Estado del Arte sobre la Salud Intestinal de Aves, Cerdos y Becerros

Hoy en día, la microbiología molecular, basada en la secuenciación de ácidos nucleícos, es una herramienta básica para investigar la diversidad y ecología de la microbiota intestinal. Gracias a la aplicación de métodos moleculares, ahora es posible definir con exactitud la diversidad del microbioma intestinal. En esta presentación definiremos las comunidades bacterianas que habitan en el intestino de mamíferos y aves; y además, se describirá la distribución ecológica de estas poblaciones. Nuestros estudios revelan que el nicho ecológico selecciona la diversidad del microbioma. Esta información incrementa el conocimiento de la biología de microorganismos patógenos y comensales.

The gastrointestinal microbiome of mammals is quite diverse, complex and is a truly interconnected consortium.  The gastrointestinal tract of swine and calves are sequentially colonized by bacteria acquired from their environments following birth, and during this period they are susceptible to infection and colonization by pathogenic bacteria, which can affect both humans and animals.  Methods to modify the microbial ecosystem have the capacity to profoundly alter the microbiome, but these methods depend on maintaining the intestinal health of the animal, however in general these methods can be grouped as: 1) pro-commensal, 2) anti-pathogen, or 3) environmental manipulation.  Pro-commensal treatments (including probiotics and competitive exclusion) can establish a stable, mature microflora that is resistant to stresses and penetration by pathogens.  Dietary manipulation, including prebiotics, can change the intestinal microbial population by providing a competitive advantage to specific members of the microbiota, including probiotic organisms that are fed to the animal.  Bacteriocins, colicins, vaccination, bacteriophage, sodium chlorate and phytochemicals are all a wide selection of anti-pathogen strategies that can be used in food animals to specifically target pathogenic organisms.  Altering management practices such as handling and transport to reduce stresses appears to offer possibilities for reducing pathogen colonization, due to stimulatory effect of norepinephrine on Salmonella populations. As our understanding of the microbial ecosystem has increased in recent years, so has our ability to alter the intestinal health of animals which can significantly improve efficiency and profitability.

The gastrointestinal microbiome of mammals is quite diverse, complex and is a truly interconnected consortium.  The gastrointestinal tract of swine and calves are sequentially colonized by bacteria acquired from their environments following birth, and during this period they are susceptible to infection and colonization by pathogenic bacteria, which can affect both humans and animals.  Methods to modify the microbial ecosystem have the capacity to profoundly alter the microbiome, but these methods depend on maintaining the intestinal health of the animal, however in general these methods can be grouped as: 1) pro-commensal, 2) anti-pathogen, or 3) environmental manipulation.  Pro-commensal treatments (including probiotics and competitive exclusion) can establish a stable, mature microflora that is resistant to stresses and penetration by pathogens.  Dietary manipulation, including prebiotics, can change the intestinal microbial population by providing a competitive advantage to specific members of the microbiota, including probiotic organisms that are fed to the animal.  Bacteriocins, colicins, vaccination, bacteriophage, sodium chlorate and phytochemicals are all a wide selection of anti-pathogen strategies that can be used in food animals to specifically target pathogenic organisms.  Altering management practices such as handling and transport to reduce stresses appears to offer possibilities for reducing pathogen colonization, due to stimulatory effect of norepinephrine on Salmonella populations. As our understanding of the microbial ecosystem has increased in recent years, so has our ability to alter the intestinal health of animals which can significantly improve efficiency and profitability

The successful rearing of calves requires quality colostrum, cleanliness of their environment, their comfort, well-balanced rations, adequate dry matter intake, and consistency.  Colostrum failure can be due to several reasons including, but not limited to, colostrum contamination, poor quality colostrum, improper storage and/or thawing of colostrum, not enough colostrum, colostrum not offered within the first 6 hours after birth, and heat stress.  Any combination of these factors can lead to failure of passive transfer, which, in turn, can cause poor performance, poor feed efficiency, and poor health.

Rapid development of the rumen in a calf is a key to transitioning it from a monogastric to a ruminant.  Establishment of bacteria in the rumen allows for production of volatile fatty acids, specifically propionate and butyrate, which promote the growth of rumen papillae increasing the absorptive ability of the tissue.  The primary driver in rumen development is the intake of fermentable carbohydrates in a calf starter.  Increasing the dry matter intake of the calf involves proper management, such as, providing calf starter that is fresh, dry, palatable, and with minimal fines.  In addition, clean water should be available to calves at all times.

