Duckweed (Lemnaceae) as a sustainable feed resource: A global bibliometric analysis of research trends and scientific development

Muhammad Ridla^1,2, Rita Mutia¹, Arif Darmawan¹ and Nahrowi^1,2

¹Department of Animal Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Kampus Dramaga, Bogor 16680, Indonesia
ritamutia@apps.ipb.ac.id
²Center for Tropical Animal Studies (CENTRAS), IPB University, Kampus IPB Baranangsiang, Jl. Raya Pajajaran, Bogor 16153, Indonesia

Abstract

Duckweed (Lemnaceae) has attracted increasing attention as a sustainable feed resource due to its rapid growth, high protein content and ability to utilize nutrients from wastewater. This study aimed to analyze global research trends, development patterns and scientific contributions related to Duckweed as an alternative feed resource using a bibliometric approach. Bibliographic data were collected from the Scopus database and analyzed using the bibliometrix package in R. The analysis examined publication trends, leading countries, influential authors, key journals and keyword co-occurrence to identify major research themes. The results indicate a significant increase in publications over the past decade, reflecting growing interest in sustainable feed sources and circular bioeconomy approaches. Major research topics include Duckweed biomass production, nutrient removal from wastewater, feed formulation for livestock and aquaculture and nutritional evaluation. The findings highlight the expanding scientific landscape of Duckweed research and its potential role in supporting sustainable animal production systems and future food security.

Keywords: duckweed, Lemnaceae, sustainable feed, bibliometric analysis, research trends

Introduction

The rapid growth of the global human population has significantly increased the demand for animal-derived food products such as meat, milk and eggs. This increasing demand places considerable pressure on livestock production systems to enhance productivity while maintaining environmental sustainability. One of the major challenges faced by the livestock sector is the availability and cost of high-quality feed ingredients. Conventional feed resources such as soybean meal, maize and fish meal are widely used due to their high nutritional value and digestibility; however, their production is often associated with environmental concerns, including deforestation, land-use competition, high water consumption and greenhouse gas emissions (Tilman et al 2011; Mottet et al 2017). Furthermore, the increasing competition between human food, animal feed and biofuel industries has contributed to fluctuating prices and limited availability of these conventional feed resources (Alexandratos and Bruinsma, 2012; FAO, 2013). Consequently, identifying alternative and sustainable feed resources has become an important research priority in animal nutrition and agricultural science (Van Huis 2013).

In recent years, aquatic plants have received increasing attention as potential alternative feed resources due to their rapid growth, high nutrient content and relatively low cultivation requirements. Among these plants, Duckweed has emerged as one of the most promising candidates for sustainable feed production. Duckweed is a small floating aquatic plant that naturally grows in freshwater environments such as ponds, lakes and slow-moving rivers. It is characterized by an exceptionally rapid growth rate and can double its biomass within a few days under optimal environmental conditions (Leng et al 1995; Appenroth et al 2017). This remarkable growth capacity allows Duckweed to produce substantial biomass in a relatively short period, making it an attractive option for large-scale feed production systems.

Another important advantage of Duckweed is its nutritional composition. Several studies have reported that Duckweed contains relatively high levels of crude protein, essential amino acids, vitamins and minerals that are important for supporting animal growth and productivity (Bairagi et al 2002; Chakrabarti et al 2018). In addition, Duckweed contains various bioactive compounds that may contribute to improved animal health and immune responses (Pagliuso et al 2020). Due to these nutritional characteristics, Duckweed has been widely evaluated as a feed ingredient for several livestock species, including poultry, fish, pigs and ruminants (Chhay et al 2011; Sosa et al 2024; Pagliuso et al 2022). In aquaculture systems, for example, Duckweed has been successfully incorporated into diets for species such as tilapia and carp, demonstrating promising results in terms of growth performance and feed utilization efficiency (Merah et al 2022; Minich and Michael 2024).

