Tilapia Oil Research Articles

Exogenous Fatty Acids Remodel the Muscle Fatty Acids Composition of the GIFT Tilapia (Oreochromis niloticus)

To reduce the negative impact of fish oil substitutes on the fatty acid composition of farmed fish, this experiment utilized different types of oils as dietary lipid sources for GIFT tilapia. Tilapia oil (FO) was used as the control, along with corn oil (CO), linseed oil (LO), algae oil (AO), and a mixture of linseed oil and algae oil in various ratios of 1 : 2, 1 : 1, and 2 : 1 (LA12, LA11, and LA21) to reshape the fatty acid profile of GIFT tilapia (0.205 ± 0.005 g) in the muscle. The weight gain and specific growth rate of tilapia in the LO and control groups were significantly higher than in other treatments (P<0.05). Meanwhile, despite the AO group exhibited the highest docosahexaenoic acid (DHA) content (P<0.05), it also exhibited the highest levels of malondialdehyde content and superoxide dismutase activity (P<0.05). The mRNA expression levels of Δ6/Δ5 fatty acyl desaturase 2 (Δ6/Δ5FADs2), Δ4 fatty acyl desaturase 2 (Δ4FADs2), acetyl-CoA carboxylase α (ACCα), and elongase of very long chain fatty acids 5 (ELOVL5) in the hepatopancreas of LO group were exhibited a significant upregulation compared to the control (P<0.05). The synthesis of DHA and eicosapentaenoic acid (EPA) in the muscles of LA12, LA11, and LA21 groups increased as the proportion of DHA decreased in the diets. In conclusion, the edible value of fatty acids of tilapia muscle, especially n-3 long-chain polyunsaturated fatty acids, can be significantly improved by adjusting the oil source in the diet through lipid metabolism.

Biodiesel and fishmeal from Nile tilapia waste: process, techno‐economic, and Monte Carlo analyses

AbstractWaste from the fish processing industry can provide a profitable and sustainable business. Industrial fish by‐products can be used as raw material to produce biofuels. This work evaluates the production process, characterization, and economic analysis for the production of biodiesel and fishmeal from tilapia processing waste. It demonstrates the potential of neutralized tilapia oil as a valuable raw material for biodiesel production. It presents specific mass, viscosity, and flash point results in line with ASTM and EN standards. Different plant sizes are modeled to evaluate biodiesel economic viability. Only the largest plant size was economically viable. In this case, the net present value (NPV) of US$ 13.89 million, the internal rate of return (IRR) of 50%, and the earnings before interest and taxes (EBIT) of US$ 7.87 million/year showed that the production of biodiesel and fishmeal using tilapia waste is economically attractive. Monte Carlo simulation was used to analyse the price distribution of biodiesel and fishmeal and their effects on the plant size. A large plant size gave 100% good scenarios, whereas a medium plant size showed 25% beneficial scenarios, and small plants did not have good scenarios. In this context, the plant size can overcome risks from price variability. The economic evaluation revealed that the production scale and the factory's location influenced the project's viability directly as raw material costs are associated with transportation expenses. The study therefore indicates that not all countries with well established tilapia production can produce biodiesel in a viable and sustainable way.

Influence of cooking methods on Oreochromis niloticus (Tilapia) oils antibacterial activity

The present study aimed to evaluate the influence of two cooking methods (boiling and microwave cooking) on antimicrobial activity of oil from Oreochromis niloticus as well as their interactions with some conventional antibiotics. Oils were extracted from raw, boiling and microwave cooked tilapia filet according to Bligh and Dyer method with chloroform/methanol/water mixture as solvent. The fatty acid profile of the crude samples was determined by gas chromatography coupled to flame ionization detector (GC-FID). The quality indices were determined by standard methods. The antibacterial activity on Gram positive and Gram negative bacteria as well as the influence on the activity of some classes of antibiotics were evaluated using the broth microdilution method. The GC-FID analysis showed that tilapia contains unsaturated fatty acids (55.64 %). The oil extracted from boiled tilapia was less oxidized compared to that obtained from the microwave cooked tilapia. The antibacterial assays revealed that all oil samples presented antibacterial activity with MIC varying from 32 to 256 mg/mL. The oil extracted from boiled tilapia was the most active over the fourteen tested bacteria. Tilapia oil was found to enhance the activity of Chloramphenicol, Ciprofloxacin, Erythromycin and Penicillin V. The overall results indicate that tilapia could be useful in preventing and improving the treatment of food-borne diseases.

