What Goes into Tilapia, Goes into You

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."

Continuing Series of Tilapia Articles

This article is one in a continuing series based on my exclusive interview with the Vice President of Marketing of Rain Forest Aquaculture, Jim Nunneley. Other articles in this series will discuss such topics as:

· The Tilapia farming industry's initial reaction to the recent publication (Chilton, 2008) by Wake Forest University researchers which stated that eating tilapia is "Worse than eating bacon" for your heart.

· The Tilapia Farming Industry's Record on the Environment

· Tilapia Farming Around the World: China vs. the Americas

· The Tilapia industry's detailed evaluation of the Wake Forest Study

If you'd like to receive an email notification when these future articles are published, you can use the subscribe button at the top of this article.

This article is based on a direct interview with additional materials sourced from:

Sell, R. Tilapia. North Dakota State University NDSU Extension Service. 1993. Retrieved July 19^th, 2008 from http://www.ag.ndsu.edu/pubs/alt-ag/tilapia.htm.