It is not just humans that are vulnerable to food poisoning, farm animals too can suffer from the ill effects of contaminated food, and the consequences for them may be long-term and severe.
Protecting UAE camels from food poisoning
It is not difficult to fall ill from eating the wrong thing, as anyone who has taken an unhappy day or two off work with food poisoning knows.
Meat and eggs may be contaminated with salmonella, while smoked salmon and soft cheeses such as Camembert can be breeding grounds for listeria. Undercooked beef and unpasteurised milk sometimes spread harmful strains of E.coli.
It is not just humans who are vulnerable. Farm animals, too, can suffer, and the consequences for them may be long-term and severe.
Forage grass sometimes contains hidden contaminants that can cause serious illness in ruminants and similar animals.
For example, perennial ryegrass (PRG) can play host to a fungus called Neotyphodium lolii that produces a neurotoxin, lolitrem B, which causes a condition called the ryegrass staggers.
The condition can affect cattle, sheep, horses, deer and – most crucially for the UAE – camels. The lolitrem B damages the chemical channels in the animals’ cell membranes that control muscle action, causing affected animals to suffer a loss of coordination that causes them to stagger about and even fall over. It can, in some cases, cause abortions, poor weight gain, tremors and muscle weakness.
As the UAE’s commercial camel herd has grown, so too has the amount of ryegrass that has to be imported from Italy, Spain and the northwest US to feed them – and with it, the danger from the lurking fungus.
Simply switching out the ryegrass is not really an option, as camels’s digestive physiology makes them somewhat – and somewhat surprisingly – picky eaters.
The problem, says Dr Jennifer Duringer, of the College of Veterinary Medicine at Oregon State University in the US, is that they are so well adapted to the harsh desert environment that they cannot cope with “better”, more nutritionally rich foods given to other grazers, such as alfalfa hay or grain. The key, then, is to make the ryegrass safe.
But “safe” is a slippery concept. There’s “safe”, meaning 100per cent guaranteed safe – ryegrass that is known to be entirely free of the dangerous fungus. But that is hardly easy. It would require the crop to be grown in almost clinical conditions, treated with fungicide, and then transported in such a way that the spores cannot enter the shipment en route. It would be technically challenging, expensive, and may even – thanks to the law of unforeseen consequences – lead to a less satisfactory crop in other respects.
And then there’s “safe” meaning what most of us mean, most of the time – safe enough. For ryegrass, that means a crop that can be fed to camels with an assurance that it is free from high levels of fungal contamination.
The question, then, is how much fungus is too much? Or more precisely, how much lolitrem B can camels tolerate before they exhibit serious symptoms of ryegrass staggers.
That is the question Dr Duringer and a team of researchers in the UAE and the US set themselves – and to which they now have an answer.
The group, which included scientists from Abu Dhabi Food Control Authority (ADFCA) and UAE University in Al Ain, bought 24 non-pregnant female camels aged from five to seven years old at Al Ain livestock market, and randomly assigned them to four groups.
For the first fortnight, all groups were given the same non-contaminated food.
Then, for the next eight weeks, camels in each group were fed ryegrass contaminated with a different amounts of lolitrem B, or none.
Sure enough, the animals that ate feed containing lolitrem B began to show symptoms, and the more lolitrem B they ate, the worse their symptoms were.
Animals fed more heavily contaminated ryegrass typically lost weight and displayed varying degrees of staggering, with this tending to become more severe as time went on. Their kidneys malfunctioned and, in some cases, their livers and brains showed abnormalities too.
Unsurprisingly, the symptoms were more severe in animals fed more heavily contaminated ryegrass, although even these creatures tended to return to normal once they were taken off their poisonous regimen.
Based on the results, published in the Emirates Journal of Food and Agriculture, the researchers believe camels can cope with feed that contains 500 parts per billion of lolitrem B. Feed that is more heavily contaminated, they say, should be diluted with clean feed until this level is reached.
“It is feasible to dilute the ryegrass to a safe level, but care must be taken to thoroughly chop and mix the feed material with a straw mixture to achieve a homogenous distribution of ‘high lolitrem B’ ryegrass with ‘low’ or ‘zero’ [feed],” said Dr Duringer. “It would be worth retesting the mixed material to make sure the lolitrem B level was below the threshold of toxicity.”
The work, she said, provides “an established threshold of toxicity” for lolitrem B in camels – meaning perennial ryegrass can be imported into the UAE as a safe feed.
Previously, a 200ppb threshold had often been used – far stricter, and therefore making the ryegrass more expensive and harder to find.
“This is a win-win for both forage exporters and camel farmers. It creates a defined standard for safe feeding, instead of relying on anecdotal or other evidence.
“That is often where many of these types of experiments start, where farmers are seeing disease occur in their animals and begin demanding investigation as to its cause.”
However, all is not yet solved. Ryegrass cannot easily be tested for lolitrem B in the UAE, as the testing is a complex, specialist process. Instead farmers currently have to ask suppliers for certification of the level of lolitrem B in their ryegrass.
This should soon change, with ADFCA planning to start offering tests that would make it much easier for farmers here to secure safe ryegrass supplies.
And that, thanks to this research, should mean happier, healthier camels.