Could probiotics help carp?

Maybe you yourself use probiotics – that collection of helpful bacteria that aids in digestion. Carp have their own types of beneficial bacteria, and as you might guess it was only a matter of time before this connection was tried in bait. From a “health” standpoint, the studies done on incorporating bacteria into carp food have generally found them to boost food conversion (how well much of the food turns into fish), promote faster growth, and in some cases help to support the immune response. The type of bacteria used is important, with different combinations of bacteria having different effects. Various Bacillus species of bacteria have successfully raised carp growth rate even after dehydration. In addition to bacteria, other probiotic organisms benefit carp. Carp anglers have long been adding brewer’s yeast (Saccharomyces cervisiae) to their bait, and this has been shown to increase growth performance of common carp at a level of .5% in the feed. Another often used additive, spirulina, has proved to have similar results .


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Dried Bacillus subtilis introduced into feed improved growth performance.

The whole picture of how probiotics work in carp is not known, but a few pieces of the puzzle are here. Some of what is known is that digestive enzyme activity is higher in carp that have been fed probiotics. This may be linked to increased colonization of the gut leading to better digestion and absorption of nutrients. Depending on the type of probiotic, protease (which helps with break down of amino acids), amylase (sugar break down), and lipase (fat break down) have all be found to increase. It seems that each type of probiotic organism can have a different effect, so–much like with human probiotics–blends of organisms can be tailored to the desired result. That being said, not enough is really known to be able to do this (at least to its full potential) so right now it is a best guess about which combinations to use.

A model of a lipase. Lipase production has been shown to increase in carp fed a diet with probiotics.

For anglers, the potential of probiotics can be viewed a few different ways. If you are wanting to make your bait as easy for the fish to digest then the inclusion of some probiotic can make a difference. This is good if you want to grow the fish in the particular venue as it will help the carp get more nutrition from your bait. If you are baiting a particular venue over a long period of time (such as the lake in your backyard) then the benefits of including some probiotics might be something worth considering. However, if you are simply wanting to catch fish the inclusion of probiotics is an added hassle that is not likely to make a difference if you are not baiting regularly.

Currently there are some generic fish probiotics on the market, but nothing specifically tailored to carp. For anglers who really like making their own bait this is a relatively new frontier with just about endless possibilities. There are so many bacteria/yeast that can be tried, and so far very few have. That comes with a word of caution: not all bacteria/yeast are friendly and you could potentially do some serious harm if the wrong type was added.

All in all probiotics, if used properly, seem to offer carp an added boost and can help them better utilize their food and in the future will likely be used in an increasing numbers of baits.