Fried Tilapia Research Articles

Evaluation of High Vacuum Flavor Extraction Device as a Novel Technique for the Extraction of Volatile Compounds

In this study, a high vacuum flavor extraction (HVE) device was developed to address the limitations of traditional extraction methods, such as extended extraction times and artifact generation during high-temperature processes. Firstly, the repeatability and precision of the HVE method were evaluated through quantitative analysis of twelve volatile odor compounds across seven replicate extractions using gas chromatography–flame ionization detection (GC-FID). The results showed that the HVE system achieved a mean relative standard deviation (RSD) of 11.60 ± 1.79% and a recovery rate of 90.55 ± 4.56%, demonstrating its precision and reproducibility. Secondly, the performance of HVE was compared with solvent-assisted flavor evaporation (SAFE) and simultaneous distillation–extraction (SDE) for extracting flavor compounds from fried tilapia mince. The results indicated that HVE was more effective, particularly in extracting aldehydes and pyrazines, which are key contributors to the flavor profile. Finally, sensory evaluations supported these findings, showing that the odor profiles obtained through HVE were most similar to the original sample, with a similarity score of 72.55%, compared to 69.25% for SAFE and 60.29% for SDE. These findings suggest that HVE is a suitable method for the extraction and analysis of volatile compounds in complex food matrices such as fried tilapia mince.

Optimization of Fresh Water Fish Culinary Tourism in Gowa Regency

This research aims to determine production factors, then analyze the amount of profit and examine the optimization of the freshwater fish culinary tourism business in the Beroanging area of the Bili-Bili Reservoir, Gowa Regency. The research was carried out in February–April 2023 using a survey method and a total sampling method of 15 respondents consisting of business owners. The data obtained was analyzed using the formula for total costs, total revenues, total profits and continued using the simplex linear programming method with POM-QM software. The research results show that the actual profit from the grilled tilapia fish menu in one month is IDR. 5,749,500 and each portion is IDR. 20,000 while the fried tilapia fish menu makes a profit of IDR 2,032,500 and each portion is IDR 13,000 where this value is influenced by the number of tourists. So the solution from the linear programming analysis is that business actors should produce 442 portions of grilled tilapia with an optimal profit of IDR. 8,840,000.

Physicochemical and Volatile Flavor Properties of Fish Skin under Conventional Frying, Air Frying and Vacuum Frying.

The aim of this study was to investigate the physicochemical characteristics and volatile flavor of fried tilapia skins under three frying methods. Conventional deep-fat frying usually increases the oil content of the fried fish skin and leads to lipid oxidation, which reduces the product quality. Alternative frying methods, such as air frying for 6 and 12 min under 180 °C (AF6, and AF12) and vacuum frying at 0.085 MPa for 8 and 24 min under 120 °C (VF8, and VF24) were compared to conventional frying for 2 and 8 min under 180 °C (CF2, and CF8) for tilapia skin. Physical properties of fried skin, such as the moisture content, water activity, L* values and breaking force decreased under all frying methods, while the lipid oxidation and a*, b* values increased with the increase in frying time. In general, VF offered higher hardness of product compared to AF which had a lower breaking force. Especially AF12 and CF8 had the lowest breaking force, which indicated higher crispness. For the oil quality inside the product, AF and VF reduced conjugated dienes formation and retarded oxidation compared to CF. The results of the flavor compositions of fish skin measured using gas chromatography mass spectrometry (GC/MS) with solid phase microextraction (SPME) showed that CF obtained higher unpleasant oily odor (nonanal, 2,4-decadienal, etc.), while AF presented greater grilling flavor (pyrazine derivatives). Because fish skin fried by AF only relied on hot air, Maillard reaction derived compounds, such as methylpyrazine, 2,5-dimethylpyrazine, and benzaldehyde were the leading flavors. This made the aroma profiles of AF very different from VF and CF. Among all the approaches, AF and VF developed lower oil content, mild fat oxidation and better flavor attributes, which proves their practical applications for frying tilapia fish skin.

