<Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> and Its Probiotic and Food Potentialities

The number of studies claiming probiotic health effects of Lactobacillus plantarum is escalating. Lb. plantarum is a lactic acid bacterium found in diverse ecological niches, highlighting its particular capabilities of adaptation and genome plasticity. Another function that needs to be underlined is the capabilities of Lb. plantarum to produce diverse and potent bacteriocins, which are antimicrobial peptides with possible applications as food preservative or antibiotic complementary agents. Taken together, all these characteristics design Lb. plantarum as a genuine model for academic research and viable biological agent with promising applications. The present review aims at shedding light on the safety of Lb. plantarum and run through the main studies underpinning its beneficial claims. The mechanisms explaining probiotic-related features are discussed.     

Functional Characterization of Potential Probiotic Lactic Acid Bacteria Isolated from <Emphasis Type="Italic">Kalarei</Emphasis> and Development of Probiotic Fermented Oat Flour

Considerable variations among probiotics with respect to their health benefitting attributes fuel the research on bioprospecting of proficient probiotic strains from various ecological niches especially the poorly unexplored ones. In the current study, kalarei, an indigenous cheese-like fermented milk product, and other dairy-based sources like curd and raw milk were used for isolation of lactic acid bacteria (LAB). Among 34 LAB isolates, 7 that could withstand simulated gastrointestinal (GI) conditions were characterized for functional probiotic attributes, viz. adhesion ability, aggregation and coaggregation, extracellular enzyme producing capability, antibacterial activity against pathogens and antibiotic resistance. The isolate M-13 (from kalarei) which exhibited most of the desirable probiotic functional properties was identified as Lactobacillus plantarum based on 16S ribosomal DNA sequence analysis and designated as L. plantarum M-13. The sequence was submitted to GenBank (accession number KT592509). The study presents the first ever report of isolation of potential probiotic LAB, i.e. L. plantarum M-13 from indigenous food kalarei, and its application for development of potential probiotic fermented oat flour (PFOF). PFOF was analysed for parameters like viability of L. plantarum M-13, acidity and pH. Results show that PFOF serves as a good matrix for potential probiotic L. plantarum M-13 as it supported adequate growth of the organism (14.4 log cfu/ml after 72 h of fermentation). In addition, appreciable acid production by L. plantarum M-13 and consequential pH reduction indicates the vigorous and active metabolic status of the potential probiotic organism in the food matrix. Thus, study shows that fermented oat flour may possibly be developed as a potential probiotic carrier especially in view of the problems associated with dairy products as probiotic vehicles.     

Safety of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> ST8Sh and Its Bacteriocin

Total DNA extracted from Lb. plantarum ST8Sh was screened for the presence of more than 50 genes related to production of biogenic amines (histidine decarboxylase, tyrosine decarboxylase, and ornithine decarboxylase), virulence factors (sex pheromones, gelatinase, cytolysin, hyaluronidase, aggregation substance, enterococcal surface protein, endocarditis antigen, adhesion of collagen, integration factors), and antibiotic resistance (vancomycin, tetracycline, erythromycin, gentamicin, chloramphenicol, bacitracin). Lb. plantarum ST8Sh showed a low presence of virulence genes. Only 13 genes were detected (related to sex pheromones, aggregation substance, adhesion of collagen, tetracycline, gentamicin, chloramphenicol, erythromycin, but not to vancomycin, and bacitracin) and may be considered as indication of safety for application in fermented food products. In addition, interaction between Lb. plantarum ST8Sh and drugs from different groups were determined in order to establish possible application of the strain in combination with commercial drugs. Cytotoxicity of the semi-purified bacteriocins produced by Lb. plantarum ST8Sh was depended on applied concentration—highly cytotoxic when applied at 25 μg/mL and no cytotoxicity at 5 μg/mL.     

