Central Roller Club
Understanding and Preventing Aflatoxin Poisoning
Posted Nov. 1, 1998
Heat and lack of rainfall this summer have caused several problems for farmers and ranchers in Southern Oklahoma and Texas. Among these is the presence of aflatoxincontaminated grain being produced in the region. Aflatoxins are poisonous by-products produced from the fungi Aspergillus flavus and A. parasiticus. These fungi are found in the soil and are responsible for decomposition of plant materials.
Aspergillus is a mold that infects corn when stressed, but can infect other crops in the region such as grain sorghum, peanuts and cotton. Aflatoxins are odorless, tasteless and have no color: thus, they are difficult to detect. These toxins are extremely poisonous to humans, livestock and poultry. Four major types of aflatoxins are B1, B2, G1 and G2. Though all of these toxins are usually found in grain at a minute level, B1 is typically more abundant and causes an increased protein requirement in livestock and poultry that consume it.
Accumulation of aflatoxins is dependent on weather conditions. A dry growing environment or drought stress tends to favor the development of aflatoxins in corn. When soil moisture is below normal and temperatures are high, the number of Aspergillus spores in the air increases. During pollination, these spores infect corn kernels either through silks (pollination tubes) or through areas of damage caused by insects, birds and weather events. Once infected, plant stress such as nutrient deficiency, continued dry weather or kernel damage during harvest may increase aflatoxin levels.
There is not a procedure for eliminating aflatoxin after it is produced. However, limiting or maintaining concentrations may allow the contaminated grain to be fed under proper management. Irrigation, if possible, has been shown to reduce the level of Aspergillus infection when applied during pollination. Harvesting corn early when moisture is above 20% and then quickly drying it to a moisture level of at least 15% will keep the Aspergillus fungus from completing its life cycle, resulting in lower aflatoxin concentrations. Ammoniating aflatoxin-contaminated grain stabilizes the level of concentration, but this does not eliminate the problem.
Aflatoxin consumption by livestock and poultry results in a disease called aflatoxicosis. Aflatoxins are metabolized in the liver of all living organisms. High concentrations can lead to acute liver disease or death within 72 hours. Lower concentrations have produced various symptoms, such as feed refusal, decreased feed efficiency, impaired reproduction, hemorrhaging in muscles and suppression of the immune system.
Feeding grain contaminated with any level of aflatoxin carries a considerable amount of risk. Testing for aflatoxin concentrations should be the first step in proper feeding management. Sampling technique is the most important factor in determining aflatoxin levels. Sampling grain as it is moving or being blended, such as harvesting and loading, will yield a representative sample. Obtaining a quality sample from stored grain is difficult since pockets of highly contaminated grain can exist within that environment. Ten to 15 probes yielding 1 pound of grain each should be obtained from different sites in the bin or truck and placed in a bucket. Mix the sample thoroughly and place a 10 pound sample in a paper bag or sack that can breathe. Then send the sample to a laboratory that conducts aflatoxin assays. Each truckload and bin should be sampled separately to achieve reliable results.
The use of a black light to detect the presence of aflatoxins at the elevator is common. However, this procedure is not reliable since it detects an acid and not the aflatoxin. It is recommended that a lab analysis be performed to accurately determine aflatoxin concentrations.
The amount of aflatoxin an animal can tolerate varies with age, sex and health of the animal. Younger animals are most susceptible to aflatoxin poisoning. Pregnant and growing animals have slightly more resistance than young animals, but less resistance than mature animals.
Recommended aflatoxin levels in feed is 0 parts per billion (ppb), but this is not always possible. If feeding contaminated grain to lactating dairy cattle, immature poultry or immature livestock, do not exceed 20 ppb aflatoxin in the total diet. Calves should not receive milk from cows fed more than 20 ppb aflatoxin. Breeding cattle, swine and mature poultry should not exceed 100 ppb in their total ration. Finishing beef cattle and swine can tolerate grain up to 300 ppb aflatoxin. Animals should not consume any level of aflatoxin in their diet for at least three weeks prior to slaughter. Any grain with levels exceeding 1000 ppb should be destroyed and not be salvaged by blending with grain of lower concentrations.
Grain in the region has become extremely affordable as a result of the drought and fear of aflatoxin contamination. Economics appear to favor feeding grain through winter as an alternative to hay as a primary energy source. Although grain containing low levels of aflatoxin can be fed to livestock and poultry, risk is increased anytime aflatoxin is present at any concentration. If symptoms occur, discontinue feeding contaminated grain and return to an aflatoxin free diet immediately.
For more information about aflatoxins or laboratory locations, contact the Noble Research Institute.
74 Years Old, Retired, and Having Fun With Pigeons
Q: Is there anything you can tell me about birds being poisoned by feed?
Yes, and do I have experience -- like they say, "hot off the press". We all have heard the word "aflatoxin" thrown around in pigeon literature, and we have an idea what causes it. But when I started asking people about the source and how it affects birds short term or long term, I had a difficult time getting an answer from my many contacts. Yet I am sure we have people out there somewhere who have expertise in this field. So let me relate to you what happened to my young bird team this year.
Here in the Midwest we finish our old bird season with a grand finale the last weekend of June. Depending how the dates fall, we usually have 4 weeks before we fly our first young bird race. This year it turned out that we had 5 weeks between seasons. My young bird team seemed to be in very good condition, so my wife and I decided to take 2 weeks off from the birds to see our friends in Florida and experience Florida in July. We have a house in pigeon mecca Spring Hill and always enjoy our stay there.
