Aquaculture is one of the fastest-growing food production sectors, supplying 51% of aquatic animal products, with China, India and Indonesia as leading producers.
P. vannamei dominates global shrimp farming due to its fast growth, high yield and environmental adaptability (
De Silva et al., 2021). In India, it has largely replaced P. monodon
(Salunke et al., 2020). However, intensified farming practices increase disease risks, leading to widespread antimicrobial use
(Riyaz et al., 2025). Major diseases include WSSV, TSV and EMS caused by toxin-producing
V. parahaemolyticus (
De Silva et al., 2021).
Excessive antimicrobial use results in residue accumulation in seafood
(Elsherbiny et al., 2025) and contributes to AMR development and transfer among aquatic and human pathogens
(Riyaz et al., 2025). With over 80% of antimicrobials entering the Aquatic environment, aquatic systems become reservoirs of active compounds and resistance genes, causing trade restrictions and economic losses. The indiscriminate use of antimicrobials in aquaculture has led to residues in aquaculture products and the associated detrimental health consequences in people
(Elsherbiny et al., 2025). This highlights the need for sustainable alternatives. Immunostimulants, particularly Chinese herbal medicines such as
A. membranaceus and
A. paniculata, offer anti-inflammatory and antimicrobial benefits
(Zheng et al., 2020; Yin et al., 2022).
Phytogenic feed additives (PFAs), including herbal extracts and plant compounds, contain bioactive molecules that enhance shrimp physiology and immunity. PFAs improve growth, stress tolerance and innate immune responses-critical in crustaceans lacking adaptive immunity
(Ashour et al., 2025; Hoa et al., 2023; Gruber et al., 2025; Ma et al., 2024; Yin et al., 2022). They elevate THC, phenoloxidase and lysozyme activity and enhance resistance to pathogens such as
V. parahaemolyticus (Ma et al., 2024; Yin et al., 2022). PFAs also modulate gut microbiota, reduce oxidative stress and support tissue integrity
(Ashour et al., 2025). Their inclusion in low-fishmeal diets maintains health and performance
(Gruber et al., 2025), supporting sustainable shrimp production. Herbal phytobiotics are increasingly recognized as eco-friendly alternatives to antibiotics in aquaculture due to their immunostimulatory, antimicrobial and growth-promoting properties.
Bharathi et al., (2021) reviewed the application of medicinal herbs in aquaculture and highlighted their potential to improve fish and shrimp health while reducing environmental risks associated with chemotherapeutics. This review aims to critically evaluate the current evidence regarding the application of
Astragalus membranaceus and
Andrographis paniculata as phytogenic feed additives in
Penaeus vannamei culture. Particular emphasis is placed on their effects on growth performance, digestive physiology, immunomodulation, antioxidant defense, disease resistance, environmental sustainability and economic feasibility. The review also discusses mechanistic insights, existing research gaps and future perspectives for the commercial application of herbal nutraceuticals in sustainable shrimp aquaculture.
Review methodology
This review was prepared using a narrative literature review approach focusing on the role of phytogenic feed additives, particularly
Astragalus membranaceus and
Andrographis paniculata, in
Penaeus vannamei aquaculture. Relevant peer-reviewed articles published between 2020 and 2025 were retrieved from PubMed, Scopus, Web of Science, Google Scholar and ScienceDirect using keywords such as “
Penaeus vannamei”, “phytogenic feed additives”, “
Astragalus membranaceus”, “
Andrographis paniculata”, “shrimp immunity” and “disease resistance”.
Studies related to growth performance, immunity, antioxidant activity, digestive physiology and sustainability in aquaculture species were included, while duplicate, non-peer-reviewed and unrelated studies were excluded. The selected literature was critically analyzed and organized into thematic sections. Because this study is a narrative review, a formal systematic review protocol was not applied.
Phytogenic feed additives: A sustainable alternative
Overview of herbal additives
Functional feed ingredients and natural nutraceuticals are increasingly being incorporated into aquaculture diets to improve feed efficiency, health status and sustainable production practices
(Singh et al., 2018). The global drive to reduce prophylactic antibiotic use in aquaculture has intensified research into sustainable feed alternatives positioning phytogenic feed additives (PFAs) as promising functional feed additives for improving health and productivity in Pacific white shrimp culture.”. PFAs, which encompass herbal extracts, essential oils and various plant derived compounds are recognized for their bioactive components such as polysaccharides, phenolic compounds and diterpene lactones that confer significant physiological and health benefits to the shrimp.
