Understanding the differences is useful, and quite important.
The word probiotic is being hijacked into other areas to mislead potential purchasers, strictly a probiotic is basically an organism (usually bacteria, sometimes a yeast) which can be given in food, or water or as a paste to animals (including humans) to have beneficial effects of the bacteria etc which currently live in that animals bowels. Some individuals for one reason or another have ‘disturbed’ bowels resulting in chronic pain, constipation, poor absorption, diarrhoea etc. This is often linked with an abnormal gut flora (the term for the bugs which normally live in the gut), sometimes this is caused by low grade infections with bacteria such as E.coli or Salmonella, or others from the host of bacterial species which can infect guts!
Prebiotics are natural, normally plant extracts which function as ‘soluble fibre’. Fibre assists the function of the gut in slowing the gut down – think of it as providing something for it to work on! Soluble fibre is a natural thickening agent, it helps to thicken gut contents and improve mixing and general gut movement, and in doing so encourages the growth and survival of probiotics which usually accompany it.
The term synbiotic has crept into use recently and usually means a product with both pre- and pro-biotics acting together synergistically (assisting each other) and actually producing a better effect than either on its own.
Over the last few years some companies have started to use the terms interchangeably for marketing purposes and to refer to products just containing a prebiotic as either a probiotic or a synbiotic. This could be viewed as misleading and may fall foul of the law now that these things are being defined in law.
What do probiotics actually do?
In a perfectly balanced gut, functioning properly etc they probably do nothing observable – because supporting a functioning system doesn’t achieve anything except that it continues to function. Of course this can mean that the animal doesn’t show levels of gut upset and ‘stress’ which it might show otherwise!
Various bacteria have been isolated and have different abilities to get through the gut. In species with a well defined stomach the bacteria has to be able to survive the acids of the stomach then the very alkaline small intestine and the bile acids. This is very challenging, so an organism which works well in cattle for instance (which don’t have a classic stomach) may not survive the pig, dog or even rabbit stomach. It isn’t just a matter of taking a bacteria that works well in one species and ‘assuming’ that will work the same way in others.
EU licensing has now formalised the process of testing and licensing. All organisms sold as probiotics must provide data similar to data used for medicines to show that they actually are manufactured properly and consistently, and that they do have a beneficial effect on the gut and on the animal in general. This begins with use in ‘production’ animals where statistical information on growth rates and disease occurrences can be shown to be beneficially changed ie. they grow faster, perhaps lay more eggs, have fewer dietary problems etc. and suffer fewer attacks from gut viruses. when given the product.
There are various ways in which probiotics operate:
- • They produce chemicals which inhibit ‘bad bacteria’ such as E.coli and Salmonella, and stabilise the gut pH to make it more ‘hospitable for the normal gut flora
- • They can simply out compete ‘bad bacteria’
- • They increase resistance to diseases of the gut, partly by stimulating the immunity in the gut wall
In production animals this means production – growth or eggs is simply better. In the pet situation it means that animals are more settled, and can better enjoy the interaction and excitement associated with people – even children!
What happens then, why do they work?
In sick rabbits with dysbiosis (an upset gut flora causing eneteritis, mucoid enteritis, bloat etc) the BAD coliforms (E.coli, and Salmonella) increase and swamp the normal Bacteroides. The probiotic organisms then 'fill the gap' making conditions again favour the normal Bacteroides.
Probiotics are not intended to take over the gut,they are'nt medicines as such, they simply act as support to keep conditions unfavourable for BAD coliforms, and favourable for the normal Bacteroides to get going again.
Why do active organisms vary/change
The EU in its wisdom has required that all probiotic organisms be licensed like medicines, so each organism manufacturer has to seek approval (based on efficacy and safety) in the chosen species - initially they do one or all of cattle, pigs and poultry. Then they can go on and license in 'lesser species.
This means that many products being imported from outside the EU are actually illegal. Its also the reason why there are a number of products on the market claiming to be probiotics but which actually only have prebiotic in them.
Products change as licensed organisms change availability in the different species.