Sources, distribution and dynamics of antibiotics in Litopenaeus vannamei farming environment

In aquaculture, antibiotics are often added to the feeds to prevent and treat bacterial diseases. Antibiotic residues in aquaculture environment can be altered by the feeds introduced in different farming phases. Currently, less information is available on the distribution and dynamics of antibiotic residues in aquaculture environment during a farming cycle. In this study, we investigated the sources, distribution, and dynamics of selected 12 antibiotics in pond water, sediment, and shrimp muscles during a whole whiteleg shrimp (Litopenaeus vannamei) farming cycle. The results showed that a total of 6 antibiotics were detectable in pond water. Oxytetracycline (OTC) and sulfamethoxazole (SMX) were the main antibiotic residues and found in all pond water samples. The total antibiotic residues in the pond water was temporarily decreased from 55.5 ng/L in phase of shrimp larvae to 33.0 ng/L in phase of juvenile shrimp, and then gradually increased to 64.4 ng/L in the later phase of mature shrimp. In the sediment, 8 of 12 antibiotics were detectable and the total amount of antibiotic residues was gradually accumulated during cultivation. The total concentration of 8 antibiotics in sediment increased nearly 5 times by comparing to the background concentration before shrimp larvae was introduced in the system. In shrimp muscle, 6 antibiotics were accumulated from juvenile shrimp (total antibiotics = 41.8 mu g/kg) to mature shrimp (total antibiotics = 134 mu g/kg) phase. SMX, OTC, and levofloxacin (LEOF) are the main antibiotic residues found in shrimp muscle. Pearson correlation analyses showed that the dynamics of antibiotics in sediment and shrimp muscle were significantly correlated with antibiotics found in feeds, indicating that feed is an important source of antibiotic residues accumulated in aquatic organism and sediment. Dietary exposure assessment indicated that the exposure risk of the selected antibiotics in shrimp muscle for human health were negligible.

Automated summary

This study investigated the sources, distribution, and dynamics of 12 selected antibiotics in pond water, sediment, and shrimp muscles during a whiteleg shrimp farming cycle. The results showed the accumulation of antibiotics in these environments and their correlation with antibiotics in feeds. The study highlighted the importance of feed as a main source of antibiotic residues in aquaculture environment.