Sex-specific lipid profiles in the muscle of Atlantic salmon juveniles

Andrew H House,Paul V Debes,Johanna Kurko,Jaakko Erkinaro,Reijo Käkelä,Craig R Primmer

doi:10.1016/j.cbd.2021.100810

Abstract

Energy allocation in juvenile fish can have important implications for future life-history progression. Inherited and environmental factors determine when and where individuals allocate energy, and timely and sufficient energy reserves are crucial for reaching key life stages involved in the timing of maturation and sea migration. In Atlantic salmon, lipid reserves are predominantly found in the viscera and myosepta in the muscle and have been shown to play a key role in determining the timing of maturity. This life-history trait is tightly linked to fitness in many species and can be different between males and females, however, the details of relative energy allocation in juveniles of different sexes is not well understood. Therefore, the aim of this study was to investigate the effects of sex, genetics and environment during juvenile development of salmon on the amount and composition of their lipid reserves. To do so, juvenile salmon were fed one of two different lipid food contents during their first summer and autumn under common-garden conditions. Muscle lipid composition and concentrations were determined by thin layer chromatography. The muscle lipid class concentrations covaried negatively with body length and males showed higher concentrations than females for phosphatidylcholine, cholesterol, sphingomyelin, and triacylglycerol. This sex-specific difference in major lipid classes presents a new scope for understanding the regulation of lipids during juvenile development and gives direction for understanding how lipids may interact and influence major life-history traits in Atlantic salmon.

Highlights

Optimal allocation of energy between activity, growth and storage are crucial for reaching key life stages, with survival to first reproduction being one of the primary determinants of success (Post & Parkinson, 2001)
Two fish with the vgll3*LL genotype were sampled, likely because the 49 individuals destined for lipid analysis were sampled randomly from the 673 individuals and the vgll3*L allele is rare in the broodstock (Craig Primmer, unpublished data), which restricted the assessment of vgll3 effects to a comparison of vgll3*EE and vgll3*EL
For the first time to the best of our knowledge, that the muscle tissue of juvenile Atlantic salmon males had on average a higher concentration of several major lipid classes compared to females

Summary

Introduction

Optimal allocation of energy between activity, growth and storage are crucial for reaching key life stages, with survival to first reproduction being one of the primary determinants of success (Post & Parkinson, 2001). A tradeoff exists between somatic growth and energy storage, with food availability and quality contributing to this tradeoff (Mogensen & Post, 2012; Post & Parkinson, 2001). Fluctuating environmental conditions affect the quantity and quality of the food available for individuals living in seasonal environments, and this variability in the dietary supply of different nutrients influences how energy is allocated within their body (Post & Parkinson, 2001). By studying lipid class profiles, it is possible to get a better understanding of the physiological status of the individual and potentially, its energetic capacity to adapt to environmental changes when passing through life stages (Murzina et al, 2016)

Objectives

Methods

Results

Conclusion