Review

Enhancing Egg Yolk Nutrition: A Review of Moringa Leaf and Microencapsulated Fish Oil as Functional Feed Ingredients

Dian Eka Darmayani*, Iman Hernaman, Dudi, Dini Widianingrum3, Liman4, Jamila Mustabi5, Emy Saelan6

Faculty of Animal Science, Universitas Padjadjaran, Jl. Raya Bandung Sumedang KM 21, Jatinangor, Sumedang, West Java, 45363, Indonesia; 3Animal Husbandry Study Program, Faculty of Agriculture, Universitas Majalengka, Jl. KH. Abdul Halim No. 103 Majalengka 45418 West Java Indonesia; 4Department of Animal Science, Faculty of Agriculture, University of Lampung, Jl. S. Brodjonegoro No. 1, Bandar Lampung, Indonesia; 5Department of Animal Nutrition, Faculty of Animal Science, Hasanuddin University. Jl. Perintis Kemerdekaan Km. 10 Tamalanrea Makassar, South Sulawesi 90245; 6Animal Husbandry Study Program, Faculty of Agriculture, Khairun University, Ternate, Indonesia.

Received | December 10, 2025; Accepted | January 30, 2026; Published | February 19, 2026

*Correspondence | Dian Eka Darmayani, Faculty of Animal Science, Universitas Padjadjaran, Jl. Raya Bandung–Sumedang KM 21, Jatinangor, Sumedang, West Java, 45363, Indonesia; Email: [email protected]

Citation | DarmayaniDE, Hernaman I, Dudi (2026). Enhancing egg yolk nutrition: a review of moringa leaf and microencapsulated fish oil as functional feed ingredients. Adv. Anim. Vet. Sci., 14(3):517-523.

DOI | https://dx.doi.org/10.17582/journal.aavs/2026/14.3.517.523

ISSN (Online) | 2307-8316

Copyright: 2026 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

INTRODUCTION

Egg yolk is widely recognized as a biologically dynamic matrix that responds rapidly to dietary manipulation, making it an effective target for producing value-added functional eggs (Cherian, 2011). With consumer preferences increasingly shifting toward foods enriched with antioxidants, essential vitamins, and omega-3 fatty acids, interest in nutritional modulation of eggs has continued to grow (Fraeye et al., 2012). In tropical poultry production systems, functional feed ingredients such as Moringa (Moringa oleifera) leaf powder and marine fish oil have emerged as promising nutritional strategies for enhancing yolk quality and nutrient density.

Moringa leaves provide a broad spectrum of bioactive compounds, including carotenoids, vitamins A and E, polyphenols, and functional proteins, which collectively exert antioxidant activity and may influence metabolic pathways involved in yolk formation and nutrient deposition (Mahfuz and Piao, 2019). In parallel, lemuru fish oil (Sardinella lemuru) is a rich source of long-chain n-3 polyunsaturated fatty acids (PUFA), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which can be effectively transferred into egg yolk through dietary supplementation (Hayat et al., 2010; Calder, 2020). Nevertheless, the application of fish oil in layer diets remains limited by its high susceptibility to oxidative degradation, which not only compromises PUFA stability but may also induce off-flavors that negatively affect egg sensory quality and consumer acceptance.

Microencapsulation has therefore gained attention as a practical technological solution to address these challenges. By entrapping PUFA within protective wall materials, microencapsulation reduces oxidative damage during feed processing, storage, and digestion, thereby enhancing fatty acid bioavailability and deposition in the egg yolk (Gharsallaoui et al., 2007; Karthik and Anandharamakrishnan, 2016). Several studies indicate that microencapsulated marine oils maintain functional efficacy while minimizing adverse effects on egg flavor and hen performance, highlighting their potential application in functional egg production systems.

Despite the expanding body of literature on phytogenic additives and omega-3 enrichment strategies, existing studies predominantly evaluate Moringa leaf powder and fish oil supplementation in isolation. Consequently, important knowledge gaps remain regarding their combined effects, optimal inclusion levels, and the extent to which natural antioxidants from plant sources can mitigate oxidative instability associated with omega-3 enrichment. In addition, substantial variability exists in reported outcomes due to differences in encapsulation matrices, dietary formulations, hen genotype, and production environments. A comprehensive synthesis integrating these factors is currently lacking.

