Effect of yogurt feeding on the small and large intestine associated lymphoid cells in mice

Weight gain by gut microbiota manipulation in productive animals

Antibiotics, prebiotics and probiotics are widely used as growth promoters in agriculture. In the 1940s, use of Streptomyces aureofaciens probiotics resulted in weight gain in animals, which led to the discovery of chlortetracycline. Tetracyclines, macrolides, avoparcin and penicillins have been commonly used in livestock agriculture to promote growth through increased food intake, weight gain, and improved herd health. Prebiotic supplements including oligosaccharides, fructooligosaccharides, and galactosyl-lactose improve the growth performance of animals. Probiotics used in animal feed are mainly bacterial strains of Gram-positive bacteria and have been effectively used for weight gain in chickens, pigs, ruminants and in aquaculture. Antibiotics, prebiotics and probiotics all modify the gut microbiota and the effect of a probiotic species on the digestive flora is probably determined by bacteriocin production. Regulations governing the introduction of novel probiotics and prebiotics vary by geographical region and bias is very common in industry-funded studies. Probiotic and prebiotic foods have been consumed for centuries, either as natural components of food, or as fermented foods and it is possible to cause the same weight gain effects in humans as in animals. This review presents the use of growth promoters in food-producing animals to influence food intake and weight gain.

Distal Mucosal Site Stimulation by Kefir and Duration of the Immune Response

Kefir is a fermented milk (drink) produced by the action of lactic acid bacteria, yeasts and acetic acid bacteria. We recently reported a comparative study on the effect of kefir containing viable or non-viable bacteria by studying their modulatory activity on the intestinal immune response. A functional dose was established in a murine model and the pattern of regulatory and pro-inflammatory cytokines induced was also studied. The existence of a common mucosal immune system implies that the immune cells stimulated in one mucosal tissue can spread and relocate through various mucosal sites. The aim of this work was to determine the effect of an oral administration of kefir on the duration of the intestinal mucosa immune response and the modulatory activity in distal mucosal sites, specifically in the peritoneal and pulmonary macrophages and in the bronchial tissue. BALB/c mice were fed with kefir or pasteurized kefir at doses previously determined as functional for intestinal mucosa immunomodulation. Kefir feeding was stopped and the number of IgA, IgG, IL-4, IL-6, IL-10, IIFNγ and TNFα producing cells was determined in the lamina propria of small intestine immediately, and after 2 and 7 days of kefir withdrawal. IgA producing cells were also measured in the bronchial tissue of lungs immediately and 2 and 7 days after kefir withdrawal. Phagocytic activity of peritoneal and pulmonary macrophages was also determined. The oral administration of kefir or pasteurized kefir increased the number of IgA+ cells not only in the gut lamina propria, but also in the bronchial tissue, supporting the concept of local antibody secretion after remote-site stimulation in the intestinal tract. Both peritoneal and pulmonary macrophages were activated by kefir or pasteurized kefir feeding. Peritoneal macrophages were stimulated faster than pulmonary macrophages (for kefir). The enhanced phagocytic activity achieved by kefir or pasteurized kefir lasted longer for the peritoneal than for the pulmonary macrophages. Due to the increased bronchial IgA and phagocytic activity of pulmonary macrophages after kefir feeding observed in this study, the oral administration of kefir could act as a natural adjuvant for enhancing the specific immune response against respiratory pathogens. The parameters studied returned to control values within a week of cessation of kefir administration. This would suggest that there is a low risk of overstimulating the gut mucosal immune system during periodic consumption of kefir.

Evaluation of kefir as a potential probiotic on growth performance, serum biochemistry and immune responses in broiler chicks

