Dynamic Elimination of Enrofloxacin Under Varying Temperature and pH in Aquaculture Water: An Orthogonal Study.

Orthogonal experiments were used to simulate the enrofloxacin (ENR) elimination dynamic in deeper water of aquaculture. Two factors at values common in fishery water (temperature of 20°C, 25°C, and 30°C; pH of 5, 7, and 9) were studied. The degradation of ENR in the nine treatment groups ranged from 44.7 to 80.1%. Variance analysis indicated that pH had a strong impact on the elimination of ENR, while temperature changes showed little effect. The ENR removal rate was highest at a combination of 25°C and pH 5. The optimal conditions of eliminating ENR were performed for exploring the generation of ciprofloxacin (CIP), which indicated that higher ENR concentrations led to the production of greater amounts of CIP. The half-time of ENR was increased 2.02-times in the ENR concentrations increasing from 20 to 2000 ng/mL. This study could increase our understanding of the behaviors of ENR and CIP during the aquaculture process.

Health risks associated with sulfonamide and quinolone residues in cultured Chinese mitten crab (Eriocheir sinensis) in China.

The occurrence of 27 antibiotics (18 sulfonamides and 9 quinolones) in 92 samples of cultured Chinese mitten crab (Eriocheir sinensis) from three provinces (Anhui, Jiangsu and Liaoning) was investigated. These 21 antibiotics were detected at least once in crabs from these provinces with detection frequencies of 3.70-90.91%. Sulfonamides were detected in 53.7% of the samples at concentrations of 0.1-10 µg/kg in Jiangsu, while quinolones were detected with 90.9% of samples containing concentrations of 1-100 µg/kg in Liaoning province. Enroflxacin, ciprofloxacin, sulfaquinoxaline, sulfameter, sulfadoxine, and sulfamethoxazole were the mainly used antibiotics and enroflxacin were present at a high concentration (>100 µg/kg). Dietary assessments showed that residual antibiotics in crabs from China were far below the maximum residue limit (MRL) of total sulfonamides and quinolones, and there was almost no risk associated with crab consumption. These results will provide meaningful indications for the safety of crab consumption.