Effect of Aerobic and Anaerobic Composting on the Removal of Antibiotics of Enrofloxacin and Ciprofloxacin in Broiler Chicken Manure

Many of the antibiotics used in poultry farms are excreted in their feces. This waste is used as organic fertilizer in agriculture and causes the release of animal antibiotics in the environment. These compounds may increase the antibiotic resistance of microbial populations or damage plants grown in these soils. The aim of this study was to determine the effect of aerobic and anaerobic poultry manure composting on the amount of enrofloxacin and ciprofloxacin antibiotics in poultry manure at two levels of high and low concentration and compare them with each other.

Two samples of fresh broiler chicken manure were prepared after the end of the chicken treatment with antibiotic enrofloxacin. The two samples contained two levels of high and low concentrations of Enrofloxacin and Ciprofloxacin. The composting of chicken manure was done using a completely randomized design with 4 treatments of 1- aerobic treatments at a low concentration,  2- aerobic treatments at high concentration 3- anaerobic treatments at low concentration 4- anaerobic treatments at a high concentration in five replicates in 75 days. Samples were prepared at specific intervals and the concentration of Enrofloxacin and Ciprofloxacin was measured by HPLC method. The obtained data were fitted with the first-order kinetic equation and the half-life of the antibiotic degradation was calculated.

The results showed that at the end of the period, in treatments 1 to 4, 54.2%, 64.3%, 65.3% and 69.7% of the Enrofloxacin and 41%, 57.8%, 57.8% and 61.8% Ciprofloxacin remained. The correlation coefficient (R2) obtained from the fitting of the first-order kinetic equation in treatments (from 0.71 to 0.92) showed that the data fit well with this equation. The half-life of the Enrofloxacin degradation was obtained between 96.27 and about 150.68 days. The half-life of degradation for Ciprofloxacin was also found to be between 57.28 and 117.48 days.

Overall, the results showed that the process of composting reduced the concentration of antibiotics and prevented its entry into the environment. The rate and total amount of antibiotic degradation in aerobic conditions was higher than anaerobic. The rate of degradation of both antibiotics at a high initial concentration was lower than its rate of degradation at low concentrations. The rate of ciprofloxacin degradation was also higher than Enrofloxacin. The results of this study can help to create relevant laws and regulations in relevant institutions, in order to reduce the release of veterinary antibiotics into the environment.