This experiment was conducted to evaluate the effect of milk or molasses kefir as a probiotic on growth performance, carcass traits, serum biochemistry and humoral immune responses in broiler chickens. A total of 192 one-d-old as hatched broiler chicks (Ross 308) were randomly allotted to 4 treatments, each with 4 replicate pens of 12 chicks. The following treatments were applied: 1) a basal diet (C) and normal drinking water, 2) 2% milk kefir in drinking water, 3) 2% molasses kefir in drinking water, and 4) the diet C supplemented with commercial probiotic. At d 42, eight birds per treatment were killed for determination of carcass traits. Broilers at 28 days of age were bled for measuring antibody titers against Newcastle disease virus (NDV) and avian influenza virus (AIV), at 30 days of age for antibody titers against sheep red blood cell (SRBC), and at 42 days of age for biochemical analysis. Supplementing 2% milk kefir increased body weight of broilers at 28 and 42 days of age (P < 0.05). Supplementing 2% molasses kefir improved feed conversation ratio (FCR) of broilers during growth period (P < 0.05), but FCR of broilers in other periods was not affected. Daily feed intake, internal organ weights, and carcass traits were not influenced by the treatments except for small intestine and ceca length. Small intestinal length significantly decreased in broilers supplemented with milk and molasses kefir (P < 0.05). Molasses kefir supplementation significantly (P < 0.05) increased antibody titer against SRBC at 31 days of age but other immune related parameters were not statistically different among treatments. Biochemical parameters including serum protein, albumin, and triglyceride concentrations were not statistically (P > 0.05) influenced. Broilers supplemented with molasses kefir, had a significantly lower concentration of serum total cholesterol, low density lipoprotein cholesterol and elevated high density lipoprotein cholesterol at 42 days of age (P < 0.05). In conclusion, the results indicated that inclusion of 2% milk kefir in drinking water would improve growth performance of broiler chickens.

Anti-inflammatory effect of yoghurt in an experimental inflammatory bowel disease in mouse

Inflammatory bowel disease (IBD; Crohn′s disease and ulcerative colitis) is the clinical outcome of three interactive pathogenic factors: genetic susceptibility, environmental triggers and immune dis-regulation. At present, only the immune response is targeted by most therapeutic or preventive strategies. The beneficial effect of yoghurt on health as well as its immunomodulator effect on the gut immune system is well documented. The aim of this work was to study the possible beneficial effects of yoghurt consumption on an experimental model of IBD in mice. Balb/c mice were fed with yoghurt for 10 consecutive days. At the end of the feeding period the mice received three inoculations of 2, 4, 6-trinitrobenzene sulphonic acid (TNBS) solutions once a week for 3 consecutive weeks. After TNBS instillation the mice received yoghurt again for 10 consecutive days. IBD control received only TNBS. After treatments we analysed the number of IgA–secreting cells, CD4+, CD8+ T cells population and the number of apoptotic cells in the large intestine. The number of erythrocytes and leucocytes in peripheral blood mononuclear cells (PBMCs) was also determined. We demonstrated the antinflammatory effect of yoghurt in an experimental model of IBD induced by TNBS. The effect was mediated by an increase in the number of the IgA+cells, a decrease in CD8+ population and by the induction of apoptosis of the infiltrative cells in the large intestine.

Effect of probiotic strains Lactobacillus acidophilus LAFTI L10 and Lactobacillus paracasei LAFTI L26 on systemic immune functions and bacterial translocation in mice

The immunostimulatory effects of Lactobacillus acidophilus LAFTI L10 and Lactobacillus paracasei LAFTI L26 were evaluated to determine their probiotic properties for functional food applications. Mice were given oral doses of either L. acidophilus L10 or L. paracasei L26 (108 CFU/50 microl/day), and the effects on immune responses and bacterial translocation were assessed after the 14-day feeding trial. The proliferative responses of splenocytes to concanavalin A and lipopolysaccharide were significantly higher in mice fed L. acidophilus. Concanavalin A-induced splenocyte proliferative responses increased significantly in mice fed L. paracasei. Interleukin 10 and interferon gamma production from the splenocytes stimulated with concanavalin A were enhanced in mice fed L. acidophilus or L. paracasei. The phagocytic activity of the peritoneal macrophages was significantly higher in mice fed either L. acidophilus or L. paracasei compared with control mice. In mice fed L. acidophilus or L. paracasei, the bacterial translocation of Lactobacillus spp. and total anaerobes to Peyer's patches and mesenteric lymph nodes was modulated compared with that in the control mice. Furthermore, there was no indication of disruption of intestinal mucosal integrity and thus no bacterial translocation to spleen, liver, or blood in mice fed either L. acidophilus or L. paracasei. The results of this study indicate that L. acidophilus and L. paracasei are potential enhancers of systemic immunity and are nonpathogenic, as suggested by their bacterial translocation profiles in healthy mice.