Beyond its nutritional value, Duckweed also offers important environmental benefits that support sustainable agricultural systems. Duckweed can be cultivated on nutrient-rich water bodies, including agricultural wastewater and livestock effluents, where it efficiently absorbs nutrients such as nitrogen and phosphorus (Liu et al 2017). This capacity contributes to water purification and nutrient recycling, reducing environmental pollution while simultaneously producing valuable biomass that can be used as animal feed. Furthermore, Duckweed cultivation requires relatively small land areas compared with conventional feed crops such as soybean or maize, making it particularly attractive in regions facing land scarcity (Mateo-Elizalde et al 2023). These characteristics position Duckweed as a promising component of circular bioeconomy systems aimed at improving resource efficiency and environmental sustainability in agriculture.

Given these advantages, scientific interest in Duckweed has increased substantially over the past decades. Researchers from diverse disciplines, including animal nutrition, aquaculture, environmental science and biotechnology, have explored various aspects of Duckweed cultivation, biomass production and nutritional applications (Femeena et al 2023; Pena et al 2017). As a result, the number of scientific publications related to Duckweed has grown steadily, reflecting the expanding global attention to this aquatic plant as a sustainable feed resource. Despite the increasing body of literature, a comprehensive evaluation of the scientific development, collaboration patterns and emerging research trends in Duckweed studies remains limited.

Bibliometric analysis is widely recognized as a useful methodological approach for quantitatively assessing the development of scientific research within a particular field. By analyzing publication data, citation patterns, and collaborative networks, bibliometric techniques can identify influential authors, institutions, countries and journals, as well as uncover major research themes and emerging topics (Donthu et al 2021; Aria and Cuccurullo, 2017). Therefore, this study aims to provide a comprehensive bibliometric evaluation of the global scientific literature on Duckweed as a sustainable feed resource, to identify research trends, key contributors and potential future directions for the development of Duckweed in animal production systems.

Materials and methods

Data source, screening and bibliometric analysis

This study applied a bibliometric approach to examine global scientific publications on Duckweed as a sustainable feed resource. Bibliographic data were retrieved from the Scopus database, one of the largest sources of peer-reviewed scientific literature. Scopus was selected because of its broad journal coverage and compatibility with bibliometric analysis tools. The literature search was conducted in March 2026 to ensure the inclusion of the most recent publications. A Boolean search strategy was developed using keywords related to Duckweed species and their utilization in animal feed. The search was performed within the title, abstract and keyword fields (TITLE-ABS-KEY) to capture relevant studies comprehensively. Only English-language publications were considered to maintain consistency in the analysis, while all document types were initially included to capture the full scope of scientific output.

To ensure the relevance and quality of the dataset, a screening process was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Moher et al 2010). The retrieved records were exported in CSV format and examined to remove duplicates and irrelevant documents. Only publications specifically addressing Duckweed in the context of animal feed, animal nutrition, or livestock production systems were retained. The final dataset formed the basis for subsequent bibliometric analysis and the screening process is summarized in Figure 1.

Bibliometric analysis was performed using the Bibliometrix package in the R environment (Aria and Cuccurullo 2017). The analysis evaluated several indicators, including annual scientific production, leading authors, major journals, productive institutions and country contributions. Citation metrics were also examined to identify influential publications and assess the scientific impact of research on Duckweed as a sustainable feed resource.

Network and science mapping analysis

To explore the intellectual structure and collaboration patterns in Duckweed research, science mapping techniques were conducted using the VOSviewer tools (Van Eck and Waltman 2010). Keyword co-occurrence analysis was conducted using all keywords to identify dominant research themes and emerging topics in Duckweed studies. The relationships among these keywords were visualized as bibliometric network maps to illustrate thematic clusters within the literature.

Figure 1. PRISMA flow diagram on Duckweed as a sustainable feed resource

Results

Main information

The bibliometric dataset consisted of 166 publications indexed in Scopus covering the period from 1976 to 2025 (Table 1). These documents were published across 98 scientific journals sources. The annual growth rate of publications was 1.4%, with an average document age of 12.9 years. The articles received an average of 18.95 citations per document and contained 1,301 cited references. In terms of content, the dataset included 544 author keywords and 959 Keywords Plus. A total of 687 authors contributed to the publications, with an average of 5.14 co-authors per article. Only seven documents were single-authored, while international collaborations accounted for 23.49% of the publications.

