1 Introduction

Tilapia, particularly Nile tilapia (Oreochromis niloticus), is a widely farmed fish species known for its adaptability and rapid growth, making it a staple in aquaculture worldwide. The nutritional quality of tilapia fillets is influenced by the fish's diet, which can be manipulated to enhance specific health benefits for human consumption. Recent studies have focused on improving the fatty acid profile of tilapia fillets, particularly by increasing the content of omega-3 polyunsaturated fatty acids (PUFAs), which are essential for human health (Shapira et al., 2009; Baldissera et al., 2020; Ibrahim et al., 2022).

Omega-3 fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are crucial for maintaining cardiovascular health, reducing inflammation, and supporting brain function. However, typical diets, especially in Western countries, are often deficient in these essential fatty acids. Increasing the omega-3 content in commonly consumed fish like tilapia can help bridge this nutritional gap. Various dietary interventions, such as the inclusion of fish oil, algae meal, and other omega-3-rich supplements, have been explored to enhance the omega-3 content in tilapia fillets (Wu et al., 2017; Stoneham et al., 2018; Duarte et al., 2020).

This study aims to evaluate the effectiveness of different dietary manipulations in increasing the omega-3 fatty acid content in tilapia fillets. By synthesizing findings from multiple studies, this report seeks to provide a comprehensive understanding of the most effective strategies for enhancing the nutritional quality of tilapia through dietary interventions. The specific objectives are to assess the impact of various omega-3-rich dietary supplements on the fatty acid profile of tilapia fillets, to evaluate the growth performance and health benefits associated with these dietary interventions, and to identify the most promising dietary strategies for commercial tilapia farming to improve the omega-3 content in fillets, thereby enhancing their nutritional value for human consumption. By achieving these objectives, this study will contribute to the development of more nutritious and health-promoting tilapia products, supporting both aquaculture sustainability and public health.

2 Current Nutritional Profile of Tilapia Fillets

2.1 Basic nutritional composition

Tilapia fillets are a popular choice for consumers due to their mild flavor and versatility in cooking. The basic nutritional composition of tilapia fillets includes a high protein content, low fat, and a variety of essential vitamins and minerals. Typically, tilapia fillets contain around 20%~23% protein, making them an excellent source of lean protein for human diets. The fat content is relatively low, usually around 2%~3%, which includes both saturated and unsaturated fats. Key vitamins and minerals found in tilapia fillets include vitamin D, vitamin B12, selenium, and phosphorus, all of which contribute to various health benefits (Stoneham et al., 2018; Liu et al., 2019; Duarte et al., 2020).

2.2 Omega-3 fatty acid content

The omega-3 fatty acid content in tilapia fillets is a critical aspect of their nutritional profile, given the well-documented health benefits of these fatty acids, including cardiovascular health and anti-inflammatory properties. However, the natural omega-3 content in tilapia is relatively low compared to other fish species. Studies have shown that the omega-3 content can be significantly enhanced through dietary manipulations. For instance, the inclusion of fish oil or algae meal in tilapia diets has been shown to increase the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the fillets. One study demonstrated that feeding tilapia with a diet containing 8.77% algae meal increased the total omega-3 content in the fillets from 151.2 mg to 438.7 mg per 113 g serving (Stoneham et al., 2018). Another study found that supplementing tilapia diets with fish oil resulted in higher levels of EPA and DHA, with a notable improvement in the omega-6 to omega-3 ratio (Al-Souti et al., 2012; Duarte et al., 2020).

