentation parameters and in vitro degradability properties, proving to be the silage with best nutritional value for feeding ruminants.

Abstract In vitro ruminal fermentation dynamics of isoenergetic (10.9 MJ ME kg-1) and isoproteic (12.1% CP) diets for cattle were determined, with gradual replacement levels of 0.0 (T0, control), 32.4 (T32), 77.6 (T78) and 100.0% (T100) of ground corn grain, on a dry basis, mainly by integral sweet potato silage. Accumulated gas production during the 96 h of in vitro fermentation was analyzed with a mixed generalized linear model. The increases in gas production during the initial stage were 73.0, 80.0, 98.0 and 103.8, in the intermediate stage were 82.0, 75.5, 73.2 and 70.5, and in the final were 50.0, 51.8, 45.2 and 44.8 mL g-1 of incubated organic matter (incOM) for T0, T32, T78 and T100, respectively. In the initial stage, the highest increases of T78 and T100 were attributed to the greater availability of soluble carbohydrates and sugars. In the intermediate period, the increase in T0 was explained by the degradation of protein matrix that surrounds corn starch. In the final stage, the lower increases were related to the limited availability of fermentable substrates and microbial recycling. On average, T78 and T100 showed greater fermentative potential (259.2 mL.g-1 incOM), microbial efficiency rate (0.13), maximum speed (12.4 mL.g-1 incOM h-1) and less time to reach maximum speed (9.90 h). It is concluded that, in in vitro conditions, diets with sweet potato integral silage provided greater nutrient availability for ruminal microorganisms, which favors energy supply for the different metabolic processes in the rumen.

Resumen Se determinó la dinámica de fermentación ruminal in vitro de dietas isoenergéticas (10.9 MJ EM kg-1) e isoproteicas (12.1 % PB) para bovinos, con niveles graduales de reemplazo de 0.0 (T0, control), 32.4 (T32), 77.6 (T78) y 100.0 % (T100) del grano de maíz molido, en base seca, principalmente, por ensilado integral de camote o boniato. La producción acumulada de gas durante las 96 h de fermentación in vitro se analizó con un modelo lineal generalizado mixto. Los incrementos en la producción de gas durante la fase inicial fueron 73.0, 80.0, 98.0 y 103.8; en la fase intermedia 82.0, 75.5, 73.2 y 70.5, y en la final 50.0, 51.8, 45.2 y 44.8 mL g-1 de materia orgánica incubada (MOinc) para T0, T32, T78 y T100, respectivamente. En la etapa inicial, los mayores incrementos en T78 y T100 se atribuyeron a la mayor disponibilidad de azúcares y carbohidratos solubles. En la intermedia, el incremento de T0 se explicó por la degradación de la matriz proteica que envuelve el almidón del maíz. En la final, los menores incrementos se relacionaron con la limitada disponibilidad de sustratos fermentables y con el reciclaje microbiano. Como promedio, T78 y T100 mostraron mayor potencial fermentativo (259.2 mL.g-1 MOinc), tasa de eficiencia microbiana (0.13), velocidad máxima (12.4 mL.g-1 MOinc h-1) y menor tiempo para alcanzar la velocidad máxima (9.90 h). Se concluye que en condiciones in vitro, las dietas con ensilado integral de camote aportaron mayor disponibilidad de nutrientes para los microorganismos ruminales, lo que favorece el aporte de energía para los diferentes procesos metabólicos en el rumen.

Abstract In order to characterize the fermentation dynamics of a silage of whole sorghum plant (Sorghum bicolor L. Moench) with inclusion levels of citrus fruit (Citrus sp.), pH, ammonia content and concentration of volatile fatty acids (acetic, propionic and butyric) were evaluated as quality indicators. A complete randomized design was applied with four treatments: a) 100 % sorghum, b) 75 % sorghum: 25 % pulp; c) 50 % sorghum: 50 % pulp, d) 25 % sorghum: 75 % pulp. Four moments were established (14, 28, 42 and 56 days) with six repetitions for each one. The silages showed pH between 3,29 and 4,32. A decrease of this indicator was observed, as the pulp percentage in the mixture increased. The silages with pulp reached the lowest pH values at 56 days of evaluation; while the sorghum silage (100 %) achieved them at 42 days. The ammoniacal nitrogen, just like pH, decreased with the inclusion of the pulp, and increased as the evaluation moments passed, with contents between 0,05 and 2,54 mg N-NH3 100 mL-1. With regards to the volatile fatty acids, acetic acid showed the highest concentrations in all the silages during the evaluation period, with values between 1,7 and 17, 2 mmole L-1. The quantities of propionic and butyric acid were negligible, and were in the range of 0,015 and 0,33 mmole L-1for propionic and 0,004 and 0,037 mmole L-1 for butyric. There were significant differences in the production of acetic and butyric acid among the treatments since day 28 of the evaluation. Propionic acid showed differences since day 42. It is concluded that the fermentation quality indicators are within the established range to classify silages as having good quality.