Characteristics of Margarine Produced from Palm Stearin and Tilapia (Oreochromis niloticus) Oil with Carrageenan as Emulsifier

One of the tilapia waste produced is offal. The content contained in the innards of tilapia contains a lot of fat which can be used as raw material for making fish oil. Fish oil plays an important role in health because it contains a source of omega 3. The application of fish oil into margarine can be used in the manufacture of bakery products. Making margarine requires an emulsion stability, which functions so that oil and water can mix. One of the emulsion stability that can be used is carrageenan. The purpose of this study was to determine the effect of using carrageenan on the stability of the emulsion on the physical properties of margarine and to determine the best concentration. This study used a completely randomized design (CRD), using one factor, namely the carrageenan concentration of 0.1; 0.2 and 0.3. The test parameters observed were water content test, spreadability test, texture test, melting point slip test, emulsion stability and hedonic test. The result shows that carrageenan plays a significant role as an emulsifier agent for the tilapia oil based margarine as it enhances the physical chracteristics of margarine. The best test results at a concentration of 0.3% with a water content value of 14.64%. The results for the basting power were 3.93%, while the slip melting point test was 33.80ᵒC, the stability test results were 93.07%, the hedonic test was 7.37 < µ < 7.76. The research suggests that there should be further analysis of margarine shelf-life time and fatty acid composition.

Chemical characterization and solvent fractionation of tilapia oil for its potential application as human milk fat substitute.

The natural source of human milk fat substitute (HMFS) is a field worth exploring. In this study, tilapia oil was extracted and analyzed. In the triacylglycerol fraction, the contents of sn-2 palmitic acid and total sn-1,3 oleic acid and linoleic acid were 48.01% and 66.62%, respectively. The optimal solvent fractionation conditions were determined to be a tilapia oil-to-acetone ratio of 1:8 (w/v), crystallization temperature of -30°C, and crystallization duration of 16h, giving a solid fraction yield of 64.20%. In fractionated tilapia oil, the total content of 1-oleoyl-2-palmitoyl-3-linoleoylglycerol (OPL) and 1,3-dioleoyl-2-palmitoylglycerol (OPO) increased by 20.38%, as determined by reversed-phase liquid chromatography. Ultra-high-performance combined-phase chromatography combined with quadrupole time-of-flight mass spectrometry analysis showed that OPL (17.45%) was the most abundant triacylglycerol in fractionated tilapia oil, followed by OPO (13.90%). Fractionated tilapia oil is thus an excellent source of OPL and has great potential for incorporation in HMFS. PRACTICAL APPLICATION: Human milk fat substitutes are an important component of infant formulas. This work provides an excellent natural source of oil rich in OPL, which has great potential in the field of preparing human milk fat substitutes highly similar to human milk fat.

Green lubricants production from Nile tilapia waste and prediction of physical properties through molecular dynamics simulations

AbstractFish farming is a worldwide growing activity and a large amount of residues is produced in this process. The present work describes a cleaner and sustainable way to produce new lubricants from fish waste oil. Oil extracted from the Nile tilapia (Oreochromis niloticus) viscera was utilized as raw material to produce basic oil for lubricants. The products were synthesized by esterification with polyols, trimethylolpropane (TMP) and pentaerythritol (PE), using p‐toluenesulfonic acid (p‐TSA) as catalyst. The synthesized esters were characterized by infrared (IR) and nuclear magnetic resonance (NMR). Computational methods were used to predict the physical characteristics of the material. In addition, the main physicochemical properties were evaluated, as well as the thermal behavior and toxicity of the products against Artemia salina. The synthesized esters showed high viscosity indexes (VI > 150) and viscosities that fit the degree of application ISO‐46 and 150. Molecular dynamics simulations indicated that at room temperature the lubricants Tilapia fatty acid ‐ trimethylolpropane ester (T‐TMPE) and Tilapia fatty acid ‐ pentaerythritol ester (T‐PEE) are in liquid and gel states, respectively, confirming the experimental data. The products did not present toxicity against A. salina. In this research, we reinforce the potential of using tilapia oil from waste to produce green lubricants as a strategy to reduce damage to the environment, as well as the use of computational methods that collaborate to predict physical properties of lubricants.

