The effect of fasting and refeeding on mRNA expression of PepT1 and gastrointestinal hormones regulating digestion and food intake in zebrafish (Danio rerio)

William Koven, Patricia Schulte

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

In vertebrates, a significant part of ingested protein is absorbed as di- and tripeptides through a brush border membrane proton/oligopeptide transporter protein called PepT1. The aim of the present study was to determine the effect of short-term food deprivation and refeeding in adult zebrafish (Danio rerio) on gastrointestinal mRNA expression of PepT1 as well as on the satiety hormones cholecystokinin (CCK), gastrin-releasing peptide (GRP) and ghrelin (GHR) in order to elucidate a potential mechanism driving compensatory growth. Sixty adult zebrafish were stocked in a 40-L aquarium and fed daily a commercial flake diet to satiation for 10 days where the digestive tracts (DT) of sampled fish (n = 5) were dissected out. Samplings were repeated following 1, 2 and 5 days of food deprivation and after 1, 2 and 5 days of refeeding. The RNA was extracted from all sampled DTs and analyzed by quantitative real-time PCR for the mRNA expression of PepT1, rRNA 18S, CCK, GRP and GHR. PepT1 mRNA expression increased with successive refeedings reaching a level approximately 8 times higher than pre-fast levels. CCK, GRP and GHR mRNA levels also decreased during fasting, but increased only to pre-fasting levels with refeeding. Overall, the results suggest that PepT1 may be a contributing mechanism to compensatory growth that could influence CCK secretion and GRP and GHR activity.

Original languageEnglish
Pages (from-to)1565-1575
Number of pages11
JournalFish Physiology and Biochemistry
Volume38
Issue number6
DOIs
StatePublished - 1 Dec 2012
Externally publishedYes

Keywords

  • CCK
  • Compensatory growth
  • GRP
  • Ghrelin
  • PepT 1
  • Protein absorption
  • Zebrafish

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Aquatic Science

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