Omega-3 Fatty Acids from Fish Oil Lower Anxiety, Improve Cognitive Functions and Reduce Spontaneous Locomotor Activity in a Non-Human Primate

Abstract

Omega-3 (ω3) polyunsaturated fatty acids (PUFA) are major components of brain cells membranes. ω3 PUFA-deficient rodents exhibit severe cognitive impairments (learning, memory) that have been linked to alteration of brain glucose utilization or to changes in neurotransmission processes. ω3 PUFA supplementation has been shown to lower anxiety and to improve several cognitive parameters in rodents, while very few data are available in primates. In humans, little is known about the association between anxiety and ω3 fatty acids supplementation and data are divergent about their impact on cognitive functions. Therefore, the development of nutritional studies in non-human primates is needed to disclose whether a long-term supplementation with long-chain ω3 PUFA has an impact on behavioural and cognitive parameters, differently or not from rodents. We address the hypothesis that ω3 PUFA supplementation could lower anxiety and improve cognitive performances of the Grey Mouse Lemur (Microcebus murinus), a nocturnal Malagasy prosimian primate. Adult male mouse lemurs were fed for 5 months on a control diet or on a diet supplemented with long-chain ω3 PUFA (n = 6 per group). Behavioural, cognitive and motor performances were measured using an open field test to evaluate anxiety, a circular platform test to evaluate reference spatial memory, a spontaneous locomotor activity monitoring and a sensory-motor test. ω3-supplemented animals exhibited lower anxiety level compared to control animals, what was accompanied by better performances in a reference spatial memory task (80% of successful trials vs 35% in controls, p<0.05), while the spontaneous locomotor activity was reduced by 31% in ω3-supplemented animals (p<0.001), a parameter that can be linked with lowered anxiety. The long-term dietary ω3 PUFA supplementation positively impacts on anxiety and cognitive performances in the adult mouse lemur. The supplementation of human food with ω3 fatty acids may represent a valuable dietary strategy to improve behavioural and cognitive functions.

Long-chain n-3 PUFAs from fish oil enhance resting state brain glucose utilization and reduce anxiety in an adult nonhuman primate, the grey mouse lemur

“…Our fi nding that n-3 LCPUFA-supplemented mouse lemurs exhibited both lower anxiety in the open-fi eld task and better performances in the Barnes maze confi rms our previous observation in comparable conditions ( 21 ) and also suggests that the two outcomes may be directly linked. Indeed, the tendency to higher exploration in the Barnes maze of the n-3 PUFA-supplemented animals (higher number of visits and lower time spent to fi nd the correct exit) may be due to lower anxiety, resulting in a higher percentage of success in comparison with the control group.…”

“…performance in adult and aged gray mouse lemurs ( 20,21 ). We showed for the fi rst time in a nonhuman primate species that n-3 PUFA supplementation decreased anxiety and spontaneous locomotor activity and concomitantly improved cognitive performance.…”

“…The circular platform task apparatus was an adaptation for mouse lemurs of the device described by Barnes ( 21 ). It consisted of a white circular platform (diameter, 100 cm) with 12 equally spaced circular holes (each 5 cm in diameter) located 3 cm from the perimeter.…”

“…In the present study, we compared the effects of a 12-month supplementation with n-3 LCPUFAs or with monounsaturated fatty acids (isocaloric control diet) on brain glucose metabolism assessed by positron emission tomography (PET) imaging. In parallel, we used a spatial memory task (adapted from the rodent Barnes maze) to assess spatial reference memory and an open-fi eld task to assess exploratory behavior and anxiety, both of which we have already extensively validated in gray mouse lemurs ( 18,20,21 ).…”

Patients With COPD With Higher Levels of Anxiety Are More Physically Active

“…Vinot and colleagues 40 found that in nonhuman primates, anxiety was associated with greater spontaneous locomotor activity. A study by Sakamoto and colleagues 41 found that a small sample of adults (14 women, two men) with panic disorder symptoms had high locomotor activity as measured by wrist actigraphy.…”