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Haas S.,GMA Gesellschaft fur Marine Aquakultur mbH | Haas S.,University of Kiel | Bauer J.L.,University of Kiel | Adakli A.,Cukurova University | And 5 more authors.
Journal of Applied Phycology | Year: 2015

In the present study, the potential of the microalga Pavlova viridis (=Diacronema viridis) as an n-3 polyunsaturated fatty acid (PUFA) source was evaluated and compared to Nannochloropsis sp. in diets for juvenile European sea bass (Dicentrarchus labrax L.) (initial weight ~12.8 ± 1.7 g) in an 8-week feeding trial. Six different isoenergetic and isonitrogenous test diets were used: (1) fish oil diet (FO), major lipid source fish oil (100 %), (2) basal diet, 40 % fish oil and 60 % plant oil (in equal parts rapeseed, sunflower, and linseed oil), (3) Pavlova 50 % (P50), 50 % of the fish oil of the basal diet was substituted by lipid content of P. viridis meal, (4) Pavlova 100 % (P100), 100 % of the fish oil of the basal diet was substituted by lipid content of P. viridis meal, (5) Nannochloropsis 50 % (N50), 50 % of the fish oil of the basal diet was substituted by lipid content of Nannochloropsis sp. meal, and (6) Nannochloropsis 100 % (N100), 100 % of the fish oil of the basal diet was substituted by lipid content of Nannochloropsis sp. meal. The specific growth rate was highest and feed conversion ratio was lowest in the P100 group (SGR 1.77 ± 0.10 % day−1; FCR 1.17 ± 0.01), although not significantly different to the results for the FO and the other algae-groups. Furthermore, the sum of PUFA was also highest in the P100 group, followed by the P50, N100, N50, and B group (mainly due to the high content of linoleic and linolenic acids coming from plant oils and microalgal products) with the lowest levels in the FO group. The highest amounts of docosahexaenoic acid (DHA) of total fatty acids were found in the FO and B group, although not significantly higher than in groups P50 and P100. The significantly highest amount of eicosapentaenoic acid (EPA, % of total fatty acids) was in the P100 samples and the lowest amount was in samples of the basal group. The histological analyses of liver and intestine samples did not reveal any negative effects caused by the experimental treatments. Based on the basal diet, a 50 % fish oil replacement by Nannochloropsis sp. meal and a total replacement by P. viridis meal were possible without negative effects on the growth performance and nutrient utilization of juvenile sea bass. © 2015 Springer Science+Business Media Dordrecht

Rehberg-Haas S.,GMA Gesellschaft fur Marine Aquakultur mbH | Rehberg-Haas S.,University of Kiel | Meyer S.,GMA Gesellschaft fur Marine Aquakultur mbH | Lippemeier S.,BlueBioTech GmbH | And 2 more authors.
Aquaculture | Year: 2015

In the present study the potential of different products of the marine microalga Pavlova sp. for the cultivation of rotifers (Brachionus plicatilis) was tested. Two growth performance trials were conducted: In a first laboratory scale experiment rotifers were cultivated for 14days with Pavlova viridis concentrate, P. viridis fresh culture, Pavlova sp. fresh culture, baker's yeast and Nannochloropsis sp. concentrate. The P. viridis fresh culture fed groups resulted in significantly the highest rotifer density (109.2rotifersmL-1) and instantaneous growth rate (G=0.14±0.02d-1). There were no significant differences found of the G between the P. viridis concentrate group and the Pavlova sp. fresh culture group. The baker's yeast fed group showed significantly the lowest rotifer numbers and growth rate. Based on the high growth rate of the P. viridis fresh culture group in the first experiment, different P. viridis products (concentrate, fresh culture, frozen concentrate, and freeze-dried powder) were examined in the second (larger scale) experiment and compared to Nannochloropsis sp. concentrate. The highest rotifer growth rate G in experiment 2 was determined for the frozen P. viridis group (G=0.09±0.03 d-1), although it was not significantly different in comparison to the G of the rotifers fed with Nannochloropsis sp. and the Pavlova concentrate and fresh culture. The frozen Pavlova product seems the most suitable Pavlova product for the cultivation of live feed and it provides advantages of storability and application. © 2014 Elsevier B.V.

Rehberg-Haas S.,GMA Gesellschaft fur Marine Aquakultur mbH | Rehberg-Haas S.,University of Kiel | Meyer S.,GMA Gesellschaft fur Marine Aquakultur mbH | Tielmann M.,GMA Gesellschaft fur Marine Aquakultur mbH | And 7 more authors.
Aquaculture | Year: 2015

An Atlantic cod larva (Gadus morhua) feeding experiment was carried out to compare three different live feed enrichment products for Brachionus ibericus and Artemia salina: 1) Nannochloropsis sp. microalgal concentrate (frozen) (N), 2) Pavlova viridis microalgal concentrate (frozen) (P), and 3) Larviva Multigain® (BioMar, Denmark) - formulated commercial product (CP). Over the experimental period of 42days larvae of groups P and CP showed significantly higher instantaneous growth rates (G: 0.074±0.001d-1 and 0.079±0.009d-1) than larvae of group N (G: 0.04±0.0d-1). Survival at the end of the trial of group CP was highest (20±8%), whereas significantly lower survival was observed for groups P (7±2%) and N (<0.5%). Live feed ingestion by means of gut fullness index (GFI), evaluated at 4, 15 and 27days post hatch (dph), was high for the larvae of group CP (GFI: 1.2±0.1, 1.4±0.0, 1.7±0.2, respectively) and group P (GFI: 1.4±0.1, 1.3±0.1, 1.8±0.2, respectively) compared to group N (1.0±0.0, 1.1±0.1, 1.2±0.1, respectively). Larvae fed with CP enriched live feed were able to withstand an extended period of feed deprivation (of 4 or 5days), whereas groups N and P were not able to re-initiate growth beyond the point-of-no-return, assessed on 5, 16 and 28dph. Bacterial community diversity of tank water, feed and larvae of the three groups revealed that treatments N and P lead to similar, highly diverse microbial communities in comparison to group CP. Microalgal enrichment using P. viridis was not able to sustain the same survival rates as the commercial product, but resulted in a similar growth performance and feed ingestion rates and had a significant effect on microbial community diversity. © 2015 Elsevier B.V.

Marxen K.,University of Kiel | Marxen K.,Helmholtz Center Geesthacht | Vanselow K.H.,University of Kiel | Hintze R.,BlueBioTech GmbH | And 6 more authors.
Journal of Applied Phycology | Year: 2010

Two different modes of UV-B irradiation of the cyanobacterium Synechocystis sp. PCC 6803 are compared: turbidostatic control and additional physiostatic control. Under turbidostatic control, the cells were exposed to different constant UV-B irradiances, whereas under physiostatic control, an electronic control loop modulated UV-B irradiance in such a way that photosynthetic efficiency PSII was kept constant at a fixed set point. The UV-B-induced stimulation of the synthesis of pigments, α-tocopherol, and the antioxidative potential of methanolic soluble components of Synechocystis showed significant differences depending on the mode of irradiation, even though the overall doses were equal. For example, compared to the initial values, the concentrations of myxoxanthophyll and zeaxanthin increased to 226-244% and 453% upon constant UV-B irradiation in turbidostatic processes, whereas maxima of 600% and 740% were reached in turbidostatic process with additional physiostatic control. The α-tocopherol concentration increased under constant UV-B irradiances, up to a maximum of 150%. Under physiological control, however, maximum increases of 390% over the initial values were measured. Furthermore, a reaction scheme is given explaining the higher yield under physiostatic control. © 2010 Springer Science+Business Media B.V.

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