Abstract #248

# 248
Lactobacillus plantarum as direct-fed microbial in high-producing dairy cow diets.
H. F. Monteiro*1, A. L. J. Lelis2, V. L. N. Brandão1, A. Faccenda3, A. S. Avila4, J. Arce-Cordero1, L. G. Silva1, X. Dai1, R. Restelatto5, P. Carvalho6, L. R. Lima6, A. P. Faciola1, 1Department of Animal Sciences, University of Florida, Gainesville, FL, 2Departamento de Zootecnia, Universidade de São Paulo, Pirassununga, SP, Brazil, 3Departamento de Zootecnia, Universidade Estadual de Maringá, Maringá, PR, Brazil, 4Departamento de Zootecnia, Universidade Estadual do Oeste do Paraná, Marechal Cândido Rondon, PR, Brazil, 5Departamento de Zootecnia, Universidade Federal do Paraná, Curitiba, PR, Brazil, 6Departamento de Zootecnia, Universidade Federal do Mato Grosso, Cuiabá, MT, Brazil.

The objective of this study was to evaluate the effects of Lactobacillus plantarum as direct fed microbials (DFM) in high-producing dairy cows’ diets on ruminal fermentation and N metabolism in vitro. A dual-flow continuous culture system was used in a replicated 4 × 4 Latin square design. A basal diet was formulated to meet the requirements of a cow producing 45 kg of milk/d (16% CP and 28% starch). There were 4 experimental treatments: the basal diet without any DFM (CTRL); a mix of Lactobacillus acidophilus 1 × 109 cfu/g and Propionibacterium freudenreichii 2 × 109 cfu/g (MLP = 0.01% of diet DM); and 2 different inclusion levels of L. plantarum 1.35 × 109 cfu/g (L1 = 0.05% and L2 = 0.10% of diet DM). The DFM contained both carrier and microbes. The MLP treatment was used as an intermediate treatment containing bacteria that produce and utilize lactic acid, while L1 and L2 only produce lactic acid. The 15N isotope was used as a microbial marker. Data were analyzed using linear and nonlinear mixed models; orthogonal contrasts were used to compare treatment means. The fermentation pH, lactate concentration, true digestibility of nutrients, and total VFA concentration were not different across treatments. All DFM treatments decreased NH3-N concentration although no other major difference in N metabolism was observed. The L1 treatment tended to have a greater propionate molar proportion compared with L2. In sum, all DFM tested decreased ruminal NH3-N in vitro, which suggests a better N utilization in the rumen. Table 1 (Abstr. 248). Effects of lactic acid-producing DFM on ruminal nitrogen metabolism in vitro
ItemTreatmentSEMP-value
CTRLDFM
MLPL1L2CTRL vs. DFMMLP vs.L1/L2L1 vs. L2
NH3-N, mg/dL15.414.114.314.70.460.050.530.51
N flows, g/d
 Total N2.732.762.792.750.060.590.920.62
 NAN2.102.172.212.170.070.350.960.51
 Bacterial-N0.840.860.900.820.040.590.990.11
 RDP-N1.751.711.711.690.050.370.910.72
 RUP-N1.271.311.301.330.050.350.990.70
Eff. of N utilization, %47.950.353.248.63.000.420.870.25
Bacterial efficiency, g/kg14.014.715.313.80.810.510.870.17

Key Words: lactic acid bacteria, starch, nitrogen metabolism

Speaker Bio
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. In his PhD studies, Monteiro has been dedicated in evaluating the effects of direct fed microbials on 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 in vitro techniques in order to better understand the ruminal fermentation and microbial interactions in the rumen.