Fate of Tylosin A and Its Effect on Anaerobic Digestion Using Two Tylosin Inclusion Methods

摘要

This study examined the fate and effects of tylosin (TYL) on anaerobic digestion of swine wastewater at two concentrations of tylosin A (TYLA) using manure collected from swine fed with TYLA (TYL_(EED)) or direct addition of TYLA (TYL_(ADD)) to antibiotic-free swine manure, to examine whether there are differences between the two TYL addition methods on methane production and other fermentation parameters. TYLA and tylosin D (TYLD) concentrations, pH, Chemical oxygen demand (COD), Total nitrogen (TN), and diversity of methanogenic archaea population were parameters used for this study. The results showed that concentrations of TYLA and TYLD in the TYL_(FDD) treatment were higher (P ＜ 0.05) than those in the TYL_(ADD) treatment. Methane production in the TYL_(FEDH) and TYL_(FEDL) was reduced by 35.52% and 37.06%, respectively, compared with the control during the 7 days addition period; but for TYL_(ADDH) and TYL_(ADDL), the decrease (P ＜ 0.05) was only 12.98% and 7.84%, respectively. The diversity index of methanogenic archaea in the TYL_(FED) treatment were lower than that in the control and the TYL_(ADD) on Day 4, but no difference (P ＞ 0.05) between the control and the TYL_(ADD) treatment was observed. pH, COD, and TN were not affected by treatment. Our results showed clear differences in the rate of methane inhibition by the two antibiotic inclusion methods; been higher for the TYL_(FED) treatment than the TYL_(ADD) treatment. Since the former method resembles more under actual farm conditions, we suggested that studies on effects of antibiotic residues on anaerobic fermentation should adopt such an approach.