Chickens fed with biomass of the red microalga Porphyridium sp. have reduced blood cholesterol level and modified fatty acid composition in egg yolk

The biomass of the red alga Porphyridium sp. constitutes a unique combination of soluble sulfated polysaccharide that accounts for about 70% of the algal dry weight, and various polyunsaturated fatty acids (PUFA) such as arachidonic and eicosapentaenoic acid (AA, 20:4 ω6 and EPA, 20:5 ω3). In view of earlier results in our laboratory showing a reduction in serum cholesterol and triglyceride levels in rodents fed with red algal biomass, we set out to examine the influence of algal biomass as a feed additive on the metabolism of chickens, with an emphasis on blood and egg cholesterol levels. For that purpose, lyophilized algal biomass was fed to 12-13, 30-week-old, White Leghorn chickens for 10 days at a proportion of 5% or 10% of the standard chicken diet. Twelve chickens fed with unsupplemented diet served as the control. No differences in body weight, egg number, and egg weight were found between the algal-fed chickens (at both concentrations) and the control. However, chickens fed with algal biomass consumed 10% less food for both groups, and their serum cholesterol levels were significantly lower (by 11% and 28% for the groups fed with 5% and 10% supplement, respectively) as compared with the respective values of the control group. Egg yolk of chickens fed with algae tended to have reduced cholesterol levels (by 10%) and increased linoleic acid and arachidonic acid levels (by 29% and 24%, respectively). In addition, the color of the egg yolk was darker as a result of the higher carotenoid levels (2.4 fold higher) for chickens that fed with 5% supplement. These results encourage the development of an improved chicken feed having dietary fibers and polyunsaturated fatty acids.