内蒙古呼伦贝尔地区传统发酵乳中乳酸菌的多样性分析

【目的】对内蒙古呼伦贝尔地区传统发酵乳制品中乳酸菌资源的生物多样性进行研究。【方法】采用纯培养和16S rRNA基因序列分析法对内蒙古呼伦贝尔地区传统发酵乳中的乳酸菌进行多样性分析。【结果】从8份传统发酵乳制品(6份酸牛奶和2份酸马奶)样品中分离到24株乳酸菌,通过16S rRNA基因序列分析和系统进化关系分析将24株乳酸菌鉴定为2株Lactobacillus kefiranofaciens、2株Lactobacillus kefiri、5株Lactobacillus paracasei、3株Lactobacillus plantarum、1株Lactobacillus rhamnosus、6株Lactococcus lactis subsp.lactis、2株Leuconostoc mesenteroides subsp.dextranicum、2株Streptococcus thermophilus和1株Enterococcus faecium。【结论】Lactococcus lactis subsp.lactis为内蒙古呼伦贝尔地区传统发酵乳制品的优势菌种,占总分离株的25%,其次为Lactobacillus paracasei,占总分离株的20.83%。     

Identification of phenotypically and genotypically related <Emphasis Type="Italic">Lactobacillus</Emphasis> strains based on nucleotide sequence analysis of the <Emphasis Type="Italic">groEL,rpoB, rplB</Emphasis>, and <Emphasis Type="Italic">16S rRNA</Emphasis> genes

Sixty-eight cultures of lactic acid bacteria were isolated and identified from national fermented milk drinks (airan, koumiss, kurunga, shubat) home-made in different regions of the Republic of Kazakhstan and the Buryat Republic of Russia. The cultures of lactic acid bacteria of the genus Lactobacillus were identified as L. paracasei and L. rhamnosus related to the L. casei group and as L. brevis, L. buchneri, L. diolivorans, and L. parabuchneri (the L. buchneri group) using the classical microbiological methods and on the basis of the 16S rRNA gene sequence analysis. The polymorphism of the nucleotide sequences of the genes groEL, rpoB, and rplB encoding specific proteins was studied for intraspecific differentiation of the lactobacilli. The analysis of these genes allowed a more accurate identification of the lactobacilli that are genetically and phenotypically related to the L. casei group as L. paracasei subsp. paracasei and L. paracasei subsp. tolerans. The gene nucleotide sequences of all the genotyped strains were deposited in the GenBank database.     

Immune enhancement in rainbow trout (Oncorhynchus mykiss) by potential probiotic bacteria (Lactobacillus rhamnosus)

The present study assessed the immune enhancement of fish by a lactic acid bacterium (LAB) Lactobacillus rhamnosus (ATCC 53103). The bacterium was administered orally at five different doses 7.9 x 10(4) (LAB4), 2.1 x 10(6) (LAB6), 2.8 x 10(8) (LAB8), 1.9 x 10(10) (LAB10) and 9.7 x 10(10) (LAB11) CFU/g feed to rainbow trout for two weeks and the feed was changed to un-supplemented diet. From the onset of feeding supplemented diets at 1, 2, 3 and 4 weeks, blood and mucus samples were taken. During the LAB feeding period L. rhamnosus persisted in the fish intestine and in the tank water in high numbers. However, L. rhamnosus disappeared from the intestine, skin mucus and tank water within one week after the change to the non-supplemented feed. In comparison to untreated control fish, respiratory burst activity of blood cells was raised significantly in the LAB4 treated group on week 2. Serum-mediated killing of Escherichia coli was increased significantly in group LAB6 on week 2. Serum immunoglobulin levels were significantly raised only in LAB8 group on week 1 and in LAB4 and LAB8 at the end of the trial. The results show that rainbow trout immune parameters were enhanced by using probiotic bacteria.     

