Ming Sun

Bio: Ming Sun is an academic researcher from Ocean University of China. The author has contributed to research in topics: Shrimp & Crassostrea. The author has an hindex of 6, co-authored 10 publications receiving 89 citations. Previous affiliations of Ming Sun include Chinese Academy of Fishery Sciences.

Environmental and human health risks of antimicrobials used in Fenneropenaeus chinensis aquaculture production in China.

Abstract: This study aimed to quantify the environmental fate of antimicrobials applied in Fenneropenaeus chinensis aquaculture production in China and to assess their potential risks for surrounding aquatic ecosystems, for the promotion of antimicrobial resistance in target and non-target bacteria and for consumers eating shrimp products that contain antimicrobial residues. For this, we first used the results of an environmental monitoring study performed with the antimicrobial sulfamethazine to parameterize and calibrate the ERA-AQUA model, a mass balance model suited to perform risk assessments of veterinary medicines applied in aquaculture ponds. Next, a scenario representing F. chinensis production in China was built and used to perform risk assessments for 21 antimicrobials which are regulated for aquaculture in China. Results of the model calibration showed a good correspondence between the predicted and the measured sulfamethazine concentrations, with differences within an order of magnitude. Results of the ecological risk assessment showed that four antimicrobials (levofloxacin, sarafloxacin, ampicillin, sulfadiazine) are expected to have adverse effects on primary producers, while no short-term risks were predicted for invertebrates and fish exposed to farm wastewater effluents containing antimicrobial residues. Half of the evaluated antimicrobials showed potential to contribute to antimicrobial resistance in bacteria exposed to pond water and farm effluents. A withdrawal period of three weeks is recommended for antimicrobials applied via oral administration to F. chinensis in order to comply with the current national and international toxicological food safety standards. The results of this study indicate the need to improve the current regulatory framework for the registration of aquaculture antimicrobials in China and suggest compounds that should be targeted in future aquaculture risk assessments and environmental monitoring studies.

Bioaccumulation and biodegradation of sulfamethazine in Chlorella pyrenoidosa

Abstract: Intensive use of sulfamethazine (SM2) in aquaculture has resulted in some detrimental effects to non-targeted organisms. In order to assess its potential ecological risk, it is crucial to have a good understanding on the bioaccumulation and biodegradation of SM2 in Chlorella pyrenoidosa. The microalgae were treated with 2, 4, and 8 mg L−1 of sulfamethazine for 13 days, respectively, showing that the inhibition effects of sulfamethazine on the growth of Chlorella pyrenoidosa increased progressively as the concentrations of sulfamethazine increasing from 2 to 8 mg L−1. The peak concentrations of sulfamethazine accumulated in C. pyrenoidosa were 0.225, 0.325, and 0.596 ng per mg FW on day 13 for three treatment groups, respectively, showing a great ability to deplete sulfamethazine from the culture media. On day 13, the percentages of biotic degradation were 48.45%, 60.21% and 69.93%, respectively. The EC50 of 10.05 mg L−1 was derived which showed no significant risk for C. pyrenoidosa with a calculated risk quotient < 1. The activities of superoxide dismutase and catalase increased progressively in response to sulfamethazine and showed a positive correlation to the treatment concentrations. The highest superoxide dismutase activity was achieved at the concentration of 8 mg L−1 after 2 d of exposure, which was 1.89 folds higher than that of the control. The activity of catalase has a similar pattern to that of superoxide dismutase with the maximum activity achieved at day 2, which was 3.11 folds higher compared to that of the control. In contrast to superoxide dismutase and catalase, the maximum glutathione S-transferase activity was observed at day 6, showing 2.2 folds higher than that of the control.

Environmental fate and pharmacokinetics of sulphamethazine in Fenneropenaeus chinensis shrimp production systems after oral administration

Abstract: The antimicrobial sulphamethazine is widely used in aquaculture for the prevention and treatment of bacterial diseases. Residues of sulphamethazine have been detected in aquatic environments and in edible tissues of aquaculture fish and shrimps at relatively low, but detectable concentrations. Detailed information on the environmental fate and pharmacokinetics of sulphamethazine in aquaculture species is essential to predict possible ecological risks and to provide recommendations on appropriate dosages and withdrawal periods. In this study we investigated the distribution of sulphamethazine in water and sediments of Fenneropenaeus chinensis shrimp ponds treated with 50, 100 and 150 mg kg−1·bw of sulphamethazine for 5 days and measured the uptake and elimination dynamics of sulphamethazine in different shrimp organs and tissues. Results of the HPLC analysis showed highest sulphamethazine concentrations in shrimp tissues, followed by sediments and water. The rank order of the mean concentrations of sulphamethazine in shrimp tissues and organs was hepatopancreas> plasma≈ stomach> muscle≈ gill≈ intestine> carapace. The results also demonstrated a significant dose-dependent accumulation of sulphamethazine in the different biological and environmental compartments. Sulphamethazine decreased gradually with the time in all of the three compartments. The mean half-life of sulphamethazine in sediment and water was 2.15 and 2.17 days respectively. A withdrawal period of 10 days or more is proposed for F. chinensis orally treated with sulphamethazine in order to meet the current food safety standards.

