November 04, 2020

Shrimp and "Anecdotal Nutrition?"

As botanical-style aquarists, we are keenly aware of the benefits of utilizing botanicals and leaves in our aquariums, so we're kind of used to the idea of them impacting our animals and aquarium habitats in a variety of ways. We are keenly aware that leaves and botanicals contain numerous compounds, ranging from humic substances and tannins, to stuff like lignin, cellulose, and even minerals.

We've seen what some of this stuff can do for our aquariums.

We've seen it with our own eyes; gauged the results for for ourselves.

And there are still more questions than answers.

We have them. We receive a lot of them.

We receive a lot of questions from shrimp keepers, asking about the various merits of utilizing botanicals for environmental enrichment and nutrition for their animals. I love shrimp keepers, because they remind me a lot of reefers- absolutely obsessed with the well-being of their animals, with a heavy focus on finding materials or approaches which will benefit the shrimp.

And, like reefers, shrimpkeepers are bombarded by a lot of marketing, inflated claims of benefits, anecdotal assumptions, and out right falsehoods. And, like reefers, many have a built-in "bullshit meter" to look at some of these claims with a skeptical eye.

And they should. There is a LOT of stuff said about botanical materials and their use as food for shrimps- and some of it IS outright BS. Some of it is not, but it's pretty anecdotal, and if taken without question, might create the incorrect impression that these materials are more beneficial to shrimp than they really are.

The problem is that we know "a little" about the potential nutritional value of botanicals for shrimp- and that might spur a lot of speculation.

Huh? Well, let's look at what we DO know about this topic. It's safe to say that most leaves and botanicals contain vitamins, amino acids, micronutrients, and other bioavailable compounds.

The real question I have is exactly how "available" they are to our shrimp from a nutritional standpoint. And how "nutrient dense" these leaves and botanicals are? Do our fishes and shrimp easily assimilate all they need in every bite, or do they have to eat tons of the stuff to derive any of these benefits?

Big questions, right?

I mean, we as hobbyists sort of assume that if these things are present in the botanicals, then our animals get a nice dose of 'em in every bite, right? And, it begs the question: Are they really directly consuming stuff like Casuarina cones, or feeding on something else on their surfaces (more on this later)?

I think it's "yes" on both.

And the nutrition that they derive from consuming them?

Well, that's the part where I say, I don't know.

I mean, it seems to make a lot of sense to me...However, is there some definitive scientific information out there to prove this hypothesis?

A lot of the "botanicals for food thing" in the hobby (no, really- it's a "thing!") comes from the world of shrimp keepers. This isn't new stuff to them. They've been touting this stuff in the hobby for a long time. A lot of it is based upon the presence of materials like leaves and such in the wild habitats where shrimp are found. I did some research online (that internet thing- I think it just might catch on...) and learned that in aquaculture of food shrimp, a tremendous variety of vegetables, fruits, etc. are utilized, and many offer good nutritional profiles for shrimp, in terms of protein, amino acids, etc.

They're all pretty good. Our friend Rachel O'Leary did a great job touching on the benefits of botanicals for shrimp in her video last Fall.

So, which one is the best? Is there one? Does it matter? In fact, other than sorting through mind-numbing numbers ( .08664, etc) on various amino acid concentrations in say, Mulberry leaves, versus say, Sugar Beets, or White Nettle, or whatever, there are not huge differences making any one food vastly superior to all others, at least from my very cursory, non-scientific hobby examination!

Now, leaves like Guava, Mulberry, etc. ARE ravenously consumed by shrimp and some fishes. It's known by scientific analysis that they do contain compounds like Vitamins B1, B2, B6, and Vitamin C, as well as carbohydrates, fiber, amino acids, and elements such as Magnesium, Potassium, Zinc, Iron, and Calcium...all important for many organisms, including shrimp. Guava leaves are particularly good, according to some of the studies I read because, apparently, the bulk of the nutrients they contain are more "readily available" to animals than other leaves.

Well, that's pretty important, isn't it?

I think so!

Now, it may be coincidental that these much-loved (by the shrimp, anyways) leaves happen to have such a good amount of nutritional availability, but it certainly doesn't hurt, right?

Other leaves, such as Jackfruit, contain "phytonutrients", such as lignans, isoflavones, and saponins that have health benefits that are wide ranging for humans. There is some conflicting data regarding Jackfruit's alleged antifungal capability However, the leaves are thought to exhibit a broad spectrum of antibacterial activity in humans. In traditional medicine, these leaves are used to help heal wounds as well.