Dietary supplementation with PFAs has been consistently shown to improve production metrics and critically, fortify the shrimp’s innate immune system, which is essential given the absence of an adaptive immune response in crustaceans. Multiple investigations have demonstrated that incorporating essential oil blends or specific herbal compounds (
e.g. andrographolide) into the feed significantly enhances nonspecific immune function. This enhancement is typically observed through an increase in immune parameters such as total haemocyte counts (THC) and elevated activities of key immune enzymes, including phenol oxidase and lysozyme
(Hoa et al., 2023; Yin et al., 2022).
Regulatory and market trends
Furthermore, PFAs provide potent anti-pathogenic and protective effects against prevalent bacterial diseases. Specifically, phytobiotic based compounds and certain plant-based extracts have proven highly effective in boosting resistance against Vibrio parahaemolyticus, the causative agent of Acute Hepatopancreatic Necrosis Disease (AHPND)
(Ma et al., 2024). The underlying mechanisms for this protection often involve the modulation of the intestinal microbiota, leading to a favourable shift away from pathogenic species, combined with the mitigation of oxidative stress and improved morphological integrity of the hepatopancreas and intestine
(Yin et al., 2022). In addition to terrestrial plant extracts, novel marine derived sources, such as polysaccharides from macro algae, continue to be explored, demonstrating promise in enhancing overall growth, nutrient utilization and immune competence in
P. vannamei juveniles
(Ashour et al., 2025). Collectively, the literature strongly supports PFAs as a viable, sustainable and effective strategy for managing health and productivity in intensive shrimp farming
(Hoa et al., 2023).
Nutritional effects of astragalus and andrographis
Digestive enzyme activity
Herbal supplementation has gained considerable attention as an eco-friendly and cost-effective strategy to enhance digestive physiology in aquaculture species
(Vijayaram et al., 2024; Zahran et al., 2014). Phytochemicals such as saponins, polysaccharides and flavonoids from medicinal herbs can stimulate secretion or expression of digestive enzymes (protease, amylase, lipase) and modulate gut function
(Pudota et al., 2025). For example, dietary
Astragalus membranaceus polysaccharides (APS) have been shown to improve growth, enzyme activities and intestinal morphology in fish and crustaceans (
Abdel-Latif et al., 2022). In shrimp, supplementation with herbal extracts of
Astragalus and
Andrographis significantly enhanced protease, amylase and lipase activities compared to control groups
(Ganesh et al., 2022).
Similarly and
rographis paniculata or its active compound andrographolide have been demonstrated to support digestive function, antioxidant capacity and growth in aquatic animals
(Shi et al., 2020). Chinese herbal mixtures more broadly have been reported to enhance endogenous digestive enzyme secretion, stimulate appetite and improve nutrient assimilation in fish
(Wang et al., 2018).
In addition, exogenous enzyme supplementation (
e.g. proteases, amylases, lipases, phytases) is often used in aquaculture to improve digestion of plant-based feed ingredients and boost nutrient absorption
(Liang et al., 2022). Overall, the literature supports that using herbal additives especially in properly optimized combinations can enhance digestive enzyme activities, thereby improving feed utilization, growth and gut health in aquaculture species.
Growth performance
Growth performance is a primary indicator of feed efficiency and physiological well-being in aquaculture. Recent research provides substantial evidence that phytogenic feed additives particularly
Astragalus membranaceus exert beneficial effects on growth performance in aquaculture species. In common carp (
Cyprinus carpio), dietary supplementation with fermented
A. membranaceus formulations resulted in significant improvements in final body weight, weight gain rate, specific growth rate and protein efficiency, while concurrently reducing feed conversion ratio (FCR)
(Han et al., 2025). Comparable trends were observed in Jian carp (
Cyprinus carpio var. Jian), where
A. membranaceus extracts were shown to markedly enhance growth performance alongside increased antioxidant capacity, indicating improved physiological resilience
(Xu et al., 2023).