Characterization of bacteriocins produced by strains of <Emphasis Type="Italic">Pediococcus pentosaceus</Emphasis> isolated from Minas cheese

Interest in obtaining bacteriocin-producing strains of lactic acid bacteria (LAB) from different sources has been increasing in recent years due to their multiple applications in health and food industries. This study focused on the isolation and characterization of metabolically active populations of bacteriocinogenic LAB and the evaluation of their antimicrobial substances as well as of some nutritional requirements of them. One hundred and fifty colonies of LAB from artisanal cheeses produced in Minas Gerais state (Brazil) were isolated and screened for their antimicrobial activity. According to their activity against Listeria monocytogenes, ten strains were selected and subsequently identified using biochemical and molecular techniques including 16s rRNA amplification and sequencing as Enterococcus faecalis, Lactobacillus spp., and Pediococcus pentosaceus. Antimicrobial substances produced by four of the selected strains, P. pentosaceus 63, P. pentosaceus 145, P. pentosaceus 146, and P. pentosaceus 147, were biochemically characterized, and presented sensitivity to proteolytic enzymes (suggesting their proteinaceous nature) and to extreme pH. Antimicrobial activity showed stability after treatment with lipase, catalase, α-amylase, and chemicals. Growth kinetics of the P. pentosaceus selected showed maximal bacteriocin production at 37 °C during the end of the exponential growth phase (25,600 AU/mL) and stable production during 24 h of incubation. Dextrose, maltose, and a mixture of peptone, meat extract, and yeast extract increased bacteriocin production. This study demonstrated that dairy products provide a good alternative for obtaining LAB, with the ability to produce antimicrobial substances such as bacteriocins that have potential use as biopreservatives in food.     

<Emphasis Type="Italic">Lactobacillus futsaii</Emphasis> CS3, a New GABA-Producing Strain Isolated from Thai Fermented Shrimp (<Emphasis Type="Italic">Kung</Emphasis>-<Emphasis Type="Italic">Som</Emphasis>)

Kung-Som is a popular traditional Thai fermented shrimp product. It is rich in glutamic acid, which is the major substrate for the biosynthesis of gamma-aminobutyric acid (GABA) by lactic acid bacteria (LAB). In the present study, LAB from Kung-Som were isolated, screened for GABA formation, and the two isolates that transform glutamic acid most efficiently into GABA were identified. Based on the API-CHL50 fermentation profile and a phylogenetic tree of 16S rDNA sequences, strain CS3 and CS5 were identified as Lactobacillus futsaii, which was for the first time shown to be a promising GABA producer. L. futsaii CS3 was the most efficient microorganism for the conversion of 25 mg/mL monosodium glutamate (MSG) to GABA, with a maximum yield of more than 99% conversion rate within 72 h. The open reading frame (ORF) of the glutamate decarboxylase (gad) gene was identified by PCR. It consists of 1410 bp encoding a polypeptide of 469 amino acids with a predicted molecular weight of 53.64 kDa and an isoelectric point (pI) of 5.56. Moreover, a good quality of the constructed model of L. futsaii CS3 was also estimated. Our results indicate that L. futsaii CS3 could be of interest for the production of GABA-enriched foods by fermentation and for other value-added products.     

Protective Effects of <Emphasis Type="Italic">Mekabu</Emphasis> Aqueous Solution Fermented by <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Sanriku-SU7 on Human Enterocyte-Like HT-29-luc Cells and DSS-Induced Murine IBD Model

Most wakame Undaria pinnatifida, a brown algae, products are made from the frond portion. In this study, the polysaccharide content and antioxidant property of aqueous extract solutions (AESs) of the four parts (frond: wakame, stem of the frond: kuki-wakame, sporophyll: mekabu, and kuki-mekabu) of wakame were investigated. Polysaccharide content was high in both the wakame and mekabu. Superoxide anion (O₂ ^?) radical-scavenging capacities were high in the mekabu. These AESs could be fermented by Lactobacillus plantarum Sanriku-SU7. The O₂ ^? radical-scavenging activity of the kuki-wakame, mekabu, and kuki-mekabu were increased by the fermentation. Fermented mekabu clearly showed a protective effect on human enterocyte-like HT-29-luc cells and in a mouse model of dextran sodium sulphate-induced inflammatory bowel disease (IBD). These results suggest that the mekabu fermented by L. plantarum Sanriku-SU7 has anti-IBD effect related to O₂ ^? radical-scavenging.     