Do these properties transfer over to our fishes and shrimp?

We are not aware of any scientific studies that have been completed to correlate one way or another. That being said, they seem to flock to these leaves and graze on them directly- and on the biofilms which accumulate on their surface tissues.

Oh, the biofilms again!

As I mentioned before, the "shrimp side" of the hobby reminds me in some ways of the coral part of the reef keeping hobby where I spent considerable time (both personally and professionally) working and interacting with the community. There are some incredibly talented shrimp people out there; many doing amazing work and sharing their expertise and experience with the hobby, to everyone's benefit!

Now, there are also a lot of people out there in that world -vendors, specifically- who make some (and this is just my opinion...), well - "stretches"- about products and such, and what they can do and why they are supposedly great for shrimp. I see a lot of this in the "food" sector of that hobby specialty, where manufacturers of various foods extoll the virtues of different products and natural materials because they have certain nutritional attributes, such as vitamins and amino acids and such, valuable to human nutrition, which are also known to be beneficial to shrimp in some manner.

And that's fine, but where it gets a bit anecdotal, or - let's call it like I see it- "sketchy"- is when read the descriptions about stuff like leaves and such on vendors' websites which cater to these animals making very broad and expansive claims about their benefits, based simply on the fact that shrimp seem to eat them, and that they contain substances and compounds known to be beneficial from a "generic" nutritional standpoint- you know, like in humans.

All well-meaning, not intended to do harm to consumers, I'm sure...but perhaps occasionally, it's just a bit of a stretch.

I just wonder if we stretch and assert too much sometimes?

Now, I'm not saying that it's "bad" to make inferences (we do it all the time with various topics- but we qualify them with stuff like, "it could be possible that.." or "I wonder if..."), but I can't stand when absolute assertions are made without any qualification that, just because this leaf has some compound which is part of a family of compounds that are thought to be useful to shrimp, or that shrimp devour them...that it's a "perfect" food for them, with enormous benefits.

It's just a food- one of many possibilities out there. That's how I think we need to look at things.

Of course, I hope I'm not out there adding to the confusion! We try to hold ourselves to higher standards on this topic; yet, like so many things we talk about in the world of botanicals, there are no absolutes here.

What is fact is that some botanical/plant-derived materials, such as various seeds, root vegetables, etc., do have different levels of elements such as calcium and phosphorous, and widely varying crude protein. Stuff that's known to be beneficial to shrimp, of course. These things are known by science, largely through studies down on shrimp farmed for human consumption.

Yet, I have no idea what some of the seed pods we offer as botanicals contain in terms of proteins or amino acids, and make no assertions about this aspect of them, above and beyond what I can find in scientific literature.

No one else does, either.

However, I suppose that one can make some huge over-generalizations that one seedpod/fruit capsule is somewhat similar to others, in terms of their "profile" of basic amino acids, vitamins, trace elements, etc. (gulp). We can certainly assume that some of this stuff, known to have nutritional value, can make these materials potentially useful as a supplemental food source for fishes and shrimps.

Yet, IMHO that's really the best that we can do until more specific, scientifically rigid studies are conducted. And we can feed a wide variety of stuff to our shrimp- sort of the equivalent of throwing a bunch of spaghetti on the wall to see what sticks!

Now, we may not know which seed pods and such in and of themselves are more nutritious to fishes and shrimp than others, but we DO know from simple observation that some are better at "recruiting" materials on their surfaces which serve as food sources for aquatic organisms!

Yeah, I'm talking about the biofilms and fungal growth, which make their appearance on our botanicals, leaves, and wood after a few weeks of submersion...

We know that shrimp seem to love grazing on biofilms, and that the nutritional benefits of biofilms are pretty well established. They are a rich source of sugars and other nutrients, and could even prove to be an interesting addition to a "nursery tank" for raising fry and larval shrimp. Like, add a bunch of leaves and botanicals, let them do their thing, and allow your fry to graze on them!

And of course, it's long been known from field studies that as leaves and other plant materials break down, they serve as "fuel" for the growth of biofilm, fungi and microorganisms...which, in turn, provide supplemental food for fishes and shrimps. I've seen a bunch of videos of shrimps and fishes in the wild "grazing" over fields of decomposing leaves and the biofilms they foster.

Ahh, biofilms again.