EFFECT OF BETEL LEAF EXTRACT (Piper betle L.) ON Aeromonas hydrophila DISEASES IN TILAPIA (Oreochromis niloticus) SEED

Seed is essential in aquaculture activities, but tilapia hatcheries often suffer from disease attacks caused by Aeromonas hydrophila bacteria, causing losses for hatchery businesses. One of the natural ingredients for treating Aeromonas hydrophila is betel leaf extract. This study aims to analyze the effect of betel leaf extract (Piper betle L.) on Aeromonas disease hydrophila on fish fry tilapia (Piper betle L.). This study used a completely randomized design (CRD) with 5 treatments and 3 replications. The treatment used was a dose of betel leaf extract (P1) 0.4 ml, (P2) 0.6 ml, (P3) 0.8 ml, (P4) positive control, (P5) negative control. The parameters observed were survival rate, specific growth rate, feed conversion ratio, absolute length growth, erythrocytes, hemoglobin, hematocrit, leukocytes, differential leukocytes, total bacteria count, and water quality. The results of this study showed that before and after the challenge test, the best average values were P3 leukocytes (1.06 and 1.4 x 10 5 ), erythrocytes (0.90 and 0.93 x 10 5 ), hemoglobin (10.9 and 9.7), hematocrit (10.7 and 10.3), total bacteria (7 x 10 1 ). Then the worst value on P1 leukocytes (0.74 and 0.87 x 10 5), erythrocytes (0.86 and 0.75 x 10 5 ), hemoglobin (10.7 and 7.7), hematocrit (10.3 and 9.3), total bacteria (74 x 10 2 ). The study concluded that the best treatment was found in treatment 3 with a dose of 0.8 ml of betel leaf extract, which significantly increased the immune system in tilapia seeds.

Characterization of the Key Aroma Constituents in Fried Tilapia through the Sensorics Concept.

The object of this study was tilapia fish that were fried in soybean oil. Volatile compounds were extracted from the fish by ASE-HVE and were studied by GC-O-MS and the AEDA analysis method. A total of 30 aroma compounds were initially determined, and these compounds contribute to the aroma of fried tilapias. The key volatile compounds in fried tilapia were quantitatively analyzed by GC-MS, and the volatile compounds in soybean-fried tilapia were studied by flavor recombination and deletion experiments. Trimethylamine, hexanal, 2,3-dimethylpyrazine, dimethyl trisulfide, trans-2-octenal, 2,3-dimethyl-5-ethylpyrazine, (E)-2-nonenal, 2-propyl-pyridine, and (E,E)-2,4-decadienal were finally determined to be the key volatile compounds in soybean-fried tilapia.

Potential of Duckweed (Lemnaperpusilla Torr) to improve the taste of Red Tilapia (Oreochromis niloticus)

Lemna perpusilla Torr is one of the freshwater plants of the duckweed group (family Lemnaceae) spread all over the world that found in inland waters such as ponds, ponds (embung), or paddy fields. This study aims to determine Lemna’s potential use as a feed for tilapia to improve the taste. Three treatments are measured organoleptically. The N1 treatment is for tilapia fed by full Lemna. The N2 treatment is tilapia that fed 50% Lemna and 50% commercial feed. The last treatment, N3 is tilapia that given full commercial feed. Thirty-two semi-trained panelists among Research Center for Limnology workers conducted organoleptic tests on four tilapia preparations. The preparations are in the form of fried fish, whole fresh fish, fillets, and slices. The analysis of the organoleptic test is by the Kruskal Wallis test with a significant level of 10% proceed with the Dunn test if there are substantial differences. The result is that in fried tilapia, there is no real difference in organoleptic colors, odors, and preferences. However, fried tilapia found that the treatment of N2 was better than N1. The same thing also found in fresh whole fish preparations. Organoleptic colors and preferences give the result that N2 is better than N1. While in fillet preparations, the treatment of N2 and N3 compared with N1 gave significantly different effects on the organoleptic components of color and likeness. In sliced fish, significant differences found in organoleptic colors, where N1 and N2 treatments had better color appearance compared to N3. Treatment of 50% Lemna and 50% commercial feed gave better organoleptic results compared to the others.

Effect of testic brahman (Bos indicus) mixed with commercial feed and different time for genital of male and female in Tilapia (Oreochromis niloticus)

The Tilapia is hermaphrodite fish, and from larva they can changing of genital for examples male or female. Male tilapia has faster growth rate than female tilapia. Many technologies were produces genital of fish male dominant population. But to produces that genital were need to prepare for the diet, ones of that were give of the feeding. These results were used of the brahman testicles and mixed with commercial feed, the data were using by immersion method. The results were found value of male seen the larvae compared for the fry tilapia. To give that feed were used at the different time of immersion treatments. The time of immersion was separated to P1 (16 hours), P2 (32 hours), P3 (48 hours) and P0 as (control). The results were observed of male tilapia, body weight, length and water quality parameters. The results of immersion time shown of tilapia larvae very significant effect compared the female. The results were found from the age of 60 days, immersion time of P0 was observed with value of 52.83%, P1 o f85.71%, P2 of 74.49% and P3 was observed and value of 62.41%.

