Results from experimentation with Daphnia Cultures- Alternate Feeding

He is the results of my latest little mad scientist experiment. I didn't get really detailed with notes and data as that effort is reserved for more telling projects. I wish I had though, the results were interesting.


I have used a number of different foods for daphnia over the years, from live yeast cultures to powdered algae. Like many other folks, I have gotten mixed results. Some methods produce vast numbers of daphnia and then crash quickly. Others keep a steady flow of daphnia available, but the yields are low.

Thanks to the flooding in my area this summer, I have been able to harvest wild daphnia continuously by (literally) five gallon bucket loads. These are the healthy lively bright orange color synonymous with good caudate food resulting in bright colors. While harvesting, I noticed a pattern. The largest, densest concentrations were all in areas of the water where straw anti-erosion matting had been inundated.

This got me to thinking about stuff I had read in this old gem of a manual:

http://www.caudata.org/forum/f1-gen...-methods-invertebrate-animals-lutz-et-al.html

I got to thinking that perhaps the daphnia were congregating near the straw mats as the straw supported a healthy community of various live microfoods daphnia thrive on. remembering that boiled straw (and various farm animal dungs) were suggested as ideal culture media for zooplankton, I started experimenting. I didn't use dung as i need that for my gardens and planting beds...

I used six of my large Sterilite tubs (48 quart talls). Filling each with a mix of dirty tank water and rain water, I placed three outdoors in full sun (the conditions I find the most daphnia in) and the other three down in my critter cave under 12/12 hydroponic lighting. Floating tube type thermometers were used. Each culture had a roughly 10 oz handful of live java moss added. Dirty tank water was added as needed to all cultures to deal with evaporation.

All cultures utilize the same aquatic substrate a mix of crushed oyster shells (the type used in chicken husbandry), dirty tank detritus, and an aquatic compost of maple leaves (which I make myself here for breeding certain soft water fish). Old storm window screens recycled from when I had to update all the windows in my house were placed on top of the outdoor cultures to keep mosquitoes and chironimids out of the culture water. I also dropped four adult ramshorn snails into each culture as for me their presence seems to make for better cultures.

Containers A,B, and C are outdoor; 1,2, and 3 are indoors. Outdoor water temperature averaged 85F. Indoor water temperatures averaged 68F.

A and 1: Standard culture. filled container and added roughly 250 daphnia. Fed every other day with a yeast/spirulina mix I modified from (I believe this is where I stole it from...) Jennewt's recipie.

B and 2: Control Culture started with 250 daphnia and left to its own devices.

C and 3: Started with rioughly 250 animals. Cultures fed nothing but handfuls of rodent alfalfa straw (which is what I have on hand as my daughter is obsessed with rodents...)


The results after running these cultures since May has been stunning. The standard cultures A and 1 crashed every few weeks and had to be restarted. Largest yields from A and 1 were experienced at first. After the first month of the straw decaying in the water, cultures C and 3 produced yields comparable to the standard cultures with the added advantage of not crashing completely. I should note that culture C outperforms all others producing more daphnia than I could use. Extra daphnia were transferred to cultures 2 and B for holding. These cultures have since been converted over to the straw method.


Seeing that rotting straw water supported just as well if not better than the standard method, I decided to dig out my microscope and compare water samples from the straw cultures, standard cultures, control cultures and ten samples from various wild sites. After a long afternoon today, I found my suspicions were correct.

based on the number of microorganisms I attempted to count from roughly 1mL samples, the live bioload in the straw cultures and the wild cultures left all others behind. In attempting to compare wild samples to my farmed cultures, I believe the farmed cultures were superior to the farmed.

I will note counting was based off of the numbers of moving things I marked down. My microscope is a battered old thing rescued from a dumpster outside a certain college, and all my well slides are home made. I utilized a bit of sheer nylon cloth with a comparatively open weave as a net to hold critters in place and make them easier to count. There was also tons of stuff in there that could have been inert matter, or non-moving algae. therefor none of my numbers are very relevant given my complete lack of knowledge of such procedures.

