ABSTRACT
This experiment was conducted using 288 32-week-old Hisex White laying hens for a period of 10 weeks, with the objective of studying the fatty acid enrichment of the egg yolk of hens fed diets supplemented with fish oil (OP) or marine algae (AM) to provide five levels of DHA (120, 180, 240, 300 and 360 mg/100 g diet) for each source. A 2 x 5 completely randomized factorial design with three replicates of 8 birds per treatment was applied in order to have the following groups: OP120, OP180, OP240, OP300, OP360, AM120, AM180, AM240, AM300 and AM360. A control group submitted to a corn/soy basal diet (CON) and another one supplemented with AM at the level of 420 mg of DHA/100 g diet (AM420) were also used. The amounts of DHA in the egg yolk in birds fed OP diets were significantly increased from 22.64 mg/egg yolk (CON) to 187.91 mg/ egg yolk (OP360). The egg-yolk n-3 PUFAs of the control group (62.16 mg) increased significantly as compared to the OP360 group (218.62 mg/yolk). For the AM source the DHA means were also linear (Y = 0.23X + 1.27, R2 = 0.86), ranging from 22.64 mg/yolk (CON) to 149.75 mg/yolk (AM420), while the n-3 PUFAs ranged from 104.18 mg/yolk (AM120) to 175.32 mg/yolk (AM420). The percentage of DHA incorporation into the egg yolk decreased linearly as the DHA levels increased in the diet. Thus, for the OP and AM sources, mean values of 85.11% (OP120) and 65.28% (AM120) decreased to 49.45% (OP360) and 34.06% (AM420). Significant improvement (P < 0.05) was found in the ratio n-6/n-3, ranging from17.50 (CON) to 3.72 (OP320) and 6.36 (AM420).
KEY WORDS
Incorporation of n-3 PUFAs; hens’ eggs; DHA; fish oil; marine algae