A randomized formula controlled trial of Bifidobacterium lactis and Streptococcus thermophilus for prevention of antibiotic-associated diarrhea in infants

GOALS

This clinical trial was carried out to determine whether oral treatment with a commercial probiotic formula containing Bifidobacterium lactis and Streptococcus thermophilus would reduce the frequency of antibiotic-associated diarrhea (AAD) in infants.

STUDY

In this double-bind formula controlled study, 80 infants, 6 to 36 months of age, were randomly assigned to receive a commercial formula containing 10 viable cells of B. lactis and 10 viable cells of S. thermophilus at the initiation of antibiotics for a duration of 15 days. The infants were assessed daily for formula intake, stool frequency, and stool consistency for a total duration of 30 days. Seventy-seven infants received nonsupplemented formula for the entire duration.

RESULTS

There was a significant difference in the incidence of AAD in the children receiving probiotic-supplemented formula (16%) than nonsupplemented formula (31%).

CONCLUSIONS

The present study shows that prevention against AAD in infants was obtained by oral treatment with daily dose of B. lactis and S. thermophilus.

Effect of Bifidobacterium longum ingestion on experimental salmonellosis in mice

AIMS

The effect of lactic acid bacteria on the immune system is well established under normal conditions and generally by in vivo determinations, but few data are available, in vivo, during an infectious challenge. The objective of this study was to obtain data on the putative protective role of bifidobacteria upon challenge with an intestinal pathogen.

METHODS AND RESULTS

The effect of oral treatment with Bifidobacterium longum Bb46 on intragastric challenge with Salmonella Typhimurium was studied. Faecal bacterial levels were determined in gnotobiotic (GN) mice and mortality, histopathology (intestines, liver), immunoglobulin levels (IgM, IgG, IgG1, IgG2a) and cytokine production (IFN-gamma, IL-10) were determined in conventional (CV) mice. Conventional mice received 0.1 ml probiotic milk (10(8) CFU) daily, 10 days before the oral pathogenic challenge (10(2) CFU). Then, probiotic treatment was continued until the end of the experiment. Probiotic treatment in germ-free mice consisted of a single dose at the beginning of the experiment. Control groups were treated with sterile skim milk and submitted to the same procedure. A higher survival (40%) was observed for probiotic-treated animals when compared with the control group (0%). This protective effect was confirmed by the histopathological and morphometric data. However, S. Typhimurium population levels in the faeces were similar among control and probiotic-treated groups. During the challenge with S. Typhimurium, a decrease in IFN-gamma and IgG2a productions was observed in probiotic-treated mice.

CONCLUSIONS

The protective effect against the pathogenic challenge may be due to a reduced inflammatory response, mediated by the probiotic treatment, but not to a population antagonism.

SIGNIFICANCE AND IMPACT OF THE STUDY

Results suggest that dietary supplementation with B. longum could provide benefits against enteric infection.

Microbes versus microbes: immune signals generated by probiotic lactobacilli and their role in protection against microbial pathogens

Probiotic lactic acid bacteria can signal the immune system through innate cell surface pattern recognition receptors or via direct lymphoid cell activation. In some cases, this action has been shown to be sufficient to modulate local- and systemic-level in vivo immune responses. Practical applications of probiotics include their use in anti-tumour and anti-allergy immunotherapy, but there is also increasing evidence that some probiotics can stimulate a protective immune response sufficiently to enhance resistance to microbial pathogens. This review outlines the experimental and clinical evidence for enhanced anti-microbial immune protection by probiotic lactic acid bacteria, focussing on those studies where a correlative or suggestive link has been shown between immune modulation and enhanced protection.