Fish oil extraction as a by-product of Tilapia (Oreochromis sp.) fish processing with dry rendering method

Tilapia (Oreochromis sp.) is the raw material for the fish fillet industry. The fish fillet process has a by-product in the form of fish viscera which is used for tilapia fish oil production. The quality of tilapia oil in Indonesia is low and only used as and additive to animal feed. The oxidation and free radicals in fish oil can be affected by high temperature and period of extraction The purpose of this study is determine the best temperature and period of extraction with the dry rendering method which can produce fish oil with quality characteristics according to International Fish Oil Standards (IFOS). Not all of the combinations of temperature and extraction time were suitable, but in the treatment of tilapia fish oil with a temperature of 50°C, 1 hour, the FFA value was 1.18%, PV 7.51mEq / kg, p-AV 5.57mEq / kg, and TOTOX 20.59mEq / kg. The quality characteristics of tilapia fish oil from bleaching magnesium silicate have met the IFOS requirements.

Nile tilapia industrialization waste: Evaluation of the yield, quality and cost of the biodiesel production process

The biodiesel produced from Nile tilapia waste consists of an alternative material for sustainable energy production, meeting the growing energy demand without damaging the environment, being this fish waste is often disposed in the inadequate form. The aim of this work was to investigate the biodiesel production from fish oil extracted from Nile tilapia processing waste (heads), through a full factorial experimental design. The biodiesel production was carried out by homogeneous alkaline transesterification using ethanol, and potassium hydroxide (KOH) as the catalyst. The best condition of biodiesel production was evaluated as a function of the catalyst concentration, oil:ethanol molar ratio and reaction time, according to the factorial design and the responses were yield, production cost, acid value, and kinematic viscosity. The maximum yield of biodiesel was 92% (w w−1), this result was obtained with KOH 2% (w w−1), molar ratio of 1:12 (oil: ethanol) and reaction time of 4 h. This condition also ensured a product with lower VA (0.63 mgKOH g−1), lower kinematic viscosity (2.78 mm2 s−1), and a low cost of biodiesel production (0.17 US$ kg−1). TLC and FTIR analyses pointed out that the triglycerides of the fish oil were converted into biodiesel. The fatty acids profiles for the crude oil, bleached oil and biodiesel from Nile tilapia oil were determined by gas chromatography and, they have not presented significant differences in their percentage values. Based on the lipid profile obtained, Nile tilapia oil showed suitable characteristics, being a promising source for biodiesel obtainment. This study showed that bleached oil from Nile tilapia heads stands out as a promising source for producing biodiesel with high yield, positive economic potential, and better physicochemical properties.

Biodiesel produced from crude, degummed, neutralized and bleached oils of Nile tilapia waste: Production efficiency, physical-chemical quality and economic viability

Crude oil extracted from tilapia heads and oils obtained from different steps of its refinement process (physically degummed, chemically degummed, neutralized, and bleached oils) were used as raw materials for biodiesel production. Extraction and refinement of the oil and, after, production and economic viability of the different biodiesels were performed. The heads corresponded to 45% of waste from Nile tilapia and of extractions yield was around 80–85% of the crude oil. The highest biodiesel yields were with the neutralized oil (80.35%, w w−1) and chemically bleached oil (83.55%, w w−1). The lowest biodiesel production costs were by the physical degumming, chemical degumming, and neutralization steps, which presented an average cost of 0.181 US$ kg−1. Neutralized oil in the transesterification reaction, besides presenting the lowest biodiesel production cost, provided a suitable product with the acid value, kinematic viscosity, and flash point according to ASTM standard for biodiesel. Regardless of the refinement process, the degradation ranges of the oil samples were 350–550 °C. TLC, GC, and FTIR confirmed the triglycerides conversion from tilapia oil into biodiesel. Based on results, Nile tilapia neutralized oil showed suitable characteristics, becoming a promising source for biodiesel production of the quality and economically viable.

Tilapia oil, poultry offal oil and their combinations, replacing soybean oil, for tilapia fingerlings

With the objective of evaluating the soybean oil replacement by tilapia oil and poultry oil for Nile tilapia fingerlings, 240 reversed tilapia fingerlings with an individual weight of approximately 0.6 ± 0.11 grams that were stored in 30 aquariums of 50 liters (6T x 5R), in the quantity of 8 units / aquarium, where they were fed with 65% lipid rations containing soybean oil (SO), tilapia oil (TO), poultry oil (PO), and their SO+TO, SO+PO, TO+PO mixtures of equal parts as a lipidic source in practical diets during 50 days. The performance parameters, the carcass composition and the fatty acids content both on the fillet and the innards were verified. The performance, survival, weight gain, and the feeding conversion characteristics were not influenced by the diet. The carcass composition on both the fillet and the innards were not influenced by the source of lipids in the content of moisture and lipids. In general, the fatty acids profile reflected the diets one with the decrease of polyunsaturated fatty acids and the increase of saturated and monounsaturated fatty acids with the replacement. Therefore, tilapia oil, poultry oil, as well as their mixtures can totally or partially replace the soybean oil in diets for Nile tilapia fingerlings without injury to the performance.

