The effect of dietary protein source (fishmeal vs. plant protein) and non-starch polysaccharide level on fat digestibility and faecal bile acid loss in rainbow trout (Oncorhynchus mykiss)

Thomas W.O. Staessen, Marc C.J. Verdegem, Paraskevi Koletsi, Johan W. Schrama*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

This study investigated in rainbow trout (Oncorhynchus mykiss) if diet composition and feeding level affect faecal bile acid loss, and whether this reflects on the apparent digestibility coefficient (ADC) of fat. Six diets were formulated with either fishmeal or plant protein as main protein source. This created a contrast in the supply of bile acids, the bile acid precursor cholesterol, taurine and the taurine precursors (methionine + cysteine) involved in bile acid conjugation. For both protein sources, three diets were formulated with increasing inclusion of a non-starch polysaccharide (NSP)-rich ingredient mixture (0.0, 82.0 and 164.2 g/kg diet). This aimed at enhancing faecal bile acid loss. Fish were fed both restrictively (1.2% BW/day) and to satiation. A similar fat ADC was found when substituting fishmeal with a plant protein mixture, suggesting that the lower content of bile acids, cholesterol, taurine, methionine and cysteine in the plant-based diets did not limit fat digestion. Faecal bile acid loss increased alongside dietary NSP level, however, only during satiation feeding and most strongly for fish fed the fishmeal-based diets. Enhanced faecal bile acid loss was not caused by NSP-bile acid binding/entrapment, but by an increase in faeces production. During satiation feeding, fat ADC negatively correlated with faecal bile acid loss. From this it is concluded that bile acid availability/synthesis can become limiting for fat digestion in rainbow trout under conditions that enhance faecal bile acid loss (i.e. dietary NSP level and feeding level).

Original languageEnglish
Pages (from-to)1170-1181
JournalAquaculture Research
Volume51
Issue number3
Early online date29 Dec 2019
DOIs
Publication statusPublished - Mar 2020

Keywords

  • bile acids
  • cholesterol
  • fat digestibility
  • non-starch polysaccharides
  • Oncorhynchus mykiss
  • taurine

Fingerprint Dive into the research topics of 'The effect of dietary protein source (fishmeal vs. plant protein) and non-starch polysaccharide level on fat digestibility and faecal bile acid loss in rainbow trout (Oncorhynchus mykiss)'. Together they form a unique fingerprint.

Cite this