Animal Science Review

An article recently published in Environmental Science and Technology details a study conducted at Johns Hopkins where when examining samples of commercially available feather meal (used as a protein supplement feed or fertilizer) they found trace amounts of fluoroquinolones, a class of antibiotics that have been banned for use in animal feed for 6 years. This is an interesting find, and definitely warrants further research before any broad sweeping conclusions can be made. You know…unless you publish a press release condemning the entire industry for breaking the law and trying to kill us all (question, if all the chicken consumers are dead, how does that lead to higher profits?).

The article itself is very well done. The authors collected samples of feather meal from several states and Canada and tested them for various pharmaceuticals. They also autoclaved the samples to see how the heating processes involved in creation of the product affected degradation/digestion of any of the compounds, and exposed E. Coli cultures to the meal to see if the presence of one or more of the compounds was enough to select for antibiotic resistant populations (they were).

The researchers examined each of the compounds of interest and proposed mechanisms for their presence. Some of them are used at various levels legally within the industry, and the presence of many others (such as caffeine) can be explained by their introduction through various feedstuffs (such as coffee pulp and green tea powder) (Love et al., 2012).

Obviously of most interest to the researchers were the levels of fluoroquinolones, and they hesitantly proposed possible mechanisms for their introduction into feather meal.

“Fluoroquinolones (enrofloxacin, norofloxacin, or ofloxacin) were detected in 6 of 10 U.S. samples, which was not expected because fluoroquinolone use in U.S. poultry production has been banned since 2005. These findings may suggest that the ban is not being adequately enforced or that other pathways, for example, through use of commodity feed products from livestock industries not covered by the ban, may inadvertently contaminate poultry feed with fluoroquinolones…To better interpret our findings, corroborating evidence in the form of antimicrobial usage practices and dosing amounts would be needed.” (Love et al., 2012)

Clearly we’re not ruling out the possibility of these antibiotics being fed, but there is no cause and effect relationship here. They also make note that feather’s contain antibiotics in higher concentrations than meat or other tissues, even after legally defined withdrawal times to remove them from edible tissue. The conclusions here are justly cautious, and place no blame or accusations upon the industry.

The other interesting find was that the feather meal tested would select for antibiotic resistant strains of E. Coli when exposed to cultures. However, this was only testable with autoclaved samples of the meal. And did we mention that the only samples tested here were sourced from China (who according to the article use many more antibiotics than we do in poultry production)?

“These initial results suggest, but cannot prove, that the inhibiting substance may be an antibiotic/bacteriostatic. Autoclaving may have attenuated the quantity and bioavailability of antimicrobial drugs originally present.” (Love et al., 2012)

Again, a cautious observation and hardly conclusive. Comparisons were made from standard cultures exposed to low levels of relevant antibiotics to see if the same strains were removed, but this data cannot be correctly compared as the feather meal was not controlled enough to isolate those compounds. The authors finish their discussion with an appreciation for the novel information they found and an invitation for others to verify, replicate, and build upon their results.

“We have previously described risks related to administration of medicated feed to food animals, which may promote selection for antimicrobial resistance. The presence of antimicrobials in feather meal, as determined in this study, is a previously unrecognized source of these drugs in animal feed. Because this is the first study of PPCPs in feather meal, we invite independent verification of our results by others. More work is needed to determine whether the detected levels of PPCPs in feather meal have an impact on the quality of food animal products and the safety of consumers.” (Love et al., 2012)

And there we have it, an exciting new study that presents a lot of questions to be used for follow-up research. So we’ll publish it and make sure to put out a press release so that not only those keeping up with the journals can read and understand what we’re currently researching.

Well…it seems like the authors like to be scientific when submitting journal articles, but prefer big headlines and sensationalizing when trying to popularize their research. In their official press release, these researchers quickly turn from cautious scientists to industry whistleblowers.

“The discovery of certain antibiotics in feather meal strongly suggests the continued use of these drugs, despite the ban put in place in 2005 by the FDA…The public health community has long been frustrated with the unwillingness of FDA to effectively address what antibiotics are fed to food animals.” – David Love, PhD

Comments from Keeve Nachman, PhD, show a level of conviction that I had no idea he possessed in the original article.

