Pyrrolizidine alkaloids in commercial feedstuffs for horses.

The research aims at identifying and assessing pyrrolizidine alkaloids in horse feeds either containing alfalfa or a blend of herbs, given the recent findings that these ingredients have been found to be contaminated with these hepatotoxic plant compounds. A high rate of contamination was indeed discovered in the samples, showing the need to regulate and reduce the amounts of these alkaloids in equine feeds.

Objective and Methodology

• The goal was to find and gauge pyrrolizidine alkaloids in compound feeds (those containing alfalfa or a mix of herbs) produced for horses as these compounds have been identified as toxic to the liver in several animal species and humans.
• A total of 48 horse feed products got included in the study. They analyzed the feeds for 28 selected pyrrolizidine alkaloids using a method known as liquid chromatography-mass spectrometry.
• The individual alkaloid concentrations were added up to ascertain the total pyrrolizidine alkaloid content.

Results

• They found that 7 out of 48 samples showed alakloid concentrations below the quantifiable limit. Median concentration of 41 samples was 58 μg/kg while 25 and 75 percentiles were 8 and 151 μg/kg respectively.
• The utmost pyrrolizidine alkaloid concentrations were found in two alfalfa-based feed products with 1306 and 1222 μg/kg, followed by an 836 μg/kg in a feed product containing herbs.
• Lycopsamine, seneciphylline, seneciphylline-N-oxide, senecionine, and senecionine-N-oxide were the most commonly occurring alkaloids.

Risk Assessment and Conclusions

• The risk assessment was established based on the level of pyrrolizidine alkaloids that exhibited no adverse effects on rats and humans. The specific susceptibility of horses to these alkaloids remains unknown.
• As per the outcome of this risk evaluation, equine compound feeds should limit pyrrolizidine alkaloid contamination to less than 90 μg/kg.
• A high percentage of feeds for horses showed pyrrolizidine alkaloids contamination. In 43% of the total samples analyzed, the alkaloid levels exceeded the maximum tolerable levels.
• From the results, there is a clear call to bring about measures that would reduce pyrrolizidine contamination in horse feeds.