A University of Missouri poultry specialist predicts the withdrawal of the poultry health drug Roxarsone from the market will have little impact on flock health or producer profitability.
Also called 3-Nitro, Roxarsone in 1944 became the first arsenic-containing new animal drug product approved by the U.S. Food and Drug Administration. It has been used by poultry growers to help control the intestinal disease coccidiosis and for weight gain, feed efficiency and improved pigmentation.
However, on June 8, Alpharma, the manufacturer and a subsidiary of Pfizer Inc., announced it will voluntarily suspend Roxarsone sales effective July 8. Alpharma was responding to an FDA study that found higher levels of inorganic arsenic in the livers of treated chickens compared to untreated ones. In a statement, FDA Deputy Commissioner for Foods Michael Taylor said the study raised “concerns of a very low but completely avoidable exposure to a carcinogen,” and added the agency was pleased that the company was cooperating to protect the public health.

Professor of Animal Science at the University of Missouri Dr. Jeff Firman, told Ozarks Farm & Neighbor that while Roxarsone has antimicrobial properties and therefore acts somewhat like an antibiotic, the anticoccidial effect was probably more important. “We’re doing without antibiotics in poultry feed to a large extent now, certainly in the broiler industry,” he said. “The bigger broiler producers like Tyson are pretty much antibiotic free. An anticoccidial is still available in other drug forms, and I assume they’ll continue to use those.”
Growers for Tyson Foods now control cocciodiosis with ionophores, which Firman said have some antimicrobial properties but are not marketed for those characteristics. “They are a product that basically breaks the cycle of the oocyst for cocciodiosis, and so act as a ‘cocciodiostat,’ he said. The organism that causes the intestinal disease is a single-celled parasite that invades and takes over animal cells; the ionophore displaces it.
Firman said he’s unaware of any other arsenic based poultry drugs on the market and, asked whether many producers were still using Roxarsone, “Not to my knowledge.” He said producers can keep disease and coccidiosis suppressed with other products and practices. “They have good husbandry and good biosecurity. The antimicrobial effect is a benefit, but it’s really not something that’s going to hurt the industry dramatically,” he said.
Dr. F. Dustan Clark, University of Arkansas Cooperative Extension poultry health veterinarian, said Roxarson was an effective product. “It is something that was there to help with cocciodiosis, and it did a good job with that,” he told OFN. He added, “There are numerous products out there that have been used as anticoccidials, or coccidiostats.”
Clark said the effectiveness of products is something that undergoes constant scrutiny.
“You have to remember in using anything as a medication or for control, there are certain methods that have to be done to ensure that the product is efficacious, and it’s a matter of following the label instructions,” he said.


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