Dietary low-fat content supplemented with oxytetracycline impairs physiological functions in Nile tilapia (Oreochromis niloticus) fingerlings

Nutrition modulates the vulnerability of animals to xenobiotics insults including antibiotics in cultured fish. However, studies exploring the role of low-fat diet (LFD) in modulating adverse effects of antibiotics are currently limited. This study explored the physiological effects of feeding LFD supplemented with oxytetracycline (OTC) in Nile tilapia (Oreochromis niloticus) fingerlings. Thirty Nile tilapia (8.64 ± 0.44 g) were tagged and randomly stocked into three tanks and fed on a control diet (CD, 70 g/kg lipid), LFD (20 g/kg lipid) and the LFD supplemented with 2.00 g/kg diet of OTC (80 mg/kg body weight/day), hereafter LFD + OTC for 9 weeks. The results indicated that the Nile tilapia fed on LFD + OTC reduced growth performance and feed utilization efficiency than those fed on CD and LFD. Moreover, the fish fed on LFD + OTC had lower body composition, nutrients digestibility and mesenteric fat index than those fed on CD and LFD. Feeding the fish with LFD + OTC decreased antioxidant capacity in the liver than those fed on CD and LFD. The Nile tilapia fed on LFD + OTC increased hepatotoxicity than those fed on CD and LFD. Feeding the Nile tilapia on LFD + OTC decreased immunity response in the kidney and liver than those fed on CD and LFD. The LFD + OTC affected nutrients metabolism in the liver and serum than other diets. Taken together, feeding LFD with OTC impairs physiological functions of Nile tilapia by inhibiting growth performance, antioxidant capacity, immunity response and nutrient metabolism.