Traditional livestock feeds such as wheat and corn – and other feedstuffs of vegetable origin, such as nuts, legumes and fruits – are also used as ingredients in commercial pet food. As a result, cats, dogs, birds, rabbits and guinea pigs can also be exposed to these potentially toxic fungal metabolites.
In addition, rising feed prices mean a greater variety of carbohydrates such as tapioca, sweet potato and pea flour have become popular as pet food ingredients. Extreme weather, a variety of harvest and storage conditions – as well as long distance transport time – all impact adversely on these feed material. Consequently the risk of mould growth and associated mycotoxin contamination has become very high.
The range of mycotoxins affecting pets
The mycotoxins commonly found in pet food include aflatoxins, ochratoxins and the Fusarium mycotoxins.
Key mycotoxins produced by Aspergillus moulds
Aspergillus flavus produces a variety of aflatoxins, which are common fungal contaminants of nuts, cottonseed, wheat and rice. They are more prevalent in tropical regions, including North and South America where they often flourish on dry corn during drought conditions.
Aflatoxins are particularly toxic to dogs if present at high enough levels, with anorexia and depression being the two most visible signs of potential food-poisoning.
Ochratoxins are found mainly in cereal grains and are more prevalent in temperate regions. They are quite widely found in pet food although the significance of their effect on companion animals is unclear. Ochratoxins accumulate in the kidneys and high exposure can cause damage to these organs.
Key mycotoxins produced by Fusarium moulds
The Fusarium mycotoxins are a chemically diverse group of compounds and many cereal ingredients contain them. Corn, for example, is commonly contaminated with fumoninsins and corn, wheat and barley produced in North America are often contaminated with deoxynivalenol, the most common tricothecene.
The effect of the Fusarium mycotoxins on pets is not as well researched as the impact of aflatoxins and ochratoxins. But they are certainly present in commercial pet foods and can cause toxic effects such as vomiting and feed refusal if present in dangerous quantities.
DID YOU KNOW?
There are several stages at which mycotoxin contamination of pet foods can occur, including pre-harvest, storage and processing. Unfortunately, high temperature processing and extrusion of pet foods cannot inactivate all toxins.
Mitigating the potential threat of mycotoxin contamination is certainly a challenge for the pet food industry. Compared with the agricultural sector there has certainly been less attention paid to the threat to companion animals. But the threat is very real and the potential feed raw material contamination risks are the same for both industries.