Lincoln Evaluates Feed Alternatives for Aquaculture Producers

Lincoln University of Missouri's Aquaculture Research team entered the final stretch of a 12-week research project this month, with only three weeks remaining until the project's conclusion.

Dr. Moureen Matuha, an assistant professor of aquaculture, is supervising the project while graduate student Sadiat Onileowo runs it.

Onileowo explained that the study is based on her thesis and seeks to evaluate alternative feeds for use in aquaculture production. Specifically, the study is testing soy-based products as partial and full replacements for traditional fishmeal in rainbow trout diets.

Traditional fishmeal is made with fish and fish by-products and is used to feed farm animals.

Aquaculture graduate student Sadiat Onileowo's thesis was the basis for her and Dr. Moureen Matuha's 12-week study on alternative feeds for rainbow trout production.

"Fishmeal has generally been the major feed in fish production because it's rich in protein and fatty acids, has balanced amino acids and producers know fish will consume it," Onileowo said. "For this project, we're trying to substitute fishmeal because it has some issues, like sustainability and cost."

The choice to test soy-based products comes from a desire to support Missouri farmers, Matuha explained. The United States is the second biggest soybean producer in the world, and Missouri is among the top-producing states in the country. However, reduced exports have prompted researchers to find new ways to support soybean farmers.

On the aquaculture side, Matuha said producers want to increase production efficiency, fish health and product quality.

By evaluating soy-based products as a fishmeal alternative, Lincoln is supporting both soybean farmers and aquaculture producers.

In pursuit of this goal, Matuha and Onileowo sourced rainbow trout from Crystal Lake Fisheries in Ava, MO, for a 12-week juvenile study.

The study used soybean meal and Fermex200, a fermented soybean meal typically used as pig feed alternative. Both alternative feeds were produced by Fermentationexperts, a global fermentation company with a branch in South Dakota.

Sadiat Onileowo, along with other graduate students and aquaculture workers, weigh and measure rainbow trout after four weeks of consuming soy-based feed alternatives.

Matuha said Fermex200 could be a promising alternative to fishmeal, lowering reliance on fish-based ingredients and supporting more sustainable and efficient aquaculture production.

"I don't think anyone has ever used Fermex200 for this kind of research," Onileowo said. "So, this is the first research project to test it."

Onileowo explained fish were split into six groups and fed varied levels of fishmeal, soybean meal and Fermex200:

• Group one (the control group) received 100 percent traditional fishmeal.
• Group two received 25 percent soybean meal and 75 percent fishmeal.
• Group three received 50 percent soybean meal and 50 percent fishmeal.
• Group four received 25 percent Fermex200 and 75 percent fishmeal.
• Group five received 50 percent Fermex200 and 50 percent fishmeal.
• Group six received 50 percent soybean meal and 50 percent Fermex200.

At four, eight and 12 weeks, the fish are weighed and measured to assess how different feed ratios affect growth. In the meantime, Onileowo feeds the fish daily, records their feed intake and monitors water quality.

When the 12-week study period ends, Onileowo and Matuha will move beyond growth and analyze other impacts.

"We want to know how these feeds impact reproductive performance and fillet quality," Matuha said. "What are their impacts on gut health, enzyme activity, gene expression and protein metabolism? How do they affect water quality and production costs?"

Fish were sedated before being measured and weighed. Then they were transferred to a cooler with a revitalizing mix to recover.

The project will also include a consumer analysis to see how sensory profiles, including flavor, smell and texture, are affected.

Matuha and Onileowo want this study to be comprehensive, looking at long-term effects over different life stages. So, when this 12-week period with juvenile rainbow trout ends, the team will begin another 12-week study with sub-adults. When that period ends, they plan to do another with adult trout.

This project was made possible by a USDA-NIFA Evans-Allen Capacity grant awarded to Matuha. The grant allows for three years of study; however, it took the entirety of last year and much of this year to get the project up and running.

Matuha explained the aquaculture team designed and built a whole new recirculating system for the project, which took time to source materials for and construct. Upon completion, the team spent time working out the kinks in the system and had to let the trout acclimate for two weeks before the study could begin.

As a result, Matuha has the remainder of 2025 and 2026 to complete this research. To continue beyond 2026, Matuha would need to write another grant proposal.

Looking to the future, Matuha expressed that she would like to run similar experiments comparing the performance of Fermex200 with other soy-based products using rainbow trout and other freshwater aquaculture species.

Aquaculture graduate students measure and weigh rainbow trout to check on their growth after consuming soy-based feed alternatives.

Matuha also wants to use the project as a means to collaborate with Missouri aquaculture producers.

She explained she wants to recreate the project at Crystal Lake Fisheries and NuTerra Farms in Puxico, Missouri, to see how results differ between a farm and lab setting.

"Our aim is to support and work with as many fish farmers in Missouri as possible and bring them on board," Matuha said. "They are the primary end users of the research we do, so we want to ensure they benefit from this research."

Click here to learn more about Lincoln University's aquaculture program.