In this series of interviews with researchers, we move to the UK with Professor Emeritus Simon J. Davies, who has spent most of his career as an aquaculture nutrition researcher and academic.
Growing up in the small Welsh coastal village of LLangennech, in Southwest Wales, Simon developed a passion for the aquatic environment and fish as a keen fisherman. This passion led him to pursue a PhD in salmonid nutrition at the Institute of Aquaculture at the University of Stirling, which he completed in 1984. He then embarked on a long-term academic career spanning over 40 years, specializing in fish nutrition and aquaculture biosciences.
“I quickly realized that aquaculture was expanding globally and that working in fish would provide a niche opportunity to make a valuable scientific and teaching contribution to the discipline,” Simon said in an interview with Aquafeed.com.
The biggest challenge for the aquafeed industry today
When asked about the biggest challenges facing the aquafeed industry, Simon highlighted the pressure of meeting the growing protein and energy demands as aquaculture expands. "The issue of scaling up the replacement of marine ingredients is a key factor for success and sustainability," he explained. While there are many promising alternative feed ingredients, Simon pointed out that supply, demand, and consistency in quality remain significant hurdles. "These challenges must be addressed. Much work has been undertaken over the decades, but more validation through efficacy trials is required," he emphasized.
In terms of alternative protein, there are some well-established commodities that have been already tested and some new such as black soldier fly larval meal, single-cell proteins and bacterial and yeast proteins as well as algae. In terms of lipids, Simon said that too much focus has been on omega-3s, but omega-6s and omega-9s should also be considered. “These fatty acids play both proinflammatory as well as anti-inflammatory and other metabolic/physiological roles during different phases of fish production. We must carefully observe and balance these in relation to disease resistance and achieve optimal immune responses,” Simon advised.
Gut microbiota and functional feed additives
The modulation of gut microbiota has become central to aquaculture research, linking diet composition to bacterial balance and improving digestive and immune function in fish and shrimp. Simon has been involved in this dynamic area for over two decades.
“Strong evidence has shown that diet and certain feed additives can modulate the intestinal microbiota in fish and shrimp leading to a better defensive mechanism primed to combat stress and bacterial invasion,” Simon said. “The mucosal/gut and integument barriers in fish and shrimp play a crucial role and can be influenced by prebiotics, probiotics and plant or herbal extracts with functional properties.”
However, one of the primary challenges in this research is the tendency to capture only a “snapshot” of the gut, gill, or skin microbiome, rather than monitoring its evolution over time. Simon emphasized the importance of using advanced sequencing technologies like High-Throughput Sequencing (HTS) or Next-Generation Sequencing (NGS) to track microbiome changes over extended periods. “As sequencing costs decline, it will be crucial to track the microbiome in fish and shrimp over an extended period to assess the effectiveness of functional feed additives,” he added.
Molecular approaches to nutrition and genetic advancements
Metabolomics, proteomics and lipidomics using advanced molecular and metabolic signatures (metabolites) in tissues and organs responding to dietary nutrient assimilation could become an important platform to better assess nutritional performance and provide invaluable information for customized nutrition for fish and crustacean species.
Simon also highlighted the potential of selective breeding and gene editing in aquaculture. “Gene editing could help reduce or remove antinutritional factors in plant-based feeds, improving digestibility and nutrient assimilation,” he explained. “Similarly, genetic modifications in fish could enhance digestive enzyme activity, making feed utilization more efficient. Though controversial, these advancements present immense opportunities to improve aquaculture efficacy while addressing ethical concerns.”
Precision nutrition
The aquafeed industry is shifting to precision nutrition. “Achieving this transition requires updated digestibility profiles of raw materials, particularly for digestible amino acids and metabolic energy values,” Simon noted. “Understanding mass balance for protein and energy retention, as well as net protein (NP) and net energy (NE) values for ingredients, will allow us to create more precise formulations.” These advances would improve feed efficiency, reduce waste, and lower costs, ultimately benefiting both fish farmers and the environment.
AI-driven feed optimization and manufacturing
Data-driven feed optimization is becoming a reality with artificial intelligence (AI). Simon believes AI will play a transformative role in aquafeed manufacturing, helping to track supply, demand, and commodity flow in feed production; optimize production capacity and streamline processes; and generate real-time data to improve diet uniformity and quality.
“The advance of AI will revolutionize manufacturing by providing full tracking and control over production,” Simon said. “Real-time data will help reduce costs and enhance feed consistency.”
