Last month [July] saw the launch of a three-year project led by researchers at the University of California (UC), Santa Cruz, with the aim of developing a fishmeal alternative from an under-utilized microalgae industry co-product.
“The proposed project is a critical part of our larger research program to advance more environmentally sound trout diets by reducing eutrophication emissions, eliminating fishmeal and fish oil and encouraging economically sustainable use of under-utilized resources to directly benefit US aquaculture operations. This grant will help strengthen sustainable environmental stewardship of aquaculture,” Pallab Sarker, Associate Professor of Environmental Studies at UC Santa Cruz, told FeedNavigator.
The project will be funded by a $1m grant from the Agriculture and Food Research Initiative at the USDA National Institute of Food and Agriculture.
“We will use this fund to conduct a series of experiments in the lab, on-farm trials, environmental and economic analysis and extension work,” said Sarker.
Aquafeed: an environmental impact hotspot
Outlining the context to the program, Sarker warned that aquafeed has become an “environmental impact hotspot”.
“The environmental sustainability of aquaculture is of critical concern due to its rapid expansion. There is a need to seek more sustainable aquafeeds to address the environmental impacts associated with aquaculture,” he said.
Sustainable expansion of aquafeeds requires alternatives to fishmeal, said Sarker.
“Diverting forage fisheries to produce fishmeal undermines marine biodiversity. Aquaculture feed is a critical production input as well as a major source of waste in aquaculture systems. Also, poorly digested feed ingredients can increase nutrient emissions (nitrogen and phosphorus) in aquaculture effluents,” he noted.
If successful, this project will result in a sustainable new microalgal aquafeed that addresses all of these issues.
Three-step plan
The first step will be to develop a new protein meal by processing the microalgae industry’s large volumes of under-utilized defatted microalgae product and conducting nutrient and anti-nutrient analysis.
The team will evaluate the digestibility, retention and waste outputs of the new co-product meals and identify a suitable level of fishmeal replacement by testing different formulations in rainbow trout aquafeeds.
Next, an extension team will conduct feed trials using the best performing experimental diets. These will take place on rainbow trout farms in California and the collaborations will be used as the basis for building a ‘community of practice’ for commercial adoption of microalgae-based trout feed.
The third phase of the project will focus on LCA (life-cycle analysis) and economic modelling. The environmental engineering team will use the results of the feeding trials to conduct an LCA to compare the environmental impacts of the commercial diet and experimental diets. Economic modelling will evaluate the financial feasibility of incorporating the co-product meal in rainbow trout diets. The results will then be applied to commercial trout farms via on-farm feed trials, and the results reported.
“The extension team will amplify the impact by disseminating results of this research to industry stakeholders along the aquaculture value chain,” said Sarker.
