The global aquaculture sector, valued at US$296.5 billion in 2023, faces a significant threat from bacterial disease outbreaks. With annual economic losses exceeding US$6 billion and increasing regulations against antibiotic use in regions such as the UK, EU, and China, the need for sustainable growth promoters is more critical than ever.

A groundbreaking study by researchers at Nanyang Technological University and the University of New South Wales has explored a promising dual approach: the combination of encapsulated probiotics and curcumin, the active compound found in turmeric, to enhance fish health and productivity.

Optimizing Delivery Through Encapsulation

One of the major challenges in using probiotics in fish feed lies in their survival throughout the fish’s digestive tract and during the feed manufacturing process. The research team utilized a patented spray-drying technique to encapsulate the probiotic strain Lactiplantibacillus plantarum in an alginate-based protective coating.

This encapsulation method served as a shield against gastric acid. While unencapsulated probiotics often lose viability when exposed to simulated stomach conditions, the encapsulated strains maintained high survival rates, ensuring that beneficial microbes reach the intestines intact for optimal gut colonization.

Synergistic Effects on Growth and Efficiency

Over a 28-week feeding trial, the researchers tested five different diets: encapsulated probiotics (EP), free curcumin (FC), a combination of free probiotics and curcumin (FPFC), a mix of encapsulated probiotics and curcumin (EPFC), and a standard control diet. Results indicated notable improvements across all experimental diets.

Fish on the encapsulated probiotic diet (EP) experienced a 33% increase in body weight compared to the control group, while those on the curcumin-only diet saw a 26.5% weight increase. Moreover, all experimental groups showed superior feed conversion ratios (FCR), indicating enhanced efficiency in converting feed into muscle mass—crucial for profitability in commercial fish farming.

The combination of probiotics and curcumin resulted in a “functional performance” that surpassed individual treatments. Probiotics modulated gut microbiota while curcumin’s antioxidant properties alleviated metabolic stress associated with intensive farming.

Strengthening Disease Resistance

Beyond growth enhancement, the study assessed the “disease resilience” of fingerlings exposed to harmful bacteria, which contribute to billions in industry losses annually. Results revealed that curcumin significantly primed immune responses.

In tests against Vibrio parahaemolyticus, both the free curcumin (FC) and the encapsulated combination (EPFC) groups achieved 100% survival rates, whereas the control group suffered 50% mortality. When challenged with Streptococcus iniae, the combination diets again excelled, demonstrating total survival rates.

The research demonstrated that probiotics improve gut health and growth, while curcumin acts as a systemic immunomodulator, enhancing antioxidant activity and strengthening intestinal barriers against pathogens.

A Sustainable Path Forward for Aquaculture

The implications of this research for the aquaculture sector are substantial. As the industry steps away from preventative antibiotic use due to antimicrobial resistance concerns, functional feeds using natural ingredients like curcumin can offer a responsible alternative that satisfies both regulatory and consumer expectations for cleaner seafood.

The team emphasized that their spray-drying encapsulation method is both scalable and cost-effective for manufacturers. By incorporating accessible bioactive compounds, producers can create high-value feeds that minimize fish mortality and enhance feed efficiency.

While laboratory outcomes are promising, the researchers acknowledged the need for large-scale validation in commercial aquaculture environments. Future research should focus on refining dosages for various species and life stages, as well as assessing long-term economic viability in bulk feed production.

In conclusion, the amalgamation of encapsulated probiotics and curcumin presents a natural platform for advancing the productivity and resilience of the global fish farming industry. The researchers stated: “These findings demonstrate the potential of curcumin-probiotic functional feeds as a sustainable alternative to antibiotics, providing a scalable strategy to improve fish health, productivity, and resilience while supporting responsible aquaculture practices.”

Source: Journal of Animal Science and Biotechnology

“Combinatorial supplementation of fish feeds enhanced growth performance and disease resilience in aquaculture”

Read the full study here

Authors: The‑Thien Tran, et al