Residual effects of abomasal 5-hydroxytryptophan administration on serotonin metabolism in cattle

E. E.L. Valente, M. L. Damasceno, J. L. Klotz, D. L. Harmon

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1 Scopus citations


Studies of serotonin in animal husbandry has received growing interest. However, there is limited information about serotonin manipulation using 5-HTP administered postruminally and its residual effects in cattle. The objective of this study was to evaluate the effectiveness of 5-HTP infused into the abomasum for enhancing circulating serotonin in cattle. Four Holstein steers (487 ± 7.6 kg) fitted with ruminal cannulas were used in a 4 × 4 Latin Square design experiment. The treatments were intra-abomasal infusion of 5-HTP at 0, 0.25, 0.5, and 1 mg/kg BW. Blood was collected from the jugular vein of each steer at -60, -30, 0, 30, 60, 120, 240, and 480 min from 5-HTP infusion for basal and short term evaluation and, at 1, 2, 4, and 7 d after 5-HTP infusion for long term evaluation. Dry matter intake was not affected (P > 0.05) by intra-abomasal infusions. The half-life of 5-HTP was dose-independent (128 min). The serum 5-HTP, serotonin, and 5-hydroxyindoleacetic acid area under the curve increased (P < 0.05) linearly with an increased dose of 5-HTP. Serum 5-HTP reached peak concentration in approximately 30 min after dosing while serum and plasma serotonin peaked after 240 min postinfusion. Serotonin was greater than control for all 5-HTP doses 1 d and 2 d after infusion in serum and plasma, respectively. Intra-abomasal infusion of 5-HTP at doses up to 1 mg/ kg BW increases circulating serotonin for up 2 days.

Original languageEnglish
Article number106627
JournalDomestic Animal Endocrinology
StatePublished - Jul 2021

Bibliographical note

Funding Information:
The authors would like to acknowledge the support of K. Vanzant, B. Cotton, and W. Lin in the conduct of this research. This work is funded by Hatch Capacity Grant Project no. KY007088 from the USDA National Institute of Food and Agriculture and Project 201807121511 from USDA/ARS and the University of Kentucky Agricultural Experiment Station.

Publisher Copyright:
© 2021


  • 5-HT
  • 5-HTP
  • Cattle
  • Neurotransmitter
  • Pharmacokinetics

ASJC Scopus subject areas

  • Food Animals
  • Animal Science and Zoology
  • Endocrinology


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