Backyard Aquaponics
A place to discuss aquaponics

With all the fears of threat to the tilapia industry I thought a post of this article would be helpful to all. Algae again shown to be the best.

Source:www.associatedcontent.com/article/895101/what_goes_into_tilapia
_goes_into_you.html


What Goes into Tilapia, Goes into You
A Look at Tilapia Feeding in Commercial Fish-Farming Operations
By Brad Sylvester, published Jul 23, 2008
Takeaways
The diet of tilapia consists largely of algae in the their natural habitat.
In farming operations, protein is added to help the tilapia reach harvest size faster.
Tilapia farms in different part of the world may use different types of feed.
With all the recent talk about farm-raised tilapia in the news, I wondered just what is being fed to tilapia in fish-farming operations around the world. The tilapia study (Chilton, 2008), about which I wrote a couple weeks ago, claimed that tilapia feed made from inexpensive corn may be causing a build-up of harmful arachidonic acid and Omega-6 fatty acids in the tissues of tilapia.
I recently had a chance to discuss this with Jim Nunneley, Vice President of Marketing for Rain Forest Aquaculture, an importer of tilapia into the United States with a tilapia farming operation located in Costa Rica.
Tilapia Feed is the Largest Cost in Raising Tilapia
According to Nunneley, the cost of feeding tilapia on a fish farm over the course of their life accounts for 75 percent of the cost of the fish when raised in a tropical environment. Tilapia are naturally a warm water fish. If tilapia are raised outside of the tropics, additional costs must be borne for heating the water. Tilapia farming operations have, therefore, a vested interest in using the most inexpensive feed they can find, while still providing enough nutrition for the tilapia to grow out to commercial size as quickly as possible.
The Ingredients of Feed for Farm-Raised Tilapia
Like most fish in the wild, tilapia are opportunistic feeders and will take most anything they can get. The main part of their diet in their natural habitat, however, is algae.
So what do tilapia eat on fish farms?
"Our feed is typically 90 to 92 percent grains such as soybean meal, rice, wheat and corn. The other farms in South America use similar ingredients, in varying proportions, depending upon supplies in the local markets," Nunneley said. "Tilapia can survive on a vegetable diet, but to thrive for commercial farming purposes they require some additional proteins, especially in the juvenile stages."
Efficient commercial production, of course, relies on rapid growth of the tilapia so they don't have to be fed and cared for any longer than necessary. Adding protein to the tilapia diet is an important factor in increasing the rate of growth. Tilapia are relatively efficient in their use of food. According to a published report by Randy Sell, of the Department of Agricultural Economics at North Dakota State University, for every 1.5 pounds of food consumed by a tilapia, the fish should gain one pound of body weight.
Nunneley says that, in practice, Rain Forest Aquaculture sees a conversion ratio closer to 2:1, but this number may vary depending upon seasonal influences.
The protein is supplied by fishmeal which makes up the remaining 8 to 10 percent of the tilapia feed. Rain Forest Aquaculture produces its own fish meal from the leftover scraps of Costa Rica's commercial fishing operations. The scraps, primarily the heads and bones of tuna, mahi mahi, and other wild caught fish, is processed into fishmeal mixed with the grain-based feed to which vitamins and minerals are added and fed to the tilapia.
"Prior to us staring this project 10 years ago all the heads and bones of local fish ended up in local landfills," Nunneley said.
Of course, there are by-products of tilapia processing as well. In fact, Rain Forest Aquaculture produces more fishmeal from its own tilapia by-products than it does from other sources. However, the fishmeal made from their tilapia is never fed back to the tilapia, but is instead sold to poultry farms in the area.
Differences in Tilapia Feed in China
I asked Nunneley if the feed he described for South American tilapia farms differed from tilapia farms in other parts of the world.
"Much of the tilapia farming in China is done by small artisanal operations that sell their whole fish to large processors," he said. "In China, many of the small farmers feed their fish the waste from chickens, ducks, etc. This model was promoted by the FAO specifically for small integrated farming operations. As feed represents 75 percent of the cost of whole fish, this explains why the frozen fillets from China are so inexpensive. In Central and South America, we all use commercially produced grain based feeds without exception.... much different than China."

What Goes into Tilapia, Goes into You!
...can be said for all fish ( better still, food of all kinds)
I totally agree with you and is the reason for the fish food source thread.
(some where there )

Did I miss something???
Poison American corn ?.....,,that after trying to poison their own people with tainted tomato's.

