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Title: Microencapsulated diets to improve the productivity of bivalve shellfish aquaculture for global food security
Author: Willer, David
ISNI:       0000 0004 9359 8952
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2020
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Food is the single strongest lever to optimise human health and environmental sustainability on earth. However, food production and consumption patterns today threaten both people and planet. We face a double-burden of malnutrition and overconsumption, with two billion people micronutrient deficient and over two billion people overweight or obese, and the global food system is now the single largest greenhouse-gas-emitting sector. Bivalve shellfish – including mussels, clams, and oysters – could be an invaluable component of our global food solution. Bivalves are nutrient rich, production has a lower environmental footprint than that of all other animal foods, and developing just 1% of the coastline suitable for bivalves worldwide would provide over one billion people with all their protein needs. To realise global potential there is an urgent need for innovation to enable increased bivalve production and consumption. This thesis aimed to test whether new innovations in microencapsulated feeding technology could be used to overcome major bivalve industry bottlenecks and help drive a step change in our global food system. The initial research focus was to assess the potential of microencapsulated feeds as a problem-solving tool in bivalve aquaculture and test viability via laboratory experiments. I performed a critical review to assess key industry challenges and identify where microencapsulation technology could most effectively be applied. Experimental tests then allowed me to demonstrate that microencapsulated feeds could be ingested by a commercially farmed bivalve, the blue mussel (Mytilus edulis), providing a foundation for research on specific industry challenges. The second phase of the thesis assessed the effectiveness of microencapsulated feeds to tackle major bivalve hatchery bottlenecks in juvenile growth and broodstock conditioning. I undertook research both in the laboratory and at a commercial hatchery to reveal that microencapsulated feeds could increase the growth and survivorship of European oyster (Ostrea edulis) juveniles relative to conventional live algal diets. I then demonstrated that the feeds could facilitate improved sexual development in O. edulis broodstock and enable this stage of bivalve production to become an order of magnitude more sustainable and economically efficient. The final phase of the thesis aimed to use both experimental and literature analyses to explore how microencapsulated diets and bivalve aquaculture could help tackle broader nutritional problems and contribute towards food security goals. I identified an optimal dosing strategy to fortify Pacific oysters (Crassostrea gigas) with vitamin A and D, and outlined how tailoring the micronutrients encapsulated and bivalve species reared could provide a low cost mechanism to tackle regional nutritional deficiencies directly through the food supply. I then built on this global perspective and reviewed how expansion of bivalve aquaculture could help tackle food security challenges in the developing world. Key components of the value chain requiring further research, industry investment and policy changes were identified, alongside the importance of a multifaceted strategy to stimulate increased consumer demand. To summarise, my work in this thesis has demonstrated how applying new innovations in microencapsulation technology to bivalve aquaculture can provide powerful solutions to a range of industry challenges. Scale up and further application of the research breakthroughs I have made can contribute towards a global revolution in food production with widespread benefit to human and planetary health.
Supervisor: Aldridge, David Sponsor: BBSRC
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
Keywords: Aquaculture ; Microencapsulation ; Food Security ; Sustainability ; Seafood ; Bivalve ; Fortification ; Nutrition