Effects of lactic acid bacteria with bacteriocinogenic potential on the fermentation profile and chemical composition of alfalfa silage in tropical conditions

Abstract

The fermentation profile, chemical composition, and microbial populations of alfalfa silages treated with microbial inoculants (MI) at different fermentation periods (T) were evaluated in tropical conditions. A 4×6 factorial arrangement was used in a randomized design with 3 replicates. Fresh alfalfa was treated with (1) no treatment (CTRL), (2) commercial inoculant (CIN), (3) Pediococcus acidilactici (strain 10.6, S1), and (4) Pediococcus pentosaceus (strain 6.16, S2). An inoculant application rate of 10(6) cfu/g of fresh forage was used. The fermentation periods were 1, 3, 7, 14, 28, and 56 d. Alfalfa was harvested 82 d after sowing at the early flowering stage, chopped into 1.5-cm particle size, and ensiled in 25 × 35 cm vacuum-sealed plastic bags. The numbers of lactic acid bacteria, enterobacteria, mold, and yeast in alfalfa before ensiling were 5.42, 5.58, 4.82, and 4.8 log cfu/g, respectively. Silage chemical composition was evaluated only at 56 d. All parameters were affected by the interaction MI × T, except the concentrations of lactic and propionic acids. Alfalfa silage treated with S1 or S2 had lower pH values than CTRL from the first day until 28 d. However, the inoculants resulted in similar pH after 56 d, and these values were lower than the CTRL. The highest concentration of lactic acid was observed in the silage treated with S1 and S2 at 7 and 14 d of ensiling. The concentration of acetic acid was lower in the silages treated with S1 and S2 than the CTRL and CIN at 3 and 28 d of fermentation. There was no effect of MI or MI × T interaction on the microbial populations. However, the number of enterobacteria decreased over the fermentation period until 14 d and increased slightly after this time point. The chemical composition of alfalfa silage was not affected by MI at 56 d of ensiling. The strain P. pentosaceus 6.16 was the most efficient in dominating the fermentation process by decreasing the pH more quickly and increasing the concentration of lactic acid, suggesting its potential use as a silage inoculant.

Effects of sodium diacetate on the fermentation profile, chemical composition and aerobic stability of alfalfa silage

“…Fresh alfalfa is critical for a successful fermentation due to its low DM and WSC concentration (51.6 g/kg) and high buffering capacity (339 mEq/kg DM). The epiphytic LAB populations (5.82 log 10 cfu/g) is adequate, considering the recommendation of 5 log 10 cfu/g as a minimum required to ensure good fermentation during the ensiling [1]. …”

“…Thus, ensiling is the preferred method for preservation of alfalfa in these regions. However, alfalfa is difficult to preserve as silage due to its relatively low concentration of water soluble carbohydrate (WSC) and high buffering capacity [1]. …”

Effects of exogenous amylase on the in vitro digestion kinetics of whole‐crop maize silages made from flint or dent grain type at different phenological stages grown in tropical condition

“…The N-NH 3 /TN concentrations may be one indicative of secondary fermentation caused by heterofermentative bacteria of the genus Clostridium with consequent decrease in lactic acid (Silva et al, 2016). In the present study, even though the N-NH 3 /TN concentration was higher in SOD and ¾M stages for the dent hybrid, the lactic acid was sufficient to maintain the appropriate fermentation process and low N-NH 3 /TN.…”

Antibacterial activity of a hexahydro‐β‐acids/methyl‐β‐cyclodextrin inclusion complex against bacteria related to foodborne illness

“…During the first 5 days, the pH value of control decreased sharply and dropped to 4.56, and then to be stable. The result indicated that sausage was rancid due to breakdown of carbohydrates such as starch and sugar into organic acids in meat products (Silva et al, ). The pH value with HBA/M‐β‐CD decreased within 7–12 days and increased with 12–17 days, this may be because the protein degraded the alkali to make the pH value rise (Sun, Zhao, Chen, Zhang, & Kong, ).…”

“…The effects of HBA/M-β-CD on the SDH activities of S. aureus and E. sakazakii are presented in Figure 5. (Silva et al, 2016). The pH value with HBA/M-β-CD decreased within 7-12 days and increased with 12-17 days, this may be because the protein degraded the alkali to make the pH value rise (Sun, Zhao, Chen, Zhang, & Kong, 2018).…”