This is all merely based on untrained observations by yours truly, but I have decided to convert all my cultures over to the straw method. Oddly enough, I could not see any difference between the indoor and outdoor straw cultures which leads me to infer that temperature was not much of a factor. But given the crude tools and methodology I employ, I suspect that the outdoor culture with its higher average temperature may actually produce more than the indoor. Given the wild variations of evaporation, weather and lighting outdoors, I am unable to give any valid conclusions on effects of temperature and lighting at this time. I would need to experiment further to do so.


Well, it is what it is. If you are looking for an alternate culture media for daphnia, I highly recommend the straw method. If you do give it a try, let me know how your results came out. I am curious to see if this is Johnny's Dumb Luck factoring in, or a real repeatable possibility.

The good news from all this is I no longer have to keep large yeast cultures in the fridge which means my poor wife has one less thing to give me the look of death for...

Hi thanks alot for the info. thats very interesting. Did you use the same type of straw the whole time? What do the crushed shells do?(change PH?)
I have used grass clippings in outdoor containers and this seems to work very well.
Did you remove any of the rotting straw? how much and how often did you add the straw?

I added new straw when the old was pretty well broken down. the very small amount of oyster shell bumps up the carbonate hardness (necessary here due to the sources of the water I use in cultures) a bit so all those daphnia have something to make carapaces with. Yes, used the same straw the whole time, as we buy a big package of it each month for my daughter's rodents.

Fantastic information, Johnny - thanks. How much straw do you add per volume of culture and how often do you do water changes (if at all)?

C

this is really awesome info; you get the blue ribbon at the caudata science fair

Could you tell us which brand of rodent straw you get? Around here I can't buy straw or hay, but could get grass clippings off the tundra.
Then, there's moose nuggets everywhere; I do wonder what kind of culture medium they would make...

I've been maintaining my Daphnia with the Spirulina/ soy protein method at 65 F and found that they grow very well but the water quality is prone to going south real fast, probably because it's almost impossible not to overfeed.

Interesting . I have tried to raise daphnia outdoors the last few years. Most failed due to a degree of my neglect. Funnily enough my current batch is doing really well, and I had thought it was due to many a healthier strain. But since reading this, it may actually be down to my small son chucking in some grass cuttings a while ago. I'll probably start another lot off and see if this is the case.
Thanks Johnny.

My parents use a wad of barley straw in their pond spring time to get rid of blanket weed/green water. Their pond is full of gigantic fat goldfish so plants rarely grow fast enough to cover the pond. No idea how it works,

Also, you say 'I believe the farmed cultures were superior to the farmed.'...which one of the two 'farmed's should be 'wild'?

All the best

Chris

This is really interesting Johnny, thanks for sharing. I wonder if the straw decays at a steady pace (compared to meat based food), providing a constant supply of bacteria for the daphnia to consume. One of the most productive and short lived daphnia cultures I had was a bucket of live bloodworm which went bad, killing all the larvae. The base of the bucket was an inch thick with dead blood worm. As there were lots of mosquito larvae also in the bucket I decided to leave it be (I’m also lazy). The resulting bloom of daphnia was spectacular but very short lived. I guess that once the food source has gone it’s game over.

I can feel a few straw based experiments coming on…

Ahh, i was about to put what chris said, it doesnt look like it makes grammatical sense to me either, unless this was intentional?

Apologies for the bad syntax. I was very tired and had one whopper of an eyestrain headache after playing with the microscope all day. Mountain biking through the heat with a five gallon bucket and a bunch of sample bottles probably didn't help either.

That line should read: (or something of the like)

"...the farmed samples were superior to the wild samples based on live counts..."

As for the brand of straw I have been using this Alfalfa straw :
http://www.petco.com/product/109426...ll-Animal-Mini-Bale.aspx?CoreCat=OnSiteSearch
We have ended up with a dozen adult guinea pigs here (all rescues). Just to help their digestion out we give them some of this dry straw once in a while. I prefer to give them the fresh pulled wads of red fescue grass I have to constantly remove from my organic garden and flower beds.