Effect of yogurt on the inhibition of an intestinal carcinoma by increasing cellular apoptosis

Yogurt consumption has been associated with decreased risk of colon cancer. The apoptosis induced by yogurt as a mechanism involved in the inhibition of an experimental intestinal tumor induced by 1,2 dimethylhydrazine (DMH) in BALB/c mice, has been studied. An imbalance between apoptosis and mitosis or cell proliferation is believed to underlie colon cancer development and progression. We determined the effect of yogurt feeding in the induction of apoptosis and the relationship between mitosis and apoptosis in mice injected with the carcinogen DMH and in mice injected with DMH and fed with a diet supplemented with yogurt. The percentage of mitotic and apoptotic cells was analyzed every 2 weeks from week 8 to 16. They were analyzed on histological slices from the large intestine by colchicine, or Tunel test for mitosis and apoptosis determination, respectively. An increase in the mitosis during the first 4 weeks of tumor development with apoptosis negative and severe dysphasia, was observed in animals treated with the carcinogen. In those animals that received DMH and were given yogurt, a moderate cell proliferation with a significant increase in the number of apoptotic cells was determined. The increase in the apoptotic activity was also observed in the group of animals that received only a diet supplemented with yogurt. The results suggest that yogurt would influence the balance between mitosis and apoptosis, which was modified during the carcinogenesis process, by increasing cellular apoptosis. Dietary supplementation of yogurt may play a role in modulating cell proliferation or apoptosis during the development of colorectal carcinoma.

Human studies with probiotics and prebiotics: clinical implications

Probiotic agents have been shown to have significant clinical beneficial effects in the prevention and management of gastrointestinal and non-gastrointestinal conditions. These observations have led to work demonstrating that an important mechanism of these agents is their close interaction with the gut associated lymphoid tissue (GALT) and suggested immunomodulatory effects on systemic immune response. Studies on the possibility that prebiotic agents might directly or indirectly induce similar immunomodulation have only recently begun. The preliminary findings of several recent human clinical trials reviewed in this article indicate that prebiotics may indeed prove to be a clinically beneficial dietary supplement, in the context of novel nutritional strategies for the management of gastrointestinal and systemic conditions.

Effect of Lactobacillus casei and yogurt administration on prevention of Pseudomonas aeruginosa infection in young mice

Pseudomonas aeruginosa is an opportunistic pathogen that rarely causes pulmonary disease in normal hosts but one that is an important cause of acute pneumonia in immunocompromised patients, including neonates, and of chronic pneumonia in patients with cystic fibrosis. The aim of this work was to study the effect of oral administration of Lactobacillus casei and yogurt on prevention of P. aeruginosa lung infection in young mice (3 weeks old). This study demonstrates that oral administration of L. casei or yogurt to young mice enhanced lung clearance of P. aeruginosa and phagocytic activity of alveolar macrophages through a dose-dependent effect. There were, however, no significant differences in white blood cell (WBC) differential counts. Furthermore, it was observed that previous administration of L. casei or yogurt induced a significant increase in IgA and IgM levels in bronchoalveolar lavages (BALs) after a P. aeruginosa infection, although there was no relationship with the serum values.

Viability and dose-response studies on the effects of the immunoenhancing lactic acid bacterium Lactobacillus rhamnosus in mice

Previous studies have indicated that the lactic acid bacterium Lactobacillus rhamnosus HN001 can enhance immune function in mice, following oral delivery. However, the influence of bacterial cell viability on immunoenhancement, and the optimum dose of HN001 required for this effect, have not been determined. In the present study, both live and heat-killed preparations of L. rhamnosus HN001 were shown to enhance the phagocytic activity of blood and peritoneal leucocytes in mice, at a dose of 109 micro-organisms daily. In contrast, only live HN001 enhanced gut mucosal antibody responses to cholera toxin vaccine. Feeding mice with 107 viable HN001/d for 14 d was shown to enhance the phagocytic capacity of blood leucocytes, with incremental enhancement observed at 109 and 1011 daily doses. In contrast, a minimum dose of 109 viable HN001/d was required to enhance the phagocytic activity of peritoneal leucocytes, and no further increment was observed with 1011 daily. This study demonstrates that L. rhamnosus HN001 exhibits dose-dependent effects on the phagocytic defence system of mice, and suggests that while the innate cellular immune system is responsive to killed forms of food-borne bacteria, specific gut mucosal immunity may only be stimulated by live forms.

