Effect of Vegetable Growth on Content and Composition of Antibiotics in Litopenaeus vannamei Pond Sediments in Crop/Aquacultural Rotation Process

Photodegradation remains the major pathway of antibiotic removal in natural ponds. This study introduced a new method of growing vegetables on the bottom substrate of shrimp ponds to improve sediment quality. The aim of the study was to investigate the effect of vegetable planting on the photodegradation of antibiotics. This study characterized antibiotic levels in the pond sediment during this phytoremediation process and investigated the antibiotic content and composition of the sediment with and without crop rotation (traditional control), as well as the shrimp yields. The results showed that total antibiotics (e.g., trimethoprim, oxytetracycline, and norfloxacin) in the sediment of all aquaculture ponds continuously decreased from 44.78 ± 4.07 μg/kg to 18.80 ± 2.26 μg/kg in the crop rotation pond. The total amount of antibiotics consistently decreased in all ponds, and the rate of decline did not greatly differ. However, oxytetracycline in the crop rotation pond decreased faster than in the control pond, presumably because the growing vegetables altered the sediment and microbial-community characteristics that promoted oxytetracycline degradation. In the following year, there was little difference in the levels of norfloxacin or oxytetracycline between the two ponds. An increase in trimethoprim in the control pond was much higher than in the crop-growing sediment. It was indicated that the system remediated the shrimp pond ecosystem as well as providing the possibility of increasing profits by planting vegetables in the winter idle period of shrimp ponds.