AI will also improve pellet coating technology, ensuring the stable incorporation of delicate feed additives such as enzymes, thermolabile vitamins, pigments, and medicated supplements. “Volatile and sensitive compounds used in flavoring and coloring, also chemotherapeutics and vaccines (medicated feeds) may be better applied under such control systems monitored by AI,” Simon added.
Extrusion technology is another area where AI can drive improvements. “Research has demonstrated the benefits of more stable extruded sinking pellets for shrimp production,” Simon noted. “Yet, 90% of shrimp feed in Asia is still produced using cheaper ‘cold-pelleting’ techniques due to cost constraints. AI can enhance consistency and uniformity in this process.”
Beyond manufacturing, AI is revolutionizing farm management. Advanced systems are being developed to monitor water quality and analyze feeding behavior through drone and satellite image learning technology. “This can lead to improved feed conversion ratios (FCR) and reduced waste, mitigating the environmental impact of intensive aquaculture operations,” Simon said.
Aquafeeds and disease prevention
Simon highlighted the crucial role of aquafeeds in disease prevention and management.
“Effective prophylactic strategies are being developed through innovations in feed additives such as prebiotics, probiotics, phytobiotics, and herbal extracts,” he stated. “The use of enzymes enhances the prebiotic potential of diets by improving fiber digestibility and supporting immune function.”
Collaboration with global partners has generated extensive evidence of these strategies' success across various species, including carp, tilapia, trout, seabass and shrimp. Simon pointed out that this research is particularly relevant in regions like the Middle East and Southeast Asia, where emerging bacterial diseases pose significant threats to the aquaculture industry.
Funding
Having built his research career in the UK, Simon identifies the UK Home Office as a constraint on aquaculture research. “Their legislation for animal experimentation is often quite complex and difficult to comprehend, even for routine fish husbandry activities,” he explained. “Working on fish, particularly in aquaculture and nutrition, can lead to misinterpretation, with views varying from local inspectors and no consistent oversight. Such legislative authorities and practitioners need to be better informed and trained regarding aquaculture and the husbandry of different species."
Due to these regulatory challenges, Simon has found it easier to conduct research overseas, particularly for disease challenge studies testing feed additives. “It has been much easier for me to engage internationally, use resources, and conduct trials that would be quite difficult to license in the UK,” he said.
Securing funding for research also remains a challenge, as industry partners often underestimate the costs and overheads of university-led projects. “Major Research Councils like NERC and BBSRC occasionally provide funding for doctoral programs, but these increasingly require industrial or commercial partnerships,” Simon noted. “Fortunately, I have had many such funded projects over the years.” However, he pointed out that industry-funded research is often tied to specific experimental goals that may not align with a broader scientific rationale.
“A well-designed study, guided by experienced academics in aquafeed research, is imperative for success,” Simon emphasized. “We must ensure industrial trials are properly structured and, from the outset, explain to sponsors the advantages and limitations of evaluating their products under controlled laboratory conditions.” He noted that some in-house commercial trials suffer from poor organization and transparency, leading to ambiguous results and conclusions.
He stresses the importance of well-planned experimental designs, including sufficient treatment numbers, appropriate ingredient incorporation levels, and consideration of facility constraints such as tank size and stocking density. “Not appreciating these factors can lead to wasteful investigations with results that may be difficult to publish in reputable journals,” he warned. Additionally, he highlighted potential conflicts between researchers and sponsors due to differing expectations, as well as complications arising from government or industry-supported grants, which may impose restrictions on intellectual property rights.
Present and future
Simon identifies the sustainability and cost-effectiveness of alternative protein sources as the primary challenge in aquafeed development, stating, "If I could solve one challenge, it would be to develop scalable, nutritionally balanced, and economically viable alternative protein sources such as insect meal, single-cell proteins, or plant-based proteins for carnivorous fish species."
Over the next decade, he envisions aquafeeds advancing through alternative proteins, nutritional precision, and functional ingredients like probiotics and immunostimulants to enhance gut health and reduce antibiotic use. "We must address antimicrobial resistance (AMR) in aquaculture to promote fish health and welfare in the food chain," he emphasized. Sustainable sourcing through circular economy practices and Life Cycle Analysis (LCA) will be essential, alongside smart aquafeed technologies such as AI and IoT for real-time monitoring and feed optimization.
“These advancements will help make aquaculture more efficient, sustainable, and resilient, ensuring long-term food security while minimizing environmental impact. Education will be the key to this and along with much better communication,” Simon concluded.
