Department of Animal Science, McGill University, Ste-Anne-de-Bellevue, QC, Canada.
FEMS Microbiol Ecol. 2013 Jul;85(1):1-13. doi: 10.1111/1574-6941.12093. Epub 2013 Mar 11.
The use of antimicrobial agents in swine production at subtherapeutic concentrations for the purpose of growth promotion remains controversial due to the potential impact on public health. Beginning at weaning (3 weeks), pigs received either nonmedicated feed or feed supplemented with subtherapeutic levels of either tylosin (11-44 ppm) or chlortetracycline (5.5 ppm). After only 3 weeks, pigs given feed supplemented with tylosin had significantly higher levels of tylosin-resistant anaerobes (P < 0.0001) compared with the control group, increasing from 11.8% to 89.6%, a level which was stable for the duration of the study, even after a 2-week withdrawal prior to slaughter. Tylosin-fed pigs had a higher incidence of detection for erm(A), erm(F), and erm(G), as well as significantly (P < 0.001) higher concentrations of erm(B) in their feces. The continuous administration of chlortetracycline-supplemented feed, however, had no significant effect on the population of chlortetracycline-resistant anaerobes in comparison with nontreated pigs (P > 0.05). The resistance genes tet(O), tet(Q), and erm(B) were detected in all pigs at each sampling time, while tet(G), tet(L), and tet(M) were also frequently detected. Neither chlortetracycline nor tylosin increased the growth rate of pigs.
在亚治疗浓度下将抗菌剂用于猪生产以促进生长的做法仍然存在争议，因为这可能对公共健康产生影响。从断奶（3 周龄）开始，猪接受无药饲料或添加亚治疗水平的泰乐菌素（11-44 ppm）或金霉素（5.5 ppm）的饲料。仅 3 周后，与对照组相比，给予添加泰乐菌素的饲料的猪的泰乐菌素抗性厌氧菌水平显著升高（P < 0.0001），从 11.8%增加到 89.6%，即使在屠宰前进行了 2 周停药，该水平在整个研究期间仍保持稳定。泰乐菌素喂养的猪 erm(A)、erm(F)和 erm(G)的检出率更高，粪便中 erm(B)的浓度也显著（P < 0.001）更高。然而，与未处理的猪相比，连续给予金霉素补充饲料对金霉素抗性厌氧菌的种群没有显著影响（P > 0.05）。在每个采样时间，所有猪都检测到了耐药基因 tet(O)、tet(Q)和 erm(B)，而 tet(G)、tet(L)和 tet(M)也经常被检测到。金霉素和泰乐菌素均未提高猪的生长速度。