Therefore, this review aims to critically synthesize recent evidence on the use of Moringa leaf powder and microencapsulated lemuru fish oil in layer diets, with particular emphasis on their complementary mechanisms in modulating egg yolk vitamin concentrations, fatty acid composition, and oxidative stability. By addressing unresolved inconsistencies and methodological limitations, this review seeks to provide a clearer framework for the development of nutritionally enhanced functional eggs, particularly within tropical poultry production systems.

MATERIALS AND METHODS

Literature search strategy

This review was conducted as a systematic narrative review following PRISMA-informed guidelines. Peer-reviewed articles published between 2007 and 2024 were identified through electronic database searches, including Scopus, ScienceDirect, PubMed, and Web of Science. The final literature search was completed in December 2024.

The search strategy combined relevant keywords and Boolean operators, including: Moringa oleifera, Microencapsulated fish oil, Lemuru fish oil, Egg yolk fatty acids, Vitamin deposition, PUFA enrichment, and Oxidative stability. Reference lists of selected articles were also manually screened to identify additional relevant studies.

Study selection and eligibility criteria

Studies were included if they met the following criteria:

(i) original peer-reviewed research articles published in English;

(ii) experiments conducted in laying hens;

(iii) dietary supplementation involving Moringa leaf powder and/or microencapsulated fish oil; and

(iv) reporting quantitative outcomes related to egg yolk fatty acid composition, vitamin concentrations, antioxidant status, or oxidative stability indicators (e.g., TBARS).

Studies were excluded if they:

(i) involved non-layer poultry species or non-avian models;

(ii) evaluated non-encapsulated fish oil without antioxidant protection; Studies using non-encapsulated fish oil supplemented with synthetic antioxidants were excluded to avoid confounding antioxidant effects when evaluating encapsulation-specific outcomes

(iii) lacked quantitative yolk-related outcomes; or

(iv) were reviews, conference abstracts, or non-peer-reviewed reports.

Screening and data extraction

Article screening was conducted in three stages: title screening, abstract screening, and full-text eligibility assessment. Data extracted from eligible studies included dietary inclusion levels, supplementation duration, microencapsulation techniques, yolk vitamin and fatty acid outcomes, oxidative stability parameters, and reported effects on hen performance.

A PRISMA-style flow diagram was developed to illustrate the literature identification, screening, eligibility, and inclusion processes as shown in Supplementary Figure 1. Of the 124 records initially identified through database searching, 38 duplicate records were removed. Following title and abstract screening, 61 articles were excluded. A total of 25 full-text articles were assessed for eligibility, of which 17 studies met the inclusion criteria and were included in the final review.

Microencapsulation technologies assessed

Microencapsulation approaches reported in the included studies comprised spray-drying, complex coacervation, and protein–polysaccharide matrix systems, which were evaluated in terms of encapsulation efficiency, oxidative protection, and effectiveness in delivering long-chain n-3 PUFA to egg yolk (Jafari and He, 2020; Guarda et al., 2021).

Data synthesis and comparative analysis

Due to heterogeneity in experimental designs, dietary formulations, and outcome variables, a meta-analysis was not conducted. Instead, findings were synthesized using a comparative narrative approach, emphasizing trends, ranges of responses, and consistencies or discrepancies among studies. Where possible, reported dose ranges and magnitude of changes in yolk vitamins, fatty acid composition, and oxidative stability were summarized and compared across studies.

Statistical considerations in reviewed studies

Rather than performing new statistical analyses, this review summarizes statistical approaches applied within the included studies. Most experiments employed analysis of variance (ANOVA) followed by post-hoc comparisons (e.g., Tukey or Duncan tests) to evaluate dietary treatment effects (Zanu et al., 2012; Sharmin et al., 2021). Several studies used regression analysis to explore dose–response relationships, while multivariate techniques, including principal component analysis (PCA) and cluster analysis, were applied to characterize changes in egg yolk fatty acid profiles (Fraeye et al., 2012).

