Philippe Guerre

Fusarium mycotoxins are major contaminants of human and animal feed and pose significant risks to health. A recent recommendation from the European Commission drastically decreased the maximum tolerated concentrations of fumonisins (FBs) and deoxynivalenol (DON) in poultry feed. The objectives of this study were to characterize the effects of a 14-day exposure to a diet containing 7.5 mg FB1 + FB2/kg, 2.5 mg DON/kg and 0.6 mg zearalenone (FDZ diet) in turkeys and chickens, and to assess the persistence of these effects following withdrawal of the contaminated diet. No clinical signs of toxicity were observed in either species, and markers of hepatic oxidative damage remained unchanged. In contrast, sphingolipidome alterations were detected, being more pronounced in turkeys than chickens and more persistent in the liver than in plasma. The C22–C24:C16 ratios measured across several sphingolipid (SL) classes emerged as sensitive biomarkers of FB exposure, whereas the sphinganine:sphingosine ratio (Sa:So) remained unchanged. Determination of the 90th percentile (P90) thresholds for SL ratios in unexposed animals provided good-to-excellent discrimination between exposed and unexposed animals. Notably, this conservative percentile-based approach detected FB exposure using the Sa:So ratio despite the absence of significant differences in group means. Multivariate analysis of the complete sphingolipidome provided the highest discriminatory power, distinguishing exposed from unexposed turkeys and chickens for up to four days after withdrawal of the FDZ diet. Finally, the biological significance of alterations in d18:1P, 18:0/2:0, 18:1/16:0, and dihydrosphingolipids induced by the FDZ diet is discussed.

Alterations in sphingolipids (SLs), oxylipins (OLs) and cytokines (CKs) are central to neuroinflammation. However, the effects of low doses Fumonisins B (FBs) on these analytes in the avian brain remain unclear.This study investigated SLs, OLs, CKs, and the activities of phospholipase A2c (PLA2c) and cyclooxygenase 2 (COX2) in the brains of chickens exposed to FB at a nominally safe dose of 14.6 mg FB1 + FB2/kg for 14 and 21 days. Targeted LC-MS/MS analyses revealed that FB exposure increased brain concentrations of sphingosine, N-acetyl-sphingosine, sphingosine 1-phosphate (So1P), ceramides (Cers), and sphingomyelins (SM). The Cer:SM ratio was elevated at 14 days but normalized by 21 days, whereas the So1P:Cer ratio rose at 14 days and continued to increase at 21 days. These changes coincided with elevated PLA2c and COX2 activities. OL profiling indicated a modest rise in pro-inflammatory arachidonic acid-derived COX metabolites at 14 days, while anti-inflammatory OLs derived from COX and lipoxygenase (LOX) pathways, including PGE2, 15-HETE, and 17-HDHA, increased significantly at 21 days. In contrast, the levels of CKs changed only slightly. Brain concentrations of Fumonisin B1 (FB1) indicated increased blood–brain barrier permeability.These findings highlight a key role of Cers in modulating OL production in FB neurotoxicity.

Background: Sphingolipids (SL) are key regulators of inflammatory processes, yet their roles in dairy cows remain poorly understood. This study investigated the effects of inflammation (plasma haptoglobin concentration), ketosis, and mastitis on plasma SL profiles in Holstein cows sampled seven days postpartum. From a cohort of 427 cows across 25 farms, 80 animals were classified into four groups: inflammation ( n = 20), ketosis ( n = 19), mastitis ( n = 21), and healthy controls ( n = 20). Plasma SL were quantified by targeted HPLC–MS/MS, while cytokines were quantified with a 15-plex bead-based assay. Both univariate and multivariate analyses were applied to assess pathological effects, along with SL ratios and correlations between SL and cytokines. Results: Systemic inflammation detected through the haptoglobin measure induced the most pronounced alterations in SL metabolism, characterized by elevated dihydrosphingomyelins (DHSM) and lactosylceramides (LacCer), higher C22–24:C16 ratios, and lower unsaturated:saturated ratios in ceramides (Cer) and sphingomyelins (SM). Although total Cer, SM, and the Cer:SM ratio remained unchanged, specific reductions were observed in both Cer and SM in C14, Cer C18:1, SM C16:1, and SM C23:1, whereas SM C25:0 and C26:0 increased. Sphingosine-1-phosphate (So1P) was positively correlated with IL-10 as well as IL-1α and TNFα, while C18–20 Cer correlated positively with multiple pro-inflammatory cytokines and chemokines such as CXCL8 and CCL2. Ketosis induced subtler changes, primarily an increase in plasma DHSM and DHSM:SM ratio (driven by C16:0), an increase in C22–24:C16 DHCer ratio, and a decrease in both LacSo:LacCer and unsaturated:saturated ratios in C23-SM. In this group, So1P correlated positively with CXCL8 and CCL2. Moreover C18–20 Cer and DHCer were positively associated with CXCL8, CCL2, CCL3, and CCL4, which also showed correlations with most LacCer species. Analysis of chronic mastitis cases yielded a clear separation from controls in multivariate analysis but only minimal changes in SL concentrations and ratios, maybe due to the localized nature of the inflammatory response. Conclusions: In summary, heightened inflammatory response in early post-partum is associated with the strongest systemic effects on SL metabolism, followed by ketosis, while mastitis induced only modest alterations. These findings highlight condition-specific patterns of SL regulation postpartum and suggest potential immunometabolic biomarkers of disease.

