Evaluation of an Echinacea-based anti-coccidial preparation against different Eimeria spp. in broilers -

Abstract

The aim of this thesis is to evaluate an Echinacea-based anti-coccidial preparation against different Eimeria spp. in broilers.The thesis is divided into three parts namely, Study A, B and C. Study A aimed at establishing a base-line data on intestinal pathogenesis in broilers with a controlled challenge by eight Eimeria spp., administered at different ages of 14, 21, 28, and 35 days old. A possible success in reproducing pathogenesis of Eimeria spp. infection in broilers by the implemented experimental design could help in evaluating the Echinacea-based preparation (EBP) in Studies B and C aiming at reducing mortality, feed conversion, lesion score, oocyst counts and improving the percent weight gain. Study A proved that birds challenged with the eight non-attenuated Eimeria spp., had a reduction of around 10 percent in the mean weight gain compared to birds in the control groups. The mean feed conversion ratio increased significantly from 1.5 in unchallenged-controls to 3.1 in challenged groups. The mean frequency of mortality increased in the challenged groups when compared to controls, associated with a significant increase in most lesion scores of the four intestinal organs, and significant presence of intestinal oocyst counts. A trend of decreased mortality was shown when broilers were challenged at older ages; this trend was associated with significant decline in lesion scores in the intestine, along with decreased oocyst counts. Study B aimed at evaluating a long term administration of EBP and its evaluation of performance in birds challenged at 14, 21, 28, and 35 days of age. Performance was evaluated by determining the percent mortality, percent weight increase, feed conversion ratio, intestinal lesion scores and oocyst counts. A clear improvement in percent weight increase was observed in birds challenged at 14 d. of age and EBP-treated for a period of 14 d.and 21 d. in comparison to positive control birds that were Eimeria-challenged but EBP-deprived, with a difference of around 65 percent. At this challenge time of 14 days of