Determination of quality and aqua veterinary drugs residues of some cultured fish and their processed products

This study was planned to determine the quality and aqua veterinary drug residues of some cultured fish and their processed products. Fish samples of the Nile tilapia (Oreochromis niloticus) and mullet (Mugil cephalus) were purchased from a fish farm at El-Fayoum, Egypt during September 2020 and cooked by grilling and frying methods. Quality indices of pH, total volatile nitrogen (TVN), trimethylamine (TMA), thiobarbituric acid (TBA) as well as safety parameters; eight aqua veterinary drugs residues, total plate count (TPC), and spore-forming bacteria (SFB) were determined. Results showed that values of quality parameters were based mainly on fish species and cooking method conditions and they were within the maximum permissible limits (MPLs). With regard to safety, although TPC and SFB were among permitted counts the raw tilapia samples contained 7428ppb tetracycline and 5000ppb aminoglycosides, respectively, however, residues of these compounds were neither detected in grilled or fried tilapia products nor in raw, grilled or fried mullet products as well. In conclusion, although cultured fish samples are of good quality they are contaminated, especially raw tilapia, by high levels with tetracycline and aminoglycosides residues. It is worthy to mention that, cooking methods could reduce those compounds up to 100%. Hence, in this study, the usage of drugs was recommended to never exceed the MPLs and to ensure withdrawal periods before fish marketing.

PREFERENSI ATLET OKU SELATAN TERHADAP CITA RASA OLAHAN IKAN MUJAIR DENGAN METODE C-SAT (CUSTOMER SATISFICATION)

Tilapia is one of the fresh water fish, and one of commodites that was cultivated by OKU Selatan specialy Ranau lake. Around the Ranau lake, tilapia usually was processed to grilled tilapia fish, turmeric seasoning, pindang Palembang and fried fish. The tilapia products had off-falvour so OKU Selatan athete ate other food like fried rice, fried chicken and tempeh, soto, instan noodles and etc. The aims for this research was to identified preference of OKU Selatan athlete to tilapia product, and analyzied flavor preference of OKU Selatan athlete based on five senses and cooking method. The data was calculated by C-Sat (Customer Satisfication). The results showed that the highest preference of OKU Selatan athelete to tilapia product at grilled tilapia such as 6.4 point and the lowest preference at Pindang such as 4.8 point. The highest preference of OKU Selatan to sensation taste at umami such as 9.9 point and the lowest at the bitter taste such as 1.5 point. The highest prefence of OKU Selatan to tilapia taste due processing at fried tilapia processed such as 9.8 point and the lowest at boiled tilapia processed such as 5.2 point. Athelete of OKU Selatan most prefer to tilapia that has umami sensation by fryied processed. Keywords : flavor, OKU Selatan athlete, tilapia product, C-Sat

Revealing a key inhibitory mechanism of 2‐amino‐3,8‐dimethylimidazo[4,5‐f] quinoxaline via trapping of methylglyoxal

The inhibitory effects of vitamins (nicotinic acid, pyridoxamine [PM], and l-ascorbic acid) and phenolic acids (ferulic acid and p-coumaric acid) on the formation of 2-amino-3,8-dimethylimidazo [4,5-f] quinoxaline (MeIQx) were studied in a glycine/glucose/creatinine model system and fried tilapia cakes. The results showed that PM was the most potential inhibitor and the inhibition rates reached 82.72% and 78.54% in model system and fried tilapia cakes, respectively. Detailed formation mechanism of MeIQx was put forward to find the inevitable species in the non-free radical formation mechanism of MeIQx. Dose-dependent analysis of PM on methylglyoxal (MGO ) and MeIQx formation were studied by using model systems and the results showed that MGO and MeIQx were both reduced about 60% in reaction mixtures when the molar ratio of PM to glycine was 1:16, which indicated that MGO is a key intermediate on the pathway of MeIQx formation. Quantum chemistry calculations showed that PM can act as a useful inhibitor to inhibit the formation of MeIQx and react with MGO to form new compounds. A pathway for the inhibitory activity of PM against MeIQx formation was proposed. PRACTICAL APPLICATION: Pyridoxamine was the most effective inhibitor against heterocyclic aromatic amines (HAAs) and could be applied to a variety of food systems. While the inhibitory mechanism is still unclear. Detailed formation mechanism of MeIQx was put forward first and suggested methylglyoxal as an inevitable species in the non-free radical formation mechanism of MeIQx in this study. Pyridoxamine trapping methylglyoxal is likely a key mechanism against the generation of MeIQx was demonstrated by quantum chemistry calculation and experimental demonstration. These findings may provide effective suggestions for reducing HAAs and similar toxicants in daily cuisine.