Probiotic Characterization of Lactobacillus paracasei subsp. paracasei KNI9 Inhibiting Adherence of Yersinia enterocolitica on Caco-2 Cells In Vitro

The study was aimed to characterize the probiotic properties of Lactobacillus paracasei subsp. paracasei strain KNI9 and its antagonistic activity against Yersinia enterocolitica subsp. enterocolitica. The strain KNI9 was susceptible to antibiotics such as chloramphenicol, tetracycline, erythromycin, and streptomycin recommended by European food safety authority (EFSA). Strain KNI9 exhibited tolerance to simulated oro-gastrointestinal (OGT) condition, adherence to Caco-2 cells, and antimicrobial activity against intestinal enteric pathogens such as Yersinia enterocolitica subsp. enterocolitica, Shigella boydii, and Listeria monocytogenes. Furthermore, the strain KNI9 inhibited the adherence and invasiveness of Y. enterocolitica subsp. enterocolitica to Caco-2 cell line. These results indicate that the L. paracasei subsp. paracasei KNI9 could be further developed into a potential probiotic strain after appropriate in vivo studies.

     

Selection of Escherichia coli-inhibiting strains of Lactobacillus paracasei subsp. paracasei

The aim of this study was to select Escherichia coli-inhibiting strains among lactic acid bacteria. On the basis of phenotypical and technological characteristics, 20 strains of lactic acid bacteria were screened from a total of 225 isolates, obtained from nine samples of artisanal Caprino d'Aspromonte cheese, made from raw goats' milk. The antagonistic activity of these 20 strains was detected in plates against three different strains of E. coli. Two strains of Lactobacillus paracasei subsp. paracasei showed a marked anti-E. coli activity against all three strains tested; the other lactic acid bacteria did not exhibit inhibiting activity. The E. coli inhibition can be ascribed to production of bacteriocin-like compounds. The use of L. paracasei subsp. paracasei strains to increase the safety of the cheeses made from raw milk is recommended because these cultures strongly inhibit E. coli, without foreseeable adverse sensory changes. Received 27 December 2001/ Accepted in revised form 28 June 2002     

Antagonistic activity of two potential probiotic bacteria from fish intestines and investigation of their effects on growth performance and immune response in rainbow trout (Oncorhynchus mykiss)

The probiotic activity of two bacterial strains, Lactobacillus casei and Lactobacillus plantarum, isolated from common carp intestines was studied using antagonistic tests in vitro against Yersinia ruckeri. Randomly assigned to triplicate groups were 450 rainbow trout (mean weight, 20 ± 3 g) fed three different diets: a commercial feed, or the same feed incorporated into either 5 × 10⁷ CFU g^?1 of L. casei or L. plantarum. After a 30‐day feeding trial, 30 fish in each group were challenged with Yersinia ruckeri by intraperitoneal injection. Growth parameters were significantly increased in both treatment groups. Immune parameters such as lysozyme activity, alternative complement activity and total immunoglobulin level were significantly higher in the L. casei group than in fish fed the control diet, while no significant differences were revealed between the L. plantarum and control groups. Mortality rates of fish fed L. casei and L. plantarum were lower than in fish fed the control diet after challenging with Y. ruckeri.     

Effect of crab shell size on bio-demineralization with lactic acid-producing bacterium, <Emphasis Type="Italic">Lactobacillus paracasei</Emphasis> subsp. <Emphasis Type="Italic">tolerans</Emphasis> KCTC-3074

Demineralization (DM) from crab shell (CS) waste was carried out using a lactic acid-producing bacterium, Lactobacillus paracasei subsp. tolerans KCTC-3074 for 7 days at 25, 30, and 35°C. DM rates were 89∼92% and slightly affected by temperature. DM was also performed for four particle-sized shell samples (0.84∼3.35, 3.35∼10, 10∼20, and 20∼35 mm) with 10% inoculum, 5% shell, and 10% glucose at 30°C and 180 rpm for 7 days. It was found out that the shell size had a slight effect on the rate of DM. Negative relationships were found between DM and residual dry weight (r² = 0.960), and between DM and pH (r² = 0.906). Conversely, positive relationships were found between DM and medium protein (r² = 0.696), and between DM and total titratable acidity (r² = 0.630).     

Lactobacillus paracasei subsp. paracasei 8700:2 Degrades Inulin-Type Fructans Exhibiting Different Degrees of Polymerization

Ten strains of lactobacilli were assessed for their capacity to degrade inulin-type fructans, which are well-known prebiotics. Both oligofructose and inulin were tested. The dairy isolate Lactobacillus acidophilus IBB 801 degraded only oligofructose. The human isolate Lactobacillus paracasei subsp. paracasei 8700:2 degraded oligofructose and long-chain inulin and grew rapidly on both energy sources. In both cases, fractions of different degrees of polymerization were fermented. Moreover, large and short fractions of oligofructose were degraded simultaneously. When L. paracasei subsp. paracasei 8700:2 grew on oligofructose-enriched inulin, oligofructose was preferentially metabolized. In all cases, lactic acid was the main metabolic end product. Significant amounts of acetic acid, formic acid, and ethanol were produced when long-chain inulin or oligofructose-enriched inulin was used as the sole energy source.     

