Potential and Metabolic Impacts of Double Enrichments of Docosahexaenoic Acid and 25-Hydroxy Vitamin D3 in Tissues of Broiler Chickens

Background

Chicken may be enriched with 25-hydroxy D₃ [25(OH)D₃] and docosahexaenoic acid (DHA) to enhance the dietary intake of the public.

Objectives

Two experiments (Expt.) were conducted to determine the potential and metabolic impacts of enriching both DHA and 25(OH)D₃ in the tissues of broiler chickens.

Methods

In Expt. 1, 144 chicks (6 cages/treatment and 6 birds/cage) were fed a corn–soybean meal basal diet (BD), BD + 10,000 IU 25(OH)D₃/kg [BD + 25(OH)D₃], BD + 1% DHA-rich Aurantiochytrium (1.2 g DHA/kg; BD + DHA), or BD + 25(OH)D₃+DHA for 6 wk. In Expt. 2, 180 chicks were fed the BD, BD + DHA-rich microalgal oil (1.5–3.0 g DHA/kg, BD + DHA), BD + DHA + eicosapentaenoic acid (EPA)-rich microalgae (0.3–0.6 g EPA/kg, BD + DHA + EPA), BD + DHA + 25(OH)D₃ [6000 to 12,000 IU/kg diet; BD + DHA + 25(OH)D₃], and BD + DHA + EPA + 25(OH)D₃ for 6 wk.

Results

Supranutrition of these 2 nutrients resulted in 57–62 mg DHA and 1.9–3.3 μg of 25(OH)D₃/100 g of breast or thigh muscles. The DHA enrichment was independent of dietary EPA or 25(OH)D₃, but that of 25(OH)D₃ in the liver was decreased (68%, P < 0.05) by dietary DHA in Expt. 1. Compared with BD, BD + 25(OH)D₃ enhanced (P < 0.05) gene expression related to D₃ absorption (scavenger receptor class B type 1 and Niemann-pick c1 like 1) in the liver and D₃ degradation (cytochrome P450 24A1) in the breast, and decreased mRNA or protein concentrations of vitamin D binding protein in the adipose tissue or thigh muscle. Supranutrition of DHA decreased mRNA concentrations of lipid metabolism-related genes (fatty acid desaturase 1,2, ELOVL fatty acid elongase 5, fatty acid desaturase 2, fatty acid synthase, and sterol regulatory element-binding protein 1).

Conclusions

Both DHA and 25(OH)D₃ were enriched in the muscles up to meeting 50%–100% of the suggested intakes of these nutrients by consuming 2 servings of 100 g of fortified chicken. The enrichments altered gene expression related to lipid biosynthesis and vitamin D transport or storage.