Friday, 27 January 2012

Three views of ractopamine in pigs

Helena Bottemiller this week writes a thorough summary of the international trade controversies over U.S. exports of pork from pigs that have been treated with the growth promoter ractopamine hydrochloride.  This animal drug is allowed under U.S. rules, but banned in many other countries, so U.S. trade negotiators have been pressing hard to get other countries to relent and allow small residues of the drug in imported pork.

Bottemiller describes the history of testing by the drug's manufacturer, Elanco, in terms that could leave a reader quite concerned:
The FDA ruled that ractopamine was safe and approved it for pigs in 1999, for cattle in 2003 and turkeys in 2008. As with many drugs, the approval process relied on safety studies conducted by the drug-maker — studies that lie at the heart of the current trade dispute.

Elanco mainly tested animals — mice, rats, monkeys and dogs — to judge how much ractopamine could be safely consumed. Only one human study was used in the safety assessment by Elanco, and among the six healthy young men who participated, one was removed because his heart began racing and pounding abnormally, according to a detailed evaluation of the study by European food safety officials.

When Elanco studied the drug in pigs for its effectiveness, it reported that “no adverse effects were observed for any treatments.” But within a few years of Paylean’s approval, the company received hundreds of reports of sickened pigs from farmers and veterinarians, according to records from the FDA’s Center for Veterinary Medicine.

USDA meat inspectors also reported an increase in the number of “downer pigs” — lame animals unable to walk — in slaughter plants. As a result of the high number of adverse reactions, the FDA requested Elanco add a warning label to the drug, and it did so in 2002.

The company also received a warning letter from the FDA that year for failing to disclose all data about the safety and effectiveness of the drug.
Some of the research literature is available on the USDA website, including this 2003 article by Marchant and colleagues, which indicates why there might be concern.
We found that there were differences in 24h behavioral time budgets, with the ractopamine-fed pigs being more active and alert and taking longer to lie down after being disturbed. However, these differences were only apparent during the first 2 weeks. In contrast, ractopamine pigs remained more difficult to handle over the entire 4-week period. At the end of the 4-week period, they also had higher heart rates than control-fed pigs and higher levels of circulating stress hormones.

We conclude therefore, that feeding ractopamine to pigs does affect behavior and physiology. Pigs that are more difficult to move are more likely to be subjected to rough handling and increased stress during transportation, implying reduced welfare, increased workload for the handlers and, potentially, poorer meat quality. However, for this conclusion to be applicable to the finishing pig population in general, other genetic lines should be tested.
I have been spending some time recently thinking about what makes many Wikipedia articles excellent, and also about the limitations of the free encyclopedia approach. Interestingly, the Wikipedia article on ractopamine is highly technical, as if written by an animal science expert, and generally downplays the safety concern. Although the Wikipedia article includes the Bottemiller article as one recent reference, its summary of the animal safety issue seems to contrast both with her article and with the Marchant article cited above. Here is the section in full:
Target animal safety

Ractopamine is safe for finishing pigs heavier than 240 pounds when administered in the diet at concentrations up to 10 ppm and fed for up to 35 days. However, there was an increase in the number of ractopamine hydrochloride-treated animals exhibiting signs of injury during the final drive to slaughter. (FDA)
I suppose the second sentence captures the animal health issues sufficiently? Of course, the great thing about Wikipedia is that articles are constantly changing and commonly improving.

No comments:

Post a Comment