2.3 Factors influencing nutritional quality

Several factors influence the nutritional quality of tilapia fillets, including diet composition, environmental conditions, and genetic factors. The type and amount of dietary oils used in tilapia feed play a significant role in determining the fatty acid profile of the fillets. For example, replacing corn oil with fish oil or algae meal in the diet has been shown to enhance the omega-3 content and improve the overall lipid profile of the fillets (Ng et al., 2013; Stoneham et al., 2018; Duarte et al., 2020). Additionally, the duration of dietary supplementation can affect the fatty acid composition, with longer supplementation periods generally leading to higher omega-3 levels (Duarte et al., 2020). Environmental factors such as water quality, temperature, and stocking density can also impact the growth and nutritional quality of tilapia. Optimal water conditions and proper management practices are essential for maintaining fish health and ensuring high-quality fillets. Furthermore, genetic selection and breeding programs aimed at improving growth rates and feed efficiency can indirectly influence the nutritional composition of tilapia fillets (Baldissera et al., 2020; Ibrahim et al., 2022). In conclusion, the nutritional profile of tilapia fillets can be significantly enhanced through targeted dietary manipulations, particularly by increasing the omega-3 fatty acid content. Understanding the factors that influence the nutritional quality of tilapia is crucial for developing effective strategies to produce healthier and more nutritious fish for consumers.

3 Dietary Manipulations to Enhance Omega-3 Content

3.1 Overview of dietary strategies

Enhancing the omega-3 fatty acid content in tilapia fillets is a significant focus in aquaculture nutrition, driven by the health benefits associated with omega-3 consumption. Various dietary strategies have been explored to achieve this goal, including the incorporation of omega-3 rich feed ingredients and alternative feed sources. These strategies aim to improve the nutritional profile of tilapia fillets without compromising growth performance or overall fish health.

3.2 Use of omega-3 rich feed ingredients

One effective approach to increasing the omega-3 content in tilapia fillets is the use of omega-3 rich feed ingredients such as fish oil and algae meal. A study demonstrated that replacing corn oil with fish oil (FO) or algae meal (AM) in tilapia diets significantly improved the fatty acid profile of the fillets. The best results were observed with a diet containing 8.77% algae meal, which increased the total omega-3 content in the fillets from 151.2 mg to 438.7 mg per 113 g serving and improved the omega-6 to omega-3 ratio from 5.19 to 1.29 (Stoneham et al., 2018). Another study highlighted the incorporation dynamics of dietary vegetable oils, including fish oil, into tilapia tissues, showing that fish oil supplementation led to a preferential accumulation of omega-3 fatty acids, particularly docosahexaenoic acid (DHA), in the fillet phospholipids (Szabó et al., 2011).

3.3. Alternative feed sources

In addition to traditional omega-3 rich ingredients, alternative feed sources have been investigated for their potential to enhance the omega-3 content in tilapia. For instance, the use of linseed oil, which is high in omega-3 fatty acids, has been shown to improve the fatty acid profile of tilapia fillets. A study found that tilapia fed a diet supplemented with linseed oil exhibited increased phagocytic activity and improved plasma protein levels, indicating enhanced health benefits alongside improved omega-3 content (Hough et al., 2016). Furthermore, the incorporation of omega-3 polyunsaturated fatty acids (PUFAs) into nanocarriers has been explored to enhance their stability and bioactivity. This innovative approach not only fortified tilapia fillets with omega-3 PUFAs but also improved fish performance, antioxidant stability, immunity, and disease resistance (Ibrahim et al., 2022). In summary, dietary manipulations involving the use of omega-3 rich feed ingredients and alternative feed sources have proven effective in enhancing the omega-3 content in tilapia fillets. These strategies not only improve the nutritional value of the fillets but also offer additional health benefits for the fish, making them a promising avenue for aquaculture nutrition.

4 Mechanisms of Omega-3 Incorporation

4.1 Digestion and absorption

The digestion and absorption of omega-3 fatty acids in tilapia begin with the breakdown of dietary lipids in the gastrointestinal tract. Enzymes such as lipases hydrolyze triglycerides into free fatty acids and monoglycerides, which are then absorbed by enterocytes in the intestine. Studies have shown that dietary supplementation with various sources of omega-3, such as fish oil, algae meal, and vegetable oils, can significantly alter the fatty acid composition in tilapia tissues. For instance, tilapia fed with diets containing fish oil or algae meal exhibited improved fatty acid profiles, with higher levels of omega-3 fatty acids in their fillets (Szabó et al., 2011; Stoneham et al., 2018; Ibrahim et al., 2022).