Comparative study of synthetic and natural antioxidants on the oxidative stability of biodiesel from Tilapia oil

A major obstacle in the commercialization of biodiesel is its susceptibility to oxidation when exposed to air and light. Approaches to improving the oxidative stability of biofuels include the addition of antioxidants, mixing of vegetable oils or modification of the fatty ester profile. This work aimed to evaluate the physicochemical properties of biodiesel synthesized from Tilapia oil and its oxidative degradation process after addition of both natural ethanolic extract of turmeric (Curcuma longa Linn.) and synthetics butylated hydroxyl anisole (BHA), butylated hydroxyl toluene (BHT), propyl gallate (PG) antioxidants. In addition, some thermodynamic and kinetic parameters were obtained in order to determine the activation energy during the biodiesel oxidation process from different temperatures. The physicochemical properties of biodiesel obtained after the addition of antioxidants are in accordance with current regulations, which suggests it as an excellent alternative source for the biofuel industry. The oxidative stability showed that the natural antioxidant has the best response in control of oxidative process compared to the other synthetic antioxidants. The kinetic study showed the addition of natural antioxidant to biodiesel increases the activation energy (Ea) hindering its oxidation process. These results reveal an improvement in biodiesel stability corresponding to an increase over 450%.

Identifikasi Asam Lemak Minyak Ikan Nila (Oreochromis niloticus), Hasil Permurnian Menggunakan Kombinasi Arang Aktif dan Bentonit

Kegiatan industri pengolahan perikanan umumnya menghasilkan limbah yang dibuang begitu saja sehingga tidak mengalami pemanfaatan kembali. Adapun komponen dari limbah ikan terdiri dari kepala, tulang-ekor, kulit, dan isi perut yang bisa dimanfaatkan sebagai minyak ikan. Salah satu faktor kendala dalam pemanfaatan minyak ikan sebagai bahan baku bagi product intermediate adalah sulitnya dalam melakukan rasio perbandingan antara minyak ikan dengan bahan lain, sehingga perlunya mengetahui komposisi asam lemak sebagai referensi formulasi aplikasi pemanfaatan limbah minyak ikan nila. Metode yang digunakan adalah metode kuantitatif yakni mengidentifikasi asam lemak pada minyak ikan nila. Analisa data menggunakan data kromatogram Gas Chromatography (GC). Berdasarkan hasil analisa bahwa komposisi asam lemak dari limbah minyak ikan nila sebagai berikut: asam lemak jenuh yang dominan adalah asam lemak palmitat sebanyak 20,96%, asam lemak tidak jenuh tunggal yang dominan adalah asam lemak oleat sebanyak 22,63%, dan asam lemak tidak jenuh ganda yang dominan adalah asam lemak linoleat sebanyak 16,77%. Sedangkan komponen asam lemak EPA dan DHA ditemukan dalam jumlah sangat kecil yakni kurang dari 0,01 %.

Identification omega 3 and 6 on the positions sn-2 triacylglycerol Nile tilapia fish oil by hydrolysis using lipase from Mucor miehei

Omega 3 and 6 are unsaturated fatty acids needed by the body for cell formation and control of inflammation. In the molecules of omega 3 and 6 fats found in the position (stereospecific numbering) sn-1, 2 and 3. The position of fatty acids affects the digestion and absorption processes in the body. In the metabolism of fat in the body, fatty acids in the sn-2 position are not hydrolyzed so they can be absorbed properly. Therefore, it is necessary to identify the position of omega 3 and 6 fatty acids in fat molecules so that the potential of fish oils Nile tilapia as a source of omega 3 and 6 can be known. Fish oils Nile is extracted with the soxhletation method. The fatty acid composition was analyzed by gas chromatography (GC) which was previously esterified using BF3, for hydrolysis of fish oil using lipase enzyme. The results showed that the composition of unsaturated fatty acids was more than saturated fatty acids. Omega-3 and 6 fatty acids in the fat molecule are found more in the sn-2 than in the sn-1+sn-3 position. Seen from the composition and position fatty acids of Nile tilapia oil which contain omega 3 and 6 and there is a sn-2 position, so that more is absorbed in fat metabolism in the body. Thus fish oils Nile tilapia has the potential as a source of omega 3 and 6 from one of the freshwater fish that is widely consumed by the public.