Annual scientific production

The annual scientific production of studies related to Duckweed in animal feed and nutrition shows a gradual increase over time (Figure 2). The earliest publications appeared in 1976, with only one article per year during the late 1970s and early 1980s, indicating limited research activity in the early period. During the 1990s, publication output began to increase slightly, reaching three to four articles per year in some years. A more noticeable growth occurred after 2010, reflecting increasing scientific interest in Duckweed as a potential feed resource. The highest publication outputs were recorded in recent years, particularly in 2024 and 2025, with 16 articles each and 14 articles in 2022. Overall, the trend demonstrates a steady expansion of research activity in this field.

Figure 2. Annual scientific production on Duckweed as a sustainable feed resource

Most productive journals

The analysis of publication sources shows that research on Duckweed as a feed resource is distributed across several journals related to animal science, aquaculture and environmental sustainability (Figure 3). The most productive source is “ Livestock Research for Rural Development|” which has published 19 articles, underscoring its significant contribution to this field. “ Aquaculture and Aquaculture Research” follows with eight publications each. Other notable journals include “ AACL Bioflux” with five articles and “Animal Feed Science and Technology”, “Animal Bioscience” , “Egyptian Journal of Aquatic Biology and Fisheries”,“Journal of Fish Biology” and “Plants”, each contributing four publications. Several additional journals, such as “ Aquaculture Nutrition and Scientific Reports”, also contribute to the dissemination of Duckweed research.

Figure 3. Most productive journals on Duckweed as a sustainable feed resource

Most productive authors

The analysis of author productivity revealed several leading contributors to research on Duckweed as an animal feed resource (Table 2). Among the most prolific authors, Rina Chakrabarti produced 7 publications with 153 total citations, indicating a strong scientific influence in this field. Similarly, Jai Gopal Sharma also contributed 7 publications with 153 citations. Avanish Kumar Shrivastav published 6 articles, receiving 138 citations, while Douglas R. Tocher contributed 6 publications with 152 citations, demonstrating a significant impact on the development of Duckweed-based feed research.

Earlier contributions were made by Thomas R. Preston, who produced 5 publications with 59 citations and Lylian J. Rodríguez, who also contributed 5 publications with 52 citations, mainly during the early development of Duckweed feed research in the 1990s. Other active researchers include Shan He with 4 publications and 160 citations, Xufang Liang with 4 publications and 160 citations, Guddu Kumar with 4 publications and 74 citations and Ravi Kumar Goswami with 3 publications and 64 citations. These results indicate that scientific productivity in this field is concentrated among a relatively small group of influential authors.

Most productive institutions

The analysis of institutional productivity indicates that research on Duckweed as a potential feed resource is supported by a wide range of international universities and research institutes (Table 3). "Universiteit Gent" was identified as the most productive institution with 9 publications. It was followed by "Delhi Technological University" and "Kasetsart University", each contributing 8 publications. "University of Delhi" produced 7 publications, while "University of Stirling" contributed 6 articles.

Several other institutions also showed notable contributions, including "Kenya Marine and Fisheries Research Institute", "Kisii University" and "Wageningen University and Research", each producing 5 publications. Institutions with four publications include "Huazhong Agricultural University", "Khon Kaen University", "Shantou University", "Soroka University Medical Center", "Sveriges Lantbruksuniversitet", "Tezpur University", "Trakia University" and "Universität Leipzig". In addition, "An Giang University", "Brawijaya University", "Chinese Academy of Fishery Sciences" and "Forschungsinstitut Für Biologischen Landbau" each contributed three publications. These results highlight the broad global institutional participation in Duckweed-related research.