The use of Saccharomyces cerevisiae fermentation products (SCFP) has been shown to increase dry matter intake, growth, and rumen papillae size in calves (Lesmeister et al., 2004). Calf health, measured as improvements in calves exhibiting fever, diarrhea, and lower mortality, occurred when treated with SCFP as compared to a control (Magalhaes, 2008).  Recently, in a study conducted at Iowa State University’s College of Veterinary Medicine, calves that were challenged with salmonella enterica serotype Typhimurium strain SL1344 were assigned to one of two treatments, an untreated control and a treatment group which contained SCFP in the milk replacer and calf starter.  SCFP-treated calves had decreased rectal temperatures, decreased diarrhea scores, and increased papillae development (P<0.05) as compared to the control calves (Brewer et al., 2014).  In addition, SCFP-treated calves had decreased fecal shedding of salmonella and decreased salmonella ileal colonization (P<0.05) as compared to the control calves (Brewer et al., 2014).

Along with proper management of the colostrum, appropriate care and feeding of calves, the use of Saccharomyces cerevisiae fermentation products can improve starter dry matter intake, rumen development, average dairy gain, and calf health.

The challenge of feeding a large and growing human population of the world makes it essential to use resources efficiently; in pig production efficiency requires keeping pigs healthy. The industry has several powerful health technologies, but we need more. Recent evidence that feed components can influence health offers the potential of using feed as part of a strong herd-health program. Feed components may improve health and productive performance through altering microbial populations in the digestive tract, modifying immune function, strengthening the gut barrier, or other physiological effects. Two examples illustrate the possibilities. First, a high dietary level of insoluble fiber, such as is found in several grain co-products, reduces diarrhea of pigs challenged with a pathogenic E. coli, although the mechanism is not yet clear. Second, mannan oligosaccharide products derived from yeast cell walls alter immune function and improve performance of pigs challenged with the porcine reproductive and respiratory syndrome (PRRS) virus. One direct effect of these mannan products is reduction of the excessive and prolonged inflammation that follows infection. The range of feed components that may influence health and performance is impressive.

Under commercial conditions, pigs are exposed to a number of potential stressors, including those related to intestinal health, that can reduce growth performance capacity to compensate for reductions in growth once the factor limiting growth has been removed.  The presentation will review research on the impact of early growth restriction on subsequent performance, with a focus on factors of relevance under commercial conditions.

La importancia de la microbiota en el apoyo a la función intestinal ha recibido mayor atención en los últimos tiempos. En esta presentación nos centramos en la importancia de apoyar la maduración de la microbiota aviar en la avicultura comercial.

El tracto intestinal de los pollitos inmediatamente después de romper el cascarón no cuentan con una microbiota establecida, estructura definida o un sistema inmunológico funcional. El desarrollo de una microbiota madura, que está predominantemente definida por Lactobacilos en el intestino delgado y Clostridios en el intestino grueso, es impulsado por la exposición ambiental, que acciona simultáneamente el desarrollo del sistema inmunitario intestinal. Estructuras linfoides foliculares organizadas, tales como placas de Peyer, no son visibles hasta aproximadamente 2 semanas de edad, un marco de tiempo de intensa rotación microbiana. El tracto intestinal es un sitio importante de entrada de patógenos, dado el alto grado de contacto con el material ingerido. Por esta razón, el tracto gastrointestinal alberga uno de los sistemas inmunológicos más grandes y complejos que deben ser regulados estrictamente.

Dado que el pollo de engorda alcanza el peso promedio para su sacrificio en tan sólo 42 días, hay poco tiempo para una maduración  microbiana e  inmunológica, dejando, potencialmente, aves susceptibles a una serie de desafíos ambientales oportunistas que dificultan el desempeño de las aves. Además, la microbiota puede ser influenciada en cualquier momento por factores ambientales, incluyendo el uso de antibióticos, cambios en la dieta y el estrés fisiológico. Esto pone de relieve la importancia fundamental de apoyar el pronto establecimiento de una microbiota de soporte para un desarrollo apropiado y mantener una abundancia relativa correcta de los microorganismos necesarios para el mantenimiento de la homeostasis intestinal y permitir el funcionamiento óptimo del intestino.

Con la creciente preocupación por el uso de antibióticos promotores del crecimiento la industria avícola está comenzando a explorar otros métodos para apoyar el desempeño delas  aves, incluyendo los probióticos a base de Bacillus. Los Bacillus se encuentran de forma ubicua en el medio ambiente con el potencial de entrar en un estado metabólico inactivo reversible conocido como endospora bacteriana. Las endosporas bacterianas son muy resistentes a las duras condiciones ambientales, tales como temperatura, pH, radiación, escasez de nutrientes y desecación, haciéndolas candidatas ideales para su inclusión en alimento peletizado para las aves. Aquí describiremos evidencia asociada con la germinación de endosporas de Bacillus en el tracto gastrointestinal aviar y la presente información ilustrará sus efectos positivos en el apoyo al rendimiento de las aves de engorda.