Determination and identification of omega 3 and 6 fatty acids position in nile tilapia oil

The fat nutritional value is determined by the composition and distribution (position) of fatty acids in glycerol molecules. Position is determined by stereospecific numbering (sn) ie sn-1, 2 and 3 positions, where the position will affect the metabolic processes in the body. This study aims to determine the components and position of omega 3 and omega 6 fatty acids in triacylglycerol of nile tilapia oil (Oreochromis niloticus L.). Nile tilapia oil is obtained by extracting the soxhletation method. Analysis of fatty acid composition by gas chromatography (GC), for determining the position of fatty acid hydrolysis by using specific immobilized lipase enzymes from Mucor miehei at sn-1,3 position. The results showed that the composition of unsaturated fatty acids is more than saturated fatty acids. The percentage of omega fatty acids at sn-2 position is higher than in sn-1 + sn-3 position. Omega 3 in sn-2 of 2.81% consisted of linolenic acid of 0.91%, EPA of 0.69%, and DHA of 1.21%, at sn-1 + sn-3 of 1.55% consisted of linolenic acid by 0.10%, EPA by 1.29% and DHA by 0.16%. Omega 6 is linoleic acid in sn-2 is 13.52% and at sn-1 + sn-3 is 1.04%. Based on the composition of fatty acid nile tilapia oil contained omega 3 and 6, and in the sn-2 position more so it is good to be consumed to improve human health.

Chemical modification of Tilapia oil for biolubricant applications

Abstract Nowadays, around 40% of the lubricant market is dominated by petroleum-derived products, resulting in a negative impact on environment. Herein, it was aimed to develop a biodegradable lubricant-grade ester using Tilapia oil as primary feedstock. The synthetic route was carried out in three steps: (1) transesterification, (2) epoxidation and (3) ring-opening reaction with different long chain alcohols, where the final esters were characterised regarding their physicochemical properties. The lubricant-grade esters showed superior biodegradability and viscosity index (>117) compared to commercial petroleum-based oils. The ester synthesized with 2-ethyl hexanol showed highest thermal stability (Tonset = 230 °C) compared to other long chain alcohols. Therefore, as mainly proposed, this study shows that esters from Tilapia oil have a great potential to obtain lubricants with high biodegradability and better physicochemical properties.

Chemical composition and thermal properties of Tilapia oil extracted by different methods

ABSTRACTFish oil is beneficial to health and its quality is significantly impacted by the extraction method. To determine the effect of various methods used to extract the oil on its chemical composition and thermal properties, tilapia oil extracted by dilute alkali hydrolysis, enzymatic hydrolysis, and microwave-assisted methods were investigated in this study. Nutrient analyses showed that freeze-dried tilapia contained fat (36.69 g/100 g freeze-dried tilapia), protein (49.95 g/100 g freeze-dried tilapia), ash (12.04 g/100 g freeze-dried tilapia) and moisture (1.21 g/100 g freeze-dried tilapia). Chemical analysis showed that the fish oil extracted by dilute alkali hydrolysis had the lowest acid value (AV) and peroxide value (POV) (AV: 0.77 mg KOH/g oil and POV: 3.76 mmol/kg oil) compared to the oil extracted using the other methods. The main fatty acid components were palmitic acid (22.78–23.16%), oleic acid (25.73–26.19%), and linoleic acid (15.69–15.98%). Furthermore, the oil extracted by dilute alkali hydrolysis showed significantly higher content of DHA+ EPA (2.30%). The thermal behaviors indicated that the aforementioned oils had significantly different crystal structures. The main endothermic peaks of fish oil extracted by dilute alkali hydrolysis, enzymatic hydrolysis and microwave-assisted methods were located at −2.03℃, −3.20℃ and −4.37℃, respectively. However, infrared spectroscopic analyses indicated them had the same characteristic functional groups. Consequently, different extraction methods significantly affect the oil’s physical and chemical properties without affecting spectral characteristics. Furthermore, these results advocated the use of alkali hydrolysis for fish oil extraction.

