Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

DEVELOPING MACROALGAE FEED INGREDIENTS FOR MARINE FISH FEEDS

Ronald Johnson*, Joseph Dietrich, Bernadita Anulacion, Frank Sommers ,  Pete Nicklason, Sean Sol

 

NOAA Fisheries

2725 Montlake Blvd E.

Seattle, WA 98112

* email: ronald.b.johnson@noaa.gov

 



The demand for fishmeal and  fish oil in aquaculture feeds has increased dramatically in recent years .   Alternative protein and oil sources are needed if further development of the aquaculture industry is to be sustained. Terrestrial plant ingredients can replace a portion of the fishmeal used in feeds for a number of species.  Complete replacement, however, is seldom achieved .   Macroalgae may prove a more appropriate feed  ingredient  than terrestrial plants products for marine fish feeds as m acroalgae contains many essential nutrients  from the marine environment that are limiting in terrestrial plants.  Additionally, there  appears to be health benefits associated with the use of  some  macroalgae  species for some  marine fish species. 

Our r ecent studies at NOAA have explored the potential of using domestically cultured macroalgae as ingredients in marine fish feeds.   Macroalgae species tested  to date include the red macroalgae Pacific d ulse Palmaria mollis and Turkish towel Chondracanthus exasperates , the green macroalgae  Ulva spp., and sugar kelp Saccharina latissima.   We additionally produced kelp protein concentrates from sugar kelp via chemical and thermal methods and evaluated these ingredients.  Using  sablefish Anoplopoma fimbria as a model cold water marine species, we evaluated the effects of these novel ingredient on fish growth, feed intake , feed efficiency, whole body nutrient composi tion,  liver histomorphology, and gut microbiome .   Results  will be presented  with some species  showing positive trends and some species demonstrating negative effects.  Of particular interest, t he addition of Turkish towel to sablef ish feeds  improved fish  liver  health and increased  fish survival when exposed  to the pathogen  atypical Aeromonas salmonicida

 Results from our research indicate some macroalgae  species may be promising alternative feed ingredients for cold water marine fish .  Further research is needed to explore reasons behind observed decreases in feed intake, feed efficiency, and protein retention with some species.  Future research directed towards improving  the performance of  kelp protein concentrates  in marine fish feeds  and the development of screening methods to identify  new  promising macroalgae species will be discussed.