4.2 Metabolism of fatty acids

Once absorbed, omega-3 fatty acids undergo various metabolic processes. They are incorporated into cellular membranes as phospholipids or stored as triacylglycerols in adipose tissues. The metabolism of these fatty acids can be influenced by the type of dietary fat provided. For example, tilapia fed with diets enriched with fish oil or algae meal showed significant increases in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels in their tissues (Sarker et al., 2016; Stoneham et al., 2018; Ibrahim et al., 2022). Additionally, the use of nanoencapsulated omega-3 fatty acids has been shown to enhance their stability and bioavailability, leading to better incorporation into tilapia tissues (Baldissera et al., 2020; Ibrahim et al., 2022) (Figure 1).

In summary, the mechanisms of omega-3 incorporation in tilapia involve efficient digestion and absorption, metabolic processing, and effective deposition in fillet tissues. These processes are significantly influenced by the type and form of dietary omega-3 sources, with fish oil, algae meal, and nanoencapsulated omega-3 fatty acids showing promising results in enhancing the omega-3 content in tilapia fillets.

5 Health Benefits of Enhanced Omega-3 Content

5.1 Benefits for human consumption

Increasing the omega-3 fatty acid content in tilapia fillets offers significant health benefits for human consumers. Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are known to reduce the risk of cardiovascular diseases, improve cognitive function, and possess anti-inflammatory properties (Al-Souti et al., 2012; Stoneham et al., 2018). Studies have shown that dietary manipulations, such as the inclusion of fish oil or algae meal, can significantly enhance the omega-3 content in tilapia fillets, thereby improving their nutritional value (Al-Souti et al., 2012; Stoneham et al., 2018). Additionally, the incorporation of omega-3 fatty acids into nanocarriers has been shown to enhance their stability and bioactivity, further fortifying the fillets with these beneficial nutrients (Ibrahim et al., 2022).

5.2 Impact on fish health and growth

The enhancement of omega-3 fatty acids in tilapia diets not only benefits human consumers but also positively impacts fish health and growth. Studies have demonstrated that omega-3 supplementation can improve growth performance, feed conversion ratios, and overall fish health. For instance, dietary supplementation with nanoencapsulated nerolidol and omega-3 fatty acids has been shown to promote growth, reduce oxidative stress, and enhance the antioxidant capacity of tilapia (Baldissera et al., 2020; Ibrahim et al., 2022). Furthermore, omega-3 enriched diets have been associated with improved immune responses and increased resistance to diseases such as Aeromonas hydrophila (Ibrahim et al., 2022). These benefits contribute to the overall sustainability and productivity of tilapia aquaculture.

5.3 Consumer acceptance and market potential

The market potential for omega-3 enriched tilapia fillets is substantial, given the growing consumer awareness of the health benefits associated with omega-3 fatty acids. Enhanced omega-3 content in tilapia fillets can attract health-conscious consumers and create new market opportunities for the aquaculture industry (Stoneham et al., 2018; Reis et al., 2018). Additionally, the use of natural products and innovative technologies, such as nanotechnology, in fish diets can further enhance consumer acceptance by promoting the perception of high-quality and health-promoting fish products (Baldissera et al., 2020; Ibrahim et al., 2022). The incorporation of carotenoids, such as β-carotene, lutein, and lycopene, into tilapia diets has also been shown to improve the nutritional quality and consumer appeal of the fillets (Reis et al., 2018). Overall, the strategic enhancement of omega-3 fatty acids in tilapia fillets holds significant promise for meeting consumer demand and expanding market potential.

6 Challenges and Considerations

6.1 Cost and feasibility of dietary changes

Implementing dietary changes to increase omega-3 fatty acid content in tilapia fillets involves significant cost and feasibility considerations. The use of fish oil (FO) and algae meal (AM) as dietary supplements has been shown to improve the fatty acid profile of tilapia fillets, but these ingredients can be expensive and may not be readily available in all regions. For instance, the study by (Stoneham et al., 2018) demonstrated that while both FO and AM effectively increased the omega-3 content in tilapia fillets, the cost of these supplements could be a limiting factor for widespread adoption. Additionally, the need for isocaloric, isonitrogenous, and isolipid diets to ensure consistent growth and health of the fish adds another layer of complexity and cost to the dietary formulations.