Resumen Para caracterizar la dinámica de fermentación de un ensilaje de planta entera de sorgo (Sorghum bicolor L. Moench) con niveles de inclusión de pulpa de cítrico (Citrus sp.), se evaluaron como indicadores de calidad el pH, el contenido de amoniaco y la concentración de ácidos grasos volátiles (acético, propiónico y butírico). Se aplicó un diseño completamente aleatorizado con cuatro tratamientos: a) 100 % sorgo, b) 75 % sorgo: 25 % pulpa; c) 50 % sorgo: 50 % pulpa, d) 25 % sorgo: 75 % pulpa). Se establecieron cuatro momentos (14, 28, 42 y 56 días) con seis repeticiones para cada uno. Los ensilajes mostraron pH entre 3,29 y 4,32. Se observó una disminución de este indicador, según aumentaba el porcentaje de pulpa en la mezcla. Los ensilajes con pulpa alcanzaron los valores más bajos de pH a los 56 días de evaluación, mientras que el de sorgo (100 %) lo logró a los 42 días. El nitrógeno amoniacal, al igual que el pH, disminuyó con la inclusión de la pulpa, y aumentó a medida que trascurrieron los momentos de evaluación, con contenidos entre 0,05 y 2,54 mg N-NH3 100 mL-1. Con respecto a los ácidos grasos volátiles, el acético mostró las mayores concentraciones en todos los ensilajes durante el período de evaluación, con valores entre 1,7 y 17, 2 mmole L-1. Las cantidades de ácido propiónico y butírico fueron despreciables, y estuvieron en el orden de 0,015 y 0,33 mmole L-1 para el propiónico y 0,037 y 0,004 mmole L-1 para el butírico. Hubo diferencias significativas en la producción de acético y butírico entre los tratamientos a partir del día 28 de evaluación. El propiónico mostró diferencias a partir del día 42. Se concluye que los indicadores de calidad fermentativa se encuentran en el rango establecido para clasificar los ensilajes de buena calidad.

The current study evaluated the diversity of yeast species in Cabernet Sauvignon grape must derived from three neighbouring vineyards from a similar terroir but on which significantly different management practices are employed. The fermentation kinetics and yeast population dynamics were monitored from the beginning to the end of spontaneous fermentation. The grape musts were characterised by distinct yeast populations comprising oxidative, weakly fermentative and strongly fermentative yeasts. Different combinations of dominant non-Saccharomyces yeasts were observed in each must, with significantly different assortments of dominant species, including Starmerella bacillaris (synonym Candida zemplinina), Lachancea thermotolerans, Hanseniaspora uvarum, Candida parapsilosis and Wickerhamomyces anomalus. None of these yeast consortia appeared to affect the growth of Saccharomyces cerevisiae or inhibit the overall progress of fermentation. However, the percentage of fermentative yeasts was positively correlated with the fermentation rate. Glucose and fructose consumption rates suggested active participation of both glucophilic and fructophilic yeasts from the onset of fermentation. The data highlight two parameters, viz. initial cell concentration and yeast community composition, as important fermentation drivers and open the possibility to predict fermentation behaviour based on the initial composition of the yeast community.

Objetivou-se caracterizar a dinâmica fermentativa, microbiológica e nutricional de colostro bovino fermentado em condições anaeróbias e diferentes temperaturas. O colostro foi homogeneizado e armazenado em garrafas PET em condições anaeróbias e incubadas em temperatura controlada (32,5 ± 1°C ou 22,5 ± 1°C) ou ambiente (17,4 - 21,5ºC), e abertas após 0, 1, 7, 14, 21, 28 e 35 dias, para determinação de parâmetros fermentativos, nutricionais e contagem de bactérias, mofos e bolores. Os valores de pH apresentaram variação durante o período de fermentação (p < 0,0001), com colostro armazenado a 32,5°C apresentando os menores valores e marcada redução nos primeiros dias. A acidez titulável e a concentração de ácido lático apresentaram valores crescentes. O desenvolvimento de BAL foi elevado, especialmente em altas temperaturas. Após 35 dias, em torno de 50% do N total estava na forma de N não-proteico e a caseína foi reduzida a 0,66% do N total. A lactose foi reduzida durante a fermentação. A concentração de gordura não foi afetada pela temperatura durante o processo. Os resultados sugerem que a temperatura na qual o colostro é fermentado em condições anaeróbias influencia diretamente na velocidade e intensidade do desenvolvimento da população microbiana e degradação dos principais componentes nutricionais como a caseína e a lactose.

