Evaluación in vitro de heno pretratado con pleurotus ostreatus para utilización en alimentación de rumiantes y Saccharomyces cerevisiae como aditivo
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Date
2023
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Universidad de Concepción
Abstract
Los forrajes y/o subproductos de la industria agrícola, se consideran de menor calidad en la medida que aumenta su contenido de lignina, a pesar de lo cual son usualmente utilizados para la alimentación de rumiantes, principalmente por razones de costos y disponibilidad. La presencia de lignina es responsable de disminuir la digestibilidad y por ende la utilización de los nutrientes contenidos en estos alimentos. La habilidad de los rumiantes de fermentar los carbohidratos es un proceso que tiene pérdidas energéticas, debido a la producción y liberación de metano (CH4) que actúa como Gas de Efecto Invernadero (GEI).
Un componente importante de investigación en nutrición de rumiantes se ha centrado en la evaluación de aditivos que aumenten la eficiencia de los rumiantes, y por ende disminuyan la intensidad de emisión de CH4, principalmente utilizando compuestos químicos que modifiquen los patrones de fermentación, inhibiendo a los metanógenos, o bien mejorando la digestibilidad de los forrajes.
El trabajo reportado por esta tesis se centró en la evaluación de heno de calidad mejorada a través fermentación sólida con Pleurotus ostreatus (el cual aportó micelios, enzimas lignoliticas y medio de crecimiento) en combinación con Saccharomyces cerevisiae como aditivo, con la finalidad de mejorar los patrones de fermentación ruminal y disminuir la producción de metano (CH4). El objetivo general fue evaluar en dietas altas en forrajes los efectos del uso de heno pretratado con Pleurotus ostreatus en combinación con Saccharomyces cerevisiae como aditivo, sobre los parámetros de fermentación ruminal, y desaparición de materia seca, en condiciones in vitro.
En el experimento 1 se concluyó que P. ostreatus realizó de manera eficiente en 14 días, fermentación de heno de ballica-festuca, disminuyendo las fracciones lignocelulósicas conalta actividad enzimática y presencia de estatinas. En el experimento 2 se evaluó dosis de inclusión de heno pretrarado con P. ostreatus (0, 3 y 6%) en dieta baja en fibra detergente ácido (aFDAom) y alta en aFDAom, a través de experimentos in vitro en lotes de 24 h de incubación. A partir de este experimento se observó mejora en la desaparición in vitro de la materia seca (DIVMS) por efecto de 3 y 6% de heno pretratado y dieta baja en aFDAom, sin diferencias en los ácidos grasos de cadena corta totales, pero con inclusiones de 6% H-PO aumentó la proporción molar de ácido acético y disminuyó la de ácido propionico y, la producción y rendimiento de CH4, estableciéndose un efecto inhibitorio de las estatinas presentes en el heno pretratado sobre los metanógenos. El experimento 3, Etapa 1 se obtuvo un inóculo de S. cerevisiae a partir de cepas panificadoras con un valor promedio de 1,54 x 106 UFC, mientras que la Etapa 2 evaluó dosis contrastantes de H-PO (0 y 6%) en dieta alta en aFDAom (mayor a 30%), y uso combinado S. cerevisiae como aditivo, utilizando la cepa comercial Yea Sacc®1026 y la cepa elaborada en el experimento 2, denominada cepa SC-UBB. A partir de los resultados se concluyó que a las 24 h de incubación in vitro, el efecto de 6% de H-PO con SC-UBB mejoró la DIVMS sin alterar la producción de gas. La inclusión de H-PO disminuyó la concentración de nitrógeno amoniacal (N-NH3), proteína microbiana estimada, y producción de ácidos grasos de cadena corta, pero no alteró la proporción molar de acetato (a las 24h), aunque disminuyó la producción y rendimiento de CH4. De manera similar, a las 48 h, se mantuvo la mejora en la DIVMS, incrementó la proporción molar de ácido acético, pero disminuyo la producción y rendimiento de CH4.
A partir de los experimentos se puede concluir que el pretratamiento de heno de ballica con festuca utilizando P. ostreatus es una alternativa viable de mejora de la calidad nutricional del heno, dada su alta actividad enzimática selectiva, con potenciales beneficios ambientales por la disminución de CH4.