Thank God I'm an Aussie.

Buddy USA AP'ers,,,,we have plenty of room here in Australia,,your VERY welcome,it's not paradise,,but seems tobe a lot safer than were you are now.

Chappo - given your background I'd have thought you would have something more constructive and relevant to say than that

Chelle - the issue you raise is a good one and one that we have touched on before. Jade Perch, one of the fish APers grow a bit of here, is said to be the #1 or #2 (??) fish when it comes to Omega 3. Problem is, like the issue your aise with Tilapia, that these levels are most probably due to the wild diet. So when I eat a Jade perch grown in my AP system, given that they are quite a fatty fish, am I eating the Omega 3 which is great for you, or some other crap that is going to kill me.

Unfortunately, without lab tests I don't think that I'll ever know. It is a bit supriosing the aquaculture trade has not done such test, but on the other hand, perhaps they don't want to know the answers

Veebs - they know the answers, it is $$$ they are doing it for!!

The public seemed to pick up on this. Only half the info usually given. Nice media impact that way...... . Liked this article. Showed it was the usual problem - in this case fish feed...GIGO.... garbage in garbage out.

Right.... is all about dollars. Feed costs are astronomical when commercially supplied. Protein is always the most expensive. If those overheads are reduced the dollar equation can be brought into healthy perameters. An interesting fact I read was that if duckweed is grown in manure it can provide up to 45% protein in the plant. I also use mulberry leaves. The fish take them readily. The silkworm eats only mulberry leaves to make its silk cocoon. Mulberry leaves are rich in protein and amino acids. This is also fodder for other stock in many parts of the world. Some people consider the mulberry a weed tree cos it grows so readily. Add to this the cost of producing algae.... zip.... zero.... nix.

There is always a better way. Growth may be slower - so rather spend the money on extra space to raise them naturally than in getting locked into the commercial grid of feed supply. My 2c.....

I remember hearing that local growers could not compete with oversea's scallops because they were grown in sewage canals. Same reason I don't eat fish from the local river because older people used to tell us that the river was clear enough to see the bottom and the fish when they were kids. I've never been able to see deeper than 10cm into that water.
People never think of biomagnification when shopping. As long as its cheap and look good.

Hi DL! You reckon that throwing a bag of cow manure into the duckweed pond and feeding it to the fish will contaminate them? What is biomagnification?

I don't think it was from a cow that had them worried.
Biomagnification is when small fish eats say a small amount of lead. Then larger fish eats lots of smaller fish. Then big fish eats lots of large fish. Then we eat big fish and wonder what that funny taste is. And why is my hair falling out Some metals and chemicals travel up the food chain getting more concentrated as they go. Also called bioamplification.

There has even been suggestion that only certain types of algae result in the Omega 3 production in the fish

Ain't life grand! Guess it's time to find out which kinds of algae... test fish when raised on local algae be the easiest.

I spelt the botanist's name wrong in previous post if anyone interested in his research on proteins produced by unhealthy plants to attract pests.... is Francis Chaboussou. Here is a link of a pdf on the subject..http://orgprints.org/12894/01/12894.pdf

So in a closed system like AP this could be minimised or even completely prevented.... Looking better all the time!

Uhuh!

That's what I am thinking. Larger ponds lower stock density's and at least 12 months to grow them out.

Hey Chappo I know you have told us before, but how do they control algae blooms in Thailand?

My experiment died on on me.. I threw in a cow turn and the algae grew rapidly and took the little fishes life.. Algae is going to be a big part of what I do the good omega 3 is just a bonus for me

Hmm.... The rapid growth probably caused a DO problem for the fish. What if nutrient for the algae was added slowly and progressively over time? I guess there has to be a way to keep it in balance. I wonder if algae grown elsewhere and thrown in as food is any good as an idea...... like the duckweed. Does it become dead food if suddenly not attached? If so any uneaten algae would just decompose. Not what I want in the tank. But algae even if grown at a slower rate in the tank could use too much of the nutrients needed for the other plants in the GB's. Trial and error. Wish I had my new system built already! Want to go as natural as possible. I have tried a business with a big infrastructure before and volatile monthly input costs make it an unpleasant juggling act. No fun. Want this to stay fun.