The ability of yoghurt supplemented with dietary fibers or brans extracted from wheat or rice to reduce serum lipids and enhance liver function in male hypercholesterolemic rats.

This study was undertaken to evaluate the effect of yoghurt supplementation with rice and wheat brans or dietary fibers on serum lipid profile, liver, and heart functionalities, and hepatopathological aspects of the liver of hypercholesterolemic rats. 48 male rats were divided into 8 groups. Group 1 was kept as negative control and fed with a standard diet, and groups 2 to 6 were fed a hypercholesterolemia-induced diet supplemented with brans or dietary fibers of both grains. G2 received yoghurt without supplementation. The experiment lasted for 4 weeks. Results revealed that hypercholesterolemic rats administrated yoghurt supplemented with brans or dietary fibers reduced serum glucose from 113.9 ± 2.72 to 85.5 ± 4.94 in the serum of animals that received dietary fibers of rice and wheat, respectively. In addition, lipids profile and liver antioxidant status were improved. In addition, liver and heart functionalities and liver histopathological architecture were all improved depending on the type of administrated brans or fibers added to yoghurt. The inclusion of 0.5% of rice or wheat brans could be recommended to be added to yoghurt. PRACTICAL APPLICATIONS: Yoghurt is the most famous fermented milk in the world. Supplementation of yoghurt with rice and wheat brans or dietary fibers increased its nutritional value. We proved that this new product contributes to reducing serum glucose, improving lipids profile, and enhancing liver and heart functions in hypercholesterolemic rats. This study confirmed the suitability to add a thesis type of brans or dietary fibers as bioactive ingredients to yoghurt and increased the varieties of functional foods.

Effectiveness of inulin-type on the iron bioavailability in anemic female rats fed bio-yogurt.

It is well-documented that iron deficiency leads to anemia, which is the utmost critical problem of nutrition worldwide. Inulin, indigestible polysaccharides, or prebiotic agents may act as vehicles to enhance the iron bioavailability through the formation of the polysaccharide-iron complex. The present study was undertaken to evaluate the therapeutic effects of yogurt fortified with iron and supplemented by long- or short-chain inulin on the growth status, blood parameters, antioxidant capacity, and liver function enzymes in anemic rats. Five animal groups were assigned as the control (G1), which were fed a standard diet and there were four anemic groups, in which haemolytic anemia was induced by phenylhydrazine. The anemic rats were divided into 4 groups according to the regime of feeding as G2: control anemic group fed low-iron diet while the remaining anemic groups were fed yogurt fortified with Fe2(SO4)3 without inulin (G3) or with either long- (G4) or short-chain (G5) inulin. The results showed that the animals subjected to treatment G4 had the highest (P ≤ 0.05) weight gain and organ coefficient compared with other anemic groups (G2, G3, and G5). Among the anemic groups, the animals that belonged to G4 showed a significant restorative effect by returning the hemoglobin and hematocrit levels and the red blood cell count to the normal control liver. Also, the liver iron content, enzymatic activities, and antioxidant capacities improved in the animals subjected to G4 and G5 treatment groups. The histological structures of the liver tissues of the animals that belonged to G4 and G5 were extremely close to that of the normal control liver. Long-chain inulin-containing yogurt exhibited the best effects in terms of iron supplementation, bioavailability, and antioxidant activities. This formula might be a potential new iron supplement and a good functional food candidate.

Comparative transcriptome analysis of Lactococcus lactis subsp. cremoris strains under conditions simulating Cheddar cheese manufacture.

Gene expression in response to technological variations can influence fermentation and flavor generation in Cheddar cheese, and can vary from one lactococcal strain to another, perceived as differences in starter performance. The aim of this study was to determine the influence of cheese cooking temperature at 38 °C and salting on the transcriptional profiles of four closely related strains of L. lactis subsp. cremoris under simulated conditions of Cheddar cheese manufacture. Two responses could be distinguished, a core gene expression, corresponding to the common response of all strains and strain-specific response during the Cheddar simulating process. For the core gene expression after heating of inoculated milk at 38 °C, two groups of differentially expressed genes were identified: i) stress response and ii) carbohydrate and amino acid metabolism. The response to combined stresses of heat, acid and salt resulted in: i) general decrease of functions linked to cell division and metabolism, ii) specific responses related to stress such as the induction of genes coding for chaperones and proteases and iii) expression of prophage lytic systems for certain strains. Strain-specific responses were mainly observed in three of the four tested strains. These responses were the induction of genes related to osmotic stress or the release of CodY repression leading to the activation of oligopeptide transporters as well as the bcaT gene, related to amino acid degradation for the production of flavor. Comparing transcriptomes provides a core expression profile that contributes to understanding gene expression responses to environmental variations. The strain-specific responses identify predictive markers for the transcriptional state of starter strains before they enter the cheese ripening phase.

Viability of probiotic bacteria in maple sap products under storage and gastrointestinal conditions.