This study investigated biomarkers of fumonisin exposure in pigs fed diets contaminated with fumonisins at the European Union’s maximum recommended level. Pigs were assigned to either a fumonisin (FB) diet or a fumonisin plus AlgoClay (FB + AC) diet for durations of 4, 9, and 14 days. At 14 days, the plasma Sa1P:So1P ratio increased in pigs fed the FB diet, while the Sa:So ratio remained unchanged. In the liver, FB1 was detected at four days of exposure, with the concentration tending to increase through day 14. The Sa:So and C22-24:C16 ratios of 18:1-, 18:2-, and m18:1-ceramides were elevated at 9 and 14 days, respectively. In the kidneys, FB1 was only detectable at 14 days, and the Sa:So and C22-24:C16 ratios of 18:1-ceramides were increased. In both the liver and kidneys, the increase in the C22-24:C16 ratio was attributed to a reduction of C16 ceramides. In the lungs, no FB1 was detected; however, the Sa:So and Sa1P:So1P ratios increased, and C16 ceramide concentrations decreased at 14 days. Feeding the pigs the FB + AC diet resulted in a reduction of the FB1 tissue-to-feed ratio in the liver and kidneys but did not affect the Sa:So or Sa1P:So1P ratios. Interestingly, the decreases in C16 ceramides observed in the FB diet group were no longer detectable in the FB + AC group. Overall, these findings highlight the complexity of the relationship between FB1 tissue concentrations and sphingolipid changes, suggesting that a comprehensive analysis of multiple biomarkers is required to fully understand fumonisin’s effects.

This study aimed to assess the effects of a diet containing 20.8 mg FB1 + FB2/kg over four and nine days on oxylipin (OL) profiles in the liver and brain of chickens. A total of 96 OLs, derived from seven polyunsaturated fatty acids (PUFAs) via the cyclooxygenase (COX), lipoxygenase (LOX), cytochrome P450 (P450), and non-enzymatic pathways, were measured using HPLC-MS/MS. In the liver, a significant increase in epoxide P450-derived OLs was detected by day 4, with smaller but notable increases in COX- and LOX-derived OLs by day 9. These alterations were independent of whether the parent PUFA was ω6 or ω3. However, OLs derived from 18-carbon (C18) PUFAs, such as linoleic acid and alpha-linolenic acid, showed greater increases compared to those derived from C20 or C22 PUFAs. The diol/epoxide ratios in the liver decreased at four and nine days, suggesting that fumonisins did not induce an inflammatory response. In the brain, at four days, the most discriminative OLs were derived from ω3-PUFAs, including docosahexaenoic acid, docosapentaenoic acid, and alpha-linolenic acid, via the LOX pathway. By nine days, several OLs derived from arachidonic acid, spanning all enzymatic pathways, became discriminative. In general, the diol/epoxide ratios in the brain were decreased at 4 days and then returned to the initial levels. Taken together, these results show strong effects of fumonisins on OLs in the liver and brain that are both specific and distinct.