6.2 Environmental and sustainability issues

The environmental impact and sustainability of using fish oil and algae meal in tilapia diets are critical considerations. The extraction and production of fish oil can contribute to overfishing and depletion of marine resources, raising sustainability concerns. On the other hand, algae meal presents a more sustainable alternative, as it can be produced with a lower environmental footprint. However, large-scale production of algae meal still faces challenges related to resource use and environmental impact. The study by (Baldissera et al., 2020) highlights the potential of using natural products and nanotechnology to improve fish health and meat quality, suggesting that sustainable alternatives to traditional fish oil could be developed. Nonetheless, the environmental implications of these new technologies need to be thoroughly assessed.

6.3 Regulatory and safety concerns

Regulatory and safety concerns are paramount when introducing new dietary supplements into aquaculture. Ensuring that the supplements are safe for both the fish and the consumers is essential. The study by (Molnár et al., 2012) found that while vegetable oils can be used to partially substitute fish oil in tilapia diets, the long-term effects on fish health and product safety need to be carefully monitored. Additionally, the use of nanotechnology, as explored in (Baldissera et al., 2020), introduces new regulatory challenges, as the safety and environmental impact of nanoencapsulated compounds must be rigorously evaluated. Regulatory frameworks need to be updated to address these emerging technologies and ensure that they do not pose risks to human health or the environment (Arshad et al., 2022).

In summary, while dietary manipulations to increase omega-3 fatty acid content in tilapia fillets show promise, several challenges and considerations must be addressed. These include the cost and feasibility of dietary changes, environmental and sustainability issues, and regulatory and safety concerns. Addressing these challenges will be crucial for the successful implementation and acceptance of these dietary strategies in the aquaculture industry.

7 Future Directions

7.1 Research opportunities

The field of nutritional improvements in tilapia fillets through dietary manipulations presents several promising research opportunities. One key area is the exploration of alternative sources of omega-3 fatty acids. While fish oil and algae meal have shown significant improvements in the fatty acid profiles of tilapia fillets, further research could investigate other sustainable and cost-effective sources of omega-3s, such as plant-based oils or genetically modified organisms (Stoneham et al., 2018). Additionally, the long-term effects of these dietary changes on fish health and consumer health benefits warrant further investigation. Studies could also explore the potential for enhancing other nutritional components, such as vitamins and minerals, through dietary supplementation (Reis et al., 2018).

7.2 Technological innovations

Technological advancements in feed formulation and processing could play a crucial role in optimizing the nutritional content of tilapia fillets. Innovations in feed technology, such as the development of microencapsulated nutrients, could improve the stability and bioavailability of omega-3 fatty acids and other beneficial compounds in fish diets (Carbonera et al., 2016; Stoneham et al., 2018). Additionally, advancements in aquaculture systems, such as recirculating aquaculture systems (RAS), could enhance the efficiency of nutrient uptake and reduce environmental impacts (Stoneham et al., 2018). The integration of precision feeding technologies, which tailor feed delivery to the specific needs of individual fish, could further optimize growth and nutritional outcomes (Stoneham et al., 2018).

7.3 Recommendations for industry practice

For the aquaculture industry, adopting dietary strategies that enhance the omega-3 content of tilapia fillets can provide a competitive edge in the market. It is recommended that producers consider incorporating algae meal or fish oil into tilapia diets, as these have been shown to significantly improve the fatty acid profiles of the fillets (Stoneham et al., 2018). Additionally, the inclusion of carotenoids such as β-carotene, lutein, and lycopene can enhance the nutritional quality and stability of the fillets, even after cooking (Reis et al., 2018). Industry stakeholders should also invest in research and development to explore new feed ingredients and technologies that can further enhance the nutritional value of tilapia products (Carbonera et al., 2016). Finally, clear labeling of the nutritional benefits of omega-3 enriched tilapia can help educate consumers and drive market demand.

