Factors affecting lipid profiles in juvenile Atlantic salmon

• Main Author: House, Andrew
• Other Authors: Kabeya, Naoki, University of Helsinki, Faculty of Biological and Environmental Sciences, Organismal and Evolutionary Biology Research Program, Doctoral Programme in Wildlife Biology, Helsingin yliopisto, bio- ja ympäristötieteellinen tiedekunta, Luonnonvaraisten eliöiden tutkimuksen tohtoriohjelma, Helsingfors universitet, bio- och miljövetenskapliga fakulteten, Doktorandprogrammet i forskning om vilda organismer, Primmer, Craig, Debes, Paul V
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Helsingin yliopisto 2023
• Subjects: ecology and Evolutionary Biology; Atlantic salmon
• Online Access: http://hdl.handle.net/10138/356683

Understanding genotype-phenotype links are important in determining underlying mechanisms involved in the life history of organisms. Gaining insight in early life history strategies and physiological processes enabling optimal progressions between important processes like maturation can help elucidate responses to the environment and how organisms allocate energy. In this thesis, we reared Atlantic salmon during early stages to understand energy allocation strategies and possible vgll3 genotype effects on its two alleles, E and L associated with early and late maturation, respectively. First, we reared Atlantic salmon with two lipid level diets and looked at muscle lipid profiles between males and females through quantifying important lipid classes. Lipid concentration differences were detected with males having a higher lipid class concentration of TG, C, PC and SM than females showing a sex-specific lipid strategy potentially helping males reach maturation at an early stage. Furthermore, we reared Atlantic salmon for two years until the occurrence of maturation in males under varying temperature treatments to look for links between vgll3 genotypes, temperature treatment and energy status. We found a seasonal vgll3 genotype effect on the direction of change of condition factor. The early maturation allele individuals had a more stable body condition over the length of the experiment compared to late maturation allele individuals showing greater seasonal changes. This could be one potential factor allowing for individuals with the early maturation allele to reach maturation during early stages. Lastly, lipidomics methods were used to obtain lipid profiles from a subset of reared individuals from liver and muscle to ascertain physiological status in immature males and females and mature males from a common garden experiment. We found a vgll3 effect on membrane lipid concentrations, PC and PE, in the liver with early maturation allele individuals showing an increase from spring to autumn while late maturation ...