Oxidative stability indicators, particularly thiobarbituric acid reactive substances (TBARS), were commonly analyzed using repeated-measures ANOVA during egg storage to assess lipid oxidation dynamics (Rahman et al., 2018). It should be acknowledged that many poultry nutrition studies included in this review employed relatively small replicate numbers (typically 6–10 hens per treatment), which may limit statistical power. This limitation increases the potential risk of Type II error, whereby biologically meaningful effects on yolk lipid composition or oxidative stability may not reach statistical significance. Consequently, some reported non-significant findings should be interpreted with caution.

RESULTS

Overview of included studies

A total of 17 experimental studies published between 2015 and 2024 met the inclusion criteria and were included in the final synthesis. The studies varied in dietary inclusion levels, supplementation duration, and microencapsulation techniques. Most experiments were conducted over 6–12 weeks and evaluated egg yolk vitamin concentrations, fatty acid composition, and oxidative stability indicators. Although these durations cover multiple egg production cycles, they may not fully capture longer-term adaptive responses or potential impacts on hen health and reproductive longevity. The main characteristics of the included studies are summarized in Table 1.

Effects on egg yolk vitamin profile

Vitamin A, carotenoids, and α-tocopherol

Across studies, dietary inclusion of Moringa leaf powder consistently increased yolk retinol and carotenoid concentrations, with reported increases ranging from approximately 15% to 45% compared to control diets (Table 2). These effects were observed even at moderate inclusion levels (1–3%) and were accompanied by significant improvements in yolk pigmentation scores, based on standardized yolk color assessment systems (e.g., Roche Yolk Color Fan or spectrophotometric L, a*, b* measurements). Yolk α-tocopherol concentrations were also elevated in Moringa-supplemented groups, particularly when combined with fish oil supplementation, suggesting enhanced antioxidant protection of yolk lipids.

 

Table 1: Characteristics of studies included in the review.

Author (Year)	Feed ingredient	Inclusion level	Duration (weeks)	Encapsulation method	Main Outcomes
Mahfuz and Piao (2019)	Moringa leaf powder	1–3%	8	–	↑ Vit A, ↑ carotenoids
Melesse et al. (2018)	Moringa leaf meal	2–4%	10	–	↑ Yolk color, ↑ antioxidants
Rahman et al. (2018)	Encapsulated fish oil	1–2%	6	Spray-drying	↑ DHA, ↓ TBARS
Guarda et al. (2021)	Encapsulated marine oil	0.5–1.5%	8	Protein–polysaccharide	↑ EPA+DHA efficiency
Sharmin et al. (2021)	Moringa + fish oil	1–2%	12	Coacervation	↑ oxidative stability

 

Table 2: Effects of Moringa leaf powder on egg yolk vitamin profile.

Study	Moringa level	Duration	Vit A/ Retinol	α-Tocopherol	Yolk color
Mahfuz and Piao (2019)	1–3%	8 wk	↑ 20–40%	↑ 15%	↑
Melesse et al. (2018)	2–4%	10 wk	↑ 25–45%	NR	↑↑
Sharmin et al. (2021)	2%	12 wk	↑ 30%	↑ 20%	↑

 

NR = not reported.

 

Table 3: Effects of microencapsulated fish oil on yolk fatty acid composition.

Study	Oil level	Encapsulation	DHA increase	EPA increase	n-6:n-3 ratio
Rahman et al. (2018)	1–2%	Spray-drying	↑ 45–70%	↑ 30–55%	↓ 40%
Guarda et al. (2021)	0.5–1.5%	Protein–polysaccharide	↑ 60–80%	↑ 45%	↓ 50%
Barroso et al. (2022)	1%	Spray-drying	↑ 35%	↑ 25%	↓ 30%

 

Note: Arrows indicate the direction and approximate magnitude of change relative to control groups. Statistical significance was reported where indicated in the original studies (typically p < 0.05).

 

Table 4: Effects on yolk lipid oxidation and fatty acid balance.

Study	Treatment	TBARS reduction	SFA change	MUFA change
Rahman et al. (2018)	Encapsulated oil	↓ 30%	↓ 8%	↑ 6%
Sharmin et al. (2021)	Moringa + oil	↓ 40%	↓ 10%	↑ 8%
Mahfuz and Piao (2019)	Moringa	↓ 15%	↓ 5%	↑ 5%

 

Note: Arrows indicate the direction and approximate magnitude of change relative to control groups. Statistical significance was reported where indicated in the original studies (typically p < 0.05).

