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Effects of Lactobacillus plantarum as direct-fed microbials on the ruminal microbial community composition using a dual-flow continuous culture system.

H. F. Monteiro




Effects of Lactobacillus plantarum as direct-fed microbials on the ruminal microbial community composition using a dual-flow continuous culture system.
H. F. Monteiro*1, P. Fan1, X. Dai2, J. Arce-Cordero1, B. C. Agustinho1,3, R. R. Lobo1, A. L. J. Lelis4, V. L. N. Brand�o1, A. Faccenda3, A. S. Avila5, R. Restelatto6, L. G. Silva7, K. C. Jeong1, A. P. Faciola1. 1Department of Animal Sciences, University of Florida Gainesville, FL, 2U.S. Dairy Forage Research Center, ARS-USDA Madison, WI, 3Departamento de Zootecnia, Universidade Estadual de Maring� Maringa, PR, Brazil, 4Departamento de Zootecnia, Universidade de S�o Paulo S�o Paulo, SP, Brazil, 5Departamento de Zootecnia, Universidade Estadual do Oeste do Paran� Marechal C�ndido Rondon, PR, Brazil, 6Departamento de Zootecnia, Universidade Federal do Paran� Curitiba, PR, Brazil, 7Departamento de Zootecnia, Universidade Estadual Paulista Jaboticabal, SP, Brazil.

The objective of this study was to evaluate the ruminal microbial community composition changes by feeding Lactobacillus plantarum as direct-fed microbials (DFM) in high-producing dairy cows' diets. A dual-flow continuous culture system was used in a replicated 4x4 Latin square design. A basal diet was formulated containing 16% protein and 28% starch and the treatments were: the basal diet without DFM (CTRL); a mix of Lactobacillus acidophilus at 1 � 109cfu/g and Propionibacterium freudenreichii at 2 � 109 cfu/g (MLP = 0.01% of diet DM); and 2 levels of L. plantarum at 1.35 � 109 cfu/g (L1 = 0.05% and L2 = 0.10% of diet DM). Bacterial samples were collected at 0, 2, 4, 6, and 8 h after feeding from the effluent containers; a composite of all time points was made for each fermenter. The microbial community composition was analyzed through sequencing the V4 region of the 16S rRNA gene using Illumina MiSeq platform. Sequencing data were analyzed on QIIME and statistical analysis was performed with R and SAS; orthogonal contrasts were used to compare treatments. The most abundant phyla from all sequences were Bacteroidetes and Firmicutes, with 42% and 34% of relative abundance, respectively. At the family level, all DFM treatments decreased the relative abundance of Lachnospiraceae (P = 0.03), Pirellulaceae (P = 0.05), and Paracaedibacteraceae (P = 0.02) populations, while L. plantarum inclusion positively affected the abundance of Anaeroplasmataceae (P = 0.04). Interestingly, the Lactobacillaceae family was not detected in our analysis, which may indicate a low survival rate of the tested DFM in the ruminal fluid. Relative abundance of 9 genera (mostly fibrolytic and proteolytic) decreased with the DFM inclusion, with emphasis on Butyrivibrio spp. (P = 0.01), while 1 genus increased with DFM inclusion (Ruminococcaceae UCG-002; P = 0.02). These findings help to explain why DFM inclusion decreased NH3-N concentration, while pH and lactate concentration were not affected by treatments.

Keywords: 16S rRNA, Butyrivibrio, Lactobacillus acidophilus.

Biography: Hugo Monteiro graduated in Animal Sciences at State University of Maringa in Brazil and is currently pursuing his PhD at the University of Florida, under advisory of Dr. Antonio Faciola. Monteiro is the current Treasurer of the ADSA (Graduate Student Division), as well is dedicated to understanding how direct-fed microbials affect ruminal fermentation and the microbial community composition of the rumen. Monteiro has also worked in setting up a new dual-flow continuous culture system at Faciola's lab, and his future research goals include studying the rumen microbiome in order to develop new techniques for ruminal fermentation assessment.