Enrichment of intestinal mucosal phospholipids with arachidonic and eicosapentaenoic acids fed to suckling piglets is dose and time dependent.

Infant formula companies began fortifying formulas with long-chain PUFA in 2002, including arachidonic acid (ARA) at approximately 0.5% of total fatty acids. The primary objective of this study was to determine the time-specific effects of feeding formula enriched with supra-physiologic ARA on fatty acid composition of intestinal mucosal phospholipids. One-day-old pigs (n = 96) were fed a milk-based formula for 4, 8, or 16 d. Diets contained either no PUFA (0% ARA, negative control), 0.5% ARA, 2.5% ARA, 5% ARA, or 5% eicosapentaenoic acid (EPA) of total fatty acids (wt:wt). Growth (299 +/- 21 g/d) and clinical hematology were unaffected by treatment (P > 0.6). Although minimal on d 4, concentrations of ARA in jejunal mucosa were enriched 47, 272 and 428% by d 8 and 144, 356, and 415% by d 16 in pigs fed the 0.5% ARA, 2.5% ARA, and 5% ARA diets, respectively, compared with the 0% ARA control pigs (P < 0.01). On d 16, ARA enrichment increased progressively with increasing dietary ARA supplementation from 0 to 2.5% but plateaued as dietary ARA rose to 5%. A similar pattern of ARA enrichment was observed in ileal mucosal phospholipids, but maximal enrichment in the ileum exceed that in the jejunum by >50%. As ARA increased, linoleic acid content decreased reciprocally. Although maximal enterocyte enrichment with EPA approached 20-fold by d 8, concentrations were only approximately 50% of those attained for ARA. Negligible effects on gross villus/crypt morphology were observed. These data demonstrate a dose-dependent response of intestinal mucosal phospholipid ARA concentration to dietary ARA with nearly full enrichment attained within 8 d of feeding formula containing ARA at 2.5% of total fatty acids and that supra-physiologic supplementation of ARA is not detrimental to growth.