| Summary: | 碩士 === 國立中興大學 === 獸醫學系 === 89 === Anticoccidial activity and toxicity of ionophorous antibiotic, salinomycin, was evaluated in turkeys in Taiwan. According to the results, older turkeys had higher resistance to coccidial inoculation than younger turkeys. In toxicity trials, the 6-week-old turkeys treated with salinomycin at 6, 9 and 12 mg/kg bw/day were found to be significantly reduced in weight-gain and feed consumption by comparing with the control group (p<0.05). There were 50% and 100% mortality of turkeys in 9 and 12 mg salinomycin/kg bw/day groups, respectively. Clinical toxic symptoms including decreasing appetite, losing weight and inability to stand were noted. In 12 mg salinomycin/kg bw/day treated group, turkeys'' leg muscles tend to pale (2/6). Also in histopathological observation, muscle fibers degenerated, and number of fibrocytes increased in 12 mg salinomycin/kg bw/day treated group (6/6). No other obvious histopathological lesion was found in other treated groups. Thus, the results indicated the no observed adverse level of salinomycin was 3 mg/kg bw/day for the 6-week-old turkeys. In the toxicity trials of 3-week-old turkeys, there was no significant difference in feed consumption and feed efficacy observed between all salinomycin treated groups and control group. Only the weight-gain of 9 mg salinomycin /kg bw/day treated group was significantly reduced by comparing with the control group (p<0.05). The results suggested that the no observed adverse level of salinomycin was 3 mg/kg bw/day for 3-week-old turkeys. The results of serum biochemistry showed the activity of creatine kinase and alkaline phosphatase significantly in 6 mg salinomycin/kg bw/day treated group.
In efficacy trails, weight gain of 3-week-old turkeys treated with 3, 4.5 and 6 mg salinomycin/kg bw/day and inoculated with turkey coccidia significantly increased comparing to the unmedicated and inoculated control groups(p<0.05). Feed consumption of 3 and 4.5 mg salinomycin /kg bw/day treated and inoculated groups significantly increased comparing to the unmedicated and inoculated control groups(p<0.05). Only the feed efficacy of 4.5 mg salinomycin/kg bw/day treated and inoculated group was improved by comparing with the unmedicated and inoculated control (p<0.05). There was no animal deceased by inoculating turkey coccidia. The oocyst of medicated turkeys was all below 105/g of feces. In the experiment of 3 week-old turkeys naturally infected with turkey coccidia, there was no any significant difference in weight-gain, feed consumption and feed efficacy between salinomycin-treated groups and control group.
In summary of toxicity and efficacy trails, salinomycin should not be recommended as an anticoccidial drug in turkeys.
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