Abstract:
This study is the first report of in vivo antimicrobial efficacy for treatment and control of L. intracellularis infection in Thailand. The aim of this study is to quantify bacterial shedding in feces, growth performance and economic outcome after selected antimicrobial intervention in growing pigs of farm in which had prevalence 30%. Four hundred and forty-eight pigs with eleven weeks of age were used and identified individually using ear-tag. The animals were divided into 5 groups of 89-90 pigs. Five groups were comprised of T1: non-medicated feed group, T2: fed with tiamulin (Triamulox®) 110 ppm, T3: fed with tiamulin 110 ppm, T4: fed with lincomycin and spectinomycin (LincoSpectin880®) 88 ppm and T5: fed with tylosin 100 ppm. All groups were treated with non-medicated feed in the first week. Then, the T2-T5 groups were treated with medicated feed for 3 weeks. The T1 group was continuously fed with non-medicated feed until the end of study. Each pig was weighed both at the beginning and at the end of study. Fecal samples of 30-33 pigs per group were collected once a week throughout the experiment, totally 5 times, from the same pig. Quantification of bacterial shedding was measured by using a quantitative PCR. The results revealed that, subclinical form of L. intracellularis infection in growing pigs under field conditions, can be benefit from using selected antimicrobials which significantly reduce the amount of bacterial shedding, number of positive pigs and number of high shedding pigs. Moreover, our results showed the economic effectiveness from using antimicrobial to reduce the loss of growth performance and bacterial shedding in subclinical pigs. The results confirmed that the use of selected antimicrobials was efficient to reduce weight loss particularly in slow growth pigs. Therefore, antimicrobial can be confirmed to reduce amount of bacterial shedding and infection of L. intracellularis in swine farm.