Use of bacterial lipopolysaccharide (LPS) as an immunostimulant for the control of Aeromonas hydrophila infections in rainbow trout Oncorhynchus mykiss (Walbaum)

Aims: To determine the effect of lipopolysaccharide (LPS) for the prevention of infection by Aeromonas hydrophila in rainbow trout (Oncorhynchus mykiss Walbaum) fingerlings. Methods and Results: Rainbow trout fingerlings were fed with 0 mg (= controls), 1·875 mg, 3·75 mg, 7·5 mg and 15 mg of LPS per 100 g of commercial feed for 14 days before experimental challenge with A. hydrophila. The results revealed a reduction in mortalities to 5% in the two lowest doses and 15% in the group, which received 15 mg LPS per 100 g of feed, compared with 45% mortalities in the control. LPS exerted a powerful oxidative burst effect and was a potent mediator of phagocytic, lysozyme, bactericidal and antiprotease activities and total protein. However, whereas there were increases in specific growth rate (SGR), feed conversion ratio (FCR) and protein efficiency ratio (PER) in LPS‐treated fish, the data were not significantly (P > 0·05) different. Conclusions: LPS was effective at preventing disease caused by A. hydrophila and in stimulating the innate immune response of rainbow trout. Significance and Impact of the Study: The results of this study highlight the role of LPS in fish disease control.     

Polyphasic characterization of a novel species in the Lactobacillus casei group from cow manure of Taiwan: Description of L. chiayiensis sp. nov.

Two Gram-stain-positive, rod-shaped, non-motile, catalase-negative and facultative anaerobic strains, NCYUAS^T and BCRC 18859 (=NRIC 1947), were isolated from cow manure of Taiwan and coconut juice of Philippines, respectively. Comparative sequence analysis of 16S rRNA gene revealed that the novel strains were members of the genus Lactobacillus. These two strains had 100% of 16S rRNA gene sequence similarity and 98.6% of average nucleotide identity (ANI) value based on whole genome sequences. On the basis of 16S rRNA gene sequence similarity, the type strains of Lactobacillus casei (99.6% similarity), Lactobacillus paracasei subsp. paracasei (99.1%), L. paracasei subsp. tolerans (99.1%), Lactobacillus rhmnosus (99.0%) and ‘Lactobacillus zeae’ (99.7%) were the closest neighbors to these novel strains. The results of phenotypic and chemotaxonomic characterization, multilocus sequence analysis (MLSA) based on the sequences of three housekeeping genes (dnaK, pheS and yycH), whole-genome sequence (WGS)-based comparison by ANI and in silico DNA–DNA hybridization (isDDH), species-specific PCR and whole-cell MALDI-TOF MS spectral pattern analyses demonstrated that the novel two strains represented a single, novel species within the L. casei group, for which the name Lactobacillus chiayiensis sp. nov., is proposed. The type strain is NCYUAS^T (=BCRC 81062^T = NBRC 112906^T).     

The Effect of Lactococcus lactis subsp. lactis PTCC 1403 on the Growth Performance,Digestive Enzymes Activity,Antioxidative Status,Immune Response,and Disease Resistance of Rainbow Trout (Oncorhynchus mykiss)

The effect of Lactococcus lactis subsp. lactis strain PTCC 1403 as a potential probiotic was investigated on the growth, hematobiochemical, immune responses, and resistance to Yersinia ruckeri infection in rainbow trout. A total of 240 fish were distributed into 12 fiberglass tanks representing four groups (× 3 replicates). Each tank was stocked with 20 fish (average initial weight: 11.81 ± 0.32 g) and fed L. lactis subsp. lactis PTCC 1403 at 0 (control, T0), 1 × 10⁹ (T1), 2 × 10⁹ (T2), and 3 × 10⁹ (T3) CFU/g feed for 8 weeks. The results showed enhanced protein efficiency ratio and reduced feed conversion ratio in the fish-fed T2 diet. Further, fish-fed T2 and T3 diets showed a significantly higher survival rate than the control (p < 0.05). Trypsin, lipase, and protease activities were increased in fish-fed L. lactis subsp. lactis PTCC 1403 compared to the control (p < 0.05). Fish fed with a T2 diet showed significantly (p < 0.05) lower glucose content than other groups. The blood lysozyme activity and IgM showed significantly (p < 0.05) higher values in fish-fed T2 and T3 diets than in other groups. The antioxidative responses were increased in fish-fed T2 and T3 diets (p < 0.05). After 7 days post-Y. ruckeri challenge, the cumulative mortality rate showed the lowest value in fish fed with T1 and T2 diets, while the highest value was recorded in the control group. In conclusion, the results revealed beneficial effects of L. lactis subsp. lactis PTCC 1403 on the feed efficiency, immune response, and resistance to Y. ruckeri infection in rainbow trout.

     

Characterization of the Lactobacillus casei group based on the profiling of ribosomal proteins coded in S10-spc-alpha operons as observed by MALDI-TOF MS

The taxonomy of the members of the Lactobacillus casei group is complicated because of their phylogenetic similarity and controversial nomenclatural status. In this study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of ribosomal proteins coded in the S10-spc-alpha operon, termed S10-GERMS, was applied in order to classify 33 sample strains belonging to the L. casei group. A total of 14 types of ribosomal protein genes coded in the operon were first sequenced from four type strains of the L. casei group (L. casei JCM 1134^T, L. paracasei subsp. paracasei JCM 8130^T, L. paracasei subsp. tolerans JCM 1171^T, and L. rhamnosus JCM 1136^T) together with L. casei JCM 11302, which is the former type strain of ‘L. zeae’. The theoretical masses of the 14 types of ribosomal proteins used as biomarkers were classified into five types and compiled into a ribosomal protein database. The observed ribosomal proteins of each strain, identified by MALDI-TOF MS, were categorized into types based on their masses, summarized as ribosomal protein profiles, and they were used to construct a phylogenetic tree. The 33 sample strains, together with seven genome-sequenced strains, could be classified into four major clusters, which coincided precisely with the taxa of the (sub)species within the L. casei group. Three “ancient” strains, identified as L. acidophilus and L. casei, were correctly re-identified as L. paracasei subsp. paracasei by S10-GERMS. S10-GERMS would thus appear to be a powerful tool for phylogenetic characterization, with considerable potential for management of culture collections.     

Diversity and Mechanisms of Alkali Tolerance in Lactobacilli

We determined the maximum pH that allows growth (pHmax) for 34 strains of lactobacilli. High alkali tolerance was exhibited by strains of Lactobacillus casei, L. paracasei subsp. tolerans, L. paracasei subsp. paracasei, L. curvatus, L. pentosus, and L. plantarum that originated from plant material, with pHmax values between 8.5 and 8.9. Among these, L. casei NRIC 1917 and L. paracasei subsp. tolerans NRIC 1940 showed the highest pHmax, at 8.9. Digestive tract isolates of L. gasseri, L. johnsonii, L. reuteri, L. salivarius subsp. salicinius, and L. salivarius subsp. salivarius exhibited moderate alkali tolerance, with pHmax values between 8.1 and 8.5. Dairy isolates of L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. lactis, and L. helveticus exhibited no alkali tolerance, with pHmax values between 6.7 and 7.1. Measurement of the internal pH of representative strains revealed the formation of transmembrane proton gradients (ΔpH) in a reversed direction (i.e., acidic interior) at alkaline external-pH ranges, regardless of their degrees of alkali tolerance. Thus, the reversed ΔpH did not determine alkali tolerance diversity. However, the ΔpH contributed to alkali tolerance, as the pHmax values of several strains decreased with the addition of nigericin, which dissipates ΔpH. Although neutral external-pH values resulted in the highest glycolysis activity in the presence of nigericin regardless of alkali tolerance, substantial glucose utilization was still detected in the alkali-tolerant strains, even in a pH range of between 8.0 and 8.5, at which the remaining strains lost most activity. Therefore, the alkali tolerance of glycolysis reactions contributes greatly to the determination of alkali tolerance diversity.     

