Experimental reproduction of ELEM. A study to determine the minimum toxic dose in ponies.

This study explores the minimum toxic dose of fumonisins in ponies, finding that consistent exposure to the toxin can lead to negative effects, including elevated liver chemistry values, transient clinical signs, and mild brain lesions.

Study Design and Methodology

• The experiment aimed to identify the minimum toxic dose of fumonisin, a common toxin found in corn screenings (CS), that would produce adverse health effects in ponies.
• The researchers prepared rations for the ponies using naturally contaminated corn screenings. These rations were blended with pellets, corn, and molasses to formulate individual daily diets.
• Two groups of ponies were used in this experiment. One group of four ponies was fed a daily diet with a fluctuating fumonisin B1 (FB1) concentration ranging from less than 1 ppm to 22 ppm. Meanwhile, a second group of five ponies was given a daily diet containing a constant 8 ppm FB1 for 180 days.

Clinical Evaluation and Findings

• The health of the ponies was assessed twice weekly, with a focus on a specific panel of clinical chemistry parameters.
• One pony in the first group, having consumed a diet with 22 ppm FB1 for the final 55 days, died after 225 total days of the study from equine leukoencephalomalacia (ELEM). This condition is a fatal disease of horses causing damage to their brain and nerve tissues. Just over a week prior to its death, the pony presented with elevated liver chemistry values, indicative of liver dysfunction.
• All five ponies from the second group, which consumed 8 ppm FB1 consistently for 180 days, exhibited mild and temporary clinical signs related to FB1 toxicity. They were euthanized at the end of the 180 days, and mild pathological changes to their brains were observed.

Conclusion

• The study indicates that consistent and prolonged exposure to even low levels of fumonisin toxin can potentially lead to a variety of negative health effects in ponies, including elevated liver chemistry values and mild brain lesions.
• This research helps in quantifying the toxic impact of fumonisins in horse feed and emphasizes the need for proper monitoring and regulation of feed quality to prevent such adverse health effects.