The fermentative, microbiological and nutritional dynamics of bovine colostrum fermented under anaerobic conditions at different temperatures is provided. Colostrum was homogenized and stored in PET bottles in anaerobic conditions and incubated at controlled temperature (32.5 ± 1°C or 22.5 ± 1°C) or at room temperature (17.4 - 21.5ºC) and opened after 0, 1, 7, 14, 21, 28 and 35 days to determine fermentative and nutritional parameters and bacteria, yeast and mold counts. Further, pH rates showed significant variations during the fermentation period (p < 0.0001), with colostrum stored at 32.5°C, exhibiting the lowest rates and significant reduction during the first days. Titratable acidity and lactic acid concentration showed increasing rates and LAB development was intense, especially at high temperatures. After 35 days, about 50% of total nitrogen became non-protein N and casein fraction was reduced to 0.66% of total nitrogen. Lactose decreased during fermentation and fat concentrations were not affected by temperature. Results suggested that the temperature at which the colostrum was fermented directly influenced the speed and intensity of microbial population development and degradation of the main nutritional parameters, such as casein and lactose.

Objetivou-se com este estudo avaliar os efeitos de aditivos químicos na ensilagem de cana-de-açúcar sobre a dinâmica fermentativa e a composição química das silagens. O experimento foi desenvolvido em delineamento inteiramente casualizado, com cinco repetições. A cana-de-açúcar foi ensilada sem aditivo ou tratada com 1% (massa verde) de cal virgem ou calcário, constituindo três tratamentos. A dinâmica fermentativa foi analisada com base nas perdas gasosas, nos ácidos orgânicos, na produção de etanol e na composição química das silagens. As menores perdas gasosas foram observadas nas silagens com cal virgem ou calcário. As silagens tratadas com esses aditivos apresentaram maior teor de carboidratos solúveis residuais e de ácidos acético e butírico, além de reduzida fermentação alcoólica. As silagens com os aditivos químicos apresentaram, no momento da abertura, maior teor de cinzas e menor concentração de componentes fibrosos. O teor de proteína observado nas silagens está de acordo com a amplitude preconizada para a forragem in natura. A adição de cal virgem ou calcário no momento da ensilagem melhorou o padrão fermentativo das silagens, promovendo redução das perdas gasosas, inibição da fermentação alcoólica e maior quantidade de carboidratos solúveis remanescentes.

The objective of this study was to evaluate the effects of chemical additives on the fermentative dynamics and chemical composition of sugarcane silages. The experiment was conducted in a randomized complete design with five replications. Sugarcane was ensiled without additives or with calcium oxide and limestone (1% as-fed basis) constituing three treatments. The fermentative dynamic was analyzed based on gas losses, organic acids and ethanol production and, silages chemical composition. The calcium oxide and limestone treatments showed the lowest values of gas losses. Silages treated with these two additives also showed higher concentrations of water soluble carbohydrates, acetic and butyric acids, and low alcoholic fermentation. The treatments containing chemical additives presented the highest ash and the lowest fiber concentration. Crude protein for all treatments was in agreement with the values of fresh sugarcane. Calcium oxide or limestone addition at ensiling resulted in a better fermentative pattern, promoting reduction in gas losses, alcoholic fermentation inhibition, and high amounts of residual soluble carbohydrates.

