The microalgae blend for a fish-free tilapia diet!

dfitzge1 on

The team is happy to share that our work developing microalgae based fish-free feed has been published in Scientific Reports. The article: Microalgae-blend tilapia feed eliminates fishmeal and fish oil, improves growth, and is cost viable (PDF) was accepted officially today, Nov. 12, 2020.

Abstract: Aquafeed manufacturers have reduced, but not fully eliminated, fishmeal and fish oil and are seeking cost competitive replacements. We combined two commercially available microalgae, to produce a high-performing fish-free feed for Nile tilapia (Oreochromis niloticus)—the world’s second largest group of farmed fish. We substituted protein-rich defatted biomass of Nannochloropsis oculata (leftover after oil extraction for nutraceuticals) for fishmeal and whole cells of docosahexaenoic acid (DHA)-rich Schizochytrium sp. as substitute for fish oil. We found significantly better (p < 0.05) growth, weight gain, specific growth rate, and best (but not significantly different) feed conversion ratio using the fish-free feed compared with the reference diet. Fish-free feed also yielded higher (p < 0.05) fillet lipid, DHA, and protein content (but not significantly different). Furthermore, fish-free feed had the highest degree of in-vitro protein hydrolysis and protein digestibility. The median economic conversion ratio of the fish-free feed ($0.95/kg tilapia) was less than the reference diet ($1.03/kg tilapia), though the median feed cost ($0.68/kg feed) was slightly greater than that of the reference feed ($0.64/kg feed) (p < 0.05). Our work is a step toward eliminating reliance on fishmeal and fish oil with evidence of a cost-competitive microalgae-based tilapia feed that improves growth metrics and the nutritional quality of farmed fish.

This project, which has been a labor of love, is the culmination of more than 6 years of work and could not have been possible without the help of many team members and collaborators. We’re happy to have this paper finally hit the press and even more excited to keep working to innovate feeds for a more sustainable aquaculture industry.

Here is a post from phys.org that highlights our publications acceptance, and a press release from the UCSC Newscenter.

To cite this paper: Sarker, P.K., Kapuscinski, A.R., McKuin, B. et al. Microalgae-blend tilapia feed eliminates fishmeal and fish oil, improves growth, and is cost viable. Sci Rep 10, 19328 (2020). https://doi.org/10.1038/s41598-020-75289-x

California Sea Grant? Granted!

dfitzge1 on

The Kapuscinkski-Sarker lab team is happy to announce we have been awarded a grants from the California Sea grant program

Check out this article, “California Sea Grant funds sustainable aquaculture project” by UCSC’s highlighting the grant’s main focus, and this article “Converting under-utilized microalgal co-product into value-added ingredient for cost-viable, fish-free aquafeed for rainbow trout” from the CA Sea grant program website

Published!

dfitzge1 on

Congratulations to Dr. Sarker and Kapuscinski for another successfully published paper in Elementa, a high quality open access journal. Check out the abstract (below) for a brief intro to:

Towards sustainable and ocean-friendly aquafeeds: Evaluating a fish-free feed for rainbow trout (Oncorhynchus mykiss) using three marine microalgae species

Aquaculture, the fastest growing food sector, is expected to expand to produce an additional 30 million metric tons of fish by 2030, thus filling the gap in supplies of seafood for humans. Salmonids aquaculture exploits the vast majority of fishmeal and fish oil rendered from ocean-dwelling forage fish. Most forage fish diverted to these commodities are human-food grade, and all are primary prey for marine predators. Rising costs, price volatility, and environmental sustainability concerns of using these commodities for aquaculture feed are driving the global search for alternatives, including marine microalgae originating from the base of marine food webs but produced in culture. We report the first evaluation of two marine microalgae, Nannochloropsis sp. and Isochrysis sp., for their potential to fully replace fishmeal and fish oil in diets of rainbow trout (Oncorhynchus mykiss), an important model for all salmonid aquaculture. We conducted a digestibility experiment with dried whole cells of Nannochloropsis sp. and Isochrysis sp., followed by a growth experiment using feeds with different combinations of Nannochloropsis sp., Isochrysis sp., and Schizochytrium sp. We found that digestibilities of crude protein, crude lipid, amino acids, fatty acids, omega 3 polyunsaturated fatty acids (n3 PUFA), docosahexaenoic acid (DHA), n6 (omega 6) PUFA in Isochrysis sp. were significantly higher than those in Nannochloropsis sp. Digestibility results suggest that for rainbow trout diets Isochrysis sp. is a better substitute for fishmeal and fish oil than Nannochloropsis sp. The lower feed intake by fish fed diets combining multiple microalgae, compared to fish fed the reference diet, was a primary cause of the growth retardation. In trout fillets, we detected an equal amount of DHA in fish fed fish-free diet and reference diet. This study suggests that Isochrysis sp. and Schizochytrium sp. are good candidates for DHA supplementation in trout diet formulations.

Introducing ENVS 135, Sustainable Aquaculture! Enroll now for Winter Quarter!

cdgreenw on

Enrollment season is upon us, and for the first time at UCSC, ENVS upper division students have the opportunity to study under the world renowned Dr. Pallab Sarker in his class ENVS 135, Sustainable Aquaculture.

All over the world, aquaculture is the fastest growing production sector, due to the combination of strongly increasing demand for seafood products and depleted fish stocks in the world’s oceans. Aquaculture needs to simultaneously pursue environmentally sound, economically viable and socially acceptable development – that is the principle of (three pillars) sustainability – in order to avoid the same mistakes of industrial agriculture.

In this course, students will learn to understand current aquaculture systems, in settings ranging from international (e.g., China, Bangladesh) to local (e.g., abalone farms in Monterey Bay area) and learn about the science and practices needed to steer aquaculture’s development to sustainability. This course will take a broad and a critical look at the practices of present-day aquaculture—and apply a sustainability framework to analyze the environmental, social, economic, and human health effects of sustainable aquaculture systems. This course will provide in-depth and practical experience which includes hands-on experiential learning at the UCSC Aquaculture lab, and visits to local aquaculture farms, contact with private seafood sector, and several guest lectures by resident UCSC experts.

Enroll now for Winter 2020, or pencil it into your schedules for a future winter quarter. Don’t miss out on this opportunity to learn from one of the best in his field!

Kapuscinski-Sarker Lab Team Recieves National Sea Grant Funding

dfitzge1 on

NOAA’s new grant from the National Sea Grant College Program awarded our team (Dr. Kapuscinki, Sarker, and Campbell, and our own Brandi McKuin) 245,000$ to help develop a better modeling tool for aquafeeds. This open access software can one day help users asses not only the environmental impact of a diet but whether or not the nutritional content meets acceptable standards.

Read more in this UC Santa Cruz Article by Jennifer McNulty here: Sustainable aquaculture initiative lands $245,000 federal grant

Good work team!