Putative probiotics decrease cell viability and enhance chemotherapy effectiveness in human cancer cells: role of butyrate and secreted proteins.

Recent advances have highlighted probiotic role in preventing colorectal cancer, by promoting differentiation, inhibiting proliferation, and inducing apoptosis in colonocytes. Here, three ascertained probiotics (L. rhamnosus GG ATCC 53103, L. reuterii DSM 17938 and L. johnsonii LC1) and four food-isolated putative probiotics (L. plantarum S2, L. plantarum O2, L. pentosus S3, L. rhamnosus 14E4) were investigated for their ability to adhere to HT29 cancer cells and to inhibit their and the chemoresistant counterpart (HT29-dx cells) proliferation. Three putative probiotics (S2, S3 and 14E4) were able to decrease viability of both sensitive and chemo-resistant HT-29 cells. Supposing this effect related to secreted metabolites (namely short chain fatty acids (SCFA), exopolysaccharides (EPS) and extracellular proteins) we tested the efficacy of extracellular extracts and butyrate with or without the chemotherapeutic agent doxorubicin (DOXO) (10 µM, 4 h). Increased production of mitochondrial reactive oxygen species (ROS) in HT29 and HT29-dx cells was observed. Moreover, cell exposure to DOXO (10 µM, 24 h) and extracellular extracts (48 h) reduced cell viability. Comparative phenotypic and secretome analyses on the effective/non effective strains, revealed quantitative/qualitative differences in EPS content and protein profiles, suggesting that P40, phage-tail-like and capsid-like proteins may be also involved. These results suggest that food-isolated bacteria releasing bioactive compounds (butyrate, EPS and peculiar proteins) may control cancer cell proliferation and improve their response to chemotherapy.

Rabbit dietary supplementation with pale purple coneflower. 2. Effects on the performances, bacterial community, blood parameters and immunity of growing rabbits.

Echinacea pallida (EPAL), a herbaceous flowering plant with immunomodulatory properties, has been chosen to determine the pre- and post-supplementary effects on the growth performances, bacterial community, blood parameters and immunity of growing rabbits. The same Grimaud does (14-week-old) from the studied in the first part of this study were randomly divided into two groups (n=50/group). The first group was fed a basal diet without supplementation (Control group, C) while the another group was fed a basal diet supplemented with 3 g EPAL/kg diet (Echinacea group, E). From the second parturition, 80 weaned kits (40 from the C does and 40 from the E does) were randomly assigned to four groups of 20 animals each and were fed a growing commercial diet supplemented with or without a 3 g EPAL/kg diet: the CC group (rabbits from the C does fed the control diet), CE group (rabbits from the C does fed the supplemented diet), EC (rabbits from the E does fed the control diet) and EE group (rabbits from the E does fed the supplemented diet). The dietary EPAL treatment did not affect the growth performance. Ten fattening rabbits from each group were selected to evaluate the bacterial community and blood parameters, while the remaining rabbits (n=10/group) were used to study phagocytosis and the humoral immune response. The variability was evaluated from hard faeces at 35, 49 and 89 days, and the caecal content at 89 days. The variability of the bacterial community of the EE group was higher than that of the other groups. The phagocytic activity was higher in the CE and EE groups than in the CC and EC ones (30.9 and 29.7 v. 21.2 and 21.8%; P<0.05), whereas no statistically significant difference was observed for the blood parameters or humoral immune response against vaccination (rabbit haemorrhagic disease virus) at 95 days old which the serum was collected at 88, 102, 109, 116 and 123 days old. In conclusion, no impact of EPAL dietary supplementation has been observed on the growth performances, bacterial community, blood parameters or humoral immune responses in growing rabbits, except for an increase in phagocytic activities.

Effect of purple loosestrife (Lythrum salicaria) diet supplementation in rabbit nutrition on performance, digestibility, health and meat quality.

In this study, 160 Hycole weaned rabbits (35 days old) were randomly divided into four groups of 40. The rabbits were studied throughout a 54-day experimentation period in order to determine the impact of dietary supplementation from herbs composed of 0.2%, 0.4% dry ground Lythrum salicaria leaves (LS) and 0.3% Cunirel(®) (CR; a commercial herb mixture containing LS as the main ingredient) on performance, digestibility, health and meat quality. The basal diet was given to the control group. No significant differences were found in performance, 10 rabbits from each group were selected for evaluation regarding apparent digestibility. The rabbits fed the control diet and the diet with the low level of LS had a higher level of CP digestibility than did the animals that were supplemented with the high LS levels and CR (85.7% and 84.9% v. 84.0% and 84.0%, respectively; P<0.05). The ether extract digestibility was lower in the treatment group with 0.4%LS addition and CR as compared with the control group (52.2% and 54.5% v. 62.6%, respectively; P<0.05). The slaughter process was performed on 89-day-old rabbits to study the carcass characteristics, meat quality, blood parameters, caecal contents and gut histology. The total leukocyte counts in the control animals were lower than they were in the rabbits fed 0.2%, 0.4%LS and CR (4.06 v. 8.25, 8.63 and 8.21×10(9)/l, respectively; P<0.05). For caecal fermentation, the caecal contents of the rabbits fed 0.4% of LS, showed higher concentrations of total volatile fatty acid (VFA; 24.1 v. 18.9 mg/kg dry matter (DM); P<0.05) and acetic acid (18.3 v. 14.4 mg/kg DM; P<0.05), but lower ammonia levels (594 v. 892 mg/kg DM; P<0.05) as compared with the control group. PCR-denaturing gradient gel electrophoresis analyses were performed to evaluate the microbial community in hard faeces, collected at days 35, 42, 49, 56, 70 and 89, whereas the caecal contents were taken after slaughtering. The results demonstrated that between the treatment groups, the similarity of the microbial communities was higher as compared with the control group. Moreover, only age was shown to influence microbiota diversity. In conclusion, the results of this study indicated that supplementation of LS in rabbit diets leads to an increase in the total white blood cells, total VFA and acetic acid concentration, and a decrease in the ammonia levels, as well as the digestibility when CR and high level of LS were supplemented, without causing any adverse effects on other parameters.

Development of a PCR microplate-capture hybridization method for simple, fast and sensitive detection of Salmonella serovars in food.

The authors have developed an easy and rapid detection and identification system for Salmonella spp. in food. The gene inv A was selected as the target sequence. Oligonucleotides derived from conserved regions of this gene were able to exclusively prime the amplification of a 389 bp fragment when Salmonella spp. DNA was used as the template. An internal Salmonella spp. specific DNA probe was used for confirmation of the amplified polymerase chain reaction(PCR)product, by Southern blot or microplate-capture hybridization assay. In this fashion the sensitivity of the method was increased 100-fold (4.5 fg total DNA). To validate the method, a total of 75 food samples were tested. The PCR-microplate capture hybridization assay is easy to perform and much faster than traditional detection methods for Salmonella spp. in food. Hybridization in microtitre plates is more readily observed than in Southern blot and is more sensitive than conventional agarose gel electrophoresis.