Four experiments were run to test the anticoccidial activity of dried Artemisia annua leaves and several of their chemical constituents for possible use as prophylactic feed additives. When fed over a period of 3 wk at a level of 5%, a dried leaf supplement of A. annua provided significant protection against lesions due to Eimeria tenella but not Eimeria acervulina or Eimeria maxima. When fed over a period of 5 wk at a level of 1% to chicks undergoing immunization with a live
vaccine, it provided significant protection in partially immunized chicks against E. acervulina and E. tenella lesions from a dual species challenge
infection. It also afforded lower mean lesion scores in challenged chicks immunized over a period of 5 wk.
Artemisinin, an
antimalarial component of A. annua, was present at a level of 0.034% in the dried leaf preparation. A 5% supplement thus afforded about 17 ppm
artemisin. When the pure compound was fed at that level for a period of 3 wk, it protected
weight gains and significantly reduced lesion scores attributable to E. tenella but not E. acervulina. Other components of A. annua,
camphor and
1,8-cineole, at 119 ppm also protected
weight gains, and reduced E. tenella lesion scores.
Camphor reduced E. acervulina lesions.
Artemisinin fed for 4 wk at levels of 2, 8.5, and 17 ppm significantly reduced oocyst output from separate E. acervulina and E. tenella
infections and a dual species
infection. Pure
artemisinin thus appears to be effective against at least two coccidia species when used as a feed additive, and its activity may depend, in part, on the length of time it is administered before a challenge
infection.