Dietary Arachidonate Differentially Alters Desaturase-Elongase Pathway Flux and Gene Expression in Liver and Intestine of Suckling Pigs

Because dietary arachicdonate (ARA) and its ecosanod derivatives are major regulators of intestinal homeostasis and repair following injury, we evaluated the effects of dietary ARA on desaturation and elongation of C-13-18:2(n-6) and mRNA abundance of Delta 6-desaturase (Gamma ADS2), elongase (ELOVL5), and Delta-5-desaturase (FADS1) in liver and intestine. Day-old pigs (n = 96) were fed milk based formula contain ng 0, 0.5, 2.5, or 5% ABA or 5% eicosapentaenoic acid of total fatty acids for 4, 8, and 16 d. In river, the desaturation rate [nmol/(g tissue.h)]o.C-13-18:2(n-6) to C-13-18:3(n-6) decreased 56% between 4 and 16 d but was not affected by diet. Whereas accumulation in C-13-20:3(n-6) also decreased with age by 67%, at increased linearly with increasing dietary ARA (P < 0.06). In comparison, artestinal flux was similar to 50% less than liver flux and was unaffected by age, but desaturation to C-13-18:3(n-6) increased linearly (by 57%) in pigs fed ABA diets (P < 0.001), equaling the rate observed in sow-fed controls. In both river are intestine, alternate elongation to C-13-20:2(n-6) (via Delta-8-desaturase) was markedly elevated in pigs fed the 0% ARA diet compared with all other dietary treatments (P < 0.01). transcript abundance of FADS2, ELOVL5, and FADS1 was rot affected in liver by diet (P > 0.05) but decreased precipitously between birth and d 4 (similar to 70%; P < 0.05). In contrast intestinal abundance of FADS2 and FADS1 increased 60% from d 4 to 16. In conclusion, dietary ARA regulated the desaturase-elongase pathway in a tissue-specific manner. In liver, ARA had modest effects on (n-6) fatty ace box, and intestinal FADS2 activity and mRNA increased. Additionally, hepatic flux decreased with postnatal age, whereas intestinal flux did not change. J. Nutr. 141. 548-553, 2011.