The Later Effects of DHA in Diet on Regulating Transcription of Lipid Genes of Broiler

Omega-3 meat enrichment and L-FABP, PPARA, and LPL genes expression are modified by the level and period of tuna oil supplementation in slow-growing chickens

This study proposes a strategy to manipulate the fatty acid (FA) content in slow-growing Korat chicken (KRC) meat using tuna oil (TO). To determine the optimal level and feeding period of TO supplementation, we conducted a study investigating the effects of dietary TO levels and feeding periods on meat quality, omega-3 polyunsaturated fatty acid (n-3 PUFA) composition, and gene expression related to FA metabolism in KRC breast meat. At 3 wk of age, 700 mixed-sex KRC were assigned to seven augmented factorial treatments with a completely randomized design, each consisting of four replicate pens containing 25 chickens per pen. The control group received a corn-soybean-based diet with 4.5% rice bran oil (RBO), while varying amounts of TO (1.5%, 3.0%, or 4.5%) replaced a portion of the RBO content in the experimental diets. The chickens were fed these diets for 3 and 6 wk, respectively, before being slaughtered at 9 wk. Our results indicated no significant interactions between TO levels and feeding periods on the growth performance or meat quality of KRC (P > 0.05). However, the liver fatty acid-binding protein gene (L-FABP, also known as FABP1), responsible for FA transport and accumulation, showed significantly higher expression in the chickens supplemented with 4.5% TO (P < 0.05). The chickens supplemented with 4.5% TO for a longer period (3 to 9 wk of age) exhibited the lowest levels of n-6 PUFA and n-6 to n-3 ratio, along with the highest levels of eicosapentaenoic acid, docosahexaenoic acid, and n-3 PUFA in the breast meat (P < 0.05). However, even a short period of supplementation with 4.5% TO (6 to 9 wk of age) was adequate to enrich slow-growing chicken meat with high levels of n-3 PUFA, as recommended previously. Our findings indicated that even a short period of tuna oil supplementation could lead to desirable levels of omega-3 enrichment in slow-growing chicken meat. This finding has practical implications for the poultry industry, providing insights into optimal supplementation strategies for achieving desired FA profiles without adversely affecting growth performance or meat quality.

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.