Avaliou-se a dinâmica de fermentação ruminal dos carboidratos totais (CT) e da fibra em detergente neutro (FDN) do pseudofruto de cinco clones de cajueiro (CP 06, CP 09, CP 76, CP 1001 e BRS 189) pela técnica in vitro semi-automática de produção de gases. As leituras de pressão foram realizadas 3, 6, 9, 12, 15, 21, 27, 33, 39, 48, 60 e 72 horas para determinação da degradação dos carboidratos totais e da FDN, pela quantificação do resíduo após 72 horas de incubação. As curvas de produção cumulativa de gases foram ajustadas utilizando-se os modelos propostos por France e Gompertz para carboidratos totais e fibra em detergente neutro, respectivamente. Na avaliação da degradação dos carboidratos totais, o potencial máximo de produção de gases (Vf) diferiu entre o CP 09 e o BRS 189. O CP 1001 foi o que apresentou menor tempo de colonização. As taxas de fermentação dos CP 09, CP 1001 e CP 06 foram ligeiramente superiores às do CP 76 e dos BRS 189. A taxa de produção de gases apresentou dois picos, às 6 e às 21 horas. O BRS 189 foi o que apresentou menor degradação às 72 horas de fermentação. Na avaliação da fermentação ruminal da FDN, O CP 09 apresentou maior potencial máximo de produção de gases e o CP 06, CP 1001 e BRS 189, maiores taxas de produção de gases. A eficiência microbiana foi maior no CP 09 e a produção cumulativa de gases, no CP 1001. Os pseudofrutos dos clones de cajueiro avaliados têm potencial para uso na alimentação de ruminantes por terem boa qualidade fermentativa.

The kinetics of ruminal fermentation of total carbohydrates (TC) and neutral detergent fiber (NDF) of false fruit from five clones of cashew tress: CP 06, CP 09, CP 76, CP 1001, BRS 189 was evaluated through semi-automated in vitro gas production technique. The pressure readings and the volume measurements were accomplished after 3, 6, 9, 12, 15, 21, 27, 33, 39, 48, 60 and 72 h. For the determination of the TC and NDF degradation, the residue was quantified after 72 h of incubation. The cumulative gas production curves were adjusted through models proposed by France and Gompertz for TC and NDF, respectively. For TC, difference between CP 09 and BRS 189 was found for potential gas production (Vf). The CP 1001 was the substrate that presented the shortest colonization time. The CP 09, CP 1001 and the CP 06 presented fermentation rates slightly higher in relation to CP 76 and BRS 189. The existence of two peaks was observed in the gas production rate, for 6 and 21 h. The BRS 189 presented lower degradation at 72 h. For the NDF, CP 09 resulted in higher Vf and the CP 06, CP 1001 and o BRS 189 presented the highest gas production rate. The CP 09 presented had higher microbial efficiency. The cumulative gas production was higher for CP 1001. The false fruit of the cashew trees clones evaluated presented potential for use in the feeding of ruminants due to their good quality, from the fermentative point of view.

O experimento foi conduzido com o objetivo de avaliar a dinâmica fermentativa e microbiológica de silagens de capins tropicais acrescidas de polpa cítrica. Os capins tanzânia (Panicum maximum cv. Tanzânia) e marandu (Brachiaria brizantha (Hochst ex. A. Rich) Stapf cv. Marandu) foram colhidos aos 64 e 49 dias de rebrota, respectivamente, e ensilados com 0, 5 ou 10% de polpa cítrica peletizada (PCP), em relação à matéria verde, durante 1, 4, 7, 14, 21, 28 e 56 dias. Foram utilizados silos experimentais de PVC adaptados com válvula do tipo Bunsen para eliminação dos gases. A forragem foi compactada visando obter densidade de 550 kg/m³. O delineamento utilizado foi o inteiramente ao acaso com três repetições, em esquema de parcelas subdivididas. A inclusão de PCP aumentou os teores de MS e diminuiu o pH das silagens. A adição de PCP influenciou os teores de N-NH3 (N total), uma vez que, nas silagens sem PCP, os teores N-NH3 foram significativamente elevados, o que as caracteriza como de qualidade duvidosa. A adição de PCP aumentou a concentração molar dos ácidos acético e propiônico. A população de enterobactérias foi detectada somente no primeiro dia de fermentação nas silagens do capim-tanzânia e até o 18º dia nas do capim-marandu. Nas silagens avaliadas, a população de bactérias homofermentativas foi semelhante à das bactérias heterofermentativas.

The experiment was carried out to evaluate the fermentative and microbiological dynamics of the tropical grass silages using pelleted citrus pulp (PCP) as an additive. The Tanzania (Panicum maximum cv. Tanzania) and Marandu (Brachiaria brizantha (Hochst. ex. A. RICH) Stapf cv. Marandu) grasses were harvested at 64 and 49 days of regrowth, respectively. The following treatments were evaluated: control (0%), addition of 5% and 10% of pelleted citrus pulp (PCP) in a fresh matter basis, and seven fermentation periods (1, 4, 7, 14, 21, 28, and 56 days) after the ensilage. Experimental PVC silos with Bunsen valve to eliminate gas were used. The forage was compacted to obtain 550 kg/m³ of bulk density. It was used a split-plot arrangement in a complete randomized experimental design, with three replications per treatment. The addition of PCP increased the DM concentration and reduced the pH values of the silages. The concentration of NH3-N (total N) was affected by the PCP addition, and the absence of PCP resulted in silages with high N-ammonia concentration, which characterizes silages with questionable quality. The addition of PCP increased the molar concentration of the acetic and propionic acids. The enterobacteria population was detected only in the first day in the tanzaniagrass silage, and until the tenth eighth day of fermentation on the marandugrass silage. The homofermentative bacteria population was similar to the heterofermentative on the evaluated silages.