Decrease of <Emphasis Type="Italic">N</Emphasis>-nitrosodimethylamine and <Emphasis Type="Italic">N</Emphasis>-nitrosodiethylamine by <Emphasis Type="Italic">Lactobacillus pentosus</Emphasis> R3 is associated with surface-layer proteins

The objective of this study was to evaluate the ability of five strains of meat-borne bacteria to decrease N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) and to elucidate the mechanism in Mann-Rogosa-Sharp (MRS) broth. Lactobacillus pentosus R3 was found to be the most effective in decreasing the concentration of the two N-nitrosamines (NAs) in MRS broth, with a rate of 22.05% for NDMA and 23.31% for NDEA. The concentration of the two NAs could not be reduced by either extracellular metabolites or intracellular extracts of Lb. pentosus R3 (P?>?0.05), and proteinaceous substances in the cell debris were found to be responsible for the decrease. These were surface-layer proteins (SLPs) located on the cell wall. Therefore, the decrease in NDMA and NDEA by Lb. pentosus R3 is associated with its SLPs. Lb. pentosus R3 may be developed as a starter culture in the production of fermented foods with lower NAs.     

In Vitro Evaluation of Beneficial Properties of Bacteriocinogenic <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> ST8Sh

Lactobacillus plantarum ST8Sh, isolated from Bulgarian salami “shpek” and previously characterized as bacteriocin producer, was evaluated for its beneficial properties. Based on the PCR analysis, Lb. plantarum ST8Sh was shown to host a gene related to the production of adhesion proteins such as Mab, Mub, EF, and PrgB. Genetic and physiological tests suggest Lb. plantarum ST8Sh to represent a potential probiotic candidate, including survival in the presence of low levels of pH and high levels of ox bile, production of β-galactosidase, bile salt deconjugation, high level of hydrophobicity, functional auto- and co-aggregation properties, and adhesion to cell lines. Application of semi-purified bacteriocin produced by Lb. plantarum ST8Sh in combination with ciprofloxacin presented synergistic effect on inhibition of Listeria monocytogenes Scott A. Based on observed properties, Lb. plantarum ST8Sh can be considered as a potential probiotic candidate with additional bacteriocinogenic properties.     

Probiotic potential of novel <Emphasis Type="Italic">Lactobacillus</Emphasis> strains isolated from salted-fermented shrimp as antagonists for <Emphasis Type="Italic">Vibrio parahaemolyticus</Emphasis>

Lactobacillus strains have been considered good candidates as biological control agents for prevention or treatment of plant and animal infections. One L. plantarum strain FB003 and three strains (FB011, FB081, and FB110) which closed to L. sakei were isolated from fermented and salted shrimp and their abilities in inhibiting growth of Vibrio parahaemolyticus were characterized. These strains were selected as potential probiotics based on their oro-gastro-intestinal resistance, gut colonization, adhesion to Caco-2 cells, antimicrobial activities, antibiotic resistance, and safety aspects. Results of this study revealed that these isolates possessed high aggregation activities against pathogens in host intestines. Strain FB011 strain showed higher coaggregation and immunomodulatory activity in the gastro-intestinal tract than L. plantarum. These difference effects of Lactobacillus strains provide valuable information about using them to prevent Vibrio infections in the aquaculture industry.     

Deletion of <Emphasis Type="Italic">ldh</Emphasis>A and <Emphasis Type="Italic">ald</Emphasis>H genes in <Emphasis Type="Italic">Klebsiella</Emphasis><Emphasis Type="Italic">pneumoniae</Emphasis> to enhance 1,3-propanediol production

Objectives

To improve 1,3-propanediol (1,3-PD) production and reduce byproduct concentration during the fermentation of Klebsiella pneumonia.

Results

Klebsiella. pneumonia 2-1ΔldhA, K. pneumonia 2-1ΔaldH and K. pneumonia 2-1ΔldhAΔaldH mutant strains were obtained through deletion of the ldhA gene encoding lactate dehydrogenase required for lactate synthesis and the aldH gene encoding acetaldehyde dehydrogenase involved in the synthesis of ethanol. After fed-batch fermentation, the production of 1,3-PD from glycerol was enhanced and the concentrations of byproducts were reduced compared with the original strain K. pneumonia 2-1. The maximum yields of 1,3-PD were 85.7, 82.5 and 87.5 g/l in the respective mutant strains.

Conclusion

Deletion of either aldH or ldhA promoted 1,3-PD production in K. pneumonia.