8 Concluding Remarks

The research on nutritional improvements in tilapia fillets through dietary manipulations has demonstrated significant advancements in enhancing the omega-3 fatty acid content. Various studies have shown that incorporating different sources of omega-3 fatty acids, such as fish oil, algae meal, and linseed oil, into the diets of tilapia can substantially improve the fatty acid profile of the fillets. For instance, the use of algae meal at 8.77% in the diet resulted in a significant increase in total omega-3 content and a favorable n-6:n-3 ratio in tilapia fillets. Additionally, supplementation with linseed oil not only improved the omega-3 content but also enhanced the immunological responses of the fish. Furthermore, the inclusion of a blend of oils and vitamin E in the diet increased the levels of alpha-linolenic acid and improved the antioxidant capacity of the fillets.

Omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are essential for human health, offering benefits such as reduced inflammation, improved cardiovascular health, and enhanced cognitive function. Enriching tilapia fillets with omega-3 fatty acids through dietary manipulations not only improves the nutritional value of the fish but also provides a healthier food option for consumers. This enrichment can help meet the dietary needs of populations that may have limited access to traditional sources of omega-3, such as fatty fish. Moreover, the improved fatty acid profile in tilapia fillets can attract new market opportunities and increase the economic value of aquaculture products.

Based on the findings, it is recommended that aquaculture practices incorporate omega-3 rich dietary supplements, such as algae meal, fish oil, and linseed oil, to enhance the nutritional quality of tilapia fillets. Specifically, diets with higher levels of algae meal (e.g: 8.77%) have shown the most significant improvements in omega-3 content and should be considered for large-scale implementation. Additionally, the inclusion of antioxidants like vitamin E can further enhance the health benefits of the fillets by improving their antioxidant capacity. Future research should continue to explore the optimal combinations and concentrations of these supplements to maximize the health benefits and economic viability of omega-3 enriched tilapia.

Acknowledgments

The authors sincerely thank the two anonymous peer reviewers for their valuable comments and suggestions on the manuscript.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

Reference

Al-Souti A., Al-Sabahi J., Soussi B., and Goddard S., 2012, The effects of fish oil-enriched diets on growth feed conversion and fatty acid content of red hybrid tilapia Oreochromis sp., Food Chemistry, 133: 723-727.

https://doi.org/10.1016/J.FOODCHEM.2012.01.080

Arshad N., Samat N., and Lee L., 2022, Insight into the relation between nutritional benefits of aquaculture products and its consumption hazards: a global viewpoint, Frontiers in Marine Science, 9: 925463.

https://doi.org/10.3389/fmars.2022.925463

Baldissera M., Souza C., Zeppenfeld C., Velho M., Klein B., Abbad L., Ourique A., Wagner R., Silva A., and Baldisserotto B., 2020, Dietary supplementation with nerolidol nanospheres improves growth antioxidant status and fillet fatty acid profiles in Nile tilapia: benefits of nanotechnology for fish health and meat quality, Aquaculture, 516: 734635.

https://doi.org/10.1016/j.aquaculture.2019.734635.

Carbonera F., Montanher P., Figueiredo I., Bonafé E., Júnior O., Sargi S., Gonçalves R., Matsushita M., and Visentainer J., 2016, Lipid composition and antioxidant capacity evaluation in tilapia fillets supplemented with a blend of oils and Vitamin E, Journal of the American Oil Chemists' Society, 93: 1255-1264.

https://doi.org/10.1007/S11746-016-2869-7.

Duarte F., Paula F., Prado C., Santos R., Rezendea C., Gebara C., and Lage M., 2020, Better fatty acids profile in fillets of Nile Tilapia (Oreochromis niloticus) supplemented with fish oil, Aquaculture, 736241.

https://doi.org/10.1016/j.aquaculture.2020.736241.

Hough T., Glaze C., Blumenthal E., and Mustafa A., 2016, Effects of omega-3 fatty acid supplementation on aquaponics system-raised tilapia (Oreochromis niloticus X Oreochromis aureus) growth physiology and immunology, Journal of Applied Aquaculture, 28: 119-130.

https://doi.org/10.1080/10454438.2016.1175830.

Ibrahim D., Arisha A., Khater S., Gad W., Hassan Z., Abou-Khadra S., Mohamed D., Ismail T., Gad S., Eid S., El-Wahab R., and Kishawy A., 2022, Impact of Omega-3 fatty acids nano-formulation on growth antioxidant potential fillet quality immunity autophagy-related genes and aeromonas hydrophila resistance in nile tilapia (Oreochromis niloticus), Antioxidants, 11(8): 1523.

https://doi.org/10.3390/antiox11081523.

