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Single cell protein as substitute for fishmeal in juvenile rainbow trout diet

A proprietary single cell protein product gets high marks as a sustainable replacement for fishmeal.

American company, Sasya LLC, developed a novel method to produce a single cell protein product intended as an ingredient for farmed fish. The nutritional value of the single cell protein can be manipulated to enhance the levels of targeted essential amino acids and fatty acids with laboratory-scale production.

“It is a great source of alternative protein ingredients for sustainable aquaculture which has a potential to replace fish meal completely,” said Vikas Kumar, assistant professor at the Aquaculture Research Institute, University of Idaho.

Kumar is the author of “Fishmeal alternative from renewable CO2 for rainbow trout feed,” published in Aquaculture Research.

Kumar and his team evaluated the effects of replacing fishmeal with Sasya’s single-cell protein on in vivo digestibility, growth, feed efficiency, wholebody proximate/amino acid composition and gene expression levels of various hepatic enzymes in rainbow trout.

They recommended 18 percent fishmeal and 13.6 percent single cell protein in the diet of rainbow trout fingerlings. “However, based on growth and muscle fatty acids data, it looks like addition of single cell protein can increase the omega-3 fatty acids, especially EPA in muscle,” Kumar said.

Diet 1 had 30 percent fishmeal and 0 single cell protein, and Diet 2 had 24 percent fishmeal and 6.8 percent single cell protein.

Survival was high in all three treatments, with 100 percent in Diets 2 and 3, and 98.9 percent in Diet 1.

During the nine-week period of the experiment, the fish grew over tenfold. Feed intake and feeding efficiency were likewise not significantly different among the treatments.

Sasya’s single cell protein can “enlarge the portfolio of alternative protein sources that can be used in fish diets and open a new market opportunity for use of a new feed resource in the feed industry,” the authors cited in the study.

Research on substitutes for fishmeal in feed formulations is often hampered by plant-based anti-nutritional factors. Depending on dosage, these may lead to reduced fish growth, feed intake and health issues.

“Due to the sensitivity of salmonids to anti-nutritional factors, research is increasingly exploring the feasibility of using non-plant-based proteins as fishmeal alternatives, which has included single cell proteins from yeast,” they said.