András Bónai

In vitro interaction between fumonisin B1 and the intestinal microflora of pigs

The caecal chyme of pigs was incubated anaerobically in McDougall buffer with and without fumonisin B1 (5 μg/ml) for 0, 24 and 48 h. The plate count agar technique was applied for enumerating the amount of bacteria including aerobic, anaerobic bacteria, coliform, Escherichia coli and Lactobacillus sp. The quantitative polymerase chain reaction was also performed to estimate the number of copies of the total bacteria, Lactobacillus, Bacteroides and Prevotella. No significant differences in the amount of bacterial groups between the experimental (buffer, chyme, and fumonisin B1) and control 1 groups (buffer + chyme) were observed in both methods. Fumonisin B1 and hydrolysed fumonisin B1 concentration were analysed by liquid chromatograghy - mass spectrometry. There was no significant difference in FB1 concentration between the experimental and the control 2 group (buffer and fumonisin B1) at 0 h incubation, 5.185 ± 0.174 μg/ml com-pared with 6.433 ± 0.076 μg/ml. Fumonisin B1 concentration in the experimental group was reduced to 4.080 ± 0.065 μg/ml at 24 h and to 2.747 ± 0.548 μg/ml at 48 h incubation and was significantly less than that of in the control group. Hydrolysed fumonisin B1 was detected after 24 h incubation (0.012 ± 0 μg/ml). At 48 h incubation time, hydrolysed fumonisin B1 concentration was doubled to 0.024 ± 0.004 μg/ml. These results indicate that fumonisin B1 can be metabolised by caecal microbiota in pigs though the number of studied bacteria did not change.

Physiological Effects of Whey- and Milk-Based Probiotic Yogurt in Rats

In an in vitro experiment commercially available probiotic products were tested for the survival of bacteria under conditions of simulated human digestion either when used alone or mixed into yogurt. In the in vivo experiment the effects of feeding a whey- and milk-based yogurt prepared with the probiotic strain showing adequate survival in the in vitro experiment, was measured on body weight, feed con¬sumption and immune response of rats (IgG and IgA level after immunisation), on the composition and volatile fatty acid production of the intestinal microbiota and on the structure of intestinal villi. The Lactobacillus acidophilus (LA-15) strain had inadequate surviving ability in rats. Bifidobacterium animalis ssp. lactis (BB-12) improved the composition of the intestinal microflora, whereas whey-containing product had a mild immunostimulating effect and exerted a favourable influence on the morphology of intestinal villi. The consumption of yogurts increased the depth of crypts in the ileum, which resulted in enhanced secretion and thus softer faeces.

Quantitative PCR with 16S rRNA-gene-targeted specific primers for analysis of caecal microbial community in growing rabbits after dietary supplementation of thyme (Thymus vulgaris) and spirulina (Arthrospira platensis)

Abstract Objective of this study was to evaluate the effect of supplementation of growing rabbits’ diet with 5% spirulina (Arthrospira platensis) and/or 3% (Thymus vulgaris L.), on composition and amount of rabbits caecal microbiota. After weaning, rabbits were randomly sorted to 4 groups (n = 42/group). The control group received a pellet without any supplementation, in treated groups the dietary supplementation was provided until 77 days of age. On 49, 63 and 77 days of age, six healthy animals/group were randomly selected and slaughtered. From the caecal content the amount of total bacteria, Bacteroides, Clostridium leptum and Clostridium coccoides were determined by quantitative polymerase chain reaction (qPCR), with the aid of bacterial ribosome coding DNA. The copy number of total bacteria, C. leptum, C. coccoides and Bacteroides varied between 2.75 × 1012 to 2.24 × 1013, 5.25 × 1011 to 1.82 × 1012, 2.5 × 1010 to 6.91 × 1011 and 5.89 × 1010 to 1.10 × 1012, respectively. The amount of investigated bacteria represented 0.6%-13.4% of the total bacteria. The use of spirulina and/or thyme supplements influenced the amount of the copy number of each bacteria examined between 49 and 77 days of age. Their effect on the total bacteria number was temporary. Spirulina resulted in more Bacteroides on day 63 but significantly lower amount of Clostridia at 63 and at 77 days of age. The antimicrobial effect of thyme on the absolute Clostridia number was temporary, prevailing on day 63. Thyme resulted in significantly decreasing percentage ratio (within total bacteria) of C. leptum and C. coccoides by 77 days of age.