Effects of fusarium moniliforme isolates on tissue and serum sphingolipid concentrations in horses.

The study explores the effects of different strains of Fusarium moniliforme on sphingolipid concentrations in horses. The 27-day feeding trial discovered that the intake of certain strains lead to symptoms consistent with equine toxicoses and significant alterations in serum sphingolipid ratios.

Study Background and Purpose

• The research was conducted to understand how the ingestion of Fusarium moniliforme (a type of fungus) impacts sphingolipid (SL) concentrations in horses. Disruption of SL metabolism can indicate exposure to fumonisins, which are mycotoxins produced by the fungus.
• The disturbances in SL metabolism due to fumonisins are considered crucial in the development of fumonisin toxicoses. However, the exact role that SL plays in this disease process is not well understood. This formed the central research question of the study.

Experimental Setup

• A 27-day feeding trial was conducted involving 3 strains of Fusarium moniliforme. The strains were RRC 415, AU 2/3, and MRC 826, procured from different locations, with each one associated with varying degrees of horse diseases.
• The experimental feeds were created by growing these strains on corn. This was then diluted with clean corn and grain mixed with molasses to obtain a range of fumonisin B1 (FB1) concentrations. Horses were fed these concoctions.

Observations and Findings

• None of the horses developed duodenitis-proximal jejunitis (DPJ), which is an inflammation of the intestinal tract. However, horses fed with MRC 826 had intestinal lesions consistent with DPJ, and horses fed with AU 2/3 and MRC 826 developed equine leukoencephalomalacia (ELEM), a neurological disease.
• Serum SL concentrations showed alterations in horses fed with the Fusarium moniliforme culture material compared to the control group. This alteration was seen predominantly as an increase in the sphinganine (Sa) to sphingosine (So) ratio, within the serum of horses fed with AU 2/3 and MRC 826.
• There were also significant changes in sphinganine and sphingosine concentrations in various parts of the brain and intestine across the different feeding groups. Most notably, elevated sphinganine concentrations in the hypothalamus-dentate gyrus and brain stem were seen in horses fed with AU 2/3 compared to healthy horses. Horses fed with MRC 826 showed significantly elevated sphingosine concentrations in the proximal duodenum and ileum compared to healthy horses.
• Interestingly, no changes were observed in the Sa:So ratio in the brain and intestinal tissues of horses with and without pathological lesions. This indicates that while serum sphingolipid levels are affected, tissue ratios remain stable.