Positive outcomes have also been reported in largemouth bass (
Micropterus salmoides), in which moderate inclusion levels of
A. membranaceus extract (0.4-0.5%) produced significantly higher final body weight and weight gain while improving FCR relative to control diets, demonstrating a clear dose-responsive effect
(He et al., 2024). However, caution should be exercised when extrapolating findings from finfish to crustaceans due to differences in digestive physiology, immune organization and metabolic responses between these groups. Evidence from crustacean production further supports the effectiveness of herbal additives:
Penaeus vannamei fed diets enriched with plant extracts such as
Lonicera japonica and
Lilium candidum exhibited superior growth performance, enhanced feed utilization efficiency and higher survival rates compared with shrimp receiving basal diets
(Fadel et al., 2025). Collectively, these findings indicate that plant-derived supplements and
A. membranaceus in particular, represent promising nutritional strategies for promoting growth and feed efficiency across diverse aquaculture species.
Immunological modulation
Prophenoloxidase and lysozyme activity
The prophenoloxidase (proPO) activating system represents a key component of the crustacean innate immune response, orchestrating melanization, pathogen encapsulation and subsequent microbial elimination
(Kumar et al., 2023). In parallel, lysozyme acts as an essential antimicrobial effector molecule, degrading the peptidoglycan layer of bacterial cell walls and thereby contributing to the immediate humoral defence against invading pathogens (
Abdel-Latif et al., 2022). These results are consistent with other reports:
Recent studies provide increasing evidence that plant-derived bioactives can significantly modulate innate immune responses in aquaculture species. For instance,
Yin et al., (2022) demonstrated that dietary
Andrographis paniculata (andrographolide) enhances key non-specific immune parameters in
Penaeus vannamei, particularly phenoloxidase and lysozyme activities, resulting in improved resistance against
Vibrio alginolyticus. Comparable immunostimulatory effects have been reported in finfish;
Abdel-Latif et al. (2022) observed elevated serum lysozyme activity in
Pangasianodon hypophthalmus supplemented with
Astragalus membranaceus extract, underscoring the broad immunomodulatory potential of Astragalus species. Although studies in finfish provide supportive evidence regarding the immunomodulatory potential of herbal additives, species-specific validation in
Penaeus vannamei remains essential because crustacean immune systems differ substantially from those of teleost fish. Synthesizing available evidence,
Kumar et al., (2023) emphasized that prophenoloxidase (proPO) and lysozyme remain among the most reliable biomarkers for assessing the efficacy of plant-derived immunostimulants in shrimp due to their sensitivity and functional relevance in innate defence. Moreover, Astragalus-derived polysaccharides have been widely documented to enhance lysozyme activity and antioxidant enzyme profiles in finfish, although direct studies evaluating their effects on proPO activity in crustaceans are still limited
(Yin et al., 2022; KV et al., 2022). Herbal immunostimulants have also been widely reported to enhance non-specific immune responses and disease resistance in aquatic organisms.
Shah et al., (2024) emphasized that phytogenic compounds can improve immune enzyme activity, antioxidant defenses and pathogen resistance, thereby supporting sustainable disease management strategies in aquaculture.
Mechanistically, bioactive constituents such as andrographolide and astragaloside are proposed to exert their immunomodulatory effects through the activation of key immune-signaling pathways, including NF-κB, MAPK and toll-like receptor (TLR)-mediated cascades. Bioactive constituents such as andrographolide and astragaloside are proposed to influence immune-related signaling pathways including NF-κB, MAPK and toll-like receptor-mediated cascades. However, much of the mechanistic evidence currently available originates from mammalian and finfish studies and direct molecular validation in
Penaeus vannamei remains comparatively limited
(KV et al., 2022).
Serum protein and antioxidant defense
Elevations in total serum protein concentration are widely recognized as indicators of enhanced systemic immunity and overall physiological status in aquatic organisms. Reviewed studies indicate that herbal-supplemented diets can increase serum protein levels and enhance antioxidant enzyme activities in aquaculture species, reflecting improved immune competence and oxidative stress resistance. Concurrently, significant enhancements in key antioxidant enzymes-superoxide dismutase (SOD) and catalase (CAT) were observed. These enzymes play essential roles in detoxifying reactive oxygen species (ROS) and mitigating oxidative stress, thereby contributing to improved disease resistance. Recent literature corroborates these findings.