Most countries' scientific production

The geographical distribution of publications indicates that Duckweed research is conducted across a wide range of countries worldwide (Figure 4). The highest scientific production was observed in "China" and "India", each contributing 44 publications, demonstrating strong research activity in these countries. They were followed by the "United States" with 28 publications and "Indonesia" with 27 publications. Other major contributors include "Thailand" (22 publications), "Mexico" (20 publications) and "Nigeria" (18 publications). Several additional countries also showed notable contributions, including "Bangladesh" (16 publications), "Israel" and "Kenya" (15 publications each) and "Belgium" (13 publications). Moderate contributions were observed from "Netherlands", "Brazil", "Germany" and the "United Kingdom". Overall, the distribution indicates that Duckweed research is globally dispersed, with strong participation from Asian, European, African and American countries, reflecting the increasing scientific interest in Duckweed as a sustainable feed and agricultural resource. This global pattern is consistent with previous studies highlighting strong contributions from Asian countries in Duckweed-related research.

Figure 4. Most countries' scientific production on Duckweed as a sustainable feed resource

Citation analysis

The analysis of the most globally cited documents shows that several papers have contributed substantially to the development of this research field (Table 4). The most cited article is “Bairagi et al 2002, Bioresour Technol” with 149 total citations, followed by “Horppila et al 2000, J Fish Biol” with 117 citations and “Zhou et al 2013, Aquaculture” with 99 citations. Other highly cited studies include “Tallentire et al 2018, J Clean Prod” (94 citations), “Negesse et al 2009, Anim Feed Sci Technol” (91 citations) and “Jorde et al 1983, J Wildl Manage” (90 citations). Additionally, “Sońta et al 2019, Ann Anim Sci” and “Fasakin et al 1999, Aquac Res” each received 88 citations, while “Schneider O, 2004, Aquac Res” recorded 79 citations. In terms of citation impact per year, “Sońta et al 2019” (11.00) and “Tallentire et al 2018” (10.44) show strong annual influence.

Keyword co-occurrence and research themes

The keyword co-occurrence analysis conducted using VOSviewer reveals the main research themes and conceptual relationships within the Duckweed research field (Figure 5). The visualization shows several interconnected clusters, indicating different but related research focuses. The red cluster is centered on “Duckweed” and “Lemna,” highlighting studies related to aquatic plants, digestibility, energy and their use as feed ingredients for animals such as pigs and fish. This cluster also connects with keywords such as “azolla,” “aquatic plant,” and “growth rate,” emphasizing applications in feed and aquaculture systems.

The green cluster focuses on broader biological and nutritional aspects, including “animals,” “animal food,” “metabolism,” “digestion,” and “dietary supplement,” reflecting studies on nutritional physiology and metabolism. The blue cluster is mainly related to aquaculture research, with keywords such as “aquaculture,” “diet,” “growth,” “tilapia,” and “Cyprinus carpio,” indicating experimental feeding trials in fish species.

Meanwhile, the yellow cluster includes biochemical and molecular themes such as “gene expression,” “microbiology,” “fatty acid,” and “enzyme activity.” Overall, the network demonstrates strong integration between nutrition, aquaculture production and biochemical research in Duckweed studies.

Figure 5. Keyword co-occurrence and research themes on Duckweed as a sustainable feed resource

Thematic evolution of Duckweed research

The thematic evolution analysis reveals how research topics related to Duckweed have developed across five time periods from 1976 to 2026 (Figure 6). During the early period (1976-2002), research primarily focused on basic themes such as “diets,” “Duckweed,” “Lemna,” and its use in “aquatic” systems and “meal” for animals, including pigs. In the following period (2004–2014), the themes expanded toward “feed,” “diets,” “protein,” and “aquatic” applications, indicating increasing interest in Duckweed as a nutritional resource in aquatic and livestock production systems. Between 2015 and 2020, research attention shifted toward production-oriented topics such as “animal,” “growth,” “carp,” “diet,” and “production,” highlighting experimental studies on aquaculture performance. In the 2021–2024 period, themes such as “growth,” “Duckweed,” “potential,” and “tilapia” emerged, suggesting a focus on evaluating Duckweed as an alternative feed ingredient. The most recent period (2025–2026) shows emerging themes including “aquatic,” “composition,” “acid,” and “fish,” indicating growing interest in nutritional composition, biochemical properties and applications in aquaculture feed development.

