Efficacy of biosynthesizing folate, riboflavin and typical probiotic traits reveal the potential use of \(\textit{Lactobacillus plantarum}\) LCN13 as a feed additive for swine farming

Abstract

Lactic acid bacteria have been advocated as probiotics to replace antibiotic growth promoters, improve growth performance, and reduce cost production in swine farming. The aim of this study is to identify and evaluate the probiotic traits of strain LCN13 isolated from traditionally fermented feed for swine. Thirty-five bacterial isolates with different morphological characteristics were isolated, among which 9 isolates showed the ability to produce lactic acid and antibacterial activity against pathogenic bacteria. Among them, isolate LCN13 exhibited a strong capacity to produce lactic acid (18.5 ± 0.31 g/L), inhibited gastrointestinal pathogens such as Salmonella typhimurium ATCC 14028 (18.3 ± 1.52 mm), Escherichia coli ATCC 11105 (24.7 ± 2.14 mm), and Staphylococcus epidermidis ATCC 35984 (31.6 ± 2.93 mm), and produced 182 ng/mL folate and 233 ng/mL riboflavin as measured by LC-MS/MS after 24 hours of incubation. Based on morphological, biochemical, and 16S rRNA gene analysis, the isolate LCN13 was identified as Lactobacillus plantarum. Phenotypic analysis revealed that L. plantarum LCN13 showed remarkable resistance to 1.2% ox-bile salt, 2.0 mM H2O2, and pH 3.0. In addition, the ability to produce high levels of folate (253.6 ± 10.7 ng/mL) and riboflavin (312.0 ± 12.2 ng/mL) after 48 hours was exploited for the first time in the L. plantarum. Taken together, L. plantarum LCN13 might serve as a potential probiotic candidate for animal farming.

Effects of microbial inoculant on chemical compositions and in vitro digestibility of elephant grass-based silage

“…Notably, the NDF value (27.9 2± 1.13 % DM) after 120 h of ensilage was reduced to approximately that of basal diet (24.02 ± 1.44 % DM). This might have occurred because the strain L. plantarum LCN13 and/or both B. velezensis VTX9 and S. cerevisiae MCN9 produced extracellular enzymes such as cellulase that decomposes cellulose and other biopolymer contents including hemicellulose, lignin, and pectin present in plants (Nguyen et al 2022). The obtained results were also consistent with previous studies indicating the advantages of microbial inoculants over a single strain (Turyk et al, 2014;Luo et al, 2021).…”

“…Moreover, as expected, the addition of microbial mixtures accelerated production of organic acids such as lactic acid, while lowering silage pH. Nguyen's study (2022) determined that L. plantarum LCN13 strain had a strong capability to produce lactic acid up to 18.5 ± 0.31 g/L and resist silage pH 2 (Nguyen et al, 2022). In this study, a significant reduction of pH value was only observed in 1% and 1.5% microbial mixtures, at pH 4.45 and pH 4.18, respectively, comparable to that of control at pH 6.5.…”

“…Three probiotic strains for swine farming including Lactobacillus plantarum LCN13, Bacillus velezensis VTX9 and yeast Saccharomyces cerevisiae MCN9 were used in silage preparation. The two strains LCN13 and VTX9 were reported previously (Quach et al, 2021Nguyen et al, 2022. The MCN9 strain obtained from the microbial collection of VAST-Culture Collection of Microorganisms, was cultured in Hansen medium containing (g/L) glucose 50, peptone 10, KH 2PO4 3, MgSO4.7H2O 3, yeast extract 1, agar 20 and adjusted to pH 6, at 30ºC and 200 rpm.…”

“…For silage preparation, 3 microbial strains were cultivated on appropriate medium (Quach et al, 2021;Nguyen et al, 2022) and then lyophilized to dried powder as previously described (Zhang et al, 2016). The microbial mixture powder made up of these 3 strains with each strain containing 10 8 CFU/g.…”

“…Living microorganisms with probiotic properties belonging to several genera including Lactobacillus, Bacillus, Streptococcus, Bifidobacterium, and Saccharomyces, maintain the intestinal microbial balance, lower cholesterol, inhibit pathogenic microbes, and stimulate immune responses (M. de Angelis et al, 2006;Konstantinov et al, 2004). In recent studies, we demonstrated that Bacillus velezensis VTX9 and Lactobacillus plantarum LCN13 were potential feed additives for pig farming (Quach et al, 2021;Nguyen et al, 2022). This study aimed to formulate and evaluate effects of microbial inoculants on quality and digestibility of elephant grass-based silage.…”