Marine microalgae as a potential source of minerals in fish diets

The incorporation of powdered marine microalgae in fish diets can substitute, at least in part, for the addition of minerals to the diet. In diets for freshwater fishes, the incorporation of 33% of powdered marine microalgae can supply some of the mineral element requirements. The incorporation of microalgal powder in diets for marine fishes appears more effective, since lower percentages are needed to cover the mineral requirements. Most mineral needs of turbot can be covered with low percentages of marine microalgal powder in the diet: 3.8% of Tetraselmis suecica, 5.7% of Isochrysis galbana, 3.57% of Dunaliella tertiolecta and 3.9% of Chlorella stigmatophora. Mn and Co must, however, be added. Thus, incorporation of small amounts of marine microalgae in diets can replace a mineral mixture

Vitamin content of four marine microalgae. Potential use as source of vitamins in nutrition

Certain marine microalgae contain water-and lipid-soluble vitamins and can be used as food supplements or food ingredients. A number of vitamins are present in higher concentrations in the microalgae than in conventional foods traditionally considered rich in them. Ingestion of relatively small quantities of microalgae can cover the requirements for some vitamins in animal nutrition, including human nutrition, while supplementing others. Marine microalgae can thus be considered to represent a non-conventional source of vitamins or a vitamin supplement for animal or human nutrition.Comision Asesora de Investigacion Cientifica y Tecnica; AC86-000

Brand Experience Events to Generate Corporate Image and Reputation

Los eventos se erigen en el ámbito de la comunicación como herramientas de marketing experiencial al generar en el público una sólida interacción con la marca. En este artículo se analizan los eventos más relevantes entre los años 2010 y 2015 que han sido reconocidos en diferentes ediciones de los Premios Evento Plus, como referencia clave en este sector a nivel nacional. Nuestro objetivo es identificar los eventos que fueron premiados en la categoría Gran Premio del Jurado, así como los sectores y características que definen el diseño de los eventos en la estrategia relacional de las organizaciones empresariales.The events are erected in the area of communication and experiential marketing tools to generate in the public a strong interaction with the brand. In this article the most important events between 2010 and 2015, which have been recognized in different editions of the Plus Awards Event as a key reference in this sector at national level are analyzed. Our goal is to identify the events that were awarded in the category Grand Jury Prize as well as the sectors and the design characteristics that define the events in the CRM strategy of business organizations

Nutritional properties of four marine microalgae for albino rats

The nutritive value of the marine microalgaeTetraselmis suecica, Isochrysis galbana, Dunaliella tertiolecta and Chlorella stigmatophora was studied in diets given to rats. Biological assays were carried out in order to determine the Protein Efficiency Ratio (PER) and the Food Conversion Efficiency (FCE). Each dried microalga was fed to weaning Wistar albino rats as the sole protein source at a protein level of 12%. Control rats were given diets containing 12 % casein. Food consumption was similar in all groups. PER values obtained were 1.14 with T. suecica diet, 1.13 with I. galbana diet, 2.07 with D. tertiolecta diet and 1.13 with C. stigmatophora diet (casein, 2.50). FCE values followed a similar pattern. The data showed that the marine microalga D. tertiolecta is a source of protein of good quality. Its PER is quite high, compared to vegetable and cereal proteins, and compares favourably with other microbial protein sources, such as yeasts or different freshwater microalgae. Haematological tests showed no significant differences among the groups in haemoglobin levels, red and white blood cell counts, differential count and mean corpuscular volume. Different blood parameters were also determined and a significant decrease in triglycerides levels appeared with all the microalgal diets, whereas a significant decrease in cholesterol appeared in D. tertiolecta and C. stigmatophora diets

Biochemical composition and growth of the marine microalga Dunaliella tertiolecta (Butcher) with different ammonium nitrogen concentrations as chloride, sulphate, nitrate and carbonate.

