Research evaluates plant compounds to boost disease resilience in catfish
Researchers at Texas A&M AgriLife are studying plant-based compounds as alternatives to antibiotics to strengthen the health, sustainability and economic resilience of U.S. catfish production, the nation's largest aquaculture industry.
The work brings together scientists from Mississippi State University, Auburn University and Texas A&M University. The goal: develop proactive strategies that help producers reduce disease-related losses while maintaining production efficiency.
"Increased international competition and rising feed and energy costs, among other issues, have led catfish farmers to adopt more intensive farming methods," said Haitham Mohammed, Ph.D., assistant professor in the Texas A&M College of Agriculture and Life Sciences Department of Rangeland, Wildlife and Fisheries Management, Bryan-College Station.
"Given the nature of the catfish immune system, bacterial infections can be a substantial challenge in these highly stocked environments."
Delbert Gatlin, Ph.D., Regents Professor in the Department of Ecology and Conservation Biology, Bryan-College Station, will join Mohammed in this research.
Plant extracts as potential health tools
Plant-derived compounds, known as phytotherapeutics, may offer an additional, cost-effective layer of protection by supporting immune health and helping reduce the risk of disease outbreaks, Mohammed said.
Although further research is needed, Mohammed said preliminary data shows that black cumin seed and other plant-derived compounds can inhibit bacterial growth in the lab.
While antibiotics remain an important tool for managing bacterial infections in aquaculture, he said they can be costly and must be used carefully to protect their long-term effectiveness.
There are only three antibiotics in the U.S. approved by the U.S. Food and Drug Administration, FDA, to treat food fish, Mohammed said.
"Even if there is no current bacterial resistance to these medications, repeated use can lead bacteria to develop resistance to the treatment over time," he said. "We are hoping to proactively provide farmers with more environmentally friendly options while supporting the health of their fish."
Furthermore, producers must also follow strict withdrawal periods after antibiotic use before marketing the fish, which can increase feed and maintenance costs if fish need to be held longer.
From the lab to the pond
In the first phase of the three-year project, the team will test the antimicrobial properties of purified plant extracts and commercial feed additives against catfish pathogens in a laboratory setting.
Specifically, the work will target the bacteria responsible for the most common diseases faced by the industry—motile aeromonas septicemia, columnaris disease and enteric septicemia of catfish.
"These diseases can cause extensive mortalities and catastrophic economic impacts for catfish producers," Mohammed said.
For context, a 2023 study published in the journal Aquaculture estimates that the annual total disease-related economic losses in western Alabama alone exceed $11 million.
Following laboratory testing, the most promising plant-based supplements will move into pond trials at the universities' respective aquaculture centers, allowing researchers to assess their efficacy under simulated commercial conditions.
Subsequent work will determine the best administration protocols for the most effective options.
In addition to slowing or preventing bacterial growth, dietary phytotherapeutics have been shown to enhance the immune system and even mitigate stress in the fish.
"Healthy fish are the foundation of a sustainable aquaculture industry," Mohammed said. "By expanding the options available to producers, we can ensure this vital food sector continues to thrive."
Provided by Texas A&M University
