Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 1, 2002
Publication Date: January 1, 2002
Citation: Shappell, N.W., Billey, L.O., Feil, V.J. 2002. Effect of clenbuterol on body stores of polychlorinated dibenzofurans (PCDFs) and dibenzo-p-dioxins (PCDDs) in rats. Journal of Animal Science. 80:2461-2475. Interpretive Summary: Dioxins and furans (polychlorinated dibenzo-p-dioxins/furans, PCDD/Fs) are persistent pollutants that result from incineration of chlorinated products. These pollutants accumulate in the food chain, posing a risk to humans through the consumption of tainted livestock. To date, no method of decontamination exists, and contaminated carcasses must be burned in special incinerators fitted to prevent further pollutant production (at great expense). In order to mimic the situation of contaminated animals, rats were given feed with or without dioxins and furans for 10 days, followed by a 16 day treatment of feed with or without clenbuterol. Animals were killed at the end of this period, and weights of various organs and tissues were measured. We found use of a leanness enhancing agent, clenbuterol, reduced PCDD/F body stores in the fat by reducing body fat(the predominant site of dioxin accumulation). Clenbuterol treatment tended to increase the concentration of PCDD/Fs in livers whether animals had received PCCD/Fs or not. In animals fed PCDD/Fs, clenbuterol decreased only TCDF in the liver, a furan that is rapidly metabolized and excreted (decreased 40% in liver and ~60% in fat and muscle). Muscle PCDD/Fs concentration and total burden were also decreased by clenbuterol. By examining the ratio of PCDD/Fs in liver and fat we found that clenbuterol increased liver's share of the body burden of contaminants from 38 to 75%. In a remediation /disposal context, these findings would be beneficial if clenbuterol lowered the meat /carcass burdens of PCDD/Fs to safe levels, requiring only livers to be disposed of as hazardous waste.
Technical Abstract: Dioxins and furans, persistent pollutants that accumulate in the food chain, pose a risk to humans through consumption of tainted livestock. Clenbuterol, a leanness enhancing agent, was tested for usefulness in reducing PCDD/F body stores by reducing body fat (the predominant site of accumulation). To mimic the situation of contaminated animals, rats were given feed with or without a mixture of PCDD/Fs (0.6 -2.7 ng / congener / d) for 10 days, followed by 16 days of feed with or without clenbuterol (2mg / kg feed). Clenbuterol reduced body fat by 28%, increased muscle mass by 25%, and decreased liver mass by 7%. While the concentration of most PCDD/Fs per gram of fat were slightly increased after clenbuterol treatment, the total amount of PCDD/Fs remaining in the fat was reduced approximately 30%. Muscle PCDD/Fs concentration and total burden were decreased by clenbuterol. In contrast, clenbuterol tended to increase concentration, but not total burden of PCDD/Fs in livers. One congener known to be rapidly metabolized and excreted, 2,3,7,8 TCDF, was the exception to this increase, decreasing 40% with clenbuterol treatment. This was also the congener that showed the greatest reduction in both fat and muscle. Examination of the ratio of PCDD/Fs in liver and fat revealed that clenbuterol resulted in an increase in the liver's share of the body burden of PCDD/Fs, from 38 to 75%. In a remediation / disposal context, these findings would be beneficial if clenbuterol lowered the meat and carcass burdens of PCDD/Fs to safe levels, requiring only livers to be disposed of as hazardous waste.