Variations in protein, carbohydrate, lipid, ash, moisture, fatty acid and amino acid contents of the seaweeds Ulva lactuca Linnaeus (Chlorophyta), Jania rubens (Linnaeus) J.V. Lamouroux and Pterocladia capillacea (S.C. Gmelin) Bornet (Rhodophyta) were studied seasonally from spring to autumn 2010. The seaweeds were collected from a rocky site near Boughaz El-Maadya on the coast of Abu Qir Bay east of Alexandria, Egypt. Remarkable seasonal variations were recorded in the levels of the studied parameters in the three species. Pterocladia capillacea was characterized by the highest protein and carbohydrate content throughout the different seasons, whereas Ulva lactuca contained more lipids (4.09 +/- 0.2%) than J. rubens and P. capillacea. The highest total fatty acids were recorded in J. rubens during the three seasons, while saturated fatty acids were predominant in P. capillacea during spring. This is due mainly to the presence of palmitic acid (C16:0), which made up 74.3% of the saturated fatty acids. The highest level of polyunsaturated fatty acids (PUFA) in these algae was measured in J. rubens; DHA (22:6 omega(3)) was the main acid, making up 26.4% of the total fatty acids especially during summer. Pro line was the major component of the amino acids in the three algal species, with maximum amounts in U. lactuca.