 

Effects on egg yolk fatty acid composition

Omega-3 PUFA enrichment

Microencapsulated lemuru fish oil markedly enhanced yolk deposition of long-chain n-3 PUFA. Reported increases in DHA content ranged from 30% to over 80% compared to non-supplemented controls (Table 3). At equivalent inclusion levels, microencapsulated formulations consistently outperformed non-encapsulated fish oil. This enrichment resulted in a substantial reduction of the yolk n-6:n-3 ratio, with reported decreases ranging from 25% to 50%, indicating a nutritionally improved lipid profile, it is reducing the yolk n-6:n-3 ratio from approximately 15:1 to 5:1, approaching dietary recommendations for human health (<4:1).

MUFA and SFA modulation

Several studies reported a modest but consistent increase in yolk MUFA content (approximately 5–10%) following Moringa supplementation, accompanied by a concurrent reduction in SFA proportion (Table 4). These changes were nutritionally favorable, although smaller in magnitude compared to omega-3 enrichment effects.

Oxidative stability of egg yolk

Oxidative stability indicators were reported in multiple studies, with TBARS values significantly reduced (10–40%) in eggs from hens receiving Moringa leaf powder, microencapsulated fish oil, or their combination (Table 4). The greatest reductions were observed when both ingredients were supplied concurrently. Several storage studies further demonstrated extended shelf-life and delayed onset of lipid oxidation in enriched eggs compared to controls.

DISCUSSION

Complementary roles of moringa leaf powder and microencapsulated fish oil

The findings synthesized in this review indicate that Moringa leaf powder and microencapsulated lemuru fish oil contribute through distinct yet complementary mechanisms to the nutritional enhancement of egg yolk. Moringa oleifera functions primarily as a biological antioxidant source, supplying carotenoids, tocopherols, and polyphenolic compounds that modulate oxidative processes associated with lipid digestion and transport (Mahfuz and Piao, 2019; Tesfaye et al., 2023). These bioactive compounds are known to stabilize lipid fractions and facilitate the efficient deposition of fat-soluble micronutrients into the yolk.

In contrast, microencapsulation of fish oil represents a technological intervention aimed at preserving the structural integrity of long-chain n-3 polyunsaturated fatty acids (PUFA), particularly EPA and DHA, during feed processing and gastrointestinal digestion (Jafari and He, 2020; Karthik and Anandharamakrishnan, 2016). This technological protection explains the consistently higher deposition efficiency of omega-3 fatty acids observed in eggs derived from hens fed encapsulated oils compared with non-encapsulated sources (Silva et al., 2020; Barroso et al., 2022).

Mechanisms governing yolk fatty acid deposition

The enrichment of egg yolk with long-chain n-3 PUFA is tightly regulated by hepatic lipid metabolism and lipoprotein transport pathways. Once absorbed, dietary fatty acids are incorporated into very-low-density lipoprotein yolk-targeted particles (VLDLy), which selectively deliver lipids to the developing follicle (Fraeye et al., 2012). The improved bioavailability of DHA and EPA from microencapsulated fish oil likely enhances their incorporation into these lipoprotein fractions, thereby increasing yolk deposition efficiency. These effects may also involve modulation of hepatic lipid metabolism, including altered expression of lipogenic and fatty acid transport genes, although direct mechanistic evidence in laying hens remains limited.

Moreover, the observed reductions in the yolk n-6:n-3 ratio are nutritionally significant, as excessive dietary n-6 relative to n-3 fatty acids is associated with pro-inflammatory metabolic responses in humans (Calder, 2020). From a functional food perspective, eggs enriched through stabilized omega-3 delivery represent a practical strategy for improving population-level intake of long-chain n-3 PUFA (Barroso et al., 2022).

