Optimizing the cultivation of the cryptophyte Rhodomonas salina for aquaculture

Christina Vinum Thoisen

Research output: Book/ReportPh.D. thesis

Abstract

In the aquaculture, marine fish species of commercial interest often require
live feed at the first-feeding stage. Commonly used live feed organisms are
rotifers and the brine shrimp Artemia although these are suboptimal due to
inadequate size and nutritional value. Copepods are the natural prey of many
marine species of fish larvae and decrease the mortality and abnormal
development of fish larvae . A large-scale production of the copepod Acartia
tonsa for aquaculture encompasses a large-scale production of a microalgal
diet for A. tonsa. Several studies show that the cryptophyte Rhodomonas is an
ideal microalgal diet as it has a superior nutritional content and increases the
survival, growth and egg production of copepods. However, Rhodomonas is a
rather sensitive genus and optimization of the cultivation is the refore required.
The effects of various cultivation parameters were studied at small-and meso-
scale and included:
1) modification of the growth medium, treatment of the water used for cultivation, and the growth rate of inocula at different initial densities,
2) evaluation of the application of commercial salts for cultivation,
3)evaluation of growth rate and production yield of densities of 5x105; 1x106,
1.5x106 and 2x106 cells ml-1in a meso-scale tubular PBR,
4)evaluation of the biochemical content of five closely related strains of
Rhodomonas at temperatures relevant for cultivation (15, 20 and 25 ̊C) to determine if there is an optimal temperature and strain more suitable for cultivation. Additional studies included an evaluation of using the heterotrophic dinoflagellate Crypthecodinium cohnii as a diet for A. tonsa compared to R.salina, and development of a simple and fast method for extraction and quantification of the pigment phycoerythrin from Rhodomonas.
Original languageEnglish
Place of PublicationRoskilde
PublisherRoskilde Universitet
Number of pages161
Publication statusPublished - 2018

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