Supplemental Docosahexaenoic-Acid-Enriched Microalgae Affected Fatty Acid and Metabolic Profiles and Related Gene Expression in Several Tissues of Broiler Chicks

This experiment was to enrich docosahexaenoic acid (DHA) in broiler tissues through feeding a DHA-rich microalgal biomass and to explore the underlying metabolic and molecular mechanisms. Hatchling Cornish male broilers (total = 192) were fed a corn–soybean meal basal diet containing a full-fatted microalgae (Aurantiochytrium) at 0%, 1%, 2%, and 4% for 6 weeks (n = 6 cages/treatment, 8 birds/cage). The inclusion of microalgae led to dose-dependent (P < 0.01) enrichments of DHA and decreases (P < 0.01) of n-6/n-3 fatty acids (FAs) in plasma, liver, muscle, and adipose tissue. The microalgae supplementation also lowered (P < 0.05−0.1) nonesterified FAs concentrations in the plasma, liver and adipose tissue. The mRNA abundances of most assayed genes involved in lipid metabolism were decreased (P < 0.05) in the liver but elevated (P < 0.05) in the adipose in response to the biomass supplementation. In conclusion, the biomass-resultant DHA enrichments in the broiler tissues were associated with a distinctive difference in the expression of lipid metabolism-controlling genes between the liver and adipose tissue.