Liu et al., (2023) reported that dietary
Astragalus membranaceus supplementation enhanced antioxidant enzyme gene expression in broiler chickens, suggesting the broader antioxidant potential of herbal bioactive compounds across animal species. However, direct validation of these mechanisms in
Penaeus vannamei remains limited and requires further species-specific investigation. Similarly,
Zhang et al., (2025) demonstrated that herbal antioxidant-enriched diets significantly elevated SOD and CAT activities in crustaceans challenged with bacterial pathogens. Consistent trends have been documented by
Maqaddas et al., (2025) and
Yousaf et al., (2025), who observed parallel improvements in antioxidant enzyme profiles and growth performance in shrimp receiving herbal-supplemented diets.
The incorporation of immunologically active herbal additives into shrimp diets offers a promising strategy for enhancing innate defense mechanisms while simultaneously reducing dependence on synthetic immunostimulants and prophylactic antibiotics. Collectively, reviewed studies suggest indicate that such herbal supplementation not only augments humoral immune responses but also reinforces the antioxidant defense system, thereby contributing to improved overall health status and heightened disease resilience in aquaculture species.
Mechanistic insights into bioactivity
Astragalus membranaceus
Astragalus membranaceus is well recognized for its diverse array of bioactive constituents, including polysaccharides (astragalans), saponins (astragalosides) and flavonoids, which collectively underpin its immunostimulatory and antioxidant activities. Among these, Astragalus polysaccharides (APS) have been extensively studied for their ability to activate Toll-like receptors, particularly TLR2 and TLR4, thereby initiating downstream NF-κB and MAPK signaling cascades. Activation of these pathways enhances macrophage function and promotes the secretion of cytokines, ultimately strengthening the innate immune response
(Zhu et al., 2019). In aquaculture systems, APS supplementation has been associated with elevated phagocytic activity, increased expression of immune-related genes such as TNF-α and IL-1β and upregulation of key antioxidant enzymes, contributing to improved disease resistance and growth performance. Supporting this, studies in
Penaeus vannamei have demonstrated that dietary APS supplementation enhances non-specific immunity and promotes growth, with optimal immunological and physiological responses observed at moderate inclusion levels around 30 g/kg
(Zahran et al., 2014; Duan et al., 2024).
These findings collectively underscore the potential of incorporating APS into aquaculture diets as an effective strategy to enhance immune function and strengthen disease resilience in aquatic species.
Andrographis paniculata
Andrographis paniculata, commonly referred to as the “King of Bitters,” is distinguished by its principal bioactive diterpenoid lactone andrographolide, which is widely recognized for its anti-inflammatory, hepatoprotective and immunomodulatory properties. Mechanistically andrographolide modulates key immune signaling pathways-including NF-κB and p38 MAPK-primarily through inhibition of phosphorylation cascades, resulting in reduced pro-inflammatory cytokine production and mitigation of oxidative damage
(Yin et al., 2022). In crustacean species, dietary supplementation with
A. paniculata has been reported to upregulate antimicrobial peptides (AMPs) and enhance the activities of immune effectors such as lysozyme and nitric oxide, thereby strengthening the non-specific immune defense of shrimp
(Palanikani et al., 2020).
Recent investigations have further clarified the immunomodulatory potential of
Andrographis paniculata in aquatic organisms.
Rajanna et al., (2021) reported that supplementation with
A. paniculata extract exerted notable immunomodulatory effects by influencing immune cell activity and cytokine profiles, while also demonstrating a favorable safety and tolerability profile. Complementary findings in Penaeus vannamei showed that dietary
A. paniculata not only enhanced growth and non-specific immune responses but also conferred protection against Vibrio alginolyticus infection, primarily through the reduction of oxidative stress and apoptosis
(Yin et al., 2023). Collectively, these studies highlight the promise of integrating
A. paniculata into aquaculture nutrition strategies to strengthen immune function and improve disease resilience in farmed aquatic species. Despite the promising outcomes reported across multiple studies, inconsistencies remain regarding optimal dosage levels, duration of supplementation and species-specific responses to herbal additives. Variability in extraction methods, feed formulation, environmental conditions and experimental design further complicates direct comparisons among studies. Additionally, many investigations rely primarily on short-term laboratory trials, while long-term field validation under commercial farming conditions remains limited.