Refresher for you:

Biofilms form when bacteria adhere to surfaces in some form of watery environment and begin to excrete a slimy, gluelike substance, consisting of sugars and other substances, that can stick to all kinds of materials, such as- well- in our case, botanicals.

Biofilms on decomposing leaves are pretty much the foundation for the food webs in rivers and streams throughout the world. They are of fundamental importance to aquatic life.

It starts with a few bacteria, taking advantage of the abundant and comfy surface area that leaves, seed pods, and even driftwood offer. The "early adapters" put out the "welcome mat" for other bacteria by providing more diverse adhesion sites, such as a matrix of sugars that holds the biofilm together. Since some bacteria species are incapable of attaching to a surface on their own, they often anchor themselves to the matrix or directly to their friends who arrived at the party first.

Hmm, sounds sort of like Instagram, huh?

(The above graphic from a scholarly article illustrates just how these guys roll.)

And we know from years of personal experience and observation in the aquarium that fishes and shrimp will consume them directly, removing them from virtually any surface they form on.

And some materials are likely better than others at recruiting and accumulating biofilm growth. The "biofilm-friendly" botanical items seem to fall into several distinct categories: Botanicals with hard, relatively impermeable surfaces, softer, more ephemeral botanical materials which break down easily, and hard-skinned botanicals with soft interiors, and...

Okay, wait- that kind of covers like, everything, lol.

Yeah.

There are a few that really stand out, like the Dysoxylum pod.

Dysoxylum binectariferum, which is found in the forests of tropical India, but ranges as far afield as Vietnam. It's found in in alluvial soil conditions (clay and sand) and along rivers and streams...right up our proverbial "alley", huh?

In India, it is also known by many other names such as, "Indian White Cedar", "Bili devdari", "Bombay White Cedar", "Velley Agil", "Porapa", "Vella agil", and "Devagarige."

The tree is an important component of tropical rain forests, typically from India, but found in other regions.

The tree grows to height of 120feet/40 m height, has bark which is greyish-yellow in color, with inner bark a creamy yellow color. The fruits that ripen during June–July are capsules. In India, apart from its economic importance for building and furniture making, it is an important ingredient in traditional medicine. The fruit has a chemical composition known by the name “ashtagandha”, which means "fragrant smell", and is used for making incense sticks that are commonly used for worship.

Interestingly, compounds derived from the tree itself are also known by modern medical researchers to have extremely valuable medicinal properties...

Notice, we said, "the tree itself?"

Dysoxylum binectariferum bark was identified as an alternative source of CPT, through a process of bioassay-guided isolation. Camptothecin ( known to clinical researchers as "CPT 1") is a potent anticancer product, which led to the discovery of two other clinically used anticancer drugs, Topotecan and Irinotecan.

Rohitukine is another compound that accumulates in a significant amount in seeds, trunk bark, leaves, twigs, and fruits of D. binectariferum. Rohitukine is an important precursor for the synthesis of other potential anticancer drugs

Wow!

And all I wanted was some seed pods to feed shrimp! With all of those medicinal uses, has anyone ever used them before in aquariums before we started playing with them for this purpose?

I'm doubtful, but you never know...

And why did I just go on a tangent about this tree and it's seed pod?

Because it's an example of the kind of information that you can extrapolate from areas of study outside of aquariums. And half of the benefits ascribed to Dysosxylum are based on its bark and leaves, neither of which we work with.

You can make all sorts of inferences and assumptions about their benefits, and how they might apply to shrimp, solely based on this kind of stuff.

Don't do that.

Don't assume that, because the tree and its other parts have compounds which are known to provide certain benefits, that it's 100% certain that the seed pods do, too.

Yeah, we utilize the seed pod. Not the bark, the branches, or the leaves. We know that our shrimp eagerly graze on its soft interior, and the biofilms which are recruited on the pod as it breaks down.

Research, experiment, and draw your own conclusions, based on the performance you experience with your shrimp. Don't rely on anecdotal assumptions. Don't assume that because the tree can do all of these things, that the leaves or seed pods can do them, too...and that they can impart such benefits to shrimps!

"Anecdotal nutrition" is something we shouldn't accept without some skepticism.

It's a lot to take in- and I see how this might be a bit disappointing to some. The reality is that this is exciting- it's invigorating, because sorting through the sea of anecdotal assumptions and hypothesis, in an effort to benefit our animals, is incredibly exciting!

Stay informed. Stay bold. Stay curious. Stay excited. Stay resourceful...

And Stay Wet.

Scott Fellman

Tannin Aquatics