Modulation of MUFA and SFA by plant-derived bioactives

Beyond omega-3 enrichment, Moringa supplementation appears to exert secondary effects on yolk lipid composition, including modest increases in monounsaturated fatty acids (MUFA) and reductions in saturated fatty acids (SFA). These changes are consistent with earlier reports indicating that plant-derived bioactives may influence hepatic desaturation and lipid synthesis pathways, potentially through modulation of Δ9-desaturase activity and regulation of genes involved in de novo lipogenesis (Cherian, 2011). Although these shifts are smaller in magnitude than PUFA enrichment, they contribute to a more favorable overall yolk lipid profile.

Such modulation aligns with previous observations that dietary manipulation of lipid sources and antioxidant intake can alter the balance of yolk fatty acids through both direct substrate availability and indirect metabolic regulation (Fraeye et al., 2012; Mahfuz and Piao, 2019).

Oxidative stability as a limiting factor in omega-3 egg production

One of the major challenges in omega-3 egg production is the increased susceptibility of yolk lipids to oxidative degradation. Long-chain PUFA are highly prone to peroxidation, leading to reduced shelf-life and potential sensory deterioration if not adequately protected (Cherian, 2011). The consistent reduction in TBARS values reported in studies incorporating Moringa leaf powder and microencapsulated fish oil highlights the importance of integrating antioxidant nutrition with technological lipid protection.

Moringa-derived polyphenols and tocopherols have been shown to act as chain-breaking antioxidants within the yolk lipid matrix, suppressing the propagation of lipid radicals (Rahman et al., 2018; Hayat et al., 2010). Simultaneously, microencapsulation physically limits oxygen exposure to vulnerable PUFA, further enhancing oxidative stability during storage (Gharsallaoui et al., 2007; Guarda et al., 2021). The superior oxidative stability observed under combined supplementation supports the concept of a dual-protection strategy, particularly relevant in warm-climate production systems.

Influence of encapsulation technology and processing variables

Variation among studies in DHA and EPA deposition can be partly attributed to differences in encapsulation techniques and wall material composition. Spray-drying remains the most widely applied method due to its scalability and cost-effectiveness, yet encapsulation efficiency and oxidative protection depend strongly on matrix formulation and processing conditions (Gharsallaoui et al., 2007; Zhang et al., 2024). Composite protein–polysaccharide matrices have been shown to improve oil retention and oxidative stability compared with single-component systems (Guarda et al., 2021).

These technological factors must therefore be considered alongside nutritional formulation when designing omega-3 enrichment strategies. Inconsistent outcomes across studies underscore the need for standardized reporting of encapsulation efficiency, particle size, and oxidative stability indices.

Implications and future research directions

Overall, the evidence reviewed supports the integration of plant-based antioxidants and microencapsulation technology as a robust strategy for producing nutritionally enhanced eggs. However, optimal inclusion levels, long-term impacts on hen health, and economic feasibility remain insufficiently explored. Dose–response relationships, particularly under combined supplementation regimes, warrant further investigation to balance enrichment efficiency with production sustainability (Barroso et al., 2022).

Future studies should also extend storage stability evaluations and assess consumer acceptance, ensuring that nutritional improvements translate into marketable functional egg products.

CONCLUSION

The integration of Moringa leaf powder and microencapsulated lemuru fish oil represents a complementary nutritional–technological strategy for enhancing egg nutritional quality. Moringa serves as a natural source of antioxidants that support vitamin deposition and mitigate lipid oxidation, while microencapsulation improves the stability, intestinal absorption, and subsequent yolk incorporation of long-chain n-3 PUFA. Together, these mechanisms facilitate efficient enrichment of egg yolk with carotenoids, retinol, EPA, and DHA, promote a more favorable n-6:n-3 fatty acid ratio, and reduce the proportion of saturated fatty acids, thereby supporting the production of functional eggs with enhanced nutritional and health value. Despite these promising outcomes, several critical gaps remain. Optimal inclusion levels under combined supplementation regimes have yet to be clearly established, and interactions between antioxidant availability and PUFA stabilization require further clarification. In addition, variability in encapsulation wall materials and processing conditions continues to influence omega-3 deposition efficiency and oxidative stability of enriched eggs. Long-term effects on hen physiology, production performance, and egg storage stability are still insufficiently documented, particularly under tropical production conditions where high ambient temperature, humidity, and accelerated feed oxidation rates pose additional challenges for omega-3 stability. Addressing these limitations through standardized encapsulation protocols, dose–response evaluations, and extended storage studies will be essential for translating experimental findings into consistent, scalable, and economically viable strategies for functional egg production across diverse poultry systems.