Pharmacokinetics of difloxacin in olive flounder Paralichthys olivaceus at two water temperatures.

Abstract: In this study, the pharmacokinetics profiles of difloxacin in the olive flounder (Paralichthys olivaceus) were investigated following intravenous and oral administration (10 mg/kg BW) at 14 and 22 °C water temperatures. Plasma and tissue samples (muscle, liver, and kidney) were analyzed using an HPLC method. The results showed that the plasma concentration-time data for difloxacin were described commendably by two-compartment open model at the two water temperatures. The absorption half-life (t(1/2ka)) of difloxacin after oral administration were 2.08 and 1.10 h at 14 and 22 °C, respectively; whereas the elimination half-life (t(1/2β)) was 4.41 and 2.38 h, respectively. The muscle concentration of 1.35 ± 0.19 μg/g was observed at 9 h at 14 °C, and 2.11 ± 0.33 μg/g at 6 h at 22 °C, respectively. For liver, the peak concentration of difloxacin 2.43 ± 0.30 μg/g occurred at 6 h at 14 °C, which was lower than the 3.34 ± 0.24 μg/g peak that occurred at 4 h at 22 °C. The calculated bioavailability of difloxacin was 68.07% at 22 °C, which was higher than the 53.43% calculated for 14 °C. After intravenous administration, the t(1/2β) were 4.79 and 2.81 h at 14 and 22 °C, respectively. The results indicate that the peak concentrations in muscle and liver at 14 °C are approximately half of those achieved at 22 °C. However, the C(max) in kidney at 14 and 22 °C were similar. The Vd values were 1.20 and 1.75 L/kg at 14 and 22 °C, respectively. These data indicated that both temperature and drug administration had significant effects on the elimination of difloxacin, and lower temperature or oral administration resulted in lower elimination.

Antibiotics and Food Safety in Aquaculture.

Abstract: Antibiotics are widely used in aquaculture. Intensive farming drives indiscriminate use of antibiotics, which results in residues of antibiotics in cultured aquatic products and bacterial resistance. This perspective attempts to present a brief update on usage, regulations, residues, and potential human health risk of antibiotics used in aquaculture. Through the comprehensive literature review, we provide a view that the safety of aquatic products still requires further attention and more rigorous risk assessment. Finally, we make a few suggestions for future research directions: reduce the use of antibiotics to bring down the speed of resistance development and monitor resistant pathogens and genes, strictly manage the environmental sanitation of aquaculture and pay attention to the quality of water bodies introduced into aquaculture, seek international cooperation to establish an information bank of antibiotic residues and antibiotic-resistant genes, and set up a quantitative model to assess the risk of antibiotic resistance associated with the antibiotic residues.

Unpacking factors influencing antimicrobial use in global aquaculture and their implication for management: a review from a systems perspective

Abstract: Global seafood provides almost 20% of all animal protein in diets, and aquaculture is, despite weakening trends, the fastest growing food sector worldwide. Recent increases in production have largely been achieved through intensification of existing farming systems, resulting in higher risks of disease outbreaks. This has led to increased use of antimicrobials (AMs) and consequent antimicrobial resistance (AMR) in many farming sectors, which may compromise the treatment of bacterial infections in the aquaculture species itself and increase the risks of AMR in humans through zoonotic diseases or through the transfer of AMR genes to human bacteria. Multiple stakeholders have, as a result, criticized the aquaculture industry, resulting in consequent regulations in some countries. AM use in aquaculture differs from that in livestock farming due to aquaculture’s greater diversity of species and farming systems, alternative means of AM application, and less consolidated farming practices in many regions. This, together with less research on AM use in aquaculture in general, suggests that large data gaps persist with regards to its overall use, breakdowns by species and system, and how AMs become distributed in, and impact on, the overall social-ecological systems in which they are embedded. This paper identifies the main factors (and challenges) behind application rates, which enables discussion of mitigation pathways. From a set of identified key mechanisms for AM usage, six proximate factors are identified: vulnerability to bacterial disease, AM access, disease diagnostic capacity, AMR, target markets and food safety regulations, and certification. Building upon these can enable local governments to reduce AM use through farmer training, spatial planning, assistance with disease identification, and stricter regulations. National governments and international organizations could, in turn, assist with disease-free juveniles and vaccines, enforce rigid monitoring of the quantity and quality of AMs used by farmers and the AM residues in the farmed species and in the environment, and promote measures to reduce potential human health risks associated with AMR.