This work was carried out, firstly for investigating the different effects of various organic carbon sources [fructose (A), lactose (B), glucose (C)], and nitrogen sources [poultry manure extract (PM) and rumen liquor (RL)] which used at ratio 50:50% F/2 medium on maximizing production of biodiesel from the marine microalga Nannochloropsis oceanica. Secondly, we apply the residual lipid-free biomass as feed additives in Red tilapia aquaculture. In phase1, the biomass (DW), biodiesel contents and biochemical compositions of N. oceanica were determined. The results showed varied biomass and biochemical analysis in DW bases between treatments. However, A was achieved significantly the maximum DW for the algal biomass and protein percentage, whereas lipid accumulation was the most in RL as well as achieving the highest biodiesel content. In phase 2, algal biomass by-product (lipid-free) from the superior treatments A and RL were applied at 4 rates (1,2,3 and 4) for concentrations 25,50,75&100%, respectively that substituting soybean for feeding red tilapia larvae as compared with control CO. The initial weight and length of the larvae were 0.32g and 1.9 cm, respectively continued for a duration of 30 days of the experiment. After the end of the experimental period , growth performance, survival percentage (SR%) and biochemical analysis were estimated. The results revealed that SR% was higher significantly for RL2 than A1 (93% & 90%) as compared to control (86.7%). Accordingly, red tilapia carcass attained maximum protein contents for diets A1 & RL2 in whereas lipid content was maximum in control. Finally, authors suggesting the use of Roman liquor as a novel treatment for cost-effective promoting biodiesel content and the remained biomass with 50% substitution of soybean in the diet (RL2)achieved also good results for improving red tilapia aquaculture.

M ICROBIAL breeding media must be cost-effective, enable high growth, meet exact requirements and be readily available. The effect of different levels of sodium bicarbonate (SB) [25, 50, 75 and 100%] in the growth medium on the biochemical constituents (protein, carbohydrates, lipids, fatty acids, and amino acids) of the Nannochloropsis oculata was assessed compared to the F/2 Guillard standard medium. The obtained results revealed that the chemical constituents of N. oculata were influenced by the used level of sodium bicarbonate. The highest total protein, carbohydrate contents, and the maximum percentage of essential amino acids (EAA) (59.68%) were obtained by using the B1 medium (25% SB) as compared to the control (100% F/2). The highest total lipid content was achieved by using the B4 medium (100% SB) producing (20.09 %). In accordance, the highest total saturated fatty acids percentage (TSFA) of N. oculata was recorded by B4 medium. However, the highest total unsaturated fatty acids percentage (USFA) was exhibited by the B1 medium. The EN 14214 and ASTM D-6751 analyzes of the production of biodiesel have shown that the produced biodiesel by B4 medium (100% SB) and the control media of high quality. In conclusion, the addition of sodium bicarbonate is an excellent policy to increase chemical composition and lipid accumulation. The present study recommended taming results for either biodiesel production or aquaculture feeding by using proposed B4 medium as a lipid promoter or B1 medium as a protein promoter.

microalgae may change due to differences of the methods of measurement used (Barbarino and Lourenço, 2005). Green algae such as Chlorella sp., Tetraselmis sp. and Nannochloropsis were commonly used as important live food microalgae in aquaculture, and therefore they have been commercially produced (Huerlimann et al., 2010).

Microalgae culture media must be efficient, give high growth, meet micro-requirement, and be available. The effect of different levels of brown lentil infusion and use at [25, 50 and 75%] levels on the chemical composition (protein, carbohydrates, fatty acids, and amino acids) in N. oceanic was evaluated. Compared to the standard F/2 Guillard. The obtained results indicated that the chemical components of N. oceanica were affected by these levels. The highest protein and carbohydrate content and the highest EAA content (55.92%) were obtained using OB3 medium (75% SBL) compared to the control group (100% F/2). The highest biomass production was obtained in OB3 medium. The highest TSFA and USFA were recorded for N. oceanica by the OB3 mean. The present study recommended that it is possible to use microalgae grown on OB3 and OB2 medium as a lipid and protein inducer in aquaculture.