Forages and/or byproducts from the agricultural industry are considered of lower quality as their lignin content increases, despite which they are usually used to feed ruminants, mainly for reasons of cost and availability. The presence of lignin is responsible for reducing the digestibility and therefore the use of the nutrients contained in these foods. The ability of ruminants to ferment carbohydrates is a process that has energy losses, due to the production and release of methane (CH4) that acts as a Greenhouse Gas (GHG). An important component of research in ruminant nutrition has focused on the evaluation of additives that increase the efficiency of ruminants, and therefore decrease the intensity of CH4 emission, mainly using chemical compounds that modify fermentation patterns, inhibiting methanogens, or improve the digestibility of forages. The work reported by this thesis focused on the evaluation of improved quality hay through solid fermentation with Pleurotus ostreatus (which provided mycelia, lignolytic enzymes, and growth medium) in combination with Saccharomyces cerevisiae as an additive, to improve the rumen fermentation patterns and reduce methane (CH4) production. The general objective was to evaluate diets high in forages and the effects of using hay pretreated with Pleurotus ostreatus in combination with Saccharomyces cerevisiae as an additive, on the parameters of rumen fermentation, and dry matter disappearance, under in vitro conditions. In experiment 1, it was concluded that P. ostreatus efficiently fermented ryegrass-fescue hay in 14 days, reducing lignocellulosic fractions with high enzymatic activity and the presence of statins. In experiment 2, inclusion doses of hay pretreated with P. ostreatus (0,3, and 6%) in a diet low in acid detergent fiber (aFDAom) and high in aFDAom were evaluated, through in vitro experiments in 24-h batches. incubation. From this experiment, an improvement was observed in the in vitro disappearance of dry matter (DIVMS) due to the effect of 3 and 6% of pretreated hay and a diet low in aFDAom, without differences in total short chain fatty acids, but with inclusions of 6% H-PO increased the molar proportion of acetic acid and decreased that of propionic acid and the production and yield of CH4, establishing an inhibitory effect of the statins present in the pretreated hay on methanogens. Experiment 3, Stage 1, an inoculum of S. cerevisiae was obtained from breadmaking strains with an average value of 1.54 x 106 CFU, while Stage 2 evaluated contrasting doses of H-PO (0 and 6%) in diet high in aFDAom (greater than 30%), and combined use of S. cerevisiae as an additive, using the commercial strain Yea Sacc®1026 and the strain prepared in experiment 2, called strain SC-UBB. From the results, it was concluded that after 24 h of in vitro incubation, the effect of 6% H-PO with SC-UBB improved the DIVMS without altering gas production. The inclusion of H-PO decreased the concentration of ammoniacal nitrogen (N-NH3), estimated microbial protein, and production of short-chain fatty acids, but did not alter the molar proportion of acetate (at 24 h), although it decreased the production and CH4 yield. Similarly, at 48 h, the improvement in DIVMS was maintained, and the molar proportion of acetic acid increased, but the production and yield of CH4 decreased. From the experiments it can be concluded that pretreatment of ryegrass hay with fescue using P. ostreatus is a viable alternative to improve the nutritional quality of hay, given its high selective enzymatic activity. With potential environmental benefits due to the reduction of CH4.
Forages and/or byproducts from the agricultural industry are considered of lower quality as their lignin content increases, despite which they are usually used to feed ruminants, mainly for reasons of cost and availability. The presence of lignin is responsible for reducing the digestibility and therefore the use of the nutrients contained in these foods. The ability of ruminants to ferment carbohydrates is a process that has energy losses, due to the production and release of methane (CH4) that acts as a Greenhouse Gas (GHG). An important component of research in ruminant nutrition has focused on the evaluation of additives that increase the efficiency of ruminants, and therefore decrease the intensity of CH4 emission, mainly using chemical compounds that modify fermentation patterns, inhibiting methanogens, or improve the digestibility of forages. The work reported by this thesis focused on the evaluation of improved quality hay through solid fermentation with Pleurotus ostreatus (which provided mycelia, lignolytic enzymes, and growth medium) in combination with Saccharomyces cerevisiae as an additive, to improve the rumen fermentation patterns and reduce methane (CH4) production. The general objective was to evaluate diets high in forages and the effects of using hay pretreated with Pleurotus ostreatus in combination with Saccharomyces cerevisiae as an additive, on the parameters of rumen fermentation, and dry matter disappearance, under in vitro conditions. In experiment 1, it was concluded that P. ostreatus efficiently fermented ryegrass-fescue hay in 14 days, reducing lignocellulosic fractions with high enzymatic activity and the presence of statins. In experiment 2, inclusion doses of hay pretreated with P. ostreatus (0,3, and 6%) in a diet low in acid detergent fiber (aFDAom) and high in aFDAom were evaluated, through in vitro experiments in 24-h batches. incubation. From this experiment, an improvement was observed in the in vitro disappearance of dry matter (DIVMS) due to the effect of 3 and 6% of pretreated hay and a diet low in aFDAom, without differences in total short chain fatty acids, but with inclusions of 6% H-PO increased the molar proportion of acetic acid and decreased that of propionic acid and the production and yield of CH4, establishing an inhibitory effect of the statins present in the pretreated hay on methanogens. Experiment 3, Stage 1, an inoculum of S. cerevisiae was obtained from breadmaking strains with an average value of 1.54 x 106 CFU, while Stage 2 evaluated contrasting doses of H-PO (0 and 6%) in diet high in aFDAom (greater than 30%), and combined use of S. cerevisiae as an additive, using the commercial strain Yea Sacc®1026 and the strain prepared in experiment 2, called strain SC-UBB. From the results, it was concluded that after 24 h of in vitro incubation, the effect of 6% H-PO with SC-UBB improved the DIVMS without altering gas production. The inclusion of H-PO decreased the concentration of ammoniacal nitrogen (N-NH3), estimated microbial protein, and production of short-chain fatty acids, but did not alter the molar proportion of acetate (at 24 h), although it decreased the production and CH4 yield. Similarly, at 48 h, the improvement in DIVMS was maintained, and the molar proportion of acetic acid increased, but the production and yield of CH4 decreased. From the experiments it can be concluded that pretreatment of ryegrass hay with fescue using P. ostreatus is a viable alternative to improve the nutritional quality of hay, given its high selective enzymatic activity. With potential environmental benefits due to the reduction of CH4.
Description
Tesis presentada para optar al grado de Doctora en Ciencias Veterinarias
Keywords
Rumiantes - Alimentación y alimentos - Chile, Saccharomyces cerevisiae