The aquaculture industry is undergoing a transformative change as it grapples with the pressing need for sustainable and cost-effective feed solutions. Traditional fishmeal and fish oil, while highly nutritious, are becoming increasingly scarce and expensive, putting significant pressure on the industry.
In this context, plant-based alternatives are gaining ground. One such promising alternative is lupine (Lupinus spp), a genus of leguminous plants recognized for its high protein content and potential as a sustainable ingredient for aquafeeds.
A team of researchers from the Tamil Nadu Dr. J. Jayalalithaa Fisheries University (India) published a scientific review exploring the potential of lupine in the aquaculture industry, focusing on its nutritional value, digestibility, and impact on the health and growth of fish. The researchers also analyze recent findings, challenges, and possible advancements to provide insights into how lupine could drive the development of sustainable aquaculture techniques.
Lupine: A Source of Nutrition
Lupine, a versatile legume grown in various regions, is rich in protein and has a balanced profile of essential amino acids crucial for the optimal growth and development of fish.
The nutritional profile of lupine, including crude protein (33 to 43 g), crude lipids (6 to 11 g), and ash content (2.9 to 4.6), makes it an attractive substitute for fishmeal for aquafeed manufacturers, which has traditionally been the most used protein source in aquaculture.
Moreover, research has indicated that the inclusion of lupine in fish diets can positively affect fish health, potentially improving their immune response and overall well-being.
Benefits of Lupine for Aquaculture Species
The study reports the following benefits of including lupine in aquafeeds:
- Lupine Digestibility: The protein digestibility of lupine in fish such as salmon and trout (85.2%) is higher than that of whole soybean meal (79.5%).
- Nutritional Deficiencies: Lupine, as a plant source, lacks essential amino acids such as methionine and lysine, resulting in reduced growth when used in high inclusions (40%).
- Antinutritional Factors: The presence of non-starch polysaccharides, oligosaccharides, and antinutritional factors in lupine can contribute to reduced growth in salmon.
Optimal Inclusion
- In rainbow trout, a 25% substitution of fishmeal with lupine improves growth and feed acceptance.
- In Atlantic salmon, a partial lupine inclusion between 20% and 40% is recommended.
- Carp: For common carp, a partial substitution of 12.5% soybean meal with lupine seed meal improves weight gain and feed efficiency. In black carp, a 30% substitution shows similar results.
- Seabass: A dietary inclusion of lupine seed meal between 40% and 50%, with proper processing techniques, enhances growth.
- Tilapia: A dietary inclusion of up to 50% produces high growth.
- Turbot: A 50% inclusion enhances growth.
- Cobia: A dietary inclusion of 10.5% provides growth comparable to that of fishmeal.
- Shrimp: In black tiger shrimp (Penaeus monodon), lupine seed meal can replace up to 40-50% of soybean meal. In white shrimp (Litopenaeus vannamei), a 10% inclusion (100 g/kg) provides better growth compared to 20% or 30% inclusions.
Immune Response
Antioxidants in Lupine:
- Studies revealed the presence of tocopherol compounds (alpha, beta, and gamma) in lupine seeds, which are essential for maintaining levels of reactive oxygen and nitrogen species.
- Long-term storage and irradiation treatments decrease tocopherol content.
Antioxidant and Antibacterial Properties:
- Antioxidants in lupine act as potent ACE inhibitors and prevent lipid oxidation and atherosclerosis.
- Polyphenolic compounds, mainly in the peripheral parts of the seed, contribute to its antioxidant and antibacterial properties.
- Antibacterial activity is due to the presence of polyphenols and alkaloids, correlating with a high total phenol content in lupine.
In summary, lupine presents itself as a promising alternative ingredient for aquafeeds due to its high digestibility and potential to enhance fish growth and health. However, its inclusion must be carefully balanced to avoid nutritional deficiencies and maximize its beneficial properties.
Environmental Benefits of Lupine
The aquaculture industry is often criticized for its environmental footprint. The excessive reliance on fishmeal contributes to overfishing and ecosystem disruption. Lupine cultivation, on the other hand, offers a more sustainable alternative. It is known for its ability to improve soil quality, reduce erosion, and enhance biodiversity. By incorporating lupine into aquafeed formulations, the industry can significantly reduce its ecological impact.
Challenges and Opportunities for the Aquaculture Industry
While lupine presents a promising pathway for sustainable aquaculture, several challenges must be addressed. These include variations in nutrient composition among different lupine varieties, the presence of antinutritional factors, and the need for optimized processing techniques to unlock lupine’s full potential.
However, ongoing research is uncovering innovative solutions. Scientists are exploring breeding programs to develop lupine cultivars with enhanced nutritional profiles and reduced antinutritional factors. Additionally, advances in processing technologies are improving the digestibility and bioavailability of lupine proteins for fish.
Conclusion
Incorporating lupine into aquafeed formulations represents a significant step towards a more sustainable and resilient aquaculture sector. By leveraging the nutritional value and environmental benefits of this versatile legume, the industry can mitigate its reliance on finite marine resources while ensuring the production of high-quality seafood.
As research progresses and our understanding of lupine’s potential deepens, we can anticipate new advancements that will solidify its position as a cornerstone of sustainable aquaculture practices.
Contact
Amit Ranjan
Institute of Fisheries Post Graduate Studies, Tamil Nadu Dr. J. Jayalalithaa Fisheries University
Chennai, India
Email: amitranjanfcri@gmail.com
Reference (open access)
Malarvizhi, K., Kalaiselvan, P. & Ranjan, A. Unlocking the potential of lupin as a sustainable aquafeed ingredient: a comprehensive review. Discov Agric 2, 43 (2024). https://doi.org/10.1007/s44279-024-00054-x