Figure 6. Thematic evolution on Duckweed as a sustainable feed resource

Three-field plot

The Three-Field Plot illustrates the relationships among authors’ affiliations (AU_UN), authors (AU) and their corresponding countries (AU_CO), highlighting the structure of international collaboration in the research field (Figure 7). Several institutions contribute prominently, including Delhi Technological University, University of Delhi, University of Stirling, Shantou University and Huazhong Agricultural University. These institutions are strongly connected to active researchers such as Tocher, Douglas R.; Chakrabarti, Rina; Sharma, Jai Gopal; and Shrivastav, Avanish Kumar, indicating their central roles in the development of this research area. The author field demonstrates that multiple researchers collaborate across institutions and countries, reflecting a diverse academic network. In the countryside, India and China emerge as the most influential contributors, with a large number of authors affiliated with institutions in these countries. Additional contributions come from the United Kingdom, Kenya, Nigeria, Switzerland, Iraq, the United States and the Netherlands. Overall, the plot reveals strong institutional participation and international collaboration patterns shaping the field’s research productivity and knowledge exchange.

Figure 7. Three-field plot relationships among authors’ affiliations (AU_UN), authors (AU) and their corresponding countries (AU_CO) on Duckweed as a sustainable feed resource

Countries' collaboration

The country collaboration analysis highlights a diverse international network in research on Duckweed as a sustainable feed resource (Figure 8). Several strong partnerships are observed, particularly between China and the United Kingdom (4 collaborations) and China and India (3 collaborations), indicating active cooperation among major research producers. India also shows strong collaboration with the United Kingdom (5), reflecting significant academic exchange in this field. The United States collaborates with several countries, including Germany, Israel, Kenya and Peru, demonstrating its broad global engagement. Additional partnerships occur across Europe, Asia, Africa and Latin America, such as Bangladesh–Denmark, Netherlands–Egypt and Mexico–South Africa. Overall, these connections suggest that Duckweed research benefits from wide international collaboration, supporting knowledge exchange and sustainable feed development.

Figure 8. Countries' collaboration world map on Duckweed as a sustainable feed resource

Discussion

The bibliometric analysis provides a comprehensive overview of the development, structure and research trends of Duckweed studies related to animal feed and nutrition. The dataset, consisting of 166 publications indexed in Scopus from 1976 to 2025, reveals that research in this field has evolved gradually over several decades. Although the annual growth rate of 1.4% appears relatively modest compared with rapidly expanding scientific fields, the steady increase in publications demonstrates sustained and growing interest in Duckweed as an alternative feed resource. Duckweed has been widely recognized for its rapid growth rate, high protein content and potential use as a sustainable feed ingredient for livestock and aquaculture (Leng et al 1995; Appenroth et al 2017; Pagliuso et al 2022). The average document age of 12.9 years and the relatively high average citation rate (18.95 citations per document) indicate that many publications in this field maintain long-term scientific relevance. This suggests that foundational studies on Duckweed nutrition and utilization continue to influence subsequent research and technological development (Appenroth et al 2017; Minich and Michael 2024).

