Supplementing dams with both arachidonic acid and docosahexaenoic acid has beneficial effects on growth and immune development beyond single fatty acid supplementation

Abstract Omega-3 long-chain polyunsaturated fatty acids (LCPUFAS) modulate immune cells in vitro and in vivo. This study investigated the effects of enriching the maternal diet with the n-6 and -3 LCPUFAs, arachidonic (20:4n-6, 0.6%wt ARA) and docosahexaenoic acid (22:6n-3, 0.32%wt DHA), or a 2:1 ratio (2ARA:1DHA) on total lipids in milk, total lipids, and immunophenotypes in plasma, lymph nodes, and spleen from isolated immune cells from 28d old pups. From day 15 of gestation to post-partum day (ppd)3, Sprague-Dawley dams were fed a commercial chow. On ppd3 litters were culled and pups (4 males and 2 females) randomly cross-fostered to dams who were randomized to one of the 3 experimental diets resulting in 20 male and 10 female pups/diet group. Dams fed ARA or ARA:DHA had 28–36% more 20:4n-6 in milk and feeding DHA or 2:1 ARA:DHA doubled 22:6n-3 in milk lipids (P<0.05). Feeding 2ARA:1DHA or ARA alone resulted in greater pup weight at weaning (P<0.05). Feeding ARA (-DHA) resulted in lower DHA in plasma and spleen while feeding DHA (-ARA) resulted in higher DHA in plasma (P<0.05). Compared to the 2ARA:1DHA pups, there was general trend for ARA fed pups to have higher and DHA fed pups to have lower total, T helper, T cytotoxic, and B lymphocytes in blood, and spleen. In summary, perinatal supplementation with 2ARA:1DHA, compared to ARA or DHA alone, resulted in a higher content of ARA and DHA in breast milk and tissues and had positive effects on growth. DHA without ARA increased 22:6n-3 in milk, plasma, spleen, and reduced 20:4n-6 in milk. Manipulation of dietary LCPUFAs was reflected by lipid content in tissues, and accompanied by evidence of effects on immunophenotype. These changes suggest functional effects but this remains to be confirmed by future investigations.