The effective inhibition of the formation of heterocyclic aromatic amines via adding black pepper in fried tilapia fillets

The effects of different concentrations of black pepper (0%, 0.5%, 1.0%, and 1.5%, wt/wt) and frying time (4, 8, and 12 min) on the contents of six heterocyclic aromatic amines (HAAs) were investigated in fried tilapia fillets. The level of total HAAs increased analogously with the increase in frying time, the total content of HAAs in fried tilapia fillets with or without black pepper ranged from 6.4 to 24.72 ng/g, and 10.43 to 33.19 ng/g, respectively. The inhibition rates of 1.0% of black pepper on 2-amino-1-methyl-6-phenylimidazo[4,5-f] pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx) levels were found to be 100% when the samples fried for 8 min, which were same as the samples fried for 12 min. The study demonstrated that 2-amino-3,4-dimethylimidazo[4,5-f] quinoline (MeIQ) and 9H-pyrido[3,4-b]-indole (Norharman) were positively correlated with the degree of protein oxidation and that black pepper can greatly reduce the content of total HAAs. Practical applications Black pepper is often added for improving flavor in foods. Moreover, due to its antioxidant properties, it can be considered as one of safe and natural additives to inhibit HAAs formation. This is the first study about the inhibition of HAAs by adding black pepper in tilapia fillets before frying. The experimental results showed that black pepper was highly effective in inhibiting HAAs, and the addition of 1.0% of black pepper led to the greatest inhibition of total HAAs in fried fish fillets. A useful approach was provided through this study to control the formation of hazardous HAAs in fried fish products, which eventually help improve the safety and quality of fried aquatic products.

Identification of ectoparasites in Fry Tilapia (Oreochromis Niloticus) in Aquaculture Pond

This study was to determine of ectoparasite type in Fry Tilapia (Oreochromis niloticus) in aquaculture, 30 of tilapia were used for this experiment. This research investigated on April to May 2018. The taking of fish samples was carried out in the Aquaculture pond of Desa Baru of Ladang Bambu District of Medan Tuntungan. Aspects of identification of ectoparasite were obtained in gills, body mucus, and fin. The results were infected to Fry Tilapia (Oreochromis niloticus). There are 4 types of ectoparasites were infect to Fry Tilapia, that is Trichodina sp., Ichthiopthirus multifiliis sp., Dactylogyrus sp., and Gyrodactylus sp.

Efficacy of Streptococcus agalactiae vaccine strains N3M and N4M in fry tilapia infected by different strains of S. agalactiae

