It is no news that aquaculture is the fastest-growing food production sector and now supplies more fish for human consumption than fisheries, but faces challenges like bacterial infection, such as Flavobacterium columnare, Edwardsiella ictaluri, and Aeromonas hydrophila, which lead to significant losses to farmers. Medicated feeds, which contain the antibiotics florfenicol (Aquaflor) and oxytetracycline (Terramycin), are among the few FDA-approved therapeutics used in aquaculture. Still, small-scale farmers often face critical delays in obtaining these feeds. Commercial suppliers can take two to three weeks to deliver medicated feeds after an order is placed. This delay may cause the fish to stop feeding or die as the disease progresses. Once fish reduce their feed intake, oral antibiotic treatment becomes ineffective, and disease-related mortality escalates.
Kentucky State University’s Fish Disease Diagnostic Laboratory (FDDL) addresses this challenge by maintaining a local inventory of medicated feeds and providing immediate availability once a disease diagnosis is performed. This allows the treatment to begin before fish stop eating. However, the long-term stability of these medicated feeds during frozen storage needs to be looked into. Evidence showed that florfenicol in medicated feed can lose 30–45% of its effect within four weeks at room temperature, whereas, when frozen, it decreased about 15%–25%. Oxytetracycline is similarly vulnerable to degradation under high temperature and light, although low-temperature, light-protected storage slows this process.
This project will quantify the chemical stability of florfenicol and oxytetracycline in commercial aquaculture feeds stored at –10 °C and also look into the proximate analysis of other ingredient in the feed. Medicated feed samples will be analyzed using validated high-performance liquid chromatography and tandem mass spectrometry (HPLC/UV and LC-MS/MS) methods to measure the concentration of antibiotics lost over time. Results will determine whether extended cold storage can preserve the therapeutic levels and also identify environmental factors, such as temperature, humidity, and light exposure, that influence degradation. By establishing science-based storage guidelines, this study will ensure that locally stocked medicated feeds remain potent, and this will lead to the rapid treatment of sick fish, a reduction in antibiotic resistance challenges, and the strengthening of fish health management for aquaculture producers in Kentucky and surrounding states.