Enhanced cognitive function and antidepressant-like effects after krill oil supplementation in rats

Lipids Health Dis. 2013 Jan 25;12:6. doi: 10.1186/1476-511X-12-6.

Abstract

Background: The purpose of the study was to evaluate the effects of krill oil (KO) on cognition and depression-like behaviour in rats.

Methods: Cognition was assessed using the Aversive Light Stimulus Avoidance Test (ALSAT). The Unavoidable Aversive Light Stimulus (UALST) and the Forced Swimming Test (FST) were used to evaluate the antidepressant-like effects of KO. Imipramine (IMIP) was used as the antidepressant reference substance.

Results: After 7 weeks of KO intake, both males and females treated with KO were significantly better in discriminating between the active and the inactive levers in the ALSAT from day 1 of training (p<0.01). Both KO and IMIP prevented resignation/depression on the third day in the UALST. Similarly, a shorter immobility time was observed for the KO and IMIP groups compared to the control in the FST (p<0.001). These data support a robust antidepressant-like potential and beneficial cognitive effect of KO. Changes in expression of synaptic plasticity-related genes in the prefrontal cortex and hippocampus were also investigated. mRNA for brain-derived neurotrophic factor (Bdnf) was specifically upregulated in the hippocampus of female rats receiving 7 weeks of KO supplementation (p=0.04) and a similar trend was observed in males (p=0.08). Males also exhibited an increase in prefrontal cortex expression of Arc mRNA, a key protein in long-term synaptic plasticity (p=0.05). IMIP induced clear effects on several plasticity related genes including Bdnf and Arc.

Conclusions: These results indicate that active components (eicosapentaenoic acid, docosahexaenoic acid and astaxanthin) in KO facilitate learning processes and provide antidepressant-like effects. Our findings also suggest that KO might work through different physiological mechanisms than IMIP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antidepressive Agents / isolation & purification
  • Antidepressive Agents / pharmacology*
  • Avoidance Learning / drug effects
  • Brain-Derived Neurotrophic Factor / genetics
  • Brain-Derived Neurotrophic Factor / metabolism
  • Cognition / drug effects*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism
  • Depression / metabolism
  • Depression / physiopathology
  • Depression / prevention & control*
  • Dietary Fats, Unsaturated / isolation & purification
  • Dietary Fats, Unsaturated / pharmacology*
  • Euphausiacea / chemistry*
  • Female
  • Gene Expression / drug effects
  • Hippocampus / drug effects
  • Imipramine / pharmacology
  • Male
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neuronal Plasticity / drug effects
  • Nootropic Agents / isolation & purification
  • Nootropic Agents / pharmacology*
  • Prefrontal Cortex / drug effects
  • Rats
  • Rats, Wistar
  • Swimming

Substances

  • Antidepressive Agents
  • Brain-Derived Neurotrophic Factor
  • Cytoskeletal Proteins
  • Dietary Fats, Unsaturated
  • Nerve Tissue Proteins
  • Nootropic Agents
  • activity regulated cytoskeletal-associated protein
  • Imipramine