HEBERT Elvira Maria
congresos y reuniones científicas
Isolation, quantification and genetic identification of lactic acid bacteria from bovine feedlot environment
Simposio; SIBAL 2016. V International Symposium on Lactic Acid Bacteria. Benefitting from Lactic Acid Bacteria. Progress in Health and Food.; 2016
The microbiome is currently considered as an organ because it provides metabolic activities, coding capabilities and some physiological functions including immunomodulation and prevention of infections in animals, being affected by different exogenous and endogenous factors. The administration of indigenous and homologous microorganisms expressing beneficial properties, isolated from the host and tract in which will be applied, is a new approach to reconstitute the balance and exert physiological effects. The research group is working on the design of alternative and safe formulas or probiotic products, for the restoration of steer?s microbiome. The objective of this study was to isolate and quantify the cultivable microbial populations, and to identify lactic acid bacteria (LAB) by molecular biology methods, from cattle feces of different ages (6, 8, 10 and 12 months), soil and foods components. Samples (n=58) were taken from feces of animals during their stage into the feedlot system. Quantification and phenotypic identification of different microbial groups were performed by standard microbiological methods, while PCR technique fingerprinting, using primers (GTG)(5) - and sequencing of 16S rRNA was applied for the genetic identification of isolates. The results showed that total cultivable microorganisms were at levels of 107 to 109 CFU/g of feces, with higher counts in younger animals (6 m). Enterobacteria ranged between 106 and 108 CFU/gr. Quantification of fungi and yeasts, and spore-former bacteria, showed no differences between the different growth stages (105 - 106 CFU/g). LAB were Isolated from fecal samples and soil at levels of 104 and 106 CFU/g with maximum values in 14 months steers. Referred to food components, viable bacteria were 2 log cycles lower than feces. A total of 500 LAB from stools, soil and food components (corn, soybean expeller, wheat, sorghum) were isolated. Genetic mapping showed that predominant LAB species in feces were Lactobacillus mucosae (34%), Enterococcus hirae (26%) and Enterococcus faecium-durans (20%), while in food E. faecium-durans (46%), Pediococcus acidilactici (17%) and Lactobacillus acidophilus (11%) were mainly isolated. Beneficial properties of strains are being evaluated for the design of a probiotic formula to be applied in intensive cattle breeding.