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

Abstract

BackgroundThe purpose of the study was to evaluate the effects of krill oil (KO) on cognition and depression-like behaviour in rats.MethodsCognition 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.ResultsAfter 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.ConclusionsThese 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.

Antidepressant‐Like Effect of Lipid Extract of Channa striatus in Chronic Unpredictable Mild Stress Model of Depression in Rats

“…In rats administered with krill oil (enriched with ω -3 fatty acids), upregulation of BDNF was observed in hippocampus [83]. Dietary supplementation with DHA increased pro and mature BDNF levels in rat hippocampus [84].…”

Antarctic Krill (Euphausia superba) Oil: A Comprehensive Review of Chemical Composition, Extraction Technologies, Health Benefits, and Current Applications

“…Treatment with krill oil at the dosage of 1.25 g per 100 g diet for 7 weeks had a positive effect on learning and memory processes in a rat experiment using the Aversive Light Stimulus Avoidance Test, the Unavoidable Aversive Light Stimulus Test, and the Forced Swimming Test. Brain‐derived neurotrophic factor (Bdnf) is a gene associated with neuronal growth and differentiation in the hippocampus, and an elevated expression level of mRNA for Bdnf was also observed in the rats supplemented with krill oil (Wibrand et al., ). These results are consistent with the study conducted by Tomé‐Carneiro et al.…”

Neuroprotective mechanisms of astaxanthin: a potential therapeutic role in preserving cognitive function in age and neurodegeneration

“…BDNF is decreased with age and is associated with reduced hippocampal volume and corresponding impaired spatial memory in aged humans (59-80 years old) (Wibrand et al 2013;Wu et al 2014). BDNF is an important nerve growth factor that not only promotes neurogenesis but also has a reported role in modulating synaptic transmission.…”

“…BDNF is an important nerve growth factor that not only promotes neurogenesis but also has a reported role in modulating synaptic transmission. While the upregulation of AKT or ERK could be the underlying mechanism driving stem cell proliferation in the hippocampus, AXT may also be influencing synaptic plasticity through inducing an upregulation in BDNF (Wibrand et al 2013;Wu et al 2014). Moreover, BDNF can facilitate LTP through ERK-dependent mechanisms (Peng et al 2010).…”