Isolation and identification of clostridia from the intestine of laboratory animals

Beneficial effects of a combination of Clostridium cochlearium and Lactobacillus acidophilus on body weight gain, insulin sensitivity, and gut microbiota in high-fat diet-induced obese mice

OBJECTIVES

Species Lactobacillus acidophilus and butyrate producer Clostridium cochlearium have been shown to have potential antiobesity effects. The aim of this study was to show that the combination of C. cochlearium and L. acidophilus (CC-LA) has beneficial effects on body weight control and glucose homeostasis in high-fat diet-induced obese (DIO) mice.

METHODS

In this study, thirty-six 6-wk-old male C57BL/6 mice were randomly assigned to three groups of 12 mice each. The experimental group (CC-LA) was administered with CC-LA mixture and fed ad libitum with a high-fat diet. High-fat diet (HF) control and low-fat diet (LF) control groups were treated with the same dose of sterile water as the CC-LA group.

RESULTS

After 17 wk of dietary intervention, the CC-LA group showed 17% less body weight gain than the HF group did (P < 0.01). The CC-LA group also showed significantly reduced incremental area under the curve of oral glucose tolerance test and homeostatic model assessment for insulin resistance compared with the HF group. The results from 16S rRNA sequencing analysis of gut microbiota showed that the CC-LA administration led to overall increased α-diversity indices, and a significant microbial separation from the HF group. The ratio of Firmicutes to Bacteroidetes (F/B) was reduced from 3.30 in the HF group to 1.94 in the CC-LA group. The relative abundances of certain obesity-related taxa were also decreased by CC-LA administration.

CONCLUSION

The present study provided evidence that the CC-LA combination reduced obesity and improved glucose metabolism in high-fat diet-treated DIO mice, potentially mediated by the modulation of gut microbiota.

Symbiotic formulation in experimentally induced liver fibrosis in rats: intestinal microbiota as a key point to treat liver damage?

AIM

Evidence indicates that intestinal microbiota may participate in both the induction and the progression of liver damage. The aim of our research was the detection and evaluation of the effects of chronic treatment with a symbiotic formulation on CCl4 -induced rat liver fibrosis.

RESULTS

CCl4 significantly increased gastric permeability in respect to basal values, and the treatment with symbiotic significantly decreased it. CCl4 per se induced a decrease in intestinal permeability. This effect was also seen in fibrotic rats treated with symbiotic and was still evident when normal rats were treated with symbiotic alone (P < 0.001 in all cases). Circulating levels of pro-inflammatory cytokine TNF-α were significantly increased in rats with liver fibrosis as compared with normal rats, while symbiotic treatment normalized the plasma levels of TNF-α and significantly enhanced anti-inflammatory cytokine IL 10. TNF-α, TGF-β, TLR4, TLR2, iNOS and α-SMA mRNA expression in the liver were up-regulated in rats with CCl4 -induced liver fibrosis and down-regulated by symbiotic treatment. Moreover, IL-10 and eNOS mRNA levels were increased in the CCL4 (+) symbiotic group. Symbiotic treatment of fibrotic rats normalized serum ALT, AST and improved histology and liver collagen deposition. DGGE analysis of faecal samples revealed that CCl4 administration and symbiotic treatment either alone or in combination produced modifications in faecal profiles vs controls.

CONCLUSIONS

Our results provide evidence that in CCl4 -induced liver fibrosis, significant changes in gastro-intestinal permeability and in faecal flora occur. Treatment with a specific symbiotic formulation significantly affects these changes, leading to improvement in both liver inflammation and fibrosis.

Infectious agents associated with epizootic rabbit enteropathy: isolation and attempts to reproduce the syndrome

Epizootic rabbit enteropathy (ERE), a highly lethal (30–80% mortality) disease of broiler rabbits aged 6–14 weeks, first appeared in 1997 in French intensive enclosed rabbitries and is of unknown aetiology. Bacteriological, virological and parasitical examination of the intestinal contents of rabbits that had died either in spontaneous field cases or after experimental reproduction of ERE, were undertaken in an attempt to identify infectious agents that may play a role in the disease. Two bacterial strains, Clostridium perfringens and non-enteropathogenic Escherichia coli were repeatedly isolated at high faecal counts from naturally infected animals. In field cases, a correlation between typical gross lesions of epizootic enteropathy and the presence of the alpha toxin of Cl. perfringens was observed (P < 0.0001; Chi-squared test). Although attempts to reproduce the disease by inoculation with different pools of cultivable bacterial strains failed, the disease was successfully reproduced by inoculation with one French and two Belgian samples of caecal contents.