<p align="center"><strong>ABSTRACT</strong></p><p class="Default"><em> </em></p><p><em>Streptococcus agalactiae </em>is a major bacterial streptococcosis disease that infects tilapia. This study aimed to analyze a specific and nonspecific immune system in fry tilapia that has been given with <em>S. agalactiae </em>vaccine from N<sub>3</sub>M and N<sub>4</sub>M strain and examine the protective immunity against <em>S. agalactiae</em> N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1, </sub>and N<sub>14</sub>G strains infection. Fry tilapia used in this study has the weight of 7.086±0.948 g and length of 7.443±0.353 cm. The <em>S. agalactiae</em> strains that used were N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1</sub>,and N<sub>14</sub>G. Fry tilapia was vaccinated through intraperitoneal injection method with 0.1 mL per fish of N<sub>3</sub>M and N<sub>4</sub>M vaccines. Fish reared in aquarium sizing of 60×30×50 cm<sup>3</sup> with a density of 10 fishes aquarium<sup>-1</sup>. Two weeks after vaccination, fry tilapia was tested with 0.1 mL fish<sup>-1</sup> of each N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1</sub>, and N<sub>14</sub>G strains through intraperitoneal injection method. Antibody level measured with indirect enzym-linked immunosorbent assay<em> </em>(ELISA) method. The result of antibody level in vaccinated fish after vaccination of N<sub>3</sub>M, N<sub>4</sub>M vaccine, N<sub>3</sub>M and N<sub>4</sub>M control were 0.767; 0.743; 0.587; and 0.544, respectively. Relative percent survival in N<sub>3</sub>M vaccinated fish after challenged with N<sub>3</sub>M and N<sub>4</sub>M was 87.50% dan 64.70%, respectively, otherwise in N<sub>4</sub>M vaccinated fish was 62.50% dan 76.47%, respectively. N<sub>3</sub>M and N<sub>4</sub>M vaccine strain have better protection as only if it tested with similar bacteria strain.</p><p> </p><p>Keywords: formalin-killed cell, tilapia, protection, <em>S</em><em>treptococcus</em><em> </em><em>agalactiae</em>, strains</p><p><strong> </strong></p><p><strong> </strong></p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p class="Paragraf"><em>Streptococcus agalactiae</em> merupakan bakteri utama penyakit streptococcosis yang menginfeksi ikan nila. Tujuan penelitian ini adalah menganalisis sistem imun spesifik dan nonspesifik pada benih ikan nila yang diberi vaksin <em>S. agalactiae </em>strain N<sub>3</sub>M dan N<sub>4</sub>M serta mengkaji imunitas protektif terhadap infeksi <em>S. agalactiae </em>strain N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1</sub>, dan N<sub>14</sub>G. Benih ikan nila yang digunakan memiliki bobot 7,086±0,948 g dan panjang 7,443±0,353 cm. Bakteri yang digunakan adalah <em>S. agalactiae </em>strain N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1</sub>,danN<sub>14</sub>G. Benih ikan nila divaksinasi menggunakan metode injeksi pada bagian intraperitoneal sebanyak 0,1 mL ekor<sup>-1</sup> vaksin N<sub>3</sub>M dan N<sub>4</sub>M. Pemeliharaan dilakukan pada akuarium berukuran 60×30×50 cm<sup>3</sup> dengan kepadatan 10 ekor akuarium<sup>-1</sup>. Dua minggu setelah vaksinasi benih ikan diuji tantang dengan strain bakteri N<sub>3</sub>M, N<sub>4</sub>M, N<sub>17</sub>O, NK<sub>1</sub>, <sub> </sub>danN<sub>14</sub>G menggunakan metode injeksi pada bagian intraperitoneal dengan dosis 0,1 mL ekor<sup>-1</sup>. Level antibodi diukur dengan metode <em>indirect enzym-linked immunosorbent assay </em>(ELISA). Hasil menunjukkan level antibodi ikan setelah vaksinasi pada perlakuan vaksin N<sub>3</sub>M, N<sub>4</sub>M, kontrol N<sub>3</sub>M, dan kontrol N<sub>4</sub>M berturut-turut 0,767; 0,743; 0,587; dan 0,544. Kelangsungan hidup relatif ikan yang divaksin N<sub>3</sub>M setelah diuji tantang dengan strain N<sub>3</sub>M dan N<sub>4</sub>M berturut-turut 87,50% dan 64,70%, sedangkan pada ikan yang divaksin N<sub>4</sub>M berturut-turut 62,50% dan 76,47%. Vaksin strain N<sub>3</sub>M dan N<sub>4</sub>M memiliki proteksi lebih baik jika diuji tantang dengan strain bakteri yang sama.<em></em></p><p class="Default"> </p><p class="Paragraf">Kata kunci: <em>formalin-killed cell</em>, <em>Streptococcus agalactiae</em>, strain, proteksi, nila</p><p> </p><p> </p>

Levels of Polycyclic Aromatic Hydrocarbons in Fried Tilapia Fish (O. niloticus) using GC-MS

This work was conducted to determine the safety levels of polycyclic aromatic hydrocarbons (PAHs) in deep oil fried tilapia fish obtained from two fish farms (A and B) located in Fayoum governorate, Egypt during June 2016. PAH compounds were determined by GC-MS. Results showed that the levels of total PAHs were 36.8 and 40.5 µg/kg in both fried samples from farm A and B. Levels of B[a]P Equivalent of PAHs in fried Tilapia fish were 1.7099 and 0.0405 in farm A and B samples. Based on our results, it could be concluded that benzo[a]pyrene compound was not detectable in all fried samples which are considered as a safe product for human consumption.