     

Diversity and dynamics of lactic acid bacteria in <Emphasis Type="Italic">Atole agrio</Emphasis>, a traditional maize-based fermented beverage from South-Eastern Mexico,analysed by high throughput sequencing and culturing

The purpose of this work was to analyse the diversity and dynamics of lactic acid bacteria (LAB) throughout the fermentation process in Atole agrio, a traditional maize based food of Mexican origin. Samples of different fermentation times were analysed using culture-dependent and -independent approaches. Identification of LAB isolates revealed the presence of members of the genera Pediococcus, Weissella, Lactobacillus, Leuconostoc and Lactococcus, and the predominance of Pediococcus pentosaceus and Weissella confusa in liquid and solid batches, respectively. High-throughput sequencing (HTS) of the 16S rRNA gene confirmed the predominance of Lactobacillaceae and Leuconostocaceae at the beginning of the process. In liquid fermentation Acetobacteraceae dominate after 4 h as pH decreased. In contrast, Leuconostocaceae dominated the solid fermentation except at 12 h that were overgrown by Acetobacteraceae. Regarding LAB genera, Lactobacillus dominated the liquid fermentation except at 12 h when Weissella, Lactococcus and Streptococcus were the most abundant. In solid fermentation Weissella predominated all through the process. HTS determined that Lactobacillus plantarum and W. confusa dominated in the liquid and solid batches, respectively. Two oligotypes have been identified for L. plantarum and W. confusa populations, differing in a single nucleotide position each. Only one of the oligotypes was detected among the isolates obtained from each species, the biological significance of which remains unclear.     

Isolation and characterization of a new fructophilic <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> FPL strain from honeydew

In the present study, a Lactobacillus plantarum FPL strain exhibiting fructophilic behavior has been isolated for the first time from honeydew. It is a probably syntrophic bacterium inhabiting the gastrointestinal tract of Coccus hesperidum L. and taking part in sugar metabolism. The promising growth characteristics and biochemical properties of Lb. plantarum FPL indicate that this may be a facultatively fructophilic species, whose properties are not associated with the loss of the alcohol/acetaldehyde dehydrogenase gene. The article attempts to classify the peculiar behavior of this strain by means of tests that are characteristic for FLAB as well as through a classic identification approach. In this study, we used a reference strain Lb. plantarum NRRL B-4496, which showed no fructophilic properties. With the FLAB group, the new strain shares the habit, such as a fructose-rich environment, the preference of this sugar for growth, and similar growth curves. However, it exceeds FLAB in terms of osmotolerance to high sugar content. The fructophilic Lb. plantarum FPL strain can proliferate and grow on a medium wherein the sugar concentration is 45 and 50% (w/v). Our findings indicate that honeydew can be a promising source of new fructophilic lactic acid bacteria.     

A metabolomics and proteomics study of the <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> in the grass carp fermentation

Background

Lactobacillus plantarum, a versatile lactic acid-fermenting bacterium, isolated from the traditional pickles in Ningbo of China, was chosen for grass carp fermentation, which could also improve the flavor of grass carp. We here explored the central metabolic pathways of L. plantarum by using metabolomic approach, and further proved the potential for metabolomics combined with proteomics approaches for the basic research on the changes of metabolites and the corresponding fermentation mechanism of L. plantarum fermentation.

Results

This study provides a cellular material footprinting of more than 77 metabolites and 27 proteins in L. plantarum during the grass carp fermentation. Compared to control group, cells displayed higher levels of proteins associated with glycolysis and nucleotide synthesis, whereas increased levels of serine, ornithine, aspartic acid, 2-piperidinecarboxylic acid, and fumarate, along with decreased levels of alanine, glycine, threonine, tryptophan, and lysine.

Conclusions

Our results may provide a deeper understanding of L. plantarum fermentation mechanism based on metabolomics and proteomic analysis and facilitate future investigations into the characterization of L. plantarum during the grass carp fermentation.