The analysis of annual scientific production further highlights the gradual expansion of research activity. During the early decades between the late 1970s and the 1980s, the number of publications remained very limited, with only one article appearing in most years. This low level of activity likely reflects the early exploratory stage of Duckweed research, when the plant was primarily investigated as a potential feed ingredient or as part of aquatic ecosystems. Early studies emphasized its potential as a protein-rich feed source for fish and livestock (Leng et al 1995; Bairagi et al 2002). During the 1990s, publication output increased slightly, suggesting growing awareness of the nutritional potential of Duckweed. However, the most significant increase occurred after 2010, when scientific interest expanded rapidly. This recent growth may be associated with global concerns regarding sustainable feed resources, environmental sustainability and the rising cost of conventional feed ingredients such as soybean meal and fishmeal (Tilman et al 2011; Mottet et al 2017). In addition, Duckweed has gained attention for its capacity to produce high biomass while removing nutrients from wastewater, making it relevant for circular bioeconomy and sustainable agriculture systems (Liu et al 2017; Pena et al 2017). The peak production observed in 2024 and 2025 indicates that Duckweed research is currently experiencing a period of intensified scientific attention, particularly in the context of alternative feed resources and sustainable aquaculture (Minich and Michael 2024; Sosa et al 2024).

The distribution of publications across journals demonstrates the interdisciplinary nature of Duckweed research. The most productive journal, “Livestock Research for Rural Development,” published 19 articles, indicating that Duckweed research is strongly connected with rural farming systems and sustainable livestock production (Leng et al 1995). Journals such as “Aquaculture,” “Aquaculture Research,” and “Journal of Fish Biology” highlight the importance of Duckweed in aquaculture nutrition studies, particularly as a partial substitute for conventional protein sources in fish diets (Bairagi et al 2002; Merah et al 2022). Meanwhile, journals such as “Animal Feed Science and Technology,” “Animal Bioscience,” and “Plants” indicate the integration of plant science, animal nutrition and feed technology. This diversity of publication outlets reflects the multifaceted role of Duckweed as both a plant resource and a feed ingredient for various livestock and aquatic species, as well as its broader relevance for sustainable food and feed systems (Appenroth et al 2017; Pagliuso et al 2022; Sosa et al 2024).

Author productivity analysis indicates that the scientific contributions in this field are concentrated among a relatively small group of researchers. Scholars such as Rina Chakrabarti, Jai Gopal Sharma, Avanish Kumar Shrivastav and Douglas R. Tocher have played particularly influential roles in advancing knowledge on Duckweed-based feed. Their relatively high publication counts combined with strong citation performance suggest that these authors have produced foundational or highly influential studies, particularly in relation to Duckweed biomass production, nutritional composition and its application in aquaculture diets (Chakrabarti et al 2018; Appenroth et al 2017). Their research has contributed to improving the understanding of the amino acid and fatty acid profiles of Duckweed and its suitability as a partial replacement for conventional protein sources in aquafeeds (Minich and Michael 2024). Earlier contributions from researchers such as Thomas R. Preston and Lylian J. Rodríguez also highlight the importance of pioneering work during the early stages of Duckweed research. These early studies helped establish the scientific basis for using aquatic plants as alternative feed resources, particularly in integrated farming systems and small-scale livestock production in developing regions (Leng et al 1995; Chhay et al 2011). Such pioneering work laid the foundation for the growing body of research exploring sustainable and locally available feed resources.

Institutional analysis further reveals the global distribution of research activity. Universities and research institutes from Europe, Asia and Africa are strongly represented in the dataset. Institutions such as Universiteit Gent, Delhi Technological University, Kasetsart University and the University of Stirling demonstrate particularly strong productivity. These institutions are widely recognized for their expertise in aquaculture, animal nutrition and sustainable agriculture research. Their contributions have supported the development of innovative feed strategies and improved understanding of alternative protein sources for livestock and aquaculture (Pagliuso et al 2022; Minich and Michael 2024). The presence of globally recognized research centers such as Wageningen University and Research and the Kenya Marine and Fisheries Research Institute further emphasizes the international nature of Duckweed research. The diversity of contributing institutions also suggests that Duckweed has broad applicability across different agroecological environments, ranging from temperate to tropical agricultural systems (Sosa et al 2024).

