This experiment was carried out on the animal production department of the faculty of agriculture at Al-Azhar university, Nasr City, Cairo, Egypt, and Noubaria experimental station, by-Products utilization department, animal production research institute, agricultural research center, Ministry of Agriculture, Egypt. An experiment to estimate the effect of adding plant sources of unsaturated fatty acids on the performance of sheep16 formulations were made to contain sunflower oil (SUN), linseed oil (LIN), and marine algae. The disappearance of dry and organic matter, protein, and the efficiency of degradation in the rumen were estimated. Algae (8%) without additives or algae (2%) mixed with SUN (2%) recorded the highest rate of disappearance of dry and organic matter, although they were less efficient in protein disappearance, Based on these results, the four best formulations were chosen to form TMR diets with the control to estimate digestibility parameters and nutritional values when fed to sheep as follows: 1. control diet (60% concentrated feed mixture and 40%berseem and rice straw), 2. control + 2% sunflower oil + 2% algae, 3. control + 1%SUN + 1% LIN oil + 4% algae, 4. control + 2% LIN oil + 2% algae, and 5. control + 8% algae. The results showed that the second followed by the fifth diets recorded the highest efficiency in dry and organic matter degradation in the rumen, the highest digestion coefficients and nutritional value (TDN), and the highest nitrogen utilization of diet, Therefore, it can be concluded that adding sunflower oil with algae has a great benefit on digestion in sheep, followed by LNS oil as alternative if SUN is not available.