     

The growth kinetics and metabolic and antioxidant activities of the functional synbiotic combination of <Emphasis Type="Italic">Lactobacillus gasseri</Emphasis> 505 and <Emphasis Type="Italic">Cudrania tricuspidata</Emphasis> leaf extract

In a previous study, the synbiotic combination of selected Lactobacillus gasseri strains and Cudrania tricuspidata leaf extract (CT) was shown to significantly improve the functionality of fermented milk, and the greatest synbiotic effect was exhibited with L. gasseri 505. The aim of the present study was to investigate the growth kinetics and fermentation metabolism of this specific synbiotic combination. Fermentation was carried out in synthetic media and milk with or without CT supplementation using L. gasseri 505. Whole genome sequencing and comparative genomics analyses were conducted to verify the novelty of strain. Titratable acidity, pH, microbial population, and organic acid production were measured during the fermentation period. The addition of CT accelerated the acidification rate, supporting the growth of L. gasseri 505, and the production of fermentation metabolites such as lactic acid and pyruvic acid also significantly increased during fermentation of both of CT-supplemented synthetic media and milk. In particular, the formic acid and propionic acid in CT were significantly utilized during fermentation of milk by L. gasseri 505. Moreover, the antioxidant capacity of CT-supplemented fermented milk increased due to the release of bioactive compounds until the exponential growth phase, after which the antioxidant activity declined due to degradation and loss of potency. Therefore, this study established that L. gasseri 505 efficiently utilized the CT-related nutrients during fermentation producing resulting metabolites with health-promoting effects, although it is necessary to control the fermentation time to obtain dairy products with optimum functionality.     

Lactic acid bacteria population dynamics during spontaneous fermentation of radish (<Emphasis Type="Italic">Raphanus sativus</Emphasis> L.) roots in brine

The aim of the present study was to assess the microecosystem development and the dynamics of the lactic acid bacteria population during spontaneous fermentation of radish (Raphanus sativus L.) roots in brine at 20 and 30?°C. In both temperatures, lactic acid bacteria prevailed the fermentation; as a result, the pH value was reduced to ca. 3.6 and total titrable acidity increased to ca. 0.4% lactic acid. Enterococci population increased and formed a secondary microbiota while pseudomonads, Enterobacteriaceae and yeasts/molds populations were below enumeration limit already before the middle of fermentation. Pediococcus pentosaceus dominated during the first days, followed by Lactobacillus plantarum that prevailed the fermentation until the end. Lactobacillus brevis was also detected during the final days of fermentation. A succession at sub-species level was revealed by the combination of RAPD-PCR and rep-PCR analyses. Glucose and fructose were the main carbohydrates detected in brine and were metabolized into lactic acid, acetic acid and ethanol.     

Effect of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> Tennozu-SU2 on <Emphasis Type="Italic">Salmonella</Emphasis> Typhimurium Infection in Human Enterocyte-Like HT-29-Luc Cells and BALB/c Mice

The probiotic properties and inhibitory effect on Salmonella Typhimurium adhesion on human enterocyte-like HT-29-Luc cells of three Lactobacillus plantarum strains isolated from fermented fish, beach sand and a coastal plant were determined. Compared with the type strain L. plantarum NBRC 15891^T, which was isolated from pickled cabbage, L. plantarum Tennozu-SU2 isolated from the acorn of a coastal tree showed high autoaggregation in de Man, Rogosa and Sharpe (MRS) broth and an antagonistic effect against S. Typhimurium in brain heart infusion (BHI) broth. Furthermore, heat-killed L. plantarum Tennozu-SU2 cells inhibited S. Typhimurium adhesion on HT-29-Luc cells. Both live and heat-killed L. plantarum Tennozu-SU2 cells showed an inhibitory effect on gut colonisation in BALB/c mice, as assessed by viable Salmonella count in faecal samples and by invasion into liver and spleen tissues. The properties shown in this study suggest that L. plantarum Tennozu-SU2 is useful as a starter and probiotic bacteria in functional food material.     

<Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> isolated from cheese: production and partial characterization of bacteriocin B391

Lactobacillus plantarum B391, a strain isolated from an artisanal French cheese, is a producer of a bacteriocin, expressing activity against Enterococcus faecalis NCTC 775, Clostridium perfringens NCTC 13170 and several Listeria monocytogenes strains. High stability was recorded after heat treatment at 121 °C for 20 min and when stored at 4 °C for more than 40 days. A challenge test performed in milk for 11 days showed potential for the control of L. monocytogenes. In the presence of the lytic bacteriocin B391, L. monocytogenes cells present numerous morphology modifications of cell shape and surface structure as well as in the cell division pattern, resulting ultimately in lysis. The high level of Listeria growth inhibition obtained in the presence of Lb. plantarum B391, and the stability of B391 bacteriocin for a long period of time, make this strain potentially interesting to use in milk products to increase food safety.     

