Algal Research, 96 Art 104750, 2026
M. do Nascimento, L. Garcia- Martinez, A. N. Bader, A. S. Mechaly, N. Zanazzi, M. I. Prario, A. Asiain, V. F. Consolo, A. Fernandez- Gimenez, L. Curatti
Highlights
- Ankistrodesmus sp. SP2–15 biomass was produced year-round in outdoor flat-panel photobioreactors.
- Microalgal biomass successfully replaced 30% of fishmeal in diets for juvenile Nile tilapia.
- Fish fed hydrolyzed biomass showed growth performance comparable to the control diet.
- Microalgal inclusion increased fillet PUFA content by 20–29%, supporting its potential as a sustainable aquafeed ingredient.
Abstract
Microalgae are promising alternative ingredients for aquafeeds, but their large-scale application depends on the development of productive strains, cost-effective biomass processing, and demonstrated nutritional value in fish.
In this study, the freshwater microalga Ankistrodesmus sp. SP2–15 was cultivated year-round under outdoor conditions and evaluated as a partial substitute for fishmeal in diets for juvenile Nile tilapia (Oreochromis niloticus). Three diets were compared during a 68-day feeding trial: a conventional control diet and two experimental diets in which 30% of the fishmeal was replaced by either crude or enzymatically hydrolyzed microalgal biomass.
Tilapia fed the hydrolyzed biomass diet achieved growth and feed conversion comparable to fish receiving the control diet, whereas the crude biomass produced only a slight reduction in growth performance. Importantly, inclusion of Ankistrodesmus biomass increased the proportion of polyunsaturated fatty acids in the fillets by 20–29%, including a marked enrichment in α-linolenic acid. No mortality was observed, and digestive enzyme activity was not negatively affected by either microalgal diet.
Together with its year-round outdoor productivity and favorable harvesting properties, these results identify Ankistrodesmus sp. SP2–15 as a promising locally produced ingredient for more sustainable aquafeed formulations.
