Title : Impact of antibiotic application on microbiome present in Catfish gut and water
Abstract:
Terramycin (oxytetracycline) is an FDA-approved antibiotic commonly used to treat enteric septicemia in catfish caused by Edwardsiella ictalurid. Despite its widespread use, its impact on the gut microbiota of catfish as well as the water mcirobiome remains poorly understood. This study evaluated the combined effects of antibiotic administration and water temperature on the catfish gut microbiome and water microbiome. Thirty-six 35-gallon tanks were set up, with four replicates per treatment. Tanks were filled with pond water and equipped with biofilters. Temperatures were maintained at 20, 25, and 30°C, with dissolved oxygen at ~6 mg/L. Each tank housed 25 channel catfish fingerlings. Terramycin-medicated feeds were administered for 10 days, followed by 21 days of withdrawal. Samples were collected at three time points (start, end of treatment, and end of withdrawal). Intestinal contents of the catfish were collected using FLOQSwabs® and the 1 L of water samples were taken from each tank at every sampling point.
Temperature had a significant impact on both the fish gut microbiome and the water microbiome. In the fish gut, the treatment led to an increased relative abundance of Mycobacterium at 20°C, Enterobacter at 25°C, and Klebsiella at 30°C. For the water microbiome, Terramycin treatment increased the relative abundance of Shewanella, Pelobium, and Aeromonas at 20°C; Pelobium at 25°C; and Pelobium and Klebsiella at 30°C.