Two-step production of gamma-aminobutyric acid from cassava powder using <Emphasis Type="Italic">Corynebacterium glutamicum</Emphasis> and <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis>

Production of gamma-aminobutyric acid (GABA) from crop biomass such as cassava in high concentration is desirable, but difficult to achieve. A safe biotechnological route was investigated to produce GABA from cassava powder by C. glutamicum G01 and L. plantarum GB01-21. Liquefied cassava powder was first transformed to glutamic acid by simultaneous saccharification and fermentation with C. glutamicum G01, followed by biotransformation of glutamic acid to GABA with resting cells of L. plantarum GB01-21 in the reaction medium. After optimizing the reaction conditions, the maximum concentration of GABA reached 80.5 g/L with a GABA productivity of 2.68 g/L/h. This is the highest yield ever reported of GABA production from cassava-derived glucose. The bioprocess provides the added advantage of employing nonpathogenic microorganisms, C. glutamicum and L. plantarum, in microbial production of GABA from cassava biomass, which can be used in the food and pharmaceutical industries.     

Functional Properties of <Emphasis Type="Italic">Lactobacillus mucosae</Emphasis> Strains Isolated from Brazilian Goat Milk

The search for probiotic candidates among lactic acid bacteria (LAB) isolated from food may uncover new strains with promising health and technological properties. Lactobacillus mucosae strains attracted recent research attention due to their ability to adhere to intestinal mucus and to inhibit pathogens in the gastrointestinal tract, both related to a probiotic potential. Properties of interest and safety aspects of three Lb. mucosae strains (CNPC006, CNPC007, and CNPC009) isolated from goat milk were investigated employing in vitro tests. The presence of genetic factors related to bile salt hydrolase production (bsh), intestinal adhesion properties (msa, map, mub, and ef-tu), virulence, and biogenic amine production were also verified. All strains exhibited the target map, mub, and ef-tu sequences; the msa gene was detected in CNPC006 and CNPC007 strains. Some of the searched sequences for virulence factors were detected, especially in the CNPC009 strain; all strains carried the hyl gene, related to the production of hyaluronidase. Lb. mucosae CNPC007 exhibited a high survival rate in simulated gastric and enteric conditions. Besides, all strains exhibited the bsh sequence, and CNPC006 and CNPC007 were able to deconjugate salts of glycodeoxycholic acid (GDC). Regarding technological properties for dairy product applications, a relatively higher milk acidification and clotting capacity, diacetyl production, and proteolytic activity were registered for CNPC007 in comparison to the other strains. Collectively, the results aim at Lb. mucosae CNPC007 as a promising probiotic candidate for application in dairy products, deserving further studies to confirm and explore its potential.     

Effects of Dietary <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> on Growth Performance,Digestive Enzymes and Gut Morphology of <Emphasis Type="Italic">Litopenaeus vannamei</Emphasis>

A 15-day feeding trial was conducted to investigate the effect of dietary Lactobacillus plantarum on growth performance, digestive enzyme activities and gut morphology of juvenile Pacific white shrimp, Litopenaeus vannamei (initial body weight = 7.96 ± 0.59 g). Four microbound diets were formulated to contain fermentation supernatant (FS), live bacteria (LB), dead bacteria (DB), and cell-free extract (CE) of L. plantarum. Results indicated that final weight was significantly higher in FS, DB, and CE group in comparison to the control group (P < 0.05). The maximum weight gain rate (WGR) and specific growth rate (SGR) of the CE diet group were significantly higher than that of other groups (P < 0.05). The FCR of CE diet group was lower than that of the control, LB, DB, and FS diets groups (P < 0.05). The highest digestive enzyme activities (amylase, lipase, and pepsin activity) in the hepatopancreas and gut of shrimp were observed in the CE diet group. Histological study revealed that dietary CE diet could significantly increase the enterocytes height of shrimp. The administration of cell-free extract of L. plantarum could effectively improve the growth performance of L. vannamei via the improvement of digestive enzyme activities and the enterocytes height of shrimp. The results of this study will be essential to promote application of probiotics in shrimp aquaculture.