The country-level analysis highlights the dominant role of several Asian countries in Duckweed research. China and India emerge as the leading contributors, each producing 44 publications. This strong representation is likely related to the large aquaculture industries and rapidly expanding livestock sectors in these countries. Both nations have strong incentives to explore alternative feed resources that can reduce reliance on imported feed ingredients and support sustainable production systems (Tilman et al 2011; Mottet et al 2017). The United States and Indonesia also show substantial research output, while countries such as Thailand, Mexico, Nigeria and Bangladesh contribute significantly to the field. The wide geographical distribution of research activity indicates that Duckweed is recognized globally as a promising resource for sustainable agriculture. Moreover, the participation of countries from Africa and Latin America highlights the relevance of Duckweed in regions where low-cost and locally available feed resources are particularly important for supporting smallholder livestock and aquaculture production systems (Appenroth et al 2017; Pagliuso et al 2022).

Citation analysis provides additional insight into the intellectual structure of the research field. Highly cited publications such as the study by Bairagi et al (2002) in Bioresource Technology and the work by Horppila et al (2000) in Journal of Fish Biology have significantly influenced subsequent research. These studies likely provided key evidence regarding the nutritional value, digestibility, or ecological role of Duckweed in aquatic systems. More recent publications, such as Tallentire (2018) in Journal of Cleaner Production and Sońta (2019) in Annals of Animal Science, demonstrate strong citation rates per year, suggesting that contemporary research increasingly focuses on sustainability and innovative feed strategies.

The keyword co-occurrence analysis reveals the conceptual structure of the field and highlights the main research themes. The central keywords “Duckweed” and “Lemna” dominate the network, reflecting the primary focus on these aquatic plants as potential feed ingredients. Duckweed species of the family Lemnaceae are widely recognized for their rapid growth, high protein content and suitability as alternative feed resources in both livestock and aquaculture systems (Appenroth et al 2017; Pagliuso et al 2022). The presence of related terms such as “digestibility,” “energy,” and “fish feed” indicates that many studies investigate the nutritional performance of Duckweed in animal diets. Previous feeding trials have demonstrated that Duckweed meal can be incorporated into fish diets as a partial substitute for conventional protein sources, supporting satisfactory growth and feed utilization (Bairagi et al 2002; Merah et al 2022). The connection between Duckweed and aquaculture-related terms such as “tilapia,” “carp,” and “aquaculture” suggests that fish species are among the most common experimental models for evaluating Duckweed-based diets (Chakrabarti et al 2018; Minich and Michael 2024).

Another important thematic cluster focuses on animal nutrition and physiology, with keywords such as “metabolism,” “digestion,” and “dietary supplement.” This cluster indicates that researchers are increasingly interested in understanding how Duckweed affects metabolic processes, nutrient absorption and overall animal performance. Studies examining the nutritional composition of Duckweed have reported high levels of essential amino acids, minerals and bioactive compounds that may influence animal metabolism and growth performance (Appenroth et al 2017; Sosa et al 2024). Additionally, the presence of biochemical and molecular keywords such as “gene expression,” “fatty acid,” and “enzyme activity” suggests that more recent studies are exploring the physiological mechanisms underlying the nutritional effects of Duckweed. Investigations of amino acid profiles, fatty acid composition and metabolic responses have further highlighted the potential of Duckweed as a nutritionally valuable feed ingredient (Chakrabarti et al 2018; Pagliuso et al 2020).

The thematic evolution analysis further illustrates how research topics have changed over time. Early studies between 1976 and 2002 primarily focused on basic themes such as “diets,” “Lemna,” and “aquatic systems.” These studies largely emphasized the basic nutritional composition and feasibility of using Duckweed as an alternative feed resource for fish and livestock (Leng et al 1995; Bairagi et al 2002). During the following decade, the research scope expanded to include topics such as “protein,” “feed,” and “aquatic production,” indicating a growing interest in evaluating Duckweed as a practical feed ingredient for aquaculture and animal production systems (Chakrabarti et al 2018).

