The seasonal variation in nitrogen, amino acid, protein and nitrogen-to-protein conversion factors of commercially cultivated Faroese Saccharina latissima

Abstract

 Users may download and print one copy of any publication from the public portal for the purpose of private study or research.  You may not further distribute the material or use it for any profit-making activity or commercial gain  You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Latitudinal, seasonal and depth-dependent variation in growth, chemical composition and biofouling of cultivated Saccharina latissima (Phaeophyceae) along the Norwegian coast

“…Specific nitrogen-to-protein conversion factors (K p ) based on total amino acids are needed for S. latissima, because the commonly used conversion factor of 6.25 previously used for seaweed tends to overestimate the protein content (Lourenço et al 2002;Maehre et al 2018), thereby misleading consumers. The overall K p average across locations, depths and seasons of 3.8 ± 0.1 found in this study lies within the range of earlier published values of 2.0 and 6.25 (Schiener et al 2015;Angell et al 2016;Nielsen et al 2016;Biancarosa et al 2017;Manns et al 2017;Sharma et al 2018;Bak et al 2019). K p was only significantly higher at 1-2 m than at 8-9 m depths when kelp was affected by freshwater runoff, suggesting that it is acceptable to use the same K p value of 3.8 for S. latissima cultivated at different depths in full marine salinity conditions.…”

“…Similarly, Manns et al (2017) found a decrease in Q N in May-July and suggested that the Q N was a more reliable indicator of the physiological nutritional state of the seaweeds than the ambient nitrate concentration. Even though the ash content of the seaweed followed the same seasonal pattern as Q N , the variation in nitrogen content has not been found to be related to the content of ash (Bak et al 2019). The ash content has, however, been found to be negatively correlated with frond length (Nielsen et al 2016), which agrees largely with our results.…”

“…Seasonally, the protein contents were higher by a factor of 3 in spring than in summer, which is in agreement with a 4-to 8-fold difference in protein content found for S. latissima between winter/spring and summer in Denmark and the Faroe Islands (Marinho et al 2015a;Mols-Mortensen et al 2017). In contrast, there was not found significant correlation between protein content and season in another experiment from the Faroe Islands, most likely the result of smaller seasonal fluctuation in nutrients (Bak et al 2019).…”

“…These locations had either poor seaweed growth, early onset of biofouling, and/or had a stratified freshwater layer. Statistical differences in protein content between depths (0-10 m) were not found either for cultivated S. latissima in the Faroe Islands (Bak et al 2019) or for wild S. latissima in Denmark (Nielsen et al 2016).…”

“…focal species, is the most suited species for cultivation in North Atlantic waters due to its high growth rate (Handå et al 2013;Peteiro and Freire 2013;Bak et al 2018;Sharma et al 2018), high content of valuable components (Holdt and Kraan 2011;Schiener et al 2015;Bak et al 2019) and welldescribed life cycle (Flavin et al 2013;Redmond et al 2014;Forbord et al 2018). Consequently, its cultivation has been prioritized by commercial actors.…”