Tuesday, January 04, 2011
I have always been curious about animals and drugs - particular farm animals.
I recently happened upon an article that included this handy chart above. In 2009 80% of all antibiotics when into animals - that's about 28 million pounds of chemicals.
In that same year humans only consumed 7 million pounds of the same drugs.
While perusing this list I cam upon ionophores. Next to tetracycline ionophores are the second most common compound used in animal feed. Now I've been around a while and most of the rest of the things on the list I have at least heard of before - but not ionophores.
Every hear of them?
No, I thought not.
So just what are these compounds?
Ionophores are compounds that affect how substances pass through the celluar membranes of microbes. So, for example, some might block the passage of sodium ions through a cell membrane. If the microbe requires sodium to live then the ionophore will cause it to die because it is unable to process sodium ions.
So specific ionophores are specific to kinds of ions. And specific ions are used by particular bacteria, for example, in the gut of cattle.
Use of ionophores in animal feed can also cause cattle to produce less methane by changing how they digest their food and how that food is absorbed into their bodies. And, more importantly, according to this "feeding of ionophores to cattle decreases the feed needed for growth and increases feed efficiency." (These sorts of statements always bring to mind the old adag "you can't get something for nothing.")
The actual effect is that these compounds delay the processing of the food consumed until after the stomach leaving the work to be done by the intestines instead. These compounds are also apparently only safe for a small number of mammals, e.g., cattle and chickens. Their use is detrimental to horses, dogs, and other common farm animals.
Ionophores are not antibiotics per se hence the FDA does require meat sold from animals feed with ionophores to be labeled as containing antibiotics.
Ionophores are not used for humans do to their potent cardiovascular effects (see this). I cannot find a lot of detail on exactly why but it seems that these compounds can damage cardiac and skeletal muscles.
Unfortunately ionophores are now found in our water and soil (see this article) - most likely through run-off and waste from large big-agra farming operations. Again, this does not seem to get much study, though with that much of this being used you would like to think it was completely harmless to humans.
Of course, big agra doesn't want you to have to worry about ionophores and are working hard to remove use of these compounds from meat product labeling.
Ionophores do also create resistant bacteria - though not in the same way as with penicillin and other traditional antibiotics - but it takes much longer.
In any case - more food (no pun intended) for thought...
Posted by John Gault at 5:27 PM