Cultures of the marine microalga Dunaliella tertiolecta were grown in ammonium chloride, sulphate, nitrate and carbonate at concentrations ranging from 0.25 to 16 mg.atom N/l. Cells were harvested in the stationary phase and cell density and biochemical composition determined. Biomass production at the end of the stationary phase, expressed as cell density, was affected by the concentration of ammonium-N in the medium but not by the ammonium compound used. Optimal growth conditions for obtaining maximum cell density, between 1.86×106 and 2.81×106 cells/ml, were 2, 4 and 8 mg.atom N/l. The compound and concentration of ammonium-N had little effect on the growth velocity of D. tertiolecta cultures in the logarithmic phase, with values of 0.35±0.06 doublings/day under all the conditions assayed. The ammonium compound and the concentration of nitrogen affected the concentration of different cellular constituents such as protein, carbohydrate, lipid and chlorophyll a, although these changes were not necessarily related to cell density in the culture. Protein, the most affected fraction, tended to increase with an increase in the nitrogen concentration for all the ammonium compounds used. Maximum protein/ml was obtained with ammonium carbonate at all the nitrogen concentrations used. Maximum protein/cell occurred at the higher nitrogen concentrations (16 and 32 mg/atom N/l) for all the ammonium compounds. Considering the optimum growth interval (2-8 mg.atom N/l), maximum protein/cell concentrations were also obtained in the cultures with ammonium carbonate. Carbohydrate and lipid concentrations varied less than protein concentration. Maximum values of carbohydrate/ml were also found in the ammonium carbonate cultures. Maximum lipid/cell concentrations occurred at the lowest nitrogen concentrations, in contrast to protein values. As a percentage of the total organic matter, protein increased and lipid decreased with the nitrogen concentration, whereas carbohydrate remained constant. Consequently, lipid seemed to be the storage product in this marine microalga. Gross energy values in the different cultures were a function of nitrogen concentration, maximum differences occurring in the ammonium carbonate cultures. The biochemicalvariability of this microalga must have a marked effect on its value as a source of single-cell protein, as chemicals or as feed in mariculture

High yield mixotrophic cultures of the marine microalga Tetraselmis suecica (Kylin) Butcher (Prasinophyceae)

The effects of three organic compounds were tested on one of the most used marine micro-algae in the aquaculture of molluscs and crustaceans, Tetraselmis suecica. Studies were made in axenic conditions with yeast extract, peptone and glucose added to the culture medium, each alone, in combinations of two or all together. Medium without any organic compound was used for the control. Cultures containing yeast extract grew best, reaching maximum cell density of 3.79 × 106 and 3.84 × 106 cells ml−1. The organic carbon source affected the biochemical composition. The components most affected were the carbohydrates, with values between 6.5 pg cell−1 in control cultures and 48.5 pg cell−1 in glucose cultures. Protein content ranged between 27.5 pg cell−1 in control cultures and 88.6 pg cell−1in yeast + glucose + peptone cultures. The lipid content changed little. Maximum protein yields were reached in cultures with yeast + glucose and with yeast - glucose - peptone, with values of 24.6 and 28.2 mg 1−1 d−1, respectively. These values are 22 and 25 times those in control cultures. A maximum carbohydrate yield of 7.9 mg carbohydrate per litre per day was obtained in yeast + glucose + peptone cultures, 27 times that in the control cultures. The maximum lipid yield was obtained with yeast + glucose + peptone and yeast + glucose. Maximum energy values were 308 kcal 1− in yeast extract - glucose - peptone cultures and 279 kcal 1−1 in yeast extract + glucose cultures. Gross energy values in control cultures were 24.5 kcal 1−1, but peptone cultures presented the minimum energy value, 22 kcal 1−1. The yeast extract: glucose ratio in the culture medium was optimized. A ratio 2:1 produced the best yields in cells, protein, carbohydrate and gross energy.Dirección General de Investigación Científica y Técnica; PB 87-049

Crecimiento y composición bioquímica de la microalga marina Tetraselmis suecica en cultivos mixotróficos con distintos azúcares y aminoácidos

