Abstract
Modulation of animal gut microbiota is a prominent function of probiotics to improve the health and performance of livestock. In this study, a large-scale survey to evaluate the effect of lactic acid bacteria probiotics on shaping the fecal bacterial community structure of 126 feedlot cattle during three experimental periods of the fattening cycle (163 days) was conducted. A feedlot industry located in northwestern Argentina was enrolled with cattle fed mixed rations (forage and increasing grain diet). High-throughput sequencing (HTS) of 16S rDNA amplicons was applied to characterize the fecal microbiota and explore its modulation as affected by the administration of five probiotic groups and experimental administration periods. The microbial diversity of fecal samples was significantly affected (p < 0.05) by the administration period compared with probiotic group supplementation. The fecal microbiome of samples was dominated by the Firmicutes (72-98%) and Actinobacteria (0.8-27%) phyla, while a lower abundance of Bacteroidetes (0.08-4.2%) was present. At the family level, probiotics were able to modulate the fecal microbiota with a convergence of Clostridiaceae, Lachnospiraceae, Ruminococcaceae and Bifidobacteriaceae associated with health and growth benefits as core microbiome members. Metabolic functional prediction comparing experimental administration periods showed an enrichment of metabolic pathways related to complex plant-derived polysaccharide digestion as well as amino acids and derivatives during the first 40 days of probiotic supplementation. Genomic-based knowledge on the benefits of autochthonous probiotics on cattle gastrointestinal tract (GIT) microbiota composition and functions will contribute to their selection as antibiotic alternatives for the feedlot industry.
Fecal Microbiome Modulation of Bacterial Communities Associated With the Administration of Probiotic Lactic Acid Bacteria to Feedlot Cattle
