Lipids

, Volume 42, Issue 6, pp 547–559

Replacement of Dietary Fish Oils by Alpha-Linolenic Acid-Rich Oils Lowers Omega 3 Content in Tilapia Flesh

  • Ioannis T. Karapanagiotidis
  • Michael V. Bell
  • David C. Little
  • Amararatne Yakupitiyage
Original Article

DOI: 10.1007/s11745-007-3057-1

Cite this article as:
Karapanagiotidis, I.T., Bell, M.V., Little, D.C. et al. Lipids (2007) 42: 547. doi:10.1007/s11745-007-3057-1

Abstract

A 20-week feeding trial was conducted to determine whether increasing linolenic acid (18:3n-3) in vegetable oil (VO) based diets would lead to increased tissue deposition of 22:6n-3 in Nile tilapia (Oreochromis niloticus). Five isonitrogenous and isoenergetic diets were supplemented with 3% of either linseed oil (LO), a mixture of linseed oil with refined palm olein oil (PO) (LO–PO 2:1) and a mixture of refined palm olein oil with linseed oil (PO–LO 3:2) or with fish oil (FO) or corn oil (CO) as controls. The PO–LO, LO–PO and LO diets supplied a similar amount of 18:2n-6 (0.5% of diet by dry weight) and 0.5, 0.7 and 1.1% of 18:3n-3, respectively. Increased dietary 18:3n-3 caused commensurate increases in longer-chain n-3 PUFA and decreases in longer-chain n-6 PUFA in the muscle lipids of tilapia. However, the biosynthetic activities of fish fed the LO-based diets were not sufficient to raise the tissue concentrations of 20:5n-3, 22:5n-3 and 22:6n-3 to those of fish fed FO. The study suggests that tilapia (O. niloticus) has a limited capacity to synthesise 20:5n-3 and 22:6n-3 from dietary 18:3n-3. The replacement of FO in the diet of farmed tilapia with vegetable oils could therefore lower tissue concentrations of 20:5n-3 and 22:6n-3, and consequently produce an aquaculture product of lower lipid nutritional value for the consumer.

Keywords

α-Linolenic acidPolyunsaturated fatty acidsLinseed oilTilapiaOreochromis niloticus

Abbreviations

CO

Corn oil

FCR

Food conversion ratio

FAME

Fatty acid methyl ester

FO

Fish oil

LO

Linseed oil

MUFA

Monounsaturated fatty acid

PER

Protein efficiency ratio

PO

Palm olein oil

PUFA

Polyunsaturated fatty acid

SFA

Saturated fatty acid

SGR

Specific growth rate

TL

Total lipid

VO

Vegetable oil

Copyright information

© AOCS 2007

Authors and Affiliations

  • Ioannis T. Karapanagiotidis
    • 1
  • Michael V. Bell
    • 1
  • David C. Little
    • 1
  • Amararatne Yakupitiyage
    • 2
  1. 1.Institute of AquacultureUniversity of StirlingStirlingScotland
  2. 2.School of Environment, Resources and DevelopmentAsian Institute of TechnologyPathumthaniThailand