[Résumé] Croissance et composition biochimique de la microalgue TetrasellIIis sllecica dans des cultures mixotrophiques avec différents sucres et aminoacides. Trois sucres, fructose, saccharose et manose et trois acides aminés (alanyne, lysine et méthyonine) ont été testés comme stimulants potentiels de la croissance chez la microalgue Tetraselmis suecica. Celle-ci est cultivée en absence de bactéries et a une intensité de lumière de 850 lux. La croissance et la composition biochimique chez T. suecica sont affectées par les substrats organiques testés. Le fructose stimule la croissance mais les autres sucres et l'alanyne sont sans effet. La lysine et la méthyonine réduisent la croissance par rapport aux cultures servant de contrôle. La composition biochimique cellulaire dépend de la nature du substrat organique testé mais elle varie à peine en fonction de la concentration. Les cultures enrichies en sucres présentent les protéines cellulaires les plus abondantes, tandis que pour les cultures enrichies en acides aminés, les lipides sont plus abondants.[Abstract] Growth and biochemical composition of the marine microalga TetrasellIIis sllecica in mixotrophic cultures witf7 different sugars and amino acids. Three sugars (fructose, sucrose and mannose) and three amino acids (alanine, lysine, and methionine) have been tested as potential growth factors for the marine microalgae Tetraselmis suecica, in axenic cultures, at 850 lux light intensity. The organic compounds assayed affected the growth and biochemical composition of T. suecica. Growth stimulation was achieved only in cultures added with fru ctose, whereas growth was not affected in the cultures with the remaining sugars and alanine. Growth was inhibited in the cultures added with lysine and methionine. Biochemical cellular composition was affected by the nature of the organic compound added, but not by the concentration used. Proteins were the main cellular constituent in the cultures carried out with sugars, while in those with amino acids the main cellular fraction was lipids.Ministerio de Educación y Ciencia; PB 87-049

β-carotene, vitamin C and vitamin E content of the marine microalga Dunaliella tertiolecta cultured with different nitrogen sources

Variations in the β-carotene, vitamin C and vitamin E content of D. tertiolecta have been shown to result from the nitrogen source used in the culture medium. Differences of 101%, 38% and 69% have been found in β-carotene, ascorbic acid and tocopherol content in mg/g of dry matter, respectively, and differences of 147%, 63% and 37% occurred in β-carotene, vitamin C and E concentrations in mg/litre of culture, respectively. Considering the β-carotene, vitamin C and vitamin E content in mg/g of chlorophyll a, maximum variations occurred in β-carotene content, with differences of 145% among the different nitrogen sources. Maximum β-carotene and vitamin C values were found in urea cultures, whereas urea cultures showed the minimum values for vitamin E. Variations in the β-carotene, vitamin C and vitamin E content of D. tertiolecta have been shown to result from the nitrogen source used in the culture medium. Differences of 101%, 38% and 69% have been found in β-carotene, ascorbic acid and tocopherol content in mg/g of dry matter, respectively, and differences of 147%, 63% and 37% occurred in β-carotene, vitamin C and E concentrations in mg/litre of culture, respectively. Considering the β-carotene, vitamin C and vitamin E content in mg/g of chlorophyll a, maximum variations occurred in β-carotene content, with differences of 145% among the different nitrogen sources. Maximum β-carotene and vitamin C values were found in urea cultures, whereas urea cultures showed the minimum values for vitamin E

Population growth study of the rotifer Brachionus sp. fed with triazine-exposed microalgae

[Abstract]Few data exist on potential toxic effects that pollutants may have on zooplankton fed microalgae exposed to pesticides. For that reason, microalgal cultures were exposed to different concentrations of the triazine herbicide terbutryn, and used as exclusive food source to Brachionus sp. females, with the aim to evaluate potential deleterious effects upon population growth, survival, reproduction and feeding of the rotifer.Chlorella vulgaris cells were able to accumulate terbutryn, removing more than 90% of the total amount of herbicide in all the exposed cultures. Growth curves of Brachionus sp. showed that population density decreased as terbutryn concentration increased in the microalgal cells. In fact, this species of rotifer did not survive beyond four days when fed with microalgae exposed to 500 nM terbutryn. Percentage of reproductive females in rotifer populations fed with terbutryn-exposed microalgae decreased significantly as herbicide concentration increased. In control cultures, reproductive females laid a maximum of three eggs per individual; whereas in 100 nM cultures, reproductive females laid only one egg per individual throughout the treatment period. Terