Immunomodulatory effect of probiotics enriched diets on Uronema marinum infected olive flounder

The effect of five probiotics, Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus sakei, Bacillus subtilis, and Saccharomyces cerevisiae as individual and mixed enriched diet on the seasonal prevalence, activity and intensity of Uronema marinum infection in olive flounder Paralichthys olivaceus is reported. The growth performance, feed efficiency, blood biochemistry, survival rate, and non-specific immune response of U. marinum infected olive flounder on week 0, 1, 2, 4, 6, and 8 were quantified. The prevalence and infection intensity reached a peak from June to December and then it declined from December to March. The scuticocidal activity in the serum was significantly higher when fed with L. plantarum, L. acidophilus, and S. cerevisiae diets on weeks 2-8. All enriched diets significantly enhanced the weight gain significantly between week 6 and 8; the feed efficiency registered a significantly increase from week 4 to 8 when compared to infected fish fed with control diet. Infected fish fed with L. plantarum-supplemented diet had higher survival rate than with other enriched diets. The serum aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) levels significantly increased when fed with L. plantarum, L. acidophilus or S. cerevisiae-supplemented diet. Total protein (TP) and glucose (GLU) level significantly increased with any enriched diet from week 4 to 8. The superoxide anion production and serum lysozyme activity registered a significant increase when fed with L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diet from week 4-8. The present study concludes that L. plantarum, L. acidophilus, and S. cerevisiae-supplemented diets act as immunostimulants enhancing the growth, feed efficiency, blood biochemistry, survival rate, and non-specific immune response in U. marinum infected olive flounder.     

Effects of lactobacillus plantarum ZJ316 on pig growth and pork quality

ABSTRACT: BACKGROUND: Lactobacillus plantarum is a plant-associated bacterial species but it has also been found in human, mouse and porcine gastrointestinal tracts. It can ferment a broad spectrum of plant carbohydrates; it is tolerant of bile salts and low pH, and it has antagonistic potential against intestinal pathogens. However, experiments reporting the use of L. plantarum as a probiotic are limited. In this study, the effects of L. plantarum ZJ316 isolated from infant fecal samples on pig growth and pork quality were investigated. RESULTS: One hundred and fifty newly weaned pigs were selected randomly and divided into five groups. Group 1 was fed a diet supplemented with the antibiotic mequindox; Groups 2, 3 and 4 were fed a diet supplemented with L. plantarum and no antibiotic; and Group 5 was fed a mixture of mequindox and L. plantarum. After a 60 days initial treatment, samples were collected for evaluation. The results showed that, the L. plantarum ZJ316 has probiotic effects on pig growth and that these effects are dose dependent. The effects of a dose of 1 x 109 CFU/d were more pronounced than those of a dose of 5 x 109 CFU/d or 1 x 1010 CFU/d. In Group 2 (1 x 109 CFU/d), the diarrhea (p = 0.000) and mortality rates (p = 0.448) were lower than in antibiotic-treated pigs (Group 1), and the daily weight gain (p = 0.001) and food conversion ratios were better (p = 0.005). Improved pork quality was associated with Lactobacillus treatment. pH (45 min, p = 0.020), hardness (p = 0.000), stickiness (p = 0.044), chewiness (p = 0.000), gumminess (p = 0.000) and restoring force (p = 0.004) were all significantly improved in Lactobacillus-treated pigs (Group 2). Although we found that L. plantarum exerted probiotic effects on pig growth and pork quality, the mechanisms underlying its action require further study. Polymerase chain reaction-denaturing gradient gel electrophoresis results showed that the gut bacterial communities in Lactobacillus- and antibiotic-treated pigs were very similar and the quantity of L. plantarum ZJ316 was below the detection limits of DGGE-band sequencing. The concentration of short-chain fatty acids in Lactobacillus- and antibiotic-treated fecal samples were not significantly different (p = 0.086). However, the villus height of ilea (p = 0.003), jejuna (p = 0.000) and duodena (p = 0.036) were found to be significantly improved by Lactobacillus treatment. CONCLUSION: L. plantarum ZJ316 was found to have probiotic effects, improving pig growth and pork quality. The probiotic mechanism might not involve L. plantarum colonization and alteration of the gut bacterial community. Rather, it might be related to the inhibition of the growth of opportunistic pathogens and promotion of increased villus height.     

Immunopotentiating activity of nigerooligosaccharides for the T helper 1-like immune response in mice

The immunopotentiating activity of nigerooligosaccharides (NOS), a mixture of nigerose, nigerosyl glucose and nigerosyl maltose, was studied in vitro and in vivo in mice. Mitogen-induced proliferation of splenocytes from normal mice was augmented in a dose-dependent manner by nigerose of NOS. NOS enhanced interleukin 12 (IL-12) and interferon-gamma (IFN-gamma) production by normal splenocytes in the presence of the potent IL-12 inducer, heat-killed Lactobacillus plantarum L-137, in vitro. Consistent with the in vitro finding, L. plantarum L-137-induced IL-12 production and IL-2-induced IFN-gamma production were augmented in mice fed with a 14.6% NOS diet for 2 weeks compared with mice fed with a control diet. Notably, mice fed with the NOS diet showed significantly longer survival time than the control mice after the induction of an endogenous infection by administering 5-fluorouracil in a lethal dose. Taken together, these results suggest that NOS may exert immunopotentiating activity through the activation of an IL-12-dependent T helper 1-like immune response.     

Dietary ratio of protein to carbohydrate induces plastic responses in the gastrointestinal tract of mice

Some vertebrates change the size of their digestive system in response to quantity and fibre content of ingested food, but the effects of dietary nutrients on gut structure remain poorly understood. Here we investigate how the protein to carbohydrate ratio of diets affects the mass of the gastrointestinal tract in mice. We fed 6-week-old male mice one of five isocaloric diets differing only in protein to carbohydrate ratio (the “no-choice” treatments), while a further four treatment groups received nutritionally complementary food pairings from which they could self-select a diet (the “choice” treatments). After 32 days, we measured the resulting dry mass of stomachs, intestines, caeca and colons. In the no-choice treatments, the stomachs were heavier in the mice fed diets containing more protein and less carbohydrate, indicating that larger stomachs may be needed for efficient digestion of the protein-rich food. In contrast, intestines, caeca and colons were heavier when diets contained more carbohydrates and less protein. This response may function to increase the digestive rate of carbohydrates when the dietary content of this macronutrient increases, but it may also indicate a compensatory response to increase amino acid uptake from a protein-deficient food. Mice in the choice treatments self-selected a diet with a protein to carbohydrate ratio of 0.46, and had gut dimensions similar to the expectation derived from no-choice treatments for this diet composition. Our results provide an example of plasticity in the differential allocation of resources to organ function, which is triggered by variation in resource quality.     

Gut microbiota-mediated xanthine metabolism is associated with resistance to high-fat diet-induced obesity

Resistance to high-fat diet-induced obesity (DIR) has been observed in mice fed a high-fat diet and may provide a potential approach for anti-obesity drug discovery. However, the metabolic status, gut microbiota composition, and its associations with DIR are still unclear. Here, ultraperformance liquid chromatography-tandem mass spectrometry-based urinary metabolomic and 16S rRNA gene sequencing-based fecal microbiome analyses were conducted to investigate the relationship between metabolic profile, gut microbiota composition, and body weight of C57BL/6J mice on chow or a high-fat diet for 8 weeks. PICRUSt analysis of 16S rRNA gene sequences predicted the functional metagenomes of gut bacteria. The results demonstrated that feeding a high-fat diet increased body weight and fasting blood glucose of high-fat diet-induced obesity (DIO) mice and altered the host-microbial co-metabolism and gut microbiota composition. In DIR mice, high-fat diet did not increase body weight while fasting blood glucose was increased significantly compared to chow fed mice. In DIR mice, the urinary metabolic pattern was shifted to a distinct direction compared to DIO mice, which was mainly contributed by xanthine. Moreover, high-fat diet caused gut microbiota dysbiosis in both DIO and DIR mice, but in DIR mice, the abundance of Bifidobacteriaceae, Roseburia, and Escherichia was not affected compared to mice fed a chow diet, which played an important role in the pathway coverage of FormylTHF biosynthesis I. Meanwhile, xanthine and pathway coverage of FormylTHF biosynthesis I showed significant positive correlations with mouse body weight. These findings suggest that gut microbiota-mediated xanthine metabolism correlates with resistance to high-fat DIO.     

Microbial Reprogramming Inhibits Western Diet-Associated Obesity

A recent epidemiological study showed that eating ‘fast food’ items such as potato chips increased likelihood of obesity, whereas eating yogurt prevented age-associated weight gain in humans. It was demonstrated previously in animal models of obesity that the immune system plays a critical role in this process. Here we examined human subjects and mouse models consuming Westernized ‘fast food’ diet, and found CD4⁺ T helper (Th)17-biased immunity and changes in microbial communities and abdominal fat with obesity after eating the Western chow. In striking contrast, eating probiotic yogurt together with Western chow inhibited age-associated weight gain. We went on to test whether a bacteria found in yogurt may serve to lessen fat pathology by using purified Lactobacillus reuteri ATCC 6475 in drinking water. Surprisingly, we discovered that oral L. reuteri therapy alone was sufficient to change the pro-inflammatory immune cell profile and prevent abdominal fat pathology and age-associated weight gain in mice regardless of their baseline diet. These beneficial microbe effects were transferable into naïve recipient animals by purified CD4⁺ T cells alone. Specifically, bacterial effects depended upon active immune tolerance by induction of Foxp3⁺ regulatory T cells (Treg) and interleukin (Il)-10, without significantly changing the gut microbial ecology or reducing ad libitum caloric intake. Our finding that microbial targeting restored CD4⁺ T cell balance and yielded significantly leaner animals regardless of their dietary ‘fast food’ indiscretions suggests population-based approaches for weight management and enhancing public health in industrialized societies.     

Gut length plasticity in perch: into the bowels of resource polymorphisms

Resource polymorphisms, intraspecific variation in morphology due to differential resource use, are common across a wide range of animal taxa. The focus in studies of such polymorphisms has been on external morphology, but the differential use of food resources could also influence other phenotypic traits such as the digestive performance. In the present study, we experimentally demonstrate that Eurasian perch ( Perca fluviatilis L.) display adaptive plasticity in gut length when exposed to different food types. Perch fed a less digestible food type developed relatively longer guts compared to fish fed a more easily digested food type. This divergence in gut length was also apparent under natural conditions because perch inhabiting the littoral and pelagic habitats of a lake differed in resource use and relative gut length. Despite that the digestive system in perch is plastic, we found that individuals switching to a novel food type might experience an initial fitness cost of the diet switch in the form of a temporary reduction in body condition. These results show the importance of gut length plasticity for an ontogenetic omnivore but also a cost that might prevent diet switching in polymorphic populations.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 517–523.     

A strain of Lactobacillus plantarum affects segmented filamentous bacteria in the intestine of immunosuppressed mice

Segmented filamentous bacteria (SFB) are present in the gastrointestinal tract of mice from weaning until the maturation of the immune system. Probiotic bacteria also have an effect on host immunity. To study the relationships established between these bacteria, samples from a mouse model fed with Lactobacillus plantarum under different immunological conditions were analysed. SFB populations were measured by a newly designed group-specific quantitative PCR assay. The results confirmed the presence of the probiotic in the intestine and an expansion of SFB in the ileum of immunocompromised mice, which was abolished upon administration of L. plantarum, an effect not described to date.     

Laboratory diet profoundly alters gene expression and confounds genomic analysis in mouse liver and lung

Nutritional studies in laboratory animals have long shown that various dietary components can contribute to altered gene expression and metabolism, but diet alone has not been considered in whole animal genomic studies. In this study, global gene expression changes in mice fed either a non-purified chow or a purified diet were investigated and background metal levels in the two diets were measured by ICP-MS. C57BL/6J mice were raised for 5 weeks on either the cereal-based, non-purified LRD-5001 diet or the purified, casein-based AIN-76A diet, as part of a larger study examining the effects of low dose arsenic (As) in the diet or drinking water. Affymetrix Mouse Whole Genome 430 2.0 microarrays were used to assess gene expression changes in the liver and lung. Microarray analysis revealed that animals fed the LRD-5001 diet displayed a significantly higher hepatic expression of Phase I and II metabolism genes as well as other metabolic genes. The LRD-5001 diet masked the As-induced gene expression changes that were clearly seen in the animals fed the AIN-76A diet when each dietary group was exposed to 100 ppb As in drinking water. Trace metal analysis revealed that the LRD-5001 diet contained a mixture of inorganic and organic As at a total concentration of 390 ppb, while the AIN-76A diet contained approximately 20 ppb. These findings indicate that the use of non-purified diets may profoundly alter observable patterns of change induced by arsenic and, likely, by other experimental treatments, particularly, altering gene and protein expression.     

Lactobacillus reuteri CRL 1098 prevents side effects produced by a nutritional vitamin B12 deficiency

Aims:  To evaluate the efficiency of the vitamin B_12-producing Lactobacillus reuteri CRL1098 strain in preventing the symptoms caused by a nutritional cobalamin-deficient diet in pregnant female mice and their weaned offspring.
Methods and Results:  Pregnant female mice were divided into three groups: animals fed with a B₁₂-deficient diet (DD), animals fed with DD plus L. reuteri CRL1098 and animals fed with a B₁₂-sufficient diet. The animals received the different feedings from the end of gestation up to weaning. At the end of the trials, they and their corresponding offspring were bled to determine haematological, immunological and histological parameters. The administration of the pseudovitamin B₁₂-producing strain prevented the symptoms observed in female and weaned young animals fed with a nutritional B₁₂-deficient diet.
Conclusions:  Our data suggest that the pseudovitamin B₁₂ produced by L. reuteri CRL1098 is biologically active and effective in preventing the pathologies caused by the nutritional deficiency of B₁₂ both in pregnant mice and their offspring.
Significance and Impact of the Study:  The ability of L. reuteri CRL1098 to prevent a nutritional vitamin deficiency was demonstrated for the first time. The addition of a GRAS micro-organism to complement the B₁₂ content in deficient foods is an interesting biotechnological alternative.     

Expression of immune-related genes in rainbow trout (Oncorhynchus mykiss) induced by probiotic bacteria during Lactococcus garvieae infection

The aim of the present study was to investigate the effect of lactic acid bacteria (LAB) on the control of lactococcosis as well as to assess the impact of probiotics on the expression of immune-related genes in the head kidney and intestine of rainbow trout (Oncorhynchus mykiss). Lactobacillus plantarum, Lactococcus lactis and Leuconostoc mesenteroides, were administered orally at 10? CFU g?1 feed to fish for 36 days. Twenty-one days after the start of the feeding period, fish were challenged with Lactococcus garvieae. Only the fish fed the diet containing Lb. plantarum showed significantly (P < 0.05) improved protection against L. garvieae compared to the control. Subsequently, real-time PCR was employed to determine the mRNA levels of IL-1β, IL-8, IL-10 and TNF-α in the head kidney, and IL-8, Tlr5 and IgT in the intestine of the control and Lb. plantarum groups. IL-1β, IL-10 and TNF-α gene expression were significantly up-regulated by Lb. plantarum. Moreover, the mRNA levels of IL-10, IL-8 and IgT were significantly higher in the Lb. plantarum group after L. garvieae infection, suggesting that Lb. plantarum can stimulate the immune response of rainbow trout. PCR-DGGE revealed no detectable levels of the probiotics or the pathogen present on the distal intestinal mucosa. These findings demonstrate that direct probiotic-host interactions with the intestine are not always necessary to induce host stimulatory responses which ultimately enhance disease resistance. Furthermore, as L. garvieae did not colonise the intestinal tract, and therefore likely did not infect via this route, the antagonistic properties of the probiotic candidate towards L. garvieae were likely of little influence in mediating the improved disease resistance which could be attributed to the elevated immunological response.     

Hyperlipidemia is a major determinant of neointimal formation in LDL receptor-deficient mice

LDL receptor-deficient (LDLR(-/-)) mice exhibit mild hyperlipidemia on a chow diet but develop severe hyperlipidemia on a high fat diet. In this study, we investigated neointimal formation after removal of the endothelium when LDLR(-/-) mice were fed chow or a Western diet containing 42% fat, 0.15% cholesterol, and 19.5% casein. At 10 weeks of age, female mice underwent endothelial denudation of the left common carotid artery. Two weeks after injury, neointimal formation was barely detectable in the injured vessel when mice developed mild hyperlipidemia on the chow diet. In contrast, neointimal lesions were obvious when mice developed severe hyperlipidemia on the Western diet. Immunohistochemical and histological analyses demonstrated the presence of macrophage foam cells and smooth muscle cells in neointimal lesions. The injured artery also exhibited a significant increase in medial area on the Western diet. Plasma levels of MCP-1 and soluble VCAM-1 were significantly elevated by feeding of the Western diet. These data indicate that hyperlipidemia aggravates neointimal growth in LDLR(-/-) mice by promoting foam cell formation and inflammation.     

Oxidized phospholipids cause changes in jejunum mucus that induce dysbiosis and systemic inflammation

We previously reported that adding a concentrate of transgenic tomatoes expressing the apoA-I mimetic peptide 6F (Tg6F) to a Western diet (WD) ameliorated systemic inflammation. To determine the mechanism(s) responsible for these observations, Ldlr^?/? mice were fed chow, a WD, or WD plus Tg6F. We found that a WD altered the taxonomic composition of bacteria in jejunum mucus. For example, Akkermansia muciniphila virtually disappeared, while overall bacteria numbers and lipopolysaccharide (LPS) levels increased. In addition, gut permeability increased, as did the content of reactive oxygen species and oxidized phospholipids in jejunum mucus in WD-fed mice. Moreover, gene expression in the jejunum decreased for multiple peptides and proteins that are secreted into the mucous layer of the jejunum that act to limit bacteria numbers and their interaction with enterocytes including regenerating islet-derived proteins, defensins, mucin 2, surfactant A, and apoA-I. Following WD, gene expression also decreased for Il36γ, Il23, and Il22, cytokines critical for antimicrobial activity. WD decreased expression of both Atoh1 and Gfi1, genes required for the formation of goblet and Paneth cells, and immunohistochemistry revealed decreased numbers of goblet and Paneth cells. Adding Tg6F ameliorated these WD-mediated changes. Adding oxidized phospholipids ex vivo to the jejunum from mice fed a chow diet reproduced the changes in gene expression in vivo that occurred when the mice were fed WD and were prevented with addition of 6F peptide. We conclude that Tg6F ameliorates the WD-mediated increase in oxidized phospholipids that cause changes in jejunum mucus, which induce dysbiosis and systemic inflammation.     

Effect of orally administered non-viable Lactobacillus cells on murine humoral immune responses

BALB/c mice were immunized intraperitoneally with the food antigen ovalbumin (OVA) while they were fed with Lactobacillus GG heated killed cell preparation. The oral administration of Lactobacillus GG did not appear to modify the antigen-augmented serum IgE in the tested mice but significantly augmented serum OVA specific IgG in the tested mice fed with a diet containing 0.1% Lactobacillus GG as the non-viable cell preparation (P< 0.05). The fecal OVA specific IgA of the tested mice fed with nonviable Lactobacillus GG cells was also significantly elevated (P< 0.05) compared to those from OVA immunized mice. The spleen cells of mice fed with non-viable Lactobacillus GG cells secreted more IL-6 (P< 0.01). These results suggest that the non-viable Lactobacillus GG can augment the systemic and mucosal immune responses in a host animal favoring secretory IgA but not IgE in an adjuvant-like manner.     

The effects of diet and digestive cycle on the gastrointestinal tract pH values in the goldfish, Carassius auratus L., Mozambique tilapia, Oreochromis mossambicus (Peters), and channel catfish, Ictalurus punctatus (Rafinesque)

The digestive tract pH values of the teleost fish Oreochromis mossambicus, Carassius auratus and Ictalurus punctatus were determined in fish that were (1) starved, (2) fed herbivorous, omnivorous and carnivorous diets and (3) fed altered pH diets. The digestive tract pH profile was determined throughout an 8 h cycle. The herbivorous or carnivorous nature of the diet did not affect the pH values in any of the species. Significant differences in gut pH values were observed when the fish ingested diets with altered pHs. There was a difference between the starved and baseline fed values in Carassius auratus which was not observed in the other species. The pH values in the digestive tracts of the three species varied during the digestive cycle.