Acknowledgement

The authors would like to acknowledge the support provided by Faculty of Animal Science, Universitas Padjadjaran during the preparation of this review article

Novelty Statement

This review provides an integrated synthesis of antioxidant-rich Moringa leaf powder and microencapsulated lemuru fish oil as complementary functional feed ingredients for egg yolk enrichment, highlighting their combined effects on vitamin deposition, fatty acid modulation, and oxidative stability within tropical poultry production systems

Author’s Contribution

D.E.D. conceptualized the review, conducted the literature search, synthesized the data, and prepared the original draft of the manuscript. All authors reviewed, revised, and approved the final version of the manuscript

Generative AI and AI-assisted technology statement

The authors declare that generative AI tools were used solely for language refinement and grammatical editing. No AI tools were used for data analysis, interpretation, or generation of scientific content. All authors reviewed and approved the final manuscript and take full responsibility for its content

Conflict of interest

The authors have declared no conflict of interest.

REFERENCES

Barroso J, Lordelo M, Freire JP (2022). Strategies for omega-3 enrichment of eggs: Nutritional and technological considerations. Food Chem., 373: 131475.

Calder PC (2020). Omega-3 fatty acids and inflammatory processes. Nutrients, 12(9): 2532.

Cherian G (2011). Lipid modification strategies for egg enrichment. Poult. Sci., 90(10): 2289-2296.

Fraeye I, Bruneel C, Lemahieu C, Buyse J (2012). Dietary modulation of egg yolk fatty acids. Poult. Sci., 91(11): 2985-2994.

Gharsallaoui A, Roudaut G, Chambin O, Voilley A (2007). Applications of spray-drying for microencapsulation of oils. Innov. Food Sci. Emerg. Technol., 8(2): 282-290.

Guarda A, Rubilar JF, Morales MA (2021). Encapsulation of omega-3 oils: Recent advances and applications. Trends Food Sci. Technol., 115: 26-36.

Hayat Z, Cherian G, Pasha TN, Jabbar MA (2010). Omega-3 enrichment and vitamin deposition in eggs. J. Appl. Poult. Res., 19(1): 31-37.

Jafari SM, He Y (2020). Microencapsulation of fish oil: stability and efficiency. J. Food Eng. 283: 110044.

Karthik P, Anandharamakrishnan C (2016). Microencapsulation techniques for fish oil delivery. J. Microencapsul., 33(6): 587-602.

Mahfuz S, Piao XS (2019). Moringa oleifera as a natural feed supplement for poultry. Animals, 9(8): 431. https://doi.org/10.3390/ani9070431

Melesse A, Tiruneh W, Negesse T (2018). Egg quality changes following dietary Moringa leaf meal. Trop. Anim. Health Prod., 50: 1021-1030.

Rahman MM, Akbar MA, Lasker MAA (2018). Influence of polyphenols on lipid oxidation in poultry tissues. Poult. Sci., 97(6): 2001-2010.

Sharmin F, Azad MAK, Rahman MM (2021). Inclusion of Moringa oleifera leaf meal in layer diets: Impact on egg quality traits. Ital. J. Anim. Sci., 20(1): 1987846.

Silva VM, Silva M, Hubinger M (2020). Microencapsulation of fish oil by spray-drying: Effect on oxidation. Food Res. Int., 136: 109302.

Tesfaye E, Habte M, Tsegaye S (2023). Moringa leaf powder and its antioxidant role in poultry. Vet. Anim. Sci., 19: 100274.

Zanu HK, Avornyo FK, Salifu AR (2012). Effect of Moringa leaf meal on omega-3 enrichment of eggs. J. Anim. Physiol. Anim. Nutr., 96(3): 427-434.

Zhang H, Liu P, Liu Z (2024). Microencapsulated DHA-rich algae oil via spray-drying. Foods, 13(23): 3827. https://doi.org/10.3390/foods13233827