Ergot alkaloids reduce circulating serotonin in the bovine

Area of Science:

• Animal Science
• Biochemistry
• Toxicology

Background:

• Ergot alkaloids interact with serotonin (5-HT) receptors, influencing physiological responses.
• The impact of ergot alkaloid consumption on 5-HT metabolism in cattle remains largely uninvestigated.

Purpose of the Study:

• To evaluate the effect of dietary ergot alkaloid feeding on serotonin metabolism in Holstein steers.
• To determine if different sources of endophyte-infected seeds impact 5-HT metabolism.

Main Methods:

• Experiment 1: 12 Holstein steers fed diets with varying ergovaline concentrations (0, 0.862, 1.282 mg/kg).
• Experiment 2: 4 ruminally cannulated steers received control or endophyte-infected tall fescue seeds (ergovaline dosage 15 μg/kg BW).
• Blood and urine samples were analyzed for 5-HT and its metabolites (5-hydroxytryptophan, 5-hydroxyindoleacetic acid).

Main Results:

• Ergot alkaloid consumption led to a linear decrease in serum 5-HT in both experiments (P = 0.004, P = 0.008).
• Serum 5-hydroxytryptophan and 5-hydroxyindoleacetic acid levels did not significantly change.
• No significant differences in 5-HT reduction were observed between different sources of endophyte-infected seeds.

Conclusions:

• Dietary ergot alkaloids significantly reduce serum 5-HT levels in cattle.
• The source of endophyte-infected seeds does not influence the decrease in serum 5-HT.
• Ergot alkaloids do not appear to affect the metabolism of 5-HT or its primary metabolites in cattle.