Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/1998
Publication Date: N/A
Interpretive Summary: Avian coccidiosis, an intestinal disease produced by infection with protozoan parasites from the genus Eimeria, is estimated to cost the U. S. poultry producer 350 million dollars annually. Control of this parasite is accomplished mainly by feeding anticoccidial compounds to bird flocks during their grow-out period. Enhanced bird performance can be accomplished dby the addition of growth promotant materials to the anticoccidials that are mixed in the feed. Recent studies done in our laboratory has shown that certain coccidia from different geographic locations will not respond to combinations of growth promotants and anticoccidial drugs. One species of coccidia obtained from a poultry facility in Louisiana actually causes a decrease in bird performance when the growth promotant roxarsone is mixed with the anticoccidial lasalocid. The same species collected from other geographic areas did not produce this effect. The results from this study show that it is necessary to carefully screen the effect of a combination of growth promotant and anticoccidial with the coccidia present in a chicken grow-out facility before initiating such a medication program.
Technical Abstract: Broiler bird performance was evaluated for the addition of 50 ppm roxarsone to 100 or 125 ppm lasalocid against different geographical field strains of Eimeria acervulina in a series of battery trials. A significant reduction in average and percent weight gain was seen with birds medicated with both levels of lasalocid + roxarsone, compared to birds medicated with only lasalocid, challenged with single or mixed species inocula from Louisiana poultry complex that contained exclusively (100%) or predominately (92%) E. acervulina. No such reduction in bird performance was seen between 125 ppm lasalocid + 50 ppm roxarsone medicated and 125 ppm lasalocid medicated birds challenged with a mixed species inocula containing predominately E. acervulina from Alabama or Georgia poultry complexes (92% and 88% respectively). No significant difference was seen between lasalocid + roxarsone and only lasalocid medicated birds for upper intestinal lesion scores or feed conversions for any of the strains of E. acervulina tested. The results of this study show that certain geographical strains of E. acervulina may cause a decrease in bird performance when 50 ppm roxarsone is used in combination with 100 or 125 ppm lasalocid.