Synergistic effects of stress and omega-3 fatty acid deprivation on emotional response and brain lipid composition in adult rats

The aim was to determine the consequences of multi-generational n-3 polyunsaturated fatty acids (PUFA) deficiency on emotional response in rats subjected to maternal separation (MS) as chronic early life stress. Pups fed a control or an n-3 PUFA deficient diet were daily separated for 2 weeks before weaning. In adult rats, reward response was assessed by sucrose consumption and reactivity to novelty using openfield test. Both n-3 PUFA deficiency and MS increased reward response and impulsivity. Moreover, nutritional deficiency and stress acted in synergy to elevate sucrose intake by 80%, compared to control conditions. n-3 PUFA deprivation induced a depletion of docosahexanoeic acid of brain membranes by 70% compensated by increase in 22:5 n-6 and arachidonic acid (AA) levels. The diet-induced AA increase was, however, significantly higher in MS rats. This suggests that n-3 PUFA deficit could be an environmental risk increasing vulnerability to depressive-like response induced by chronic stress.