One note, I do not recommend using barley straw. it is used in ponds as an algae control. I do not know how it works, but I do know killing algae could be detrimental to the daphnia.

As for the amount of straw per volume I used the extremely accurate, scientific amount of "a big-effin' handful per container" roughly every three weeks, or when ever I felt the soggy old stray was looking "weak".

As for alternatives, I have not really played around with anything else straw-wise, but as I write this, I am waiting for my wife to go out of town. This means I can drag more tubs out to the yard and set them up with just water and straw and then do a few counts of bioload in a few weeks. If I wait till she leaves town, she will never notice her biology nerd husband added more "experiments" to the yard.

I suspect that fresh straw may be superior to dry. I say, let us all play with this concept and see what happens!

As for moose dung...According to the book any ruminant dung should work. I would suggest boiling the heck out of it (preparing it as you would the other critter poo described in the book). I bet just about any fibrous plant would work for this. I know that nutritionally worthless iceberg lettuce when shredded into tank water makes a great paramecium culture media. Do not laugh too hard, but I am actually considering a test tub using boiled guinea pig pellets, if you know what I mean.....

Also with water changes, I do not do water changes for daphnia cultures. I run them until the crash, then let them dessicate. After a few weeks in the warm and dry, I fill hem back up with dirty tank and rain water and they tend to start back up on their own. I do add water to combat evaporation, but only as needed. I find this method much easier than trying to hand sort epiphia, by hand.

SludgeMunkey said:

Do not laugh too hard, but I am actually considering a test tub using boiled guinea pig pellets, if you know what I mean.....

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If life give you lemons, make lemonade. If life gives you guinea pig dung, make dung soup for your daphnia. Makes perfect sense to me!:rofl:

I've already collected my moose nuggets. Finally I have a purpose for those things, which the moose leave all over my place all winter long!

One Q: why boil the dung? Won't that kill all the good micro-organisms that are on / in it?

I believe that the entire boiled dung bit relates to killing off all the bacteria in it, both harmful and helpful so that the resulting mess can be inoculated with what is wanted in the culture, rather than suffering the "potluck" effect.


That is the official answer. Personally, I suspect it kills off the stink for easier use indoors. When I first read the book years ago, I laughed aloud at how many times they suggest you boil dung. I myself have never been in THAT much of a mad scientist mood....yet...

Besides, look at the bright side Molch. With family visiting, you can honestly answer dinner won't be ready until "...this %^# is done cooking..."

Guinea pig and rabbit pellets are largely composed of alfalfa, thus making them a good equal of some hays. Alfalfa is a legume [bean], which may mean that it's a better source of protein than other hays like timothy [which is a grass]. As for why hay or other plant materials seem to be important - my bet is on cellulose. Cellulose is reportedly an essential nutrient for crustaceans, and the abundance of woodlice in logs and copepods in flooded fields or tundra puddles may both reflect the large amount of cellulose present.

Commendable work Johnny, and hardly worthy of "mad" scientist designation!

Thanks for the reply. I don't add any shells or anything as we have pretty limey water.
Would be interesting to see whether grass clippings is better/worse/same as expensive lucerne hay. Do you buy lucerne from the pet store? because if you do you should buy it from a farm. It'll save you big $$. Pet stores I've seen sell small bags for $10+ where you can buy a whole bale for roughly $4 if you have the space.

FrogEyes said:

Guinea pig and rabbit pellets are largely composed of alfalfa, thus making them a good equal of some hays. Alfalfa is a legume [bean], which may mean that it's a better source of protein than other hays like timothy [which is a grass]. As for why hay or other plant materials seem to be important - my bet is on cellulose. Cellulose is reportedly an essential nutrient for crustaceans, and the abundance of woodlice in logs and copepods in flooded fields or tundra puddles may both reflect the large amount of cellulose present.

