Frontiers in Immunology (May 2024)

Dietary 5-hydroxytryptophan improves sheep growth performance by enhancing ruminal functions, antioxidant capacity, and tryptophan metabolism: in vitro and in vivo studies

  • Zhe Sun,
  • Zhe Sun,
  • Zhe Sun,
  • Zhe Sun,
  • Natnael D. Aschalew,
  • Natnael D. Aschalew,
  • Natnael D. Aschalew,
  • Long Cheng,
  • Long Cheng,
  • Yuanhong Xia,
  • Yuanhong Xia,
  • Longyu Zhang,
  • Longyu Zhang,
  • Guopei Yin,
  • Guopei Yin,
  • Shikun Wang,
  • Ziyuan Wang,
  • Ziyuan Wang,
  • Jianan Dong,
  • Jianan Dong,
  • Weigang Zhang,
  • Wei Zhao,
  • Guixin Qin,
  • Guixin Qin,
  • Xuefeng Zhang,
  • Xuefeng Zhang,
  • Rongzhen Zhong,
  • Tao Wang,
  • Tao Wang,
  • Tao Wang,
  • Yuguo Zhen,
  • Yuguo Zhen,
  • Yuguo Zhen

DOI
https://doi.org/10.3389/fimmu.2024.1398310
Journal volume & issue
Vol. 15

Abstract

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BackgroundHydroxytryptophan (5-HTP) can regulate the synthesis of 5-Hydroxytryptamine (5-HT) and melatonin (MT). In a previous metabolome analysis, we found that 5-HTP is an effective ingredient in yeast culture for regulating rumen fermentation. However, research on the effect of this microbial product (5-HTP) as a functional feed additive in sheep production is still not well explained. Therefore, this study examined the effects of 5-HTP on sheep rumen function and growth performance using in vitro and in vivo models.MethodsA two-factor in vitro experiment involving different 5-HTP doses and fermentation times was conducted. Then, in the in vivo experiment, 10 sheep were divided into a control group which was fed a basal diet, and a 5-HTP group supplemented with 8 mg/kg 5-HTP for 60 days.ResultsThe results showed that 5-HTP supplementation had a significant effect on in vitro DMD, pH, NH3-N, acetic acid, propionic acid, and TVFA concentrations. 5-HTP altered rumen bacteria composition and diversity indices including Chao1, Shannon, and Simpson. Moreover, the in vivo study on sheep confirmed that supplementing with 8 mg/kg of 5-HTP improved rumen fermentation efficiency and microbial composition. This led to enhanced sheep growth performance and increased involvement in the tryptophan metabolic pathway, suggesting potential benefits.ConclusionDietary 5-HTP (8 mg/kg DM) improves sheep growth performance by enhancing ruminal functions, antioxidant capacity, and tryptophan metabolism. This study can provide a foundation for the development of 5-HTP as a functional feed additive in ruminants’ production.

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