Abstract

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.

Data Availability

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.

Abbreviations

  • BCS:: Body condition score
  • Cer:: Ceramide
  • CerS:: Ceramide synthase
  • Con:: Control
  • DHCer:: Dihydroceramid
  • DHSL:: Dihydrosphingolipid
  • DHSM:: Dihydrosphingomyelin
  • GlyCer:: Glycosylceralide
  • Hap:: Haptoglobin
  • HexCer:: MonoHexosylceramide
  • HPLC–MS/MS:: High Performance Liquid Chromatography coupled with Mass Spectrometry
  • Ket:: Ketosis
  • LacCer:: Lactosylceramid
  • LacSo:: Lactosylsphingosine
  • LysoSM:: Lysosphingomyelin
  • Mas:: Mastitis
  • PLS-DA:: Partial least squares discrimination analysis
  • S1PR:: Sphingosin 1P receptor
  • SB:: Sphingoid base
  • SCC:: Somatic cell count
  • SL:: Sphingolipids
  • SM:: Sphingomyelin
  • So1P or S1P:: Sphingosine-1-phosphate

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Acknowledgements

Not applicable.

Funding

The sample collection was partly funded by APIS-GENE and the project was supported by a grant Bonus Qualité Recherche (BQR)s from ENVT.

Ethics Declaration

Ethics approval and consent to participate

The experimental study adhered to EU Directive 2010/63/EU and French regulations on animal care, and were approved by the Animal Ethics Committee, SSA N°115, under protocol SSA_2022_009. All breeders and project partners provided informed consent.

Consent for publication

Not applicable.

Competing interests

The authors declare no conflicts of interest.

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