This study was undertaken to develop new probiotic products based on liquid maple sap or its concentrate. Sap and concentrate, with or without inulin (2%) were inoculated with Bifidobacterium lactis Bb12 and Lactobacillus rhamnosus GG valio at initial counts of 107-108 CFU/ml. Viability was assessed over four weeks of storage at 4 °C and under in vitro simulated gastrointestinal conditions using dynamic gastrointestinal model known as TIM-1. Viability was maintained throughout the storage period at the same order of 107 to 108 CFU/ml. Inulin significantly enhanced the survivability during passage through the gastrointestinal tract simulator. The developed products could be an excellent alternative for delivering probiotics, especially for individuals suffering from lactose intolerance to dairy products.

Evaluation of the genetic polymorphism among Lactococcus lactis subsp. cremoris strains using comparative genomic hybridization and multilocus sequence analysis.

Genetic diversity of Lactococcus lactis subsp. cremoris provides an important reservoir of industrial functions. Knowledge of strain diversity is an important step for the selection of starter cultures, because technological and sensorial attributes are strain-dependent and it may help to distinguish strains with particular technological properties and performances. In the present study, microarray-based comparative genomic hybridization (CGH) and multilocus sequence analysis (MLSA) were used to investigate the genetic variation among eight strains of Lactococcus lactis subsp. cremoris. The CGH analysis allows strain grouping and identification of absent or divergent genes involved in metabolism, amino acid biosynthesis, osmoregulation and proteolysis. The MLSA clustering of strains based on the partial sequence of eight genes shows good correlation with the CGH grouping. Strains HP, ATCC 19257 and Wg2 were clustered together, followed by E8, and finally SK11 was in a separate cluster. The combined information provides genetic markers for distinguishing between strains and their variants. By selecting strains according to their genetic profiles, compatible and complementary mixed starters can be formulated, opening new avenues for industrial applications.

In vivo study on the effectiveness of pediocin PA-1 and Pediococcus acidilactici UL5 at inhibiting Listeria monocytogenes.

The anti-listerial effect of pediocin PA-1 and its producing strain, Pediococcus acidilactici UL5, was investigated in vivo using an ICR mouse model. The effect of intra-gastric administration of a single dose of P. acidilactici UL5 (4 x 10(10) CFU/animal) on the propagation of Listeria monocytogenes LSD348 in intestine, liver and spleen was negligible. P. acidilactici UL5 did not appear competitive with the mouse intestinal flora and was not detectable in fecal samples collected two days after administration. However, double-agar-layer activity assay showed the ability of P. acidilactici UL5 colonies recovered from fecal samples one day after administration to produce pediocin PA-1 and inhibit L. monocytogenes. Moreover, repeated doses (250 microg/day for three consecutive days) of purified pediocin PA-1 provided up to 2-log reductions in fecal listerial counts compared to the infected control group and slowed pathogen translocation into the liver and spleen, leading to the disappearance of L. monocytogenes infection in these two organs within six days. Neither P. acidilactici UL5 nor ingested purified pediocin PA-1 had any negative effect on feed intake or body weight development. Pediocin PA-1 did not affect the composition of the mouse intestinal flora, suggesting a potential advantage over other inhibitory agents as a prophylactic measure against L. monocytogenes.

Effect of Bifidobacterium thermacidophilum probiotic feeding on enterohemorrhagic Escherichia coli O157:H7 infection in BALB/c mice.

The effectiveness of Bifidobacterium thermacidophilum RBL 71 as a probiotic against enterohemorrhagic Escherichia coli O157:H7 infection was studied using a murine model. BALB/c mice were fed the probiotic for 7 days before or after single challenge with E. coli O157:H7. Fecal B. thermacidophilum RBL 71 and E. coli O157:H7 counts obtained by selective culturing methods were assessed for 1 week before and after infection while feed intake, body weight and composition were monitored during 1 week after infection. Histology of gut tissue (jejunum, ileum and colon) and production of fecal IgA antibodies and serum IgG+IgM antibodies to E. coli O157:H7 were analyzed until 1 and 2 weeks post-infection, respectively. The pathogenicity of E. coli O157:H7, marked by body weight loss and intestinal histopathological changes in the infected group, was significantly reduced in the B. thermacidophilum-treated group. Feeding B. thermacidophilum RBL 71 for 7 days before infection resulted in greater post-challenge feed intake and weight gain and lower fecal levels of E. coli O157:H7. Post-infection levels of anti-E. coli O157:H7-specific IgA in feces and IgG+IgM in serum were higher in mice fed bifidobacteria. Intestinal injuries were also attenuated and reaction of the lymphoid component in the mucosa of the ileum was greater in the bifidobacteria-fed group. A lesser degree of protection against E. coli O157:H7 infection was observed when bifidobacteria were given during the 7 days after E. coli O157:H7 infection. These results demonstrate that feeding the probiotic B. thermacidophilum RBL 71 to mice can reduce the severity of E. coli O157:H7 infection, and suggest that this strain represents a good candidate for the prevention of enteric infections in human.