Effects of ingestion of yogurts containing Bifidobacterium and Lactobacillus acidophilus on spleen and Peyer's patch lymphocyte populations in the mouse

Certain probiotic lactic acid bacteria have been reported to improve immune system function. Here, the effects of ingesting yogurts on lymphocyte populations in the spleens and Peyer's patches were determined in mice. Three probiotic-supplemented yogurts containing Streptococcus thermophilus, Lactobacillus bulgaricus, Bifidobacterium, and Lactobacillus acidophilus and one conventional yogurt containing only S. thermophilus and L. bulgaricus were prepared from commercial starter cultures and used in the study. B6C3F1 female mice were fed the four different types of yogurts mixed with an AIN-93G diet in a 50:50 (wt/wt) ratio. Nonfat dry milk mixed at a 50:50 (wt/wt) ratio with AIN-93G diet was used as the control. After a 14-day feeding period, spleen and Peyer's patches were removed and lymphocytes subjected to phenotype analysis by flow cytometry. Ingestion of the four yogurts had no effect on percentages of CD8+ (cytotoxic T cells), B220+ (B cells), IgA+, or IgM+ cells in spleen or Peyer's patches. The percentage of CD4+ (T helper) cells was significantly increased in the spleens from one group of mice fed a yogurt containing Bifidobacterium and L. acidophilus, and a similar trend was found in the remaining two probiotic-supplemented yogurts. Effects on CD4+ populations were not observed in spleens of mice fed conventional yogurt or in the Peyer's patches of any of the four yogurt groups. In total, the results suggested that ingestion of conventional or probiotic-supplemented yogurts for 2 weeks had very little effect on lymphocyte distribution in the systemic or mucosal immune compartments.

Kefir milk enhances intestinal immunity in young but not old rats

The adjuvant effect of kefir fermented milk on the mucosal and systemic immune systems was examined in young (6 mo old) and old (26 mo old) rats. Kefir-fed rats consisted of young or old rats consuming kefir-fermented milk ad libitum on a daily basis in addition to the standard diet, for 28 d. Control rats consumed only the standard diet. The rats were immunized intraduodenally with cholera toxin (CT) on d 7 and 21 and killed on d 28. The nonspecific serum immunoglobulin (Ig)A titers in kefir-fed and control rats did not differ in either age group. The serum anti-CT IgA antibody concentrations were significantly higher in the kefir-fed young rats compared with their age-matched controls (+86%, P: < or = 0.05). This difference was associated with enhanced in vitro antibody secretion by cultured lymphocytes isolated from the Peyer's patches and the intestinal lamina propria (+180%, P: < or = 0.05). These enhanced responses were found only in the young rats. However, the nonspecific serum IgG titer was higher (>120%, P: < or = 0.05) and the anti-CT IgG titer was lower (-80%, P: < or = 0.05), in both young and old kefir-fed rats compared with their respective controls. Nevertheless, these results demonstrate that a kefir-supplemented diet affects the intestinal mucosal and systemic immune responses to intraduodenal CT differently in young and old rats. Most importantly, our data suggest that orally administered kefir enhances the specific intestinal mucosal immune response against CT in young adult, but not in senescent rats.

A novel efficient method to identify beta-glucuronidase activity in rat small intestine

BACKGROUND

Recent epidemiologic studies promote the notion that high intake of food rich in phytochemicals protects against degenerative diseases such as coronary heart diseases and cancer. Phytochemicals are detoxified in mammalian tissues by conjugation with glucuronic acid yielding less active glucuronide conjugates. However, in several tissues glucuronide conjugates are reactivated by the cleaving enzyme beta-glucuronidase. The aim of the present study was to develop a routinely manageable, rapid technique to localize the beta-glucuronidase activity in the small intestinal tissue.

METHODS

Histologic slices of rat duodenum, jejunum, and ileum were incubated with a specific chromogenic beta-glucuronidase substrate, 5-bromo-4-chloro-3-indolyl-beta-D-glucuronide (X-GlcU). After enzymatic cleavage, X-GlcU yields 5-bromo-4-chloro-3-indol, a dark blue crystalline precipitate easily monitored by light microscopic technique.

RESULTS

The number and intensity of the crystals were highest in the jejunum and lowest in the ileum. In all three sections of the small intestine, the highest activity was observed at the villar tip and in the tela submucosa and only moderate activity in other layers of the intestinal tissue.

CONCLUSIONS

By using the X-GlcU-technique, it could be demonstrated convincingly that beta-glucuronidase exists in all three segments of the rat small intestine. The proposed method is an efficient, simple, and convenient method to visualize beta-glucuronidase activity.