Date Published: May 8, 2019
Publisher: Public Library of Science
Author(s): Qiao Gao, Wenhui Deng, Zhenghui Gao, Mengya Li, Wen Liu, Xiaoping Wang, Fen Zhu, Sartaj Ahmad Bhat.
Antibiotics are commonly used in livestock and poultry farming. Residual antibiotics in manure may lead to antibiotic pollution of soil, surface water, and groundwater through land application and run-off rainfall. The black soldier fly (BSF) Hermetia illucens is a good candidate for manure management. We evaluated the effect of sulfonamide pollution on the growth of H. illucens. Four treatments were considered with a sulfonamide content in the feed of 0 (control group), 0.1, 1, and 10 mg/kg. The control larvae were fed without sulfonamide. Survival and development status of the individuals were recorded daily. The weights of the fifth instar larvae, prepupae, and pupae were checked. Antioxidant enzyme activity was determined with the fifth instar larvae. The results showed that a low (0.1 and 1 mg/kg) concentration of sulfonamides had no effects on larval survival, pupation, and eclosion of BSFs. A high sulfonamide concentration of 10 mg/kg had a significant effect on the survival of larvae and pupae and on the body weight of larvae, prepupae and pupae. Peak of the cumulated pupation rate and eclosion rate in the sulfonamide treatment of 10 mg/kg was very low. Pupation and eclosion in this group peaked later than that of the control and low sulfonamide concentration treatment groups (0.1 mg/kg and 1 mg/kg). Larvae from the sulfonamides group showed lower antioxidase activities than that of the control. In sulfonamide groups, the activity of peroxidase and superoxide dismutase was reduced in a concentration-dependent manner. Sulfamonomethoxine, sulfamethoxazole, and sulfamethazine were not detected in the harvested prepupae. Only sulfadiazine was discovered in the sulfonamide treatments of 1 and 10 mg/kg. In conclusion, BSFs can tolerate certain concentrations of sulfonamide contamination.
With the rapid growth of the global population and the increasing demands for food from animal origin, industrial livestock and poultry production have expanded significantly in recent decades [1, 2]. The yield of livestock manure reached 2.121 billion tons in 2011, which will continue to increase rapidly to 2.875 billion tons by 2020 and 3.743 billion tons by 2030 [3, 4]. The total amount of pig manure discharge is the first in several livestock manure [3, 4]. Subsequently, the large amount of livestock manure has created serious environmental pollution. Commonly, manure is used as organic fertilizer directly or after simple processing, such as anaerobic digestion or composting. The mismanagement of manure wastes may lead to greenhouse gas emissions, hazardous substances contamination and disease transmission [5–8]. Moreover, residual veterinary antibiotics in manure can be another environmental pollution problem that cannot be ignored. In many countries, antibiotics are widely used in livestock and poultry farming as feed additives for the prevention and treatment of infectious diseases or for improving feed efficiency and growth rate at a relatively low dose . However, antibiotics in animal feed cannot be absorbed completely, and some of them are excreted with feces . These contaminated feces might lead to secondary antibiotic pollution to soil, surface water and groundwater through land application and run-off rainfall [10–12]. Some studies have indicated that antibiotics in the soil can be absorbed and cumulated by crops, especially vegetables such as cucumbers, lettuce, radish and tomatoes, and finally enter into the food chain [10, 13]. These antibiotics eventually lead to the development of antibiotic resistance, which has resulted in the reduction of therapeutic potential against human and animal pathogens .
By studying the effect of sulfonamide pollution on the growth of H. illucens, we found that BSF larvae have the ability to tolerate certain levels of sulfonamide contamination and may be used for sulfonamide attenuation, especially for sulfamonomethoxine, sulfamethoxazole, and sulfamethazine. This promising ability is encouraging, especially for reducing antibiotic residues in the environment. Level of SA contamination in rearing substrates less than 10 mg/kg is usable by BSF. However sulfadiazine (SD) is found in the preupae at treatment levels of 1 and 10 mg/kg. This suggests that some other ways should be found for SD attenuation.