Mouldy feed: A possible explanation for the excretion of anabolic-androgenic steroids in horses.

This study is about determining if the consumption of mouldy feed could be responsible for horses excreting steroids. It concludes that most feeds, even when mouldy, do not lead to excretion of steroids, but mouldy corn was found to contain a testosterone precursor, which could potentially lead to unintended positive doping results.

Research Background

• The regulations around competitive horse racing require that horses should compete on their own merits, without any unfair influence from drugs.
• In line with this rule, most anabolic-androgenic steroids, which could give unjust advantages, are forbidden.
• This study aimed to investigate a question relevant to this rule: whether or not the consumption of mouldy feed could result in the excretion of anabolic steroids, due to the transformation of plant phytosterols into steroids.

Methodology

• An already validated method involving rapid ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used as a means of quantitatively measuring steroids in various sample types.
• Multiple mouldy feed samples were tested for the presence of anabolic steroids.
• The researchers simulated the horse’s digestive process in a controlled lab environment, in order to see the effects of digestion on the steroid content of the mouldy feed samples.

Results

• The study found that most feed samples, even mouldy ones, contained no traceable steroids.
• However, mouldy corn samples contained up to 3.0 ± 0.4 µg/kg of 4-androstenedione (AED), a precursor to the hormone testosterone.
• This concentration of AED increased when the mouldy corn was simulated through the digestion process in vitro.
• An herbal phytosupplement was also found to contain α-testosterone.

Study Conclusion

• The researchers concluded that it is vital to caution against the consumption of any type of feed or supplement whose ingredients and their quantities are not clearly stated.
• They stressed the need to avoid feeding horses mouldy corn particularly, not just for horses’ best health and welfare, but also to prevent unintentional positive test results for doping.