Denagard has also shown a synergistic activity with the tetracyclines. [?] When combined with chlortetracycline there was a 5 times increase in activity against M. gallisepticum and 4-8 times increase against Pasteurellae.
Similar results have been shown with Denagard and doxycycline. [?]
| Synergistic activity with tetracyclines |
| MIC’s (µg/ml) |
| |
Denagard |
Chlortetracycline |
Tia/CTC |
Factor |
| M. gallisepticum |
0.05 |
4.0 |
0.01/0.8 |
5/5 |
| H. paragallinarum |
8.00 |
0.5 |
1.00/0.125 |
8/4 |
| P. multocida |
1.00 |
1.00 |
0.25/0.25 |
4/4 |
| P. gallinarum |
2.00 |
4.00 |
0.25/0.5 |
8/8 |
|
Both Denagard and the tetracyclines are bacteriostatic antibiotics both acting on the ribosome, the sites where proteins are produced in the organism. It is thought their complimentary modes of action enhance their antimicrobial activity.
Recent studies have shown that Denagard at 50 ppm and chlortetracycline at 150 ppm, in both feed and water, to be very effective in preventing M. gallisepticum infections in broilers and 100ppm/300ppm for treatment.
| 
