ABSTRACT
The demand for healthier foods with high nutritional value has resulted in intensive fish farming. In this production system, high-frequency infections occur, and antibiotics are administrated for control. Only two antibiotics are allowed for use in Brazilian aquaculture, one of which is florfenicol. In this work, a bioconcentration assay was performed to assess the accumulation of florfenicol in the muscle of Nile tilapia (Oreochromis niloticus). Tilapia was evaluated as it is the most produced fish species in Brazil. The fish were exposed to florfenicol at a nominal concentration of 10 mg/L, through the water. Muscle and water were collected at 0, 1.5, 3, 6, 24, and 48 h during the exposure phase and at 1.5, 3, 6, 24, 48, and 120 h during the depuration phase. Quantification was performed using an LC-MS/MS. The results showed rapid absorption and elimination of the antibiotic (half-life, t1/2 = 5 h), with low potential for accumulation of florfenicol in tilapia muscles. The study was performed to determine the bioconcentration factor (BCF) and withdrawal period of florfenicol, being 0.05 mL/µg and 1.8 h, respectively. The results contribute to set protocols for the safe use of florfenicol in tilapia transport, avoiding residues in fish that may pose risks to human health.
Subject(s)
Cichlids , Tilapia , Animals , Anti-Bacterial Agents , Bioaccumulation , Brazil , Chromatography, Liquid , Humans , Tandem Mass Spectrometry , Thiamphenicol/analogs & derivatives , WaterABSTRACT
Intensive fish cultivation has a high incidence of infection, which is often controlled by administering antibiotics. Florfenicol (FF) is one of the two antimicrobial drugs permitted for aquaculture in Brazil. Due to their intensive use, potentially harmful effects on aquatic organisms are of great concern. In this sense, we investigated whether the presence of FF in cultivation water could change the health parameters of Nile tilapia. For this, we evaluated hemoglobin, hematocrit, mean corpuscular hemoglobin (MCHC) concentration, mean corpuscular volume (MCV), total plasma protein (TPP), number of circulating red blood cells and leukocytes, as lipid peroxidation levels, catalase activity and glutathione S-transferase activity of fish exposed to 11.72 mg L-1 of FF in water for 48 h. The fish were divided into two groups: Nile tilapia in water with FF or without FF (control). Exposure to FF in cultivation water for a short period didn't change the hematological variables analyzed, but caused changes in liver ROS (Reactive oxygen species) markers of the Nile tilapia, which was revealed by lipid peroxidation levels, catalase activity, and glutathione S-transferase. The 48h exposure period was enough to induce oxidative stress in hepatocytes, causing cellular oxidative damage. Therefore, the antibiotic florfenicol may cause toxicity to organisms and aquatic ecosystems, even at a sublethal concentrations near 1/100 LC50-48h for fish species.
ABSTRACT
A novel capillary electrophoresis method using capacitively coupled contactless conductivity detection is proposed for the determination of the biocide tetrakis(hydroxymethyl)phosphonium sulfate. The feasibility of the electrophoretic separation of this biocide was attributed to the formation of an anionic complex between the biocide and borate ions in the background electrolyte. Evidence of this complex formation was provided by (11) B NMR spectroscopy. A linear relationship (R(2) = 0.9990) between the peak area of the complex and the biocide concentration (50-900 µmol/L) was found. The limit of detection and limit of quantification were 15.0 and 50.1 µmol/L, respectively. The proposed method was applied to the determination of tetrakis(hydroxymethyl)phosphonium sulfate in commercial formulations, and the results were in good agreement with those obtained by the standard iodometric titration method. The method was also evaluated for the analysis of tap water and cooling water samples treated with the biocide. The results of the recovery tests at three concentration levels (300, 400, and 600 µmol/L) varied from 75 to 99%, with a relative standard deviation no higher than 9%.