Commendable work Johnny, and hardly worthy of "mad" scientist designation!

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That is very interesting. Methinks I need to do a bit of reading on this cellulose bit, I had another crazy idea while reading. I hadn't thought of using rodent food pellets. That is definitely worth some experimentation. I set up a bunch more tubs while my wife was away, she hasn't noticed these large white bins appear to multiply like mushrooms yet.

JP100 said:

Thanks for the reply. I don't add any shells or anything as we have pretty limey water.
Would be interesting to see whether grass clippings is better/worse/same as expensive lucerne hay. Do you buy lucerne from the pet store? because if you do you should buy it from a farm. It'll save you big $$. Pet stores I've seen sell small bags for $10+ where you can buy a whole bale for roughly $4 if you have the space.

Click to expand...

The main reason I use the alfalfa hay is it is what I have on hand. Being in the dead heart of farm country, it is fairly cheap here. I hesitate to buy it from local sources due to the extremely high risk of contamination. My area is in the flight path of a large Air Force base, the entire side of the state is a lead-in-the-soil superfund site, and I live roughly ten miles away from the highest usage concentration of the herbicide atrazine in North America if not the world. While the risk of transferring any of this awful stuff to my pets through cultured live foods is probably pretty slight, I learned a long time ago it is better to be paranoid. I pay barely half of the price in the link in my previous post, as I tend to buy in bulk quantities and the store manage cuts me a juicy discount.

Normally I wouldn't resurrect a dead thread, 'specially my own....but it is now six months later and the outdoor cultures are frozen solid/gone dry.

I used the alfalfa straw method and the outdoor cultures to get three huge ones going indoors.

Additionally, as discussed, I experimented with alfalfa pellets, clover, boiled guinea pig dung, and some grocery store "spring mix" lettuces.


They all work. Really, really well. But at different "speeds"! This merely serves to further prove the cellulose theory.

In January, I will begin experimenting with this in detail, as I am very quickly building a "real" bio lab here in the basement. I have almost finished my incubator, and am purchasing parts to build an HD video microscope. (I am building various rigs for DNA experimentation too...don't get too scared, garage biotech is the hobby of the future.

The fastest, heaviest producing cultures used the animal feed alfalfa pellets and the boiled guinea pig dung...

In fact, I got lazy, and tired of my daughter making fun of me for harvesting turds with tweezers so I took to just using gloved-handfuls of used bedding from the rodent enclosures.


Lessons learned:

Whatever you use it works best when masticated with a blender.

O.K. Now wipe the tears from your eyes and quit laughing. Science ain't pretty.

I found the best concoction is one liter of water from an existing culture blended with roughly a sandwich bag full of material, (bedding, turds, leftover salad, lawnmower clippings, straw, whatever...)

Set it on liquefy for five minutes.
Bring it to a roiling boil and let it stew for 10 minutes.
Let it cool overnight, covered.
Once cooled, dump the entire mess into a large container of dirty tank water.
Add live daphnia.

With the strain of daphnia I am working with I get an initial population bloom that produces far more than I could ever use in three weeks outdoors, four weeks indoors.
Then as always, the standard "S" curve of population forms. Even in the downslope though these cultures produce results unlike anything I have achieved in the past.


So, in short, get a few thrift store pots and a garage sale blender and get to cooking vegetable and guinea pig waste.

Next spring I am going to try the infamous "boiled cow" and "boiled horse" methods.

Seriously. I have taken to boiling poo and plant material to make daphnia shakes.
Anyway, work with the microscope seems to show a trend that may explain the results. I need to replicate them a few more times, but it appears these masticated messes have nothing to do with the daphnia directly. What I find is that cultures developed this way have an exponentially large population of protists when compared to standard culture methods. To me, this makes sense, as we all know what daphnia eat....


Anyway, did anyone else get a chance to experiment with this sort of thing over the last six months? Or I am I going to have to start selling bags of "pre-boiled poop" online?

:lol:

P.S.

