Fumonisin (FUM) toxicity is associated with the blocking of ceramide synthases (CerS), which affects the equilibrium of sphingolipids like sphinganine (Sa) and sphingosine (So) within cells. While Sa accumulates in cells, the level of So is compensated, consequently affecting the Sa:So ratio which is used as a biomarker for exposure to fumonisins in many animal species.
However, compensatory mechanisms to maintain ceramide level in cells make irrelevant the use of this biomarker in some studies (depending on the level and time of exposure). Indeed, in this study, the Sa:So ratio was not significantly affected in the plasma of chickens exposed to fumonisins.
However, a complete analysis of different classes of sphingolipids revealed that the ratio of the phosphate forms of Sa and So (Sa1P:So1P) was significantly increased by feeding fumonisins.
This result is consistent with previous results suggesting that Sa1P:So1P ratio is a better biomarker for fumonisins exposure in plasma than Sa:So ratio. Similar effects of fumonisins were observed according to the size of the carbon chain of the ceramides.
A significant increase in the C22-C24:C16 ratio was observed in plasma. Although the mechanisms behind these effects are not yet understood, this result suggests that C22-C24:C16 sphingolipids ratios, in conjunction with the Sa1P:So1P ratio, could be good candidates for revealing fumonisin exposure in chicken plasma at doses that had no effect on the Sa:So ratio.
Figure: Discriminant analyses (PLS-DA) of sphingolipids in plasma of chickens fed a control diet free of mycotoxins and chickens fed a diet containing circa 15 mg FUM/kg for 14 or 21 days.
Reference: Lassallette E., Nyvall-Collen P., Guerre P., Targeted sphingolipidomics indicates increased C22-C24:16 ratios of virtually all assayed classes in liver, kidney, and plasma of fumonisin-fed chickens. Ecotoxicology and Environmental Safety 268 (2023) 115697. https://doi.org/10.1016/j.ecoenv.2023.115697
Interested in the work done by this research team on fumonisin effects in chickens? Check out their previous study on the accumulation of FUM on chicken liver and breast tissue, and how Olmix Algoclay technology can reduce it.