Between 2015 and 2020, research themes increasingly emphasized animal performance and production outcomes, as reflected by keywords such as “growth,” “carp,” and “animal production.” This shift suggests that researchers began conducting more controlled feeding trials to evaluate the effectiveness of Duckweed-based diets in improving growth performance and feed efficiency (Merah et al 2022; Minich and Michael 2024). In the most recent years, new themes such as “composition,” “acid,” and “fish” have emerged, indicating a growing focus on detailed nutritional characterization and biochemical analysis. Recent studies have increasingly investigated the biochemical composition, bioactive compounds and nutritional quality of Duckweed biomass for food and feed applications (Pagliuso et al 2020; Sosa et al 2024). This progression reflects the maturation of the research field from exploratory studies toward more specialized and technologically advanced investigations.

The Three‑Field Plot analysis provides additional insights into the collaborative structure of the research community. The connections between institutions, authors and countries demonstrate the importance of international collaboration in advancing Duckweed research. For instance, Puri and Puri (2024), in their bibliometric analysis of Duckweed in aquaculture practices based on Scopus data, identified strong co-authorship linkages and publication contributions from institutions in India, China and the United States , suggesting that these countries form central hubs in the research network.

Authors affiliated with institutions in India and China appear prominently in the network, reflecting strong research activity in these countries. This international pattern of collaboration mirrors findings by Krzywonos et al (2023), who conducted a Scopus-based bibliometric and content analysis of Lemnaceae use for biofuel production and highlighted the global spread of authors contributing to the field.

At the same time, collaborations involving institutions from Europe, Africa, and North America indicate that the field benefits from diverse scientific perspectives and expertise, a characteristic of mature and globally integrated research fields identified through quantitative mapping of Scopus publications (Puri and Puri 2024).

Overall, the bibliometric results demonstrate that Duckweed research has evolved from a relatively niche topic into an increasingly important area of study within animal nutrition and sustainable agriculture. The upward trend in the number of publications indexed in Scopus, the diversity of contributing institutions and countries and the emergence of new research themes all indicate that Duckweed is gaining recognition as a valuable alternative feed resource with environmental and economic potential.

Future research will likely continue to focus on optimizing cultivation methods, improving nutritional utilization in different animal species and integrating Duckweed production into circular and environmentally sustainable agricultural systems, a direction already emerging in recent Scopus-indexed analyses exploring Duckweed’s role in sustainable aquaculture and bioresource utilization.

The country collaboration network reveals that research on Duckweed as a sustainable feed resource is supported by a broad international partnership structure. Strong collaborations are observed between major research contributors such as China–United Kingdom and China–India, indicating active scientific exchange between Asia and Europe. Similarly, India shows frequent collaboration with the United Kingdom, suggesting strong institutional or project-based partnerships. The United States also demonstrates wide international engagement through collaborations with countries such as Germany, Israel, Kenya and Peru. In addition, emerging collaborations involving countries in Africa, Southeast Asia and Latin America highlight the growing global interest in Duckweed research. These collaborative networks facilitate knowledge sharing, technological exchange and multidisciplinary approaches that support the development of sustainable feed resources and environmentally friendly agricultural systems.

Conclusion

This bibliometric study provides an overview of the global development of research on Duckweed as an alternative feed resource for animal nutrition and aquaculture. Scientific interest in this topic has expanded progressively over the past decades, particularly since 2010, reflecting increasing global attention to sustainable feed resources and environmentally friendly agricultural systems. The body of literature is distributed across multiple scientific disciplines, including animal nutrition, aquaculture, plant science and environmental sustainability, demonstrating the interdisciplinary nature of Duckweed research.

Scholarly contributions are concentrated among several influential authors, institutions and countries, with particularly strong participation from China and India, alongside contributions from Europe, Africa and the Americas. Research themes have gradually evolved from basic investigations of Duckweed as a feed ingredient toward more advanced studies addressing growth performance, nutritional composition and biochemical mechanisms.

Duckweed is increasingly recognized as a promising sustainable feed resource. Continued interdisciplinary research, technological innovation, and international collaboration will be essential to further develop its applications in future livestock and aquaculture production systems.

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