Forgot to not the presence of rahshorn snails in all indoor cultures. For a reason I have yet to determine, indoor cultures with live ramshorns in them do well. snail free cultures collapse in a week. This could be due to my own procedure, but I treat all the cultures the same, which is to say I ignore them for the most part. I should also add that I keep all indoor cultures on a 12 on 12 off lighting scheme using plant grow lights left over from my... "ahem"...misspent youth.

I did try this, or a variant. I purchased some daphnia from my LFS, added them to a 10 g tank of old newt water, and then threw in a handful of timothy hay. I have been a 'tard with past daphnia cultures and I rarely get them to last long. However, this seems to be working so far; granted, is only been like 2 weeks but I see lots of little daphnia and do think the population is growing- these are better results than I have had in the past, because, like I said, I'm daphnia challenged.
It does smell, though, so I will try boiling it a bit next time. And its messy - there are bits of straw floating all over the place and its made water changes and harvesting a challenge - I scoop up too much straw in the brine shrimp net, and the line gets easily plugged when I do water changes (I siphon the water out with an airline tube). I was going to try to rectify this by bundling the straw with string or stuffing it in a mesh bag. But maybe I will blend it.
So I have not taken the time or done things as fancy as you have Johnny, but so far I am pleased with the results I have gotten and plan to use more of your method. Thanks for all your work with this, AND for posting it for all us daphnia spazz's to learn from (I can't be the only one, right? Right?...)

The secret to harvesting daphnia and brineshrimp is this:

Do it at night after they have been in darkness for a while. Then place a one watt LED (LED works best in my opinion, probably as most consumer grade white LEDs are actually blue)flashlight so it shines through the side of the container. Wait 20 minutes and then extract the critters with a turkey baster. I place them in a plastic Tupperware-type box and let them "settle" for a few minutes, then suck off the excess water with the turkey baster.

I didn't have a problem with odor or floating debris. After a week it all became waterlogged and sank. I bet you could place it in a mesh bag and sink it with a few glass marbles to keep the mess out. As for odor, truth be told, I have been doing this kind of thing for so long, I doubt I would notice any smell. My wife hasn't complained yet, so I assume there is no stink.

Additionally, bad smells in aquatic cultures are usually due to low oxygen. Are you using any aeration? Is your culture container high on volume, but low on atmospheric surface area?

I do not do water changes on daphnia cultures. In my experience they do better if you only top them off with dirty tank water once in a while. In my own experience over the years I was fast to observe that the common obsession with "cleanliness" and "sterility", relatively speaking, of aquariums is why many folks struggle with water chemistry balance and cycling.

Truth be told, I personally do not even do water chemistry checks on my cultures. I used to, but found that even this was a waste of time and money. The beauty of the Nitrogen Cycle is that with some patience and laziness, it takes care of itself.

I have to put my camera back together, as I upgraded the CMOS and never got around to finishing, but I'll put some pictures up eventually of my zero maintenance indoor rigs.

Thanks for the harvesting tip - I will try that!

I do have aeration in the form of an open airline tube with a small pebble tied to it to prevent it from floating, but I have the tube pinched half way shut. Perhaps I will open it all the way and see if I notice a difference. I would not think the surface area to volume ratio would be a problem - I am using a standard 10 gallon tank, but maybe its dimensions aren't as ideal as I thought. The smell is not great, but I do notice it a bit when I "stir" the straw to the side to try and harvest (or just peek in to witness the glory of live daphnia - in my tank!). Even if the smell remains it is not that bad.

And any excuse to not do water changes is great in my book! I have placed that tank in a somewhat awkward place and though its easy to siphon water out of, the shelf above it has made adding water kind of tricky (brilliantly I left about 3 inches of space between the bottom of the overhead shelf and the top of the tank). If I am not routinely taking water OUT, then I don't routinely have to put water IN.

Again, I really appreciate that you have shared your findings with all of us. I can't imagine I and my newts are the only ones who have benefited from it.

Heather