Los sistemas de producción ganadero en el trópico se desarrollan básicamente, bajo pastoreo con monocultivos de gramíneas, generalmente con contenidos nutricionales de regular a baja calidad, principalmente por su alto contenido de fibra y bajos niveles de proteína. Frente a esta situación, se presentan los SSP (sistemas silvopastoriles) bajo pastoreo o corte y acarreo como una alternativa, que generalmente potencia la calidad total de la dieta, entre otros factores benéficos. El componente arbóreo y arbustivo, involucrado en estos sistemas, presentan amplios efectos en el marco nutricional de los bovinos. Sus efectos en el animal pueden ser variados, debido a la divergencia que se da en su composición, frente a las gramíneas. Esta diferencia se da, no solo a nivel de nutrientes primarios, sino también de metabolitos secundarios, también denominados FAN (factores antinutricionales). Tradicionalmente, algunos metabolitos han sido considerados factores antinutricionales, por sus efectos negativos sobre el proceso fermentativo a nivel ruminal o en general sobre el proceso digestivo en el tracto total. Pero los efectos dependen, en términos generales, del nivel de consumo. Considerando el espectro de las principales arbóreas y arbustivas tropicales (leguminosas y no leguminosas) con potencial en la alimentación de los bovinos, son diversos los metabolitos secundarios estudiados, taninos, saponinas, mimosina, glucósidos cianogénicos, fitoestrógenos, entre otros.

The cattle production systems in the tropic are developed, basically, under systems of pasturing with monocultures of grasses, generally with nutritional contents from mid to low quality, mainly because of their high content of fiber and low protein levels. As opposed to this situation it appears the SPS (silvopastoral systems) under pasturing or cuts and transportation as an alternative that generally empowers the total quality of the diet, among other beneficial factors. The arboreal and shrubs component involved in these systems presents ample effects in the nutritional framework of bovines. Their effects in the animal can be varied, due to the divergence that occurs in its composition, when compared to the grasses. This difference occurs, not only at the primary nutrients level, but also at that of secondary metabolites (also denominated ANF, or anti nutritional factors). Traditionally, some metabolites have been considered anti nutritional factors because of their negative effects on the fermentative process at a ruminal level or, in general, on the digestive process in the total tract. But the effects depend, in general terms, on the consumption level. Considering the spectrum of main arboreal and arbustives, the tropical ones (legumes and non legumes) with potential in the feeding of the bovines, there are diverse studied secondary metabolites, such as tannins, cianogenic glycosides, phytotoestrogens, saponines and mimosine, among others.

This paper presents two approaches for the design of an asymptotic observer for a fermentative process described by partial differential equations (PDE). In the first approach, termed late lumping, the observer is designed for the PDE model and then both the observer and the model are reduced to a set of ordinary differential equations (ODE) by means of the Orthogonal Collocation Method (OCM). In the second approach, termed early lumping, the PDE model is initially reduced to an ODE set by using the OCM and then the asymptotic observer is designed for the reduced model. The study demonstrates that by analyzing the estimation error dynamics for both design approaches, the dynamic behavior of the asymptotic observer is fully independent of the design approach used.

En este artículo, se presentan dos enfoques de diseño de un observador asintótico para un sistema fermentativo descrito por ecuaciones diferenciales parciales (EDP). En el primer enfoque, denominado reducción posterior, se diseña el observador directamente sobre el modelo en EDP y después, tanto el modelo como el observador, son reducidos a un conjunto de ecuaciones diferenciales ordinarias (EDO) mediante el Método de Colocación Ortogonal (MCO). En el segundo enfoque, denominado reducción temprana, el modelo en EDP, es inicialmente reducido a EDO, usando también el MCO y luego, el observador asintótico es diseñado para el modelo reducido. El estudio muestra, mediante un análisis de la dinámica del error de estimación para ambos enfoques, que el comportamiento dinámico del observador asintótico es independiente del enfoque de diseño utilizado.