Early biomarker indicators of health in two commercially produced microalgal species important for aquaculture

Dietary Exposure of Pacific Oyster (Crassostrea gigas) Larvae to Compromised Microalgae Results in Impaired Fitness and Microbiome Shift

“…Batch cultures of Chaetoceros calcitrans (CC) and Tisochrysis lutea (T-Iso) were grown according to Rolton et al (2020) . Briefly, carboys for both algal species were prepared with 18 L of 0.35 μm FSW to which double strength F2 culture medium (Cell Hi F2P, Varicon Aqua Solutions Ltd., Worcester, United Kingdom) and Si (for CC only) were added.…”

“…Such assessments are tedious and unlikely to detect problems with algal health in a timely manner, increasing the risk of feeding compromised algae to larvae for several days prior to detection. In a recent study by Rolton et al (2020) , in which two commercially important species for aquaculture, Tisochrysis lutea (T-Iso) and Chaetoceros calcitrans , were reared in a stressful environment by intentionally subjecting the cultures to high-pH conditions, Pulse Amplitude Modulation (PAM) fluorometry and flow cytometry (FCM) were successfully used to identify a variety of indicators of algal function, including photosynthetic parameters and morphological changes. This allowed earlier detection of ‘compromised’ algae compared to traditional algal health measurements ( Rolton et al, 2020 ).…”

“…In a recent study by Rolton et al (2020) , in which two commercially important species for aquaculture, Tisochrysis lutea (T-Iso) and Chaetoceros calcitrans , were reared in a stressful environment by intentionally subjecting the cultures to high-pH conditions, Pulse Amplitude Modulation (PAM) fluorometry and flow cytometry (FCM) were successfully used to identify a variety of indicators of algal function, including photosynthetic parameters and morphological changes. This allowed earlier detection of ‘compromised’ algae compared to traditional algal health measurements ( Rolton et al, 2020 ). In the same study, the bacterial abundance and populations were measured using FCM, showing increased bacterial density per algal cell for both algal species and higher bacterial diversity (T-Iso) in the high pH treatment compared to control, hence providing valuable information on the condition of algal cultures during periods of relatively mild stress ( Rolton et al, 2020 ).…”

“…This allowed earlier detection of ‘compromised’ algae compared to traditional algal health measurements ( Rolton et al, 2020 ). In the same study, the bacterial abundance and populations were measured using FCM, showing increased bacterial density per algal cell for both algal species and higher bacterial diversity (T-Iso) in the high pH treatment compared to control, hence providing valuable information on the condition of algal cultures during periods of relatively mild stress ( Rolton et al, 2020 ).…”

Microalgae culture quality indicators: a review

“…The assessment of biomarker responses throughout the culture process provides early warning signals that predicts when a microorganism will not be able to withstand a certain stress, since changes in such responses often precede changes in the cellular content of a culture. In this respect, some studies have demonstrated that the responses of different biomarkers to a particular stress in a microalga culture were detected prior to changes in the cell density [151][152][153]. Bearing this in mind, measures can be taken in advance such as either harvesting the culture, or ceasing the stress in order to continue with the growth and obtain a higher amount of biomass.…”