In vitro evaluation of Lactobacillus plantarum as direct-fed microbials in high-producing dairy cows diets

Abstract

The objectives of this study were: 1) to compare the effects of live yeast (LY), yeast fermentation product (YFP), a mix of Lactobacillus acidophilus and Propionibacterium freudenreichii (MLP), and Lactobacillus plantarum included as additives in dairy cows’ diets on in vitro ruminal fermentation and gas production (GP); and 2) to evaluate the effects of L. plantarum as direct-fed microbials (DFM) in dairy cows’ diets on in vitro ruminal fermentation, GP, nutrient digestibility, and N metabolism. Three experiments were carried out: Exp. 1 had the objective to compare all additives regarding ruminal fermentation parameters: an Ankom GP system was used in a completely randomized design, consisting of four 48 h incubations, and eight replications per treatment. There were eight treatments: a basal diet without additive (CTRL) or with one of the following additives: LY, YFP, MLP, or L. plantarum at four levels (% of diet Dry Matter (DM)): 0.05% (L1), 0.10% (L2), 0.15% (L3), and 0.20% (L4). In Exp. 2, a batch culture was used to evaluate ruminal fermentation, and CO2 and CH4 production using the same treatments and a similar experimental design, except for having 16 replications per treatment. Based on Exp. 1 and 2 results, Exp. 3 aimed at evaluating the effects of the L. plantarum on ruminal true nutrient digestibility and N utilization in order to evaluate the use of L. plantarum as DFM. The treatments CTRL, MLP, L1, and L2 were used in a replicated 4 × 4 Latin square design using a dual-flow continuous culture system. Data were analyzed using linear and nonlinear regression; treatment means were compared through contrasts, and L treatments in Exp. 1 and 2 were tested for linear, quadratic, and cubic effects. In Exp. 1, all treatments containing additives tended to reduce OM digestibility as well as reduced total volatile fatty acids (VFA) concentration and total GP. The YFP had greater OM digestibility than LY, and MLP treatment had greater total VFA concentration compared to L. plantarum treatments. In Exp. 2, additives reduced CO2 production, and there were no major differences in CH4. In Exp. 3, all additives reduced NH3-N concentration. In conclusion, pH and lactate concentration were not affected in all three experiments regardless of additive tested, suggesting that these additives may not improve ruminal fermentation by pH modulation; and L. plantarum may improve ruminal N metabolism when used as DFM in high-producing dairy cows’ diets, mainly by reducing NH3-N concentration.

Lactobacillus plantarum as feed additive to improvement in vitro ruminal biofermentation and digestibility of some tropical tree leaves

“…However, in an in vitro experiment (Monteiro et al . 2020) using levels of 0·05, 0·10, 0·15 and 0·20% of DM of diets, LP inclusion (1·35 × 10 9 CFU per g) had no effect on ammonia‐N concentration in dairy cow. On the other hand, the reduction of ammonia‐N in the non‐LP treatments could be explained by the effect of tannins on the population of protozoa and consequently their decreased proteolytic and deamination activity and ammonia‐N as reported by Yanez Ruiz et al .…”

Effect of sugarcane bagasse as industrial by‐products treated withLactobacillus caseiTH14, cellulase and molasses on feed utilization, ruminal ecology and milk production of mid‐lactating Holstein Friesian cows

“…The LAB from the silage and lactic acid utilizing bacteria in the rumen function on scavenging the hydrogen atom to form C3 caused a lack of hydrogen as the main substrate of methanogenic bacteria to form CH 4 in the rumen. Monteiro et al 49 . similarly found a reduction in CH 4 by direct‐fed L. plantarum in high‐producing dairy cow diets.…”

Roughage to Concentrate Ratio and Saccharomyces cerevisiae Inclusion Could Modulate Feed Digestion and In Vitro Ruminal Fermentation

“…The increase in VFA concentrations in this present study indicates enhanced microbial activity in terms of fermentation and agrees with previous findings regarding total bacteria populations [ 2 , 4 ]. The decrease in the ruminal NH 3 -N concentration seemed to be due to increased absorption of NH 3 -N into microbial proteins, probably because of the stimulation of microbial activity by S. cerevisiae [ 38 , 39 ].…”