Islam K M S, Afrin S, Khan M J, Das P M, Hassan M M, Valks M, Burch D G S, Pesti G M
Department of Animal Nutrition, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh.
Poult Sci. 2008 Aug;87(8):1565-8. doi: 10.3382/ps.2008-00071.
The pleuromutilin antibiotic tiamulin (TIA) is known to produce a negative interaction in broilers when administered in combination with several ionophore anticoccidials such as salinomycin (SAL). Chlortetracycline (CTC), when administered simultaneously with TIA, has demonstrated a synergistic antimicrobial effect. A 35-d feeding study was conducted in cages to evaluate the interaction effect of a combination of TIA plus CTC at increasing inclusion levels when administered concurrently with SAL. A total of 200 one-day-old broiler chicks were distributed into 4 groups, and each group consisted of 5 cages containing 10 birds in each. Replicate cages were distributed randomly. Feed for all groups contained 60 ppm SAL, but additionally, 0, 20, 30, and 50 ppm TIA and 0, 60, 90, and 150 ppm CTC were included, respectively. Several enzymes (creatine phosphokinase, lactate dehydrogenase, and aspartate aminotransferase) were determined from blood samples taken at the end of the trial. Blood samples were also collected during d 0, 19, and 35 and were analyzed for antibody titers against Mycoplasma gallisepticum and Mycoplasma synoviae. Necropsy of a few birds (20, 8, 20, 12, and 12 on d 7, 14, 21, 28, and 35, respectively) was conducted at weekly intervals. Results indicated that there was a significant depression of weight gain (P < 0.05) in group 4 (TIA 50 + CTC 150) only. The final weights were 1,809 +/- 130, 1,859 +/- 52, 1,703 +/- 47, and 1,617 +/- 98 g for groups 1 (TIA 0 + CTC 0), 2 (TIA 20 + CTC 60), 3 (TIA 30 + CTC 90), and 4 (TIA 50 + CTC 150), respectively. However, feed intake and feed conversion efficiency (g of weight gain/kg of feed intake) were not significantly affected in any of the groups. There was no dose-related adverse effect on mortality or clinical signs exhibited during the trial, and this was supported by necropsy. Maternally derived antibodies against M. gallisepticum were present at the beginning of the trial but disappeared within 19 d. Otherwise, there was no apparent infection by M. gallisepticum or M. synoviae throughout the trial. The results demonstrate that 50 ppm TIA plus 150 ppm CTC along with 60 ppm SAL caused only a depression of growth, but no adverse signs of interaction were detected. Taking into consideration all the aspects of the cost of production, the 20 ppm TIA plus 60 ppm CTC was the most cost-effective level to administer continuously with 60 ppm SAL via the feed, but it would be important to do an additional study using an artificial infection with M. gallisepticum or M. synoviae to know whether this inclusion rate would be sufficient to protect against an infectious challenge.
已知截短侧耳素类抗生素泰妙菌素（TIA）与几种离子载体抗球虫药（如盐霉素，SAL）联合使用时，会在肉鸡中产生负面相互作用。金霉素（CTC）与TIA同时给药时，已显示出协同抗菌作用。进行了一项为期35天的笼养饲养研究，以评估TIA加CTC组合在与SAL同时给药时，增加添加水平时的相互作用效果。总共200只1日龄肉鸡雏鸡被分为4组，每组由5个笼子组成，每个笼子中有10只鸡。重复笼子随机分布。所有组的饲料都含有60 ppm的SAL，但另外分别含有0、20、30和50 ppm的TIA以及0、60、90和150 ppm的CTC。在试验结束时采集的血样中测定了几种酶（肌酸磷酸激酶、乳酸脱氢酶和天冬氨酸转氨酶）。在第0、19和35天也采集了血样，并分析了针对鸡毒支原体和滑液支原体 的抗体滴度。在第7、14、21、28和35天分别对几只鸡（分别为20、8、20、12和12只）进行了每周一次的剖检。结果表明，仅第4组（TIA 50 + CTC 150）的体重增加显著下降（P < 0.05）。第1组（TIA 0 + CTC 0）、第2组（TIA 20 + CTC 60）、第3组（TIA 30 + CTC 90）和第4组（TIA 50 + CTC 150）的最终体重分别为1,809 +/- 130、1,859 +/- 52、1,703 +/- 47和1,617 +/- 98克。然而，任何一组的采食量和饲料转化率（增重克数/采食量千克数）均未受到显著影响。在试验期间，对死亡率或临床症状没有剂量相关的不良影响，剖检结果也证实了这一点。试验开始时存在母源抗鸡毒支原体抗体，但在19天内消失。否则，在整个试验过程中未发现明显的鸡毒支原体或滑液支原体感染。结果表明，50 ppm的TIA加150 ppm的CTC以及60 ppm的SAL仅导致生长抑制，但未检测到相互作用的不良迹象。考虑到生产成本的所有方面，20 ppm的TIA加60 ppm的CTC是通过饲料与60 ppm的SAL连续给药时最具成本效益的水平，但使用鸡毒支原体或滑液支原体人工感染进行额外研究以了解该添加率是否足以预防感染性挑战将很重要。