Ibrahim D., El-Hamid M., Al-zaban M., Elhady M., El-Azzouny M., ElFeky T., Sadik G., Samy O., Hamed T., Albalwe F., Alenezi M., and Omar A., 2022, Impacts of fortifying nile tilapia (Oreochromis niloticus) diet with different strains of microalgae on its performance fillet quality and disease resistance to aeromonas hydrophila considering the interplay between antioxidant and inflammatory response, Antioxidants, 11(11): 2181.

https://doi.org/10.3390/antiox11112181.

Liu Y., Jiao J., Gao S., Ning L., Limbu S., Qiao F., Chen L., Zhang M., and Du Z., 2019, Dietary oils modify lipid molecules and nutritional value of fillet in Nile tilapia: a deep lipidomics analysis, Food chemistry, 277: 515-523.

https://doi.org/10.1016/j.foodchem.2018.11.020.

Molnár T., Biró J., Hancz C., Romvári R., Varga D., Horn P., and Szabó A., 2012, Fatty acid profile of fillet liver and mesenteric fat in tilapia (Oreochromis niloticus) fed vegetable oil supplementation in the finishing period of fattening, Archives Animal Breeding, 55: 194-205.

https://doi.org/10.5194/AAB-55-194-2012.

Ng W., Chong C., Wang Y., and Romano N., 2013, Effects of dietary fish and vegetable oils on the growth tissue fatty acid composition oxidative stability and vitamin E content of red hybrid tilapia and efficacy of using fish oil finishing diets, Aquaculture, 372: 97-110.

https://doi.org/10.1016/J.AQUACULTURE.2012.10.030.

Reis E., Galuch M., Silveira R., Santos H., Sary C., Magon T., Figueiredo I., Ribeiro R., Visentainer J., and Santos O., 2018, Fatty acid composition and carotenoids in raw and grilled tilapia gift fillets supplemented with Lycopene β-Carotene and Lutein, Journal of the Brazilian Chemical Society, 29: 1742-1750.

https://doi.org/10.21577/0103-5053.20180049.

Sarker P., Kapuscinski A., Lanois A., Livesey E., Bernhard K., and Coley M., 2016, Towards sustainable aquafeeds: complete substitution of fish oil with marine Microalga Schizochytrium sp., PLoS ONE, 11(6): e0156684.

https://doi.org/10.1371/journal.pone.0156684.

Shapira N., Weill P., Sharon O., Loewenbach R., and Berzak O., 2009, n-3 PUFA fortification of high n-6 PUFA farmed tilapia with linseed could significantly increase dietary contribution and support nutritional expectations of fish, Journal of Agricultural and Food Chemistry, 57(6): 2249-2254.

https://doi.org/10.1021/jf8029258.

Stoneham T., Kuhn D., Taylor D., Neilson A., Smith S., Gatlin D., Chu H., and O'keefe S., 2018, Production of omega-3 enriched tilapia through the dietary use of algae meal or fish oil: Improved nutrient value of fillet and offal, PLoS ONE, 13(4): e0194241.

https://doi.org/10.1371/journal.pone.0194241.

Szabó A., Mézes M., Hancz C., Molnár T., Varga D., Romvári R., and Fébel H., 2011, Incorporation dynamics of dietary vegetable oil fatty acids into the triacylglycerols and phospholipids of tilapia (Oreochromis niloticus) tissues (fillet liver visceral fat and gonads, Aquaculture Nutrition, 17(2): e132-e147.

https://doi.org/10.1111/J.1365-2095.2009.00743.X.

Wu F., Jiang M., Wen H., Liu W., Tian J., Yang C., and Huang F., 2017, Dietary vitamin E effects on growth fillet textural parameters and antioxidant capacity of genetically improved farmed tilapia (GIFT) Oreochromis niloticus, Aquaculture International, 25: 991-1003.

https://doi.org/10.1007/s10499-016-0089-7.