Heart arachidonic acid is uniquely sensitive to dietary arachidonic acid and docosahexaenoic acid content in domestic piglets

Abstract

This study determined the sensitivity of heart and brain arachidonic acid (ARA) and docosahexaenoic acid (DHA) to the dietary ARA level in a dose-response design with constant, high DHA in neonatal piglets. On day 3 of age, pigs were assigned to 1 of 6 dietary formulas varying in ARA/DHA as follows (% fatty acid, FA/FA): (A1) 0.1/1.0; (A2) 0.53/1.0; (A3-D3) 0.69/1.0; (A4) 1.1/1.0; (D2) 0.67/0.62; and (D1) 0.66/0.33. At necropsy (day 28) higher levels of dietary ARA were associated with increased heart and liver ARA, while brain ARA remained unaffected. Dietary ARA had no effect on tissue DHA accretion. Heart was particularly sensitive, with pigs in the intermediate groups having different ARA (A2, 18.6±0.7%; A3, 19.4±1.0%) and a 0.17% increase in dietary ARA resulted in a 0.84% increase in heart ARA. Further investigations are warranted to determine the clinical significance of heart ARA status in developing neonates.

FIGURE 1

ARA tissue dose-response to dietary ARA with constant DHA (1.0% total FA). Dietary ARA content for A1, A2, A3 and A4 was 0.09, 0.53, 0.69 and 1.06% total FA, respectively. (A) Heart and (b) Liver responded significantly (P < 0.0001) while (C) Brain (cerebral cortex) and (D) Retina did not. Each point represents one animal (n = 32 per panel). P < 0.05 indicates significant correlation between dietary ARA content and tissue ARA level; NS, not significant. Student's t-test used to determine significance of pairwise comparisons of mean tissue ARA content; means not sharing a common letter were significantly different (P < 0.05).

FIGURE 2

DHA tissue dose-response to dietary DHA with constant ARA (0.67% total FA). Dietary DHA content for D1, D2 and D3 was 0.32, 0.62 and 1.01% total FA, respectively. Tissue DHA rises with dietary DHA in all tissues presented, (A) Heart, (B) Liver, (C) Brain (Cerebral cortex) and (D) Retina. Each point represents one animal (n = 24 per panel). P < 0.05 indicates significant correlation between dietary DHA content and tissue DHA level; NS, not significant. Student's t-test used to determine significance of pairwise comparisons of mean tissue DHA content; means not sharing a common letter were significantly different (P < 0.05).

FIGURE 3

DHA tissue dose-response to dietary ARA content with constant DHA (1.0% total FA). Dietary ARA content for A1, A2, A3 and A4 was 0.09, 0.53, 0.69 and 1.06% total FA, respectively. Increasing ARA had no effect on DHA levels in (A) Heart, (B) Liver, (C) Brain (Cerebral cortex) or (D) Retina. Each point represents one animal (n = 24 per panel). P < 0.05 indicates significant correlation between dietary ARA content and tissue DHA level; NS, not significant. Student's t-test used to determine significance of pairwise comparisons of mean tissue DHA content; means not sharing a common letter were significantly different (P < 0.05).

FIGURE 4

ARA tissue dose-response to dietary DHA content with constant ARA (0.67% total FA). Dietary DHA content for D1, D2 and D3 was 0.32, 0.62 and 1.01% total FA, respectively. Increasing DHA reduced ARA levels in (B) Liver but not (A) Heart, (C) Brain (Cerebral cortex) or (D) Retina. Each point represents one animal (n = 24 per panel). P < 0.05 indicates significant correlation between dietary DHA content and tissue ARA level; NS, not significant. Student's t-test used to determine significance of pairwise comparisons of mean tissue ARA content; means not sharing a common letter were significantly different (P < 0.05).