Elsevier

Aquatic Living Resources

Volume 11, Issue 6, November–December 1998, Pages 379-385
Aquatic Living Resources

Habitat related variations in fatty acids of catadromous Galaxias maculatusVariabilité des acides gras du poisson catadrome Galaxias maculatus en fonction de l'habitat

https://doi.org/10.1016/S0990-7440(99)80003-5Get rights and content

Abstract

The fatty acid profile of the galaxiid fish Galaxias maculatus (Salmoniformes) collected from an estuarine habitat (a river mouth), a freshwater creek and two land-locked freshwater lakes in Victoria, Australia, were investigated with a view to evaluating habitat influences on the fatty acid profile. Fish from the freshwater creek were unpigmented, fresh-run juveniles (referred to as whitebait), the others adult fish. The fatty acids that predominated in adult G. maculatus muscle were 16:0 and 22:6(n-3), and 16:0 and 18:1(n-9), respectively. In whitebait 22:6(n-3), 20:5(n-3) and 16:0 were predominant. Hopkins estuary fish had the highest amount of 18:2(n-6) but the lowest 18:3(n-3). In all galaxiid populations, polyunsaturated fatty acids (PUFA) were the main group of fatty acids in total lipid in muscle, and accounted for more than 40 %, followed by saturates and monoenes. In landlocked populations, the amount of monoenes was lower than in other galaxiid populations. G. maculatus whitebait had significantly lower amount of saturates and the highest amount of n-3 fatty acids. The ratio of n-3 to n-6 PUFA ranged from 4.6 (Hopkins estuary) to 7.6 (whitebait), and the former differed significantly from all the other populations. The main fatty acids predominating in the liver of galaxiids from landlocked (Lake Bullen Merri) and estuarine populations were 16:0, 22:6(n-3) and 18:1 (n-9), and generally reflected the corresponding pattern in muscle. A principal component analysis of the fatty acid composition of muscle samples confirmed and highlighted the distinct fatty acid profile of the populations investigated, when three groupings could be discerned. The study suggests that in addition to the diet, other habitat related factors may influence the fatty acid profile in catadromous G. maculatus.

Résumé

L'influence de l'habitat sur le profil en acides gras de poissons Galaxidés Galaxias maculatus (Salmoniformes) a été étudiée en réalisant des analyses sur des échantillons prélevés dans un estuaire (embouchure de fleuve), dans un ruisseau et dans deux lacs d'eau douce à Victoria (Australie). Les poissons provenant du ruisseau étaient des juvéniles non pigmentés, tandis que les autres poissons étudiés étaient des adultes. Les acides gras prédominant dans le muscle des adultes G. maculatus étaient 16:0 et 22:6 de la série n-3 et 16:0 et 18:1 de la série n-9. Chez les juvéniles, 22:6(n-3), 20:5(n-3) et 16:0 étaient majoritaires. Ce sont les poissons péchés dans l'estuaire de Hopkins qui contenaient le plus de 18:2(n-6) et le moins de 18:3(n-3). Dans toutes les populations de Galaxidés, les acides gras polyinsaturés (PUFA) constituaient le groupe le plus important (plus de 40 %) parmi les lipides du muscle, suivi par les acides gras saturés et les mono-insaturés. La proportion d'acides gras mono-insaturés était plus faible chez les Galaxidés des lacs que chez les autres. Par rapport aux adultes, les juvéniles avaient des acides gras saturés en quantité significativement inférieure mais le taux le plus élevé de n-3. Le rapport n-3/n-6 variait de 4,6 (estuaire du Hopkins) à 7,6 (juvéniles), ce dernier étant significativement différent des autres populations. Les acides gras dominants dans le foie des poissons de lac (lac de Bullen Merri) et des populations estuariennes étaient 16:0, 22:6(n-3) et 18:1(n-9) et reflétaient généralement le profil en acides gras du muscle. Une analyse des composants principaux de la composition en acides gras du muscle a confirmé et mis en évidence le profil précis en acides gras des différentes populations étudiées où trois groupes peuvent être distingués. Cette étude suggère qu'en plus du régime alimentaire, d'autres facteurs liés à l'habitat peuvent influencer le profil en acides gras chez le poisson catadrome G. maculatus.

References (33)

  • BellJ.G. et al.

    Effects of different dietary arachidonic acid:docosahexaenoic acid ratios on phospholipid fatty acid compositions and prostaglandin production in juvenile turbot (Scophthalmus maximus)

    Fish Physiol. Biochem.

    (1995)
  • CadwalladerP.L.

    Feeding relationships of galaxiids, bullies, eels and trout in a New Zealand river

    Aust. J. Mar. Freshw. Res.

    (1975)
  • CadwalladerP.L. et al.
  • CheesmanB.C. et al.

    A note on the diet of Galaxias maculatus (Jenyns) (Pisces, Salmoniformes, Galaxiidae) in a closed saline lake in western Victoria

    Bull. Aust. Soc. Limnol.

    (1987)
  • ChristieW.W.

    Gas chromatography and lipids

    (1989)
  • De SilvaS.S. et al.

    Changes in the fatty acid profile of the Australian shortfin eel in relation to development

    J. Fish Biol.

    (1997)
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