Use of tuna industry waste in diets for Nile tilapia, Oreochromis niloticus, fingerlings: effect on digestibility and growth performance

During the tuna canning process, about 52~54% of the total weight of the fish is discarded as waste, which can be processed in order to obtain tuna byproducts meal (TBM), or stabilized as tuna silage hydrolysates (TSH). Both products were tested as replacements of soybean meal (SBM), in diets for fingerling male Nile tilapia Oreochromis niloticus. Seven test diets were isonitrogenous (35% CP) and isoenergetic (19 kJ g-1): a basal diet contained SBM as main protein source (TSH0); four experimental diets had increasing inclusion levels of TSH replacing 25, 50, 75 and 100% of the SBM protein. The sixth diet contained TBM as sole protein source, and a commercial feed for tilapia was used as reference diet (RD). The diets were fed for eight weeks to triplicate tanks, each with 15 fry tilapia (initial weight of 0.89 ± 0.29 g). Tilapia fed the TBM diet had greater weight gain and feed intake, and lower feed conversion ratios than those fed diets containing with TSH. The RD, TSH25 and TSH50 diets gave the similar growth response. Fish fed diets TSH0, TSH75% and TSH100% showed reduced growth performance.

Use of Biochemically Improved Shrimp Industry Waste in Fry Tilapia (Oreochromis Niloticus, Linnaeus 1758) Diets: Effects on Growth Performance and Carcass Composition

To evaluate the nutritional quality of the shrimp by-products four approximately isonitrogenous (32 ± 2% crude protein) diets containing different types of shrimp waste meal were fed to duplicate groups of ten fry with an initial mean weight 1.43 ± 0.22g /fish for forty two (42) days. Fishes fed with diet D had the highest mean weight gain (MWG) and specific growth rate (SGR) and those fed with the control diet A had the lowest MWG and SGR. There were no noticeable change in food conversion ratio (FCR) of the fishes fed with diets B, C and D which are significantly different from the FCR of those that fed with control diet A. The survival of fry tilapia ranged from 70 to 100%, being 70% for D, 80% for B, 90% for C and 100% for A. There were no significant differences in body protein content among the fish fed with diets B, C, D and the initial fish. The lowest body protein was obtained in the fish fed with control diet. The tilapia fed with control diet had the highest body lipid content as compared to the initial fish. However, there were no significant differences in body lipid content among the fish fed test diets B, C and D as compared to the initial fish. The variations in body ash content of initial fish and those fed with test diets were significantly different. The initial fish had the highest body ash content.

Effect of dietary protein level, initial body weight, and their interaction on the growth, feed utilization, and physiological alterations of Nile tilapia, Oreochromis niloticus (L.)

A 10-week feeding trial was conducted to assess the interaction between dietary protein level and fish weight on the growth, feed utilization, and physiological alterations of Nile tilapia, Oreochromis niloticus (L.). Fish were categorized into three weights; 0.4–0.5 g (fry), 17–22 g (fingerling), and 37–43 g (advanced juvenile). Diets containing 25, 35, or 45% crude protein (CP) were fed by triplicate to each fish weight. Fish growth, feed utilization, and protein turn-over were significantly affected by dietary protein level and fish weight, meanwhile their interaction significantly affected specific growth rate and protein efficiency ratio (PER) only. Unionized ammonia was significantly affected by dietary protein level, fish weight, and their interaction. Moreover, protein and lipid contents in whole-body of fish were significantly affected by dietary protein level and fish weight, while their interaction significantly affected total lipids content only. Ash content significantly differed with fish weight only. The optimum feed conversion ratio (FCR) was obtained with fry tilapia fed the 45%-CP diet; whereas, the poorest FCR was observed for advanced juveniles fed the 25%-CP diet. The lowest PER and protein productive value (PPV) values were obtained with the 45%-CP diet fed to advanced juveniles; whereas, the highest values were obtained with the 25%-CP diet fed to fry. The highest protein growth rate (PGR) was obtained with fry tilapia fed the 45%-CP diet, while the lowest one was obtained with advanced juvenile fed the 25%-CP diet. Hematological variables were significantly affected by protein level, fish weight, and their interaction except for serum lipids which was not significantly affected by the interaction. Activities of aspartate amninotransferase (AST) and alanine aminotransferase (ALT) in serum, liver, and muscles were significantly affected by dietary protein level and fish weight. The interaction significantly affected enzyme activities except for serum AST, which was not significant. The optimum growth of fry tilapia was obtained at 45% CP, while fingerling and advanced juvenile showed optimum growth performance with the 35%-CP diet. Excess protein in fingerling and advanced juvenile might be deaminated and used as energy source resulting in increased blood glucose, protein, and lipids as well as increased unionized ammonia in the environment.