Fermentation of a milk-soymilk and Lycium chinense Miller mixture using a new isolate of Lactobacillus paracasei subsp. paracasei NTU101 and Bifidobacterium longum

A milk–soymilk mixture was fermented using Lactobacillus paracasei subsp. paracasei NTU101 and Bifidobacterium longum BCRC11847 at different inoculum ratios (1:1, 1:2, 1:5, 2:1, and 5:1). When the inoculum ratio was 1:2, the cell numbers of both strains were balanced after 12 h of cultivation. The pH and titratable acidity were very similar at the various inoculum ratios of cultivation. The milk–soymilk mixture was supplemented with 5, 10, 15, and 20% Lycium chinense Miller juice and fermented with Lactobacillus paracasei subsp. paracasei NTU101 and B. longum BCRC11847. Sensory evaluation results showed that supplementation with 5% Lycium chinense Miller juice improved the acceptability of the fermented milk–soymilk. The fermented beverage was stored at 4°C for 14 days; variations in pH and titratable acidity were slight. The cell numbers of L. paracasei subsp. paracasei NTU101 and B. longum BCRC11847 in the fermented beverage were maintained at 1.2×10⁹ CFU/ml and 6.3×10⁸ CFU/ml, respectively, after 14 days of storage.     

Development of human lactic acid (LAB) gastrointestinal microbiota in a Greek rural population

In order to investigate the Lactic Acid Bacteria (LAB) of the gut, fecal samples were collected and analyzed from 120 healthy Greek volunteers ranging from age 1 to age 85, all of whom declared daily consumption of local fermented dairy products. LAB strains were isolated using selective media under aerobic or anaerobic conditions. Identification of the isolates was based on their growth patterns, morphological characteristics, and carbohydrate fermentation profiles. There was no significant difference in the abundance of Lactobacillus brevis, Lactococcus lactis subsp. cremoris, Lactococcus lactis, Lactobacilus paracasei and Bifidobacterium sp., in all samples. Lactobacillus fermentum, Lactobacillus plantarum, Lactococcus casei, Lactococcus pentosus, Lactococcus lactis subsp. lactis, Lactococcus delbrueckii subsp. lactis, Enterococcus casseliflavus, Enterococcus faecalis, Enterococcus faecium, Enterococcus avium and Leuconostoc sp. were also recovered, mainly from the adults and elders rather than the children’s group. Despite the above differences in LAB species observed mostly between the younger and the other two age groups, differences were also observed within all groups, indicating that healthy subjects of all ages are colonized by a diverse lactoflora in terms of total or dominant species.     

Yeast colonizing the intestine of rainbow trout (Salmo gairdneri) and turbot (Scophtalmus maximus)

Yeast were isolated from the intestine of farmed rainbow trout (Salmo gairdneri), turbot (Scophtalmus maximus), and free-living flat-fish (Pleuronectes platessa and P. flesus). The average number of viable yeasts recovered from farmed rainbow trout was 3.0 × 10³ and 0.5 × 10² cells per gram homogenized intestine for white and red-pigmented yeasts, respectively. The dominant species were Debaryomyces hansenii, Saccharomyces cerevisiae, Rhodotorula rubra, and R. glutinis. In 5 of 10 free-lving marine fish, > 100 viable yeast cells per gram intestinal mucus were recovered. Red-pigmented yeasts dominated and composed >90% of the isolates. Colonization experiments were performed by inoculating rainbow trout and turbot with fish-specific, isolated yeast strains and by examining the microbial intestinal colonization at intervals. Inoculation of experimental fish with pure cultures of R. glutinis and D. hansenii HF1 yielded colonization at a level several orders of magnitude higher than before the inoculation. Up to 3.8 × 10⁴, 3.1 × 10⁶, and 2.3 × 10⁹ viable yeast cells per gram intestine or feces were recovered in three separate colonization experiments. The high level of colonizing yeasts persisted for several weeks. The concentrations of yeasts in the tank water never exceeded 10³ viable cells per milliliter. No traces of fish sickness as a result of high yeast colonization were recorded during any of the colonization experiments. For periods of the experiments, the concentration of aerobic bacteria in the fish intestine was lower than the intestinal yeast concentration. Scanning electron microscopy studies demonstrated a close association of the yeasts with the intestinal mucosa. The mucosal colonization was further demonstrated by separating intestinal content, mucus, and tissue. All compartments were colonized by >10³ viable yeast cells per gram. No bacteria were detected on the micrographs, indicating that their affinity for the intestinal mucosa was less than that of the yeasts. Correspondence to: Thomas Andtid     