So I left my young bird team in the hands of a non-pigeon flyer, a man with a lot of animal sense, with detailed instructions. When I returned from Florida, Pietro had the birds working beautifully. They were exercising 1 1/2 hours in the morning and he had them under excellent gentle control; in fact, probably the best my young bird team has ever been. They were trained almost like circus animals, trapping on command, etc.
Well, I was ready to road train, so into the basket they went, 3 weeks before the first race. The only thing not up to par was that I thought they needed some reserve to get them into racing condition. So being smart and to help the situation along, I decided to give them an extra noon meal of 2 one-pound coffee cans full of ground peanuts. In typical pigeon flyer fashion, I did not want to waste any time. I poured the peanuts to them to get a quick response. Since my birds did not know how to eat peanuts, I ground them in a food processor. The birds ate them immediately and they all got a uniform amount. All went well for 3 days. By the end of the third day, the team was looking good physically . I had accomplished exactly what I had set out to do.
The 4th morning, because of weather conditions, I could not train, and that turned out to be a stroke of luck. The birds flew 5 minutes and then landed, desperately hanging on the traps, mouths wide open, wings hanging. Something was terribly wrong. From that day on, every time I turned them out, they would go sky high, but within 5 to 6 minutes on my stop watch, they would be down and hanging on the traps, totally gasping for air when they landed. Their bodies overheated as if they were unable to dissipate the heat. To call the situation extreme and severe is probably an understatement. I have never in 40 years seen birds with their mouths gaping open as wide as these, with their wings hanging, and with their bodies feeling so hot.
I played "detective". What had I done that was different? A friend had procured an ample supply of peanuts for me. I did not know at the time that these peanuts had been allowed to stay in a warm humid garage before I got them.
What was wrong with the peanuts? It is called aflatoxin, which really means a fungus poisoning. You can get this fungus poisoning (mold) on a number of grains, but probably the most prevalent one would be nuts. This mold growth and aflatoxin production are favored by warm temperatures and high humidity. It also seems to be prevalent during periods of drought. Besides the peanuts, it can be found in other grains such as corn, safflower, and canola. Aflatoxins primarily affect the liver of an animal. However, if high dosages are involved, it will also affect the lungs, heart, and kidney tissue.
The good news is that eventually some of the birds recuperated from the aflatoxin poisoning. I found that after 3 weeks, one bird from our original team of 75 was capable of flying a race. I was able to spot this pigeon since I'm in the process of developing some white grizzles. This had been the only white on the first race team and now was the only bird to take to the air with 12 late hatches I was settling that had not been exposed to the aflatoxin. So the first race of the young bird season I showed up with one lone entry, and a white one at that. I was fortunate enough that the bird flew an acceptable race, clocking in the middle of the race sheet.
The 2nd week of racing (4 weeks after the poisoning), we limped along by shipping 2 birds. Again the white one put us in the middle of the race sheet. The 3rd week of racing I was able to pick 7 birds out of a team of 75 to ship to a race successfully. We won that race.
The 4th week (6th week after poisoning), I was able to ship 12 pigeons. The 5th week of racing we were up to 20 pigeons. Now these pigeons are flying well and winning. I see further improvement of the team daily as the maroon skin coloration is starting to turn back to pink on more and more birds. However, I have also noticed that the birds do not have the same resilience as before. They cannot be repeated back the week after they have flown a race.
As I said, this was an extreme form of aflatoxin poisoning. I am sure there is a good amount of aflatoxin poisoning going on in much smaller doses, resulting in poorly performing teams of birds. We are not aware of it, but it cripples our race results. Peanuts, of course, are a very in-vogue and excellent food supplement used by fanciers. But remember, buy them at a health food store where they are intended for human consumption. And you must keep them refrigerated so you don't get in trouble.
74 Years Old, Retired, and Having Fun With Pigeons
Q: I'm trying to find evidence, other than anecdotal, that aflatoxins do in fact harm birds. Are you aware of any such figures or research?
When you are dealing with the pigeon world, you are dealing in an area of almost no scientific study. In regard to our medications as well as most knowledge, if it has a scientific basis, then it is borrowed and adapted from the poultry or other animal science world.
We are a hobby of such small proportions that medications, for instance, are never approved for pigeons in this country because the market is just not there for the manufacturer to get a return. Observations and hopefully some knowledge that I pass on to others is mostly self-learned.
I do know when affected with aflatoxins, my pigeons will not be able to dissipate their body heat efficiently through their normal respiratory functions. Their skin also turns a tell-tale color and has a leathery feel to it and they will not want to take a bath. These are things I had to learn the hard way. I never read or saw this discussed elsewhere.
When I use a new feed, or I should say "grain," I test the feed by giving it to individual birds to see how they react. I have learned what the color of the breast, for instance, will be if something is not in order. Instead of being pink, it is more a maroon color. Also, the droppings of the birds give me an indication. Now do I know what scientific precise problem I have? Definitely not. But I have learned to correct by changing feed. I am a very competitive loft and perhaps somewhat paranoid with the possibility of my birds being handicapped by being partially poisoned.
I have taken birds to an excellent veterinarian, Dr. Kevin Zollars, who then sends tissue samples, especially of the liver, to a California lab. The results will show that the birds are toxic, but no further specific scientific analysis. In trying to research aflatoxins, the only solid material that I found was that the US government specifies how much tainted corn a cow that gives milk for human use can consume . Again, not much help scientifically for a pigeon fancier.
So although I do not have any research available to me, I react to the condition of my birds in order to fly competitively to the best of my ability. Should you find specific scientific knowledge that addresses the harm aflatoxins do to our birds or to their performance, I would be very interested in hearing from you. Or perhaps someone more knowledgeable can pick up this topic and enlighten us with some concrete facts. Good luck in your endeavor --