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Open Access Highly Accessed Research

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

Karin Wibrand1, Kjetil Berge2, Michaël Messaoudi3, Anaïs Duffaud3, Debabrata Panja1, Clive R Bramham1 and Lena Burri2*

Author Affiliations

1 Department of Biomedicine and KG Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Jonas Lies vei 91, Bergen, NO-5009, Norway

2 Aker Biomarine ASA, Fjordalleen 16, Oslo NO-0115, Norway

3 ETAP-Applied Ethology Department of Neuropsychopharmacology, 13 rue Bois de la Champelle, Vandoeuvre-lès-Nancy, 54500, France

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Lipids in Health and Disease 2013, 12:6  doi:10.1186/1476-511X-12-6

Published: 25 January 2013

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.

Keywords:
BDNF; Cognition; Depression; Imipramine; Krill oil; Omega-3; Fatty acids; Phospholipids