Background The inhibitory effect of fumonisins on ceramide synthases results in several effects on the sphingolipidome, and recent results in chickens suggest that the C22–24:C16 sphingolipid ratios may be complementary biomarkers to Sa:So. Feeding diets containing fumonisins, deoxynivalenol, or zearalenone alone or in combination up to the maximum levels recommended by the European Commission for 35 days in chickens and 12 days in ducks resulted in no effects on performance or toxicity. The aim of this study was to investigate their effects on the liver sphingolipidome. Results Sphingolipids were characterised by UHPLC-MSMS. Numerous significant effects of fusariotoxins on sphingolipids were observed at the class and analyte levels. Fusariotoxins alone decreased sphingolipids in chickens but had weak effects in ducks. Feeding fumonisins in combination with deoxynivalenol and zearalenone increased sphingolipid levels in chickens but not in ducks. These increases were mainly due to an increase in C22–24 sphingolipids, whereas C16 sphingolipids decreased. The Sa:So ratio and the C22–24:C16 ratio for ceramides, sphingomyelins, monohexosylceramides, dihydroceramides, and dihydrosphingomyelins were unaffected in chickens and ducks fed the diets containing deoxynivalenol or zearalenone but increased in animals fed the fumonisin diets. Interestingly, while the effects of feeding fumonisins alone or in combination on the total amount of sphingolipids differed in chickens, the Sa:So and C22-24:C16 ratios were similar. Partial least squares-discriminant analysis of sphingolipids did not allow discrimination of the animals exposed to deoxynivalenol or zearalenone from the unexposed animals. By contrast, good discrimination of the animals fed the diets containing fumonisins was achieved. Sphinganine, d20 sphinganine, a large number of C16 sphingolipids, and dihydrosphingomyelins for which the fatty acid contains more than 18 carbon atoms, were important variables in the models obtained in chickens and ducks. Conclusions The C22–24:C16 ratios of sphingolipids are increased in chickens and ducks by intake of fumonisins but not deoxynivalenol or zearalenone. The increases were similar when fumonisins were fed alone or in combination with deoxynivalenol or zearalenone. The increase in the C22–24:C16 ratio may be an important factor in explaining the interspecies differences in sensitivity to fumonisin toxicity.

Sphingolipids are key molecules in inflammation and defense against pathogens. Their role in dectin-1/TLR2-mediated responses is, however, poorly understood. This study investigated the sphingolipidome in the peritoneal fluid, peritoneal cells, plasma, and spleens of mice after intraperitoneal injection of 0.1 mg zymosan/mouse or PBS as a control. Samples were collected at 2, 4, 8, and 16 h post-injection, using a total of 36 mice. Flow cytometry analysis of peritoneal cells and measurement of IL-6, IL-1β, and TNF-α levels in the peritoneal lavages confirmed zymosan-induced peritonitis. The concentrations of sphingoid bases, dihydroceramides, ceramides, dihydrosphingomyelins, sphingomyelins, monohexosylceramides, and lactosylceramides were increased after zymosan administration, and the effects varied with the time and the matrix measured. The greatest changes occurred in peritoneal cells, followed by peritoneal fluid, at 8 h and 4 h post-injection, respectively. Analysis of the sphingolipidome suggests that zymosan increased the de novo synthesis of sphingolipids without change in the C14–C18:C20–C26 ceramide ratio. At 16 h post-injection, glycosylceramides remained higher in treated than in control mice. A minor effect of zymosan was observed in plasma, whereas sphinganine, dihydrosphingomyelins, and monohexosylceramides were significantly increased in the spleen 16 h post-injection. The consequences of the observed changes in the sphingolipidome remain to be established.

Alteration of sphingolipid synthesis is a key event in fumonisins toxicity, but only limited data have been reported regarding the effects of fumonisins on the sphingolipidome. Recent studies in chickens found that the changes in sphingolipids in liver, kidney, lung, and brain differed greatly. This study aimed to determine the effects of fumonisins on sphingolipids in heart, gizzard, and breast muscle in chickens fed 20.8 mg FB1 + FB2/kg for 9 days. A significant increase in the sphinganine:sphingosine ratio due to an increase in sphinganine was observed in heart and gizzard. Dihydroceramides and ceramides increased in the hearts of chickens fed fumonisins, but decreased in the gizzard. The dihydrosphingomyelin, sphingomyelin, and glycosylceramide concentrations paralleled those of ceramides, although the effects were less pronounced. In the heart, sphingolipids with fatty acid chain lengths of 20 to 26 carbons were more affected than those with 14–16 carbons; this difference was not observed in the gizzard. Partial least squares-discriminant analysis on sphingolipids in the heart allowed chickens to be divided into two distinct groups according to their diet. The same was the case for the gizzard. Pearson coefficients of correlation among all the sphingolipids assayed revealed strong positive correlations in the hearts of chickens fed fumonisins compared to chickens fed a control diet, as well as compared to gizzard, irrespective of the diet fed. By contrast, no effect of fumonisins was observed on sphingolipids in breast muscle.