Comparative life cycle assessment of heterotrophic microalgae Schizochytrium and fish oil in sustainable aquaculture feeds.

Congratulations to Dr. McKuin, and team, who recently published an LCA tracking the environmental impact of Schizochytirum; a microalgae species high in DHA. This species is an excellent candidate to replace fish-meal in commercial aquaculture feeds.  For more check out the paper:

Comparative life cycle assessment of heterotrophic microalgae Schizochytrium and fish oil in sustainable aquaculture feeds.

Abstract:

Fish oil is primarily extracted from small marine pelagic fishes, reducing their availability for marine wildlife forage and artisanal fishing catches that support food security in lower income coastal nations. A primary use of fish oil is in feeds for aquaculture, the world’s fastest growing food sector. Efforts to transition fed aquaculture to sustainability includes replacing fish oil in aquafeeds with more environmentally responsible alternative ingredients. The heterotrophic marine microalga Schizochytrium sp., one of the first commercialized alternatives, lacks an open-access, systematic analysis of environmental impacts of substituting fish oil with heterotrophic microalgae from biorefineries. This study compared the “cradle to factory-gate” life cycle impacts of fish oil to whole-cell or extracted oil of Schizochytrium combined with canola oil. We conducted an attributional life cycle assessment using inventory data collected from published literature and patents and received feedback on commercial relevance of model assumptions from industry advisors. We examined sugar from a Brazilian sugarcane biorefinery and sucrose from U.S. sugar beets as feedstocks for heterotrophic cultivation of Schizochytrium; and compared life cycle impacts of extracting Schizochytrium oil using solvent-free microwave extraction to conventional solvent extraction. Results were that: cultivation processes had the largest overall effect for both products in both regions; whole-cell Schizochytrium combined with canola oil had significantly lower environmental impacts, in all assessed categories, than Schizochytrium oil blended with canola oil; and conventional solvent extraction had significantly lower environmental impacts compared to solvent-free microwave extraction except global warming potential. Schizochytrium products, compared to fish oil, had substantially lower biotic resource depletion and, in the case of whole cells combined with canola oil, had significantly lower global warming potential but higher impacts for all other categories, primarily because commercial Schizochytrium production used sugar feedstocks as carbon and energy sources. The mix of lower and higher environmental impacts of Schizochytrium products illustrates the importance of openly identifying environmental trade-offs to inform evidence-based decisions for commercial practices. Environmental impacts should also be weighed against potential human health benefits of maintaining omega-3 fatty acids and avoiding contaminants in fish flesh when considering alternatives to fish oil.

 

 

ABO Dispatch: Algae in Aquaculture Workshop

Three lab members, Dr. Sarker, Dr. McKuin, and Dr. Kapuscinski, participated a national Algae in Aquafeed workshop (March 5, 2022) at which researchers, algae production companies, aquaculture businesses, and environmental non-profits addressed opportunities, barriers and challenges for scaling up inclusion of microalgae and macroalgae in aquaculture feeds. Dr. Sarker presented on R&D on algae replacement of fishmeal and oil;  Dr. McKuin presented progress on developing an open-access decision support tool for sustainable aquafeed; and Dr. Kapuscinski commented on the sustainability imperative and moderated a breakout group. A full recording of the workshop is now available and included below.

ABO Workshop: Algae in Aquafeed – Opportunities, Barriers and Challenges on March 5, 2022 from Algae Biomass Organization on Vimeo.

Ever wonder how we weigh our fish?

Check out our most recent post on Instagram to find out! Weight samples are routinely performed to monitor fish growth and to help us calculate the proper feed amounts to administer to each tank daily. The final picture is included as evidence of the substantial growth we have seen thus far while feeding our trout a microalgae based diet. Growth trials are off to a fantastic start, and we cannot wait to publish our findings! Thank you California SeaGrant for making this work possible!

Fish in at last! Plus an amazing lecture from Anne Kapuscinski

We are excited to announce that we finally have fish in our RAS systems! After over a year of preparation, we now have trout that we will soon be acclimating to our micro-algae based diet in an attempt to reduce aquaculture’s dependency on fish meal and fish oil taken from forage fish populations. The trout fry are currently adapting to their new homes and initially will have to be fed around five times a day, six days a week due to their very small digestive tracks. Nick Gonzales, a photographer with UC Santa Cruz, was there to capture the magical first moments in their new homes.

To top off an amazing week, Anne Kapuscinski gave a fantastic lecture as part of the Kraw series, a series of lectures made possible by UC Santa Cruz alumnui George Kraw, featuring UC Santa Cruz scientists and technologist grappling with some of the biggest questions of our time. Anne discussed our research on tilapia and trout, and why it is so important that we find alternative feed ingredients that are nutritious, economically viable, and sustainable.

Anne spent the second half of her lecture explaining the workings of her Coastal Science and Policy Graduate Department and outlining a few of her students fascinating projects; attempting to solve issues facing coastal communities and the environment alike through innovation and policy reformation.

A recording of Anne’s lecture can be found here on youtube.

For more Craw lectures click here.

The articles keep rolling out.

Dr. Sarker has gotten some great interviews in this week all on the momentum from our recent paper published in Scientific Reports. Take a look at these three articles:

Another great piece on our “vegetarian” diet for fish.

Online magazine, Anthropocene, picked up the news of our recently published paper in Scientific Reports. Emma Bryce does a great job highlighting the importance of novel aquaculture diet ingredients, like microalgae.

Our very own Dr. Sarker is quoted to explain that “the potential environmental impacts are enormous, as we fully eliminated wild-caught forage fish from aquaculture feed.”

Can industrial aquaculture grow vegetarian fish? is an article well worth the read.