“In recent years, we’ve seen the rate of fluoroquinolone resistance slow, but not drop…With such a ban, you would expect a decline in resistance to these drugs. The continued use of fluoroquinolones and unintended antibiotic contamination of poultry feed may help explain why high rates of fluoroquinolone-resistant Campylobacter continue to be found on commercial poultry meat products over half a decade after the ban.” (I guess we know for sure they’re still being used in the US, I must have missed that citation in your introduction)

“A high enough concentration was found in one of the samples to select for bacteria that are resistant to drugs important to treat infections in humans” (Note: the concentration comment is true, however, your study stated that there was not controlled enough testing to prove that any specific compound present caused the bacterial selection)

“We strongly believe that the FDA should monitor what drugs are going into animal feed…Based on what we’ve learned, I’m concerned that the new FDA guidance documents, which call for voluntary action from industry, will be ineffectual. By looking into feather meal, and uncovering a drug banned nearly 6 years ago, we have very little confidence that the food animal production industry can be left to regulate itself.”

Wow, this press release from the actual authors of the article must be legit, after all, they wrote it, and they wouldn’t write/act completely differently so as to both dangle a carrot to the media and still get their research published in a peer-reviewed journal right?

I knew the Colonel was lying to me. Source: kfc.com

Well, the press release did its job, and Nachman can be found interviewing left and right about how he was “floored” by the result, and how that the more he learns, “the more [he is] drawn to Organic”. There’s a severe lack of integrity here, and the misrepresentation of your data and analysis to cater to anti-big-Ag sentiments is irresponsible and unethical.

So, future scientific corespondents for the Daily Mail aside, what are some other proposed mechanisms for the presence of these banned antibiotics? After all, I’m suggesting that they aren’t being fed routinely as the authors apparently really believe. Let me rephrase that, I’m not ignoring multiple unproven mechanisms for the purpose of shock science.

I spoke with James Hermes PhD, a professor and Poultry Science Extension Specialist here at Oregon State University, about the article. He had obviously heard of it and shared with me some discussions he had had with his colleagues. Their proposed mechanism for the introduction of the pharmaceuticals was through groundwater.

“Feather meal is boiled at the rendering plant, it’s processed with a lot of water, so anything in the groundwater can end up in the meal…Just recently near [Corvallis] they did some testing and found nearly everything we use at home. For years they told us to flush our excess medications…It’s always been there, we’ve just only recently been able to look at such small concentrations 1 parts per billion, trillion, or even possibly quadrillion.” – James Hermes, PhD

So in addition to whatever chickens could be exposed to via drinking the water and concentrating pollutants in their feathers, additional water and pollutants are introduced during the rendering of the product. He encouraged me to find some research showing that ground water contains any and all of the things discovered in the feather meal, and I found it.

So is this a possible mechanism for the introduction of these contaminants? I suggest the authors of the study follow their own advice in the article and explore this mechanism. Perhaps see if the levels of the pharmaceuticals change in the feathers both prior to and after rendering/boiling, explore if they are present in organically produced feather meal, and find out if there are still large concentrations of fluoroquinolones in the groundwater of the areas processing feather meal. And hey, if they want to keep on trucking with scare tactics, I think finding this stuff in the water supply will be much more frightening to the public given that we can’t buy organic water (don’t start).

Finally, in evaluating consumer exposure to the present antibiotics in feather meal, we should keep in mind the steps necessary in the shortest route to the consumer. First, there have to be high concentrations of antibiotics in feather meal; second, that feather meal must be fed to an animal used for food, third; those antibiotics must be retained and remain active until slaughter of that animal at a high enough concentration; fourth, they have to survive gastric juices and be absorbed into the small intestine of the person eating the meat/milk. Nevermind that along the way, the authors of the relevant study note that at any point the vector for the antibiotics is heated most of them will degrade.

Obviously, if the feather meal is used as fertilizer instead of a by product feed, then there are a few more steps that need to take place to get those pollutants onto the plate.

Now if you’ll excuse me, I need to finish this compelling article on how those fat cats selling nautral almond extract are trying to murder me .

D.C. Love, R.U. Halden, M.F. Davis, & K.E. Nachman (2012). Feather Meal: A Previously Unrecognized Route for Reentry into the Food Supply of Multiple Pharmaceuticals and Personal Care Products (PPCPs) Environmental Science and Technology, 46, 3795-3802

Kolpin, D., Furlong, E., Meyer, M., Thurman, E., Zaugg, S., Barber, L., & Buxton, H. (2002). Pharmaceuticals, Hormones, and Other Organic Wastewater Contaminants in U.S. Streams, 1999−2000: A National Reconnaissance Environmental Science & Technology, 36 (6), 1202-1211 DOI: 10.1021/es011055j

Update: following this post I had a chance to talk with one of the Authors of the article, read about our discussion here.

Tags: antibiotics, Biochemistry, Chickens, Public Health