Synergistic and additive effects
Combined supplementation of
Astragalus membranaceus and
Andrographis paniculata at low inclusion levels has been reported to improve growth performance, immune responses and digestive enzyme activities in aquaculture species, suggesting potential synergistic interactions between their bioactive compounds. These observations may indicate potential additive or complementary effects between the bioactive compounds of both herbs. However, definitive confirmation of synergistic interactions would require dedicated combination studies and quantitative synergy analyses, which remain limited in aquaculture research
(Hassan et al., 2018; Fadel et al., 2025). Comparable improvements following multi-herbal supplementation have been reported in several aquaculture species, although the precise nature of herb-herb interactions has not yet been comprehensively characterized
(Elumalai et al., 2020; Vijayaram et al., 2024). Such findings are particularly valuable for the development of cost-efficient, low-dose herbal feed additives that reduce the need for high inclusion levels while optimizing growth, immunity and overall health in aquaculture systems.
Impact on water quality and environmental sustainability
Beyond enhancing growth and immune function, herbal supplementation in aquafeeds can improve nutrient utilization and contribute to better environmental conditions in culture systems. Shrimp receiving herbal-enriched diets exhibited reduced ammonia and nitrite accumulation in tank water, suggesting more efficient protein assimilation and improved nitrogen excretion dynamics (
Goncalves and Santos, 2015) and more recent studies indicating that phytogenic feed additives can beneficially modulate gut microbiota, enhance feed efficiency and subsequently improve water quality by reducing organic loading and toxic nitrogenous metabolites (
Al-Musalam et al., 2014;
Islam et al., 2024). The integration of such herbal interventions thus supports more sustainable aquaculture practices by promoting circular nutrient flows and lowering the environmental footprint-an essential step toward achieving low-emission, eco-friendly shrimp farming systems.
Economic and practical implications
Phytogenic feed additives such as
Astragalus membranaceus and
Andrographis paniculata not only promote growth, immunity and digestive efficiency in shrimp but also offer substantial economic benefits at the farm level. Previous studies have suggested that herbal supplementation may improve economic returns in shrimp farming through enhanced feed efficiency, improved survival and reduced disease-related losses. These findings align with recent reports by
Okon et al., (2025) and other studies demonstrating that herbal supplementation can reduce production costs, enhance yield and improve the economic viability of aquaculture operations
(Kesselring et al., 2021; Nolasco-Alzaga et al., 2025). Additionally, the reduced reliance on antibiotics lowers treatment expenses and facilitates compliance with international export standards that require residue-free products. From a practical perspective, the incorporation of such herbal additives into commercial feed formulations is technically feasible, scalable and suitable for both small- and large-scale operations, offering a sustainable and cost-effective strategy to enhance productivity and profitability in modern aquaculture systems.
Research gaps and future perspectives
Although phytogenic feed additives demonstrate considerable potential in shrimp aquaculture, several critical research gaps remain unresolved. Priority should be given to long-term feeding trials evaluating tissue residue accumulation, food safety and chronic physiological effects in
Penaeus vannamei. Standardization of herbal extraction methods, bioactive compound characterization and optimal dosage strategies is also necessary to improve reproducibility across studies
(Balasubramaniam et al., 2025; Kazempoor et al., 2022). Future investigations should emphasize species-specific molecular studies using transcriptomics, proteomics, metabolomics and microbiome analyses to validate the proposed immunological and antioxidant mechanisms in crustaceans. In addition, large-scale commercial field trials across diverse environmental conditions are needed to assess the practical consistency, economic feasibility and environmental sustainability of phytogenic supplementation under real farming systems
(Holt et al., 2021; Duan et al., 2023). Multi-location field trials across varied farming systems and climatic zones are also essential to evaluate the reproducibility and robustness of laboratory findings under commercial production conditions. Finally, research efforts should focus on optimizing commercial-scale herbal formulations in terms of bioavailability, palatability, stability and cost-effectiveness. Addressing these gaps will not only support wider adoption and regulatory approval but also facilitate the integration of herbal feed additives into sustainable, high-efficiency shrimp farming practices.
