By
Eric C Henry, PhD, Research Scientist, Reed Mariculture Inc
For many years Tetraselmis has been one of the microalgae most frequently recommended as a feed for early life stages of shrimp. Fortunately, Tetraselmis is easier to identify by light microscopy, at least to correct genus, than some other flagellates. This is because it is relatively large (8-12 µm), and very few other green flagellates bear four equal flagella.
Many Tetraselmis strains have proved to be easy to grow under hatchery conditions and are valued as feed because they contain significant levels of the essential Omega-3 fatty acid Eicosapentaenoic acid (EPA). Some strains contain significant levels of taurine, a sulfur amino acid that may have significant nutritional value for larval and juvenile shrimp. Taurine has been only rarely reported in microalgae, but in some Tetraselmis strains it may constitute as much as 10 percent of total amino acids.
Several studies have reported that Tetraselmis has value beyond providing essential nutritional components. Addition of Tetraselmis to a formula feed diet was found to lower several measures of oxidative activity and consequent stress in vannamei shrimp. Suppression of Vibrio bacteria by Tetraselmis has been shown in culture of shrimp, as well as Artemia and finfish.
The performance of larval and post-larval shrimp what have been fed Tetraselmis with larvae and fed other algae have been compared, either singly or in combination with Tetraselmis or other algae. By far, the most comprehensive study was by Ronquillo, who cultured Tetraselmis at six different salinities, nine pH levels, and two temperatures, as well as varying culture medium nutrients. Tetraselmis produced under this wide range of conditions was then fed to Metapenaeus ensis, Metapenaeopsis barbata, Trachypenaeus curvirostris, Penaeus chinensis, P. indicus, P. japonicus, P. latisulcatus, P. merguiensis, and P. semisulcatus.
Later studies focused on Penaeus monodon or Litopenaeus vannamei. In none of the trials did Tetraselmis serve well as the sole feed; this is not surprising because it lacks the Omega-3 fatty acid DHA, which has been shown to be required by some shrimp.
This finding is consistent with the general principle that no single species of algae is likely to provide the truly optimal diet for any animal, and indeed the combination of Tetraselmis with other algae almost always yielded improved performance, even for algae that could support development of shrimp as sole feeds.
Read the full article in International Aquafeed magazine online, HERE.
For many years Tetraselmis has been one of the microalgae most frequently recommended as a feed for early life stages of shrimp. Fortunately, Tetraselmis is easier to identify by light microscopy, at least to correct genus, than some other flagellates. This is because it is relatively large (8-12 µm), and very few other green flagellates bear four equal flagella.
Many Tetraselmis strains have proved to be easy to grow under hatchery conditions and are valued as feed because they contain significant levels of the essential Omega-3 fatty acid Eicosapentaenoic acid (EPA). Some strains contain significant levels of taurine, a sulfur amino acid that may have significant nutritional value for larval and juvenile shrimp. Taurine has been only rarely reported in microalgae, but in some Tetraselmis strains it may constitute as much as 10 percent of total amino acids.
Several studies have reported that Tetraselmis has value beyond providing essential nutritional components. Addition of Tetraselmis to a formula feed diet was found to lower several measures of oxidative activity and consequent stress in vannamei shrimp. Suppression of Vibrio bacteria by Tetraselmis has been shown in culture of shrimp, as well as Artemia and finfish.
The performance of larval and post-larval shrimp what have been fed Tetraselmis with larvae and fed other algae have been compared, either singly or in combination with Tetraselmis or other algae. By far, the most comprehensive study was by Ronquillo, who cultured Tetraselmis at six different salinities, nine pH levels, and two temperatures, as well as varying culture medium nutrients. Tetraselmis produced under this wide range of conditions was then fed to Metapenaeus ensis, Metapenaeopsis barbata, Trachypenaeus curvirostris, Penaeus chinensis, P. indicus, P. japonicus, P. latisulcatus, P. merguiensis, and P. semisulcatus.
Later studies focused on Penaeus monodon or Litopenaeus vannamei. In none of the trials did Tetraselmis serve well as the sole feed; this is not surprising because it lacks the Omega-3 fatty acid DHA, which has been shown to be required by some shrimp.
This finding is consistent with the general principle that no single species of algae is likely to provide the truly optimal diet for any animal, and indeed the combination of Tetraselmis with other algae almost always yielded improved performance, even for algae that could support development of shrimp as sole feeds.
Read the full article in International Aquafeed magazine online, HERE.
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