Stabilization of freeze-dried Lactobacillus paracasei subsp. paracasei JCM 8130T with the addition of disaccharides,polymers, and their mixtures

Although freeze-drying is a widely used dehydration technique for the stabilizing of unstable lactic acid bacteria, Lactobacillus paracasei subsp. paracasei JCM 8130^T (L. paracasei) is destabilized after freeze-drying and subsequent storage. In order to improve the stability of freeze-dried L. paracasei, effects of disaccharides (sucrose and trehalose), polymers (maltodextrin; MD and bovine serum albumin; BSA), and their mixtures on the survival rate of freeze-dried L. paracasei were investigated. The survival rate of non-additive sample decreased slightly after freeze-drying but decreased drastically after subsequent storage at 37 °C for 4 weeks. The reduction was diminished by the addition of disaccharides and polymers. The stabilizing effect of disaccharides was not affected by the co-addition of MD. In contrast, the disaccharide–BSA mixtures had a synergistic stabilizing effect, and the survival rates were largely maintained even after storage. It is suggested that the synergistic effect originates from the conformational stabilization of the dehydrated bacteria.     

Population dynamics of lactobacilli in Grana cheese

A survey on the presence, microbial diversity, and population dynamics of lactobacilli in Grana cheese is presented. Evolution of thermophilic rod lactic acid bacteria within the first two days from cheese making and during ripening was different according to different bacterial groups, which were selectively enumerated and identified by molecular methods. Species-specific microbial counts indicated prevalence ofLactobacillus helveticus in both the whey starter and the cheese at moulding, and ofLactobacillus delbrueckii subsp.lactis in cheese after two months of ripening. In more advanced ripening, a decrease of total thermophilic lactobacilli and an increase of mesophilic lactobacilli (mostly belonging toLactobacillus casei/paracasei andLactobacillus rhamnosus) was observed. PCR fingerprinting of lactobacilli, which was performed by PCR-fingerprinting, indicated a marked microbial heterogeneity within theLactobacillus spp. populations, which enabled strain (or group)-specific fingerprints to be observed.     

Effects of Lactobacillus rhamnosus ATCC 7469 on Different Parameters Related to Health Status of Rainbow Trout (Oncorhynchus mykiss) and the Protection Against Yersinia ruckeri

In the current study, we investigated the effect of a probiotic bacterium (Lactobacillus rhamnosus ATCC 7469) microencapsulated with alginate and hi-maize starch and coated with chitosan on improving growth factors, body composition, blood chemistry, and the immune response of rainbow trout (initial weight: 18.41 ± 0.32 g). Four experimental diets were formulated to feed fish for 60 days. They were control diet without any additive (C), diet added with beads without probiotic (E), a probiotic sprayed to the diet (L.r), and encapsulated probiotic supplemented diet (E-L.r). The results indicated that feeding with E-Lr significantly improved weight gain (84.98 g) and feed conversion ratio (0.95) compared to the other groups (P < 0.05). Also, fish fed E-Lr diet had a significantly higher value of whole-body protein (17.51%), total protein in the blood (4.98 g/dL), lysozyme (30.66 U/mL), alternative complement pathway hemolytic activity (134 U/mL), superoxide dismutase (203 U/mg protein), and catalase (528.33 U/mg protein) (P < 0.05) as compared to those fed the control diet. Similarly, a higher relative expression of immune-related genes such as interleukin-1 (Il-1) and tumor necrosis factor-alpha (TNF-1α) were reported in those fed E-L.r and L.r diets respectively. Interestingly, the fish fed dietary E-L.r had a significantly lower value of lipid in the whole body (4.82%) and cholesterol in the blood (160.67%) in comparison with those fed the control diet (P < 0.05). At the end of the experiment, all groups were challenged by Yersinia ruckeri where the survival rate of rainbow trout fed dietary E-L.r (70.36%) was statistically higher than that of the others (P < 0.05). Overall, the results suggested that encapsulated probiotic Lact. rhamnosus ATCC 7469 acted better than unencapsulated probiotic and has a potential to improve growth performance, flesh quality, and the immune response of rainbow trout.