Relação 18:3n3/18:2n6 sobre a digestibilidade de ácidos graxos em pacu

O objetivo do presente trabalho foi determinar o efeito de dietas com relações 18:3n3/18:2n6 de: 2,98; 1,68; 1,03; 0,61 e 0,35 (tratamentos 1 a 5 respectivamente) sobre o coeficiente de digestibilidade aparente (CDA) dos ácidos graxos em dietas vegetais para juvenis de pacu (Piaractus mesopotamicus). Dezoito grupos de 16 peixes cada um foram alimentados por 34 dias com dieta controle contendo óleo de tilápia como único ingrediente de origem animal (tratamento 6). Numa segunda fase, durante 72 dias, cada dieta foi fornecida a três grupos aleatórios e, finalmente, determinados os CDAs dos ácidos graxos. A dieta controle resultou em maiores CDAs de ácidos graxos saturados (97,3%) e monoinsaturados (98,24%), e o tratamento 1, em maiores CDAs de poli-insaturados (99,25%) e 18:3n3 (99,83%). O CDA de 18:3n3 variou de forma decrescente, de acordo com a variação da relação 18:3n3/18:2n6 e foi sempre superior ao CDA do 18:2n6, apesar da ação não especí­­fica das lipases. Conclui-se que o CDA dos ácidos graxos, ou de grupos deles, aumenta com a elevação do grau de insaturação do ácido e da concentração deste na dieta e que a fluidez do óleo afeta o CDA de 18:3n3 - ALA e não o de 18:2n6 - LA, quando estes são os únicos ácidos graxos poli-insaturados do alimento.

Temporal changes in hepatic antioxidant enzyme activities after ischemia and reperfusion in a rat liver ischemia model: effect of dietary fish oil.

This study investigated the hypothesis that administration of tilapia fish oil diet would attenuate warm liver ischemia/reperfusion injury (IRI) and whether fish oil modulates prooxidant/antioxidant status. Male Wistar rats were subjected to 30 min of approximately 70% hepatic ischemia followed by 1, 12, and 24 h reperfusion. Rats were randomly divided into three groups: sham-operated group (SO), control-warm hepatic ischemia (WI) group, and Oil-WI group given tilapia oil for 3 weeks followed by liver IRI. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured in the plasma. Levels of thiobarbituric acid reactive substances (TBARS) and antioxidant enzymes as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were measured in liver fractions. In the sham group, there was no enzymatic or histological change. I/R caused significant increase in serum AST, ALT, and tissue TBARS levels. As compared to the control group, animals treated with tilapia oil experienced a significant decrease (p < 0.05) in AST and ALT levels in reperfusion periods. Tissue TBARS levels in Oil-WI group were significantly (p < 0.05) reduced as compared to control group at 60 min after reperfusion. After ischemia, 1, 12, and 24 h of reperfusion, CAT, SOD, and GPx values were the lowest in the Oil-WI group and highest in the control group and were statistically significant (p < 0.05). Histological analysis also revealed that fish oil provided some protection compared with the control group. Tilapia oil exerts a protective effect during the early phase of reperfusion, and it modulates prooxidant/antioxidant status of rat liver subjected to warm IRI.

Influence of emulsion composition and spray-drying conditions on microencapsulation of tilapia oil.

The influence of processing conditions on the microencapsulation of tilapia oil by spray drying was studied. Trehalose, gelatin, sucrose and xanthan were used as emulsion composition. The experimental parameters of spray drying such as inlet air temperature, solid content, drying air flow rate and atomizing pressure were optimized using a central composite design. Encapsulation efficiency and lipid oxidation were determined. Bulk density, powder morphology and particle size were also analyzed. Trehalose improved the glass transition temperature of wall material significantly and prevented the oxidation of the fish oil. Encapsulation efficiency reached a maximum of 90% under optimum conditions with an inlet air temperature of 121°C, a drying air flow rate of 0.65m(3)/min and a spray pressure of 100kPa.

Substituição parcial e total do óleo de soja pelo óleo de tilápia em rações para larvas de tilápia do Nilo (Oreochromis niloticus)

The present experimentwas undertaken out to evaluate the performance and the survival of Nile tilapia (Oreochromis niloticus) in the sexual reversion phase. The fish were fed with rations with different levels of tilapia oil in substitution of the soy oil. 7 larvae, with average weight of 0,012 ±0,002 g e 0,931 ±0,144 cm, respectively were used. Fish were distributed in 25 aquariuns with 15 larvae in an entirely randomly design with 5 treatments and 5 repetitions. The rations contained levels of 0,0; 2,5; 5,0; 7,5 e 10,0% of tilapia oil inclusion. Rations with 3.800 Kcal/kg of digestible energy and 38.6% of digestible protein were used. Differences for the final weight, final length, survival and condition factor were not observed. The tilapia oil can totaly substitute the soy oil in Nile tilapia larvae diets during sexual reversion.