Europe tries to define a probiotic benefit, while intestinal microflora tinker with the metabolism. Fish also get a piece of the action and can be protected from pathogenic bacteria by friendly ones.
Good Microbes Mediate Metabolism
Scientists use germ-free mice to analyze the contributions of microorganisms on the health and well-being of their hosts. In the Netherlands, a study was performed to determine how re-colonization of germ-free mice with normal microflora would affect gene activity and metabolic parameters within the small intestine. It was found that major metabolic changes arose as soon as one day after the mice were re-populated, including changes in glucose and energy homeostasis. The researchers consider that these results could be used to find ways to treat type 2 diabetes mellitus.
What Is a Probiotic Benefit?
In Europe, the European Food Safety Authority (EFSA) is responsible for evaluating health claims made by companies about probiotics. An analysis performed by Dutch researchers on the claim applications published between 2005 and 2013 attempted to determine the general guidelines used by the EFSA to determine if a probiotic is beneficial or not. While they found that approximately 75% of the probiotic preparations had some indication of being beneficial, most were still deemed to have insufficient evidence and were rejected. The researchers suggest that future applications need to be more carefully formulated.
Probiotic Culture in Fish Filters
It’s easy to forget that probiotics are also useful for keeping fish healthy. Beneficial bacteria are extremely important for staving off disease in fish breeding facilities. To study the effects of the bacteria Phaeobacter 27-4 on turbot, scientists added the probiotic culture to the water filter to determine if it would prevent infections of pathogenic Vibrionaceae bacteria in young fish. The filter was extremely effective in removing the pathogen from the water and significantly improved fish survival.
Beneficial Bacteria Modulate Immunity of Sea Bass
The European sea bass is a highly farmed fish, and infectious diseases plague many farms. Finding ways to reduce the need for antibiotic treatment is high priority. Many consider that probiotics may be a possible alternative. To determine if the immune response was modulated in the sea bass after exposure to the probiotic Vagoccus fluvialis L-21, white blood cells were isolated from the head-kidney regions and analyzed for gene expression. The scientists were able to detect increases in gene activation in many immune-associated genes showing that the probiotic was certainly interacting with the immune system.
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- El Aidy S, Merrifield CA, Derrien M, van Baarlen P, Hooiveld G, Levenez F, Doré J, Dekker J, Holmes E, Claus SP, Reijngoud DJ, Kleerebezem M. The gut microbiota elicits a profound metabolic reorientation in the mouse jejunal mucosa during conventionalisation. Gut. 2013 Sep;62(9):1306-14. doi: 10.1136/gutjnl-2011-301955. Epub 2012 Jun 21.
- Prol-García MJ, Pintado J. Effectiveness of Probiotic Phaeobacter Bacteria Grown in Biofilters Against Vibrio anguillarum Infections in the Rearing of Turbot (Psetta maxima) Larvae. Mar Biotechnol (NY). 2013 Aug 6. [Epub ahead of print]
- Román L, Real F, Padilla D, El Aamri F, Déniz S, Grasso V, Acosta F. Cytokine expression in head-kidney leucocytes of european sea bass (Dicentrarchus Labrax L.) After incubation with the probiotic Vagococcus Fluvialis L-21. Fish Shellfish Immunol. 2013 Aug 5. pii: S1050-4648(13)00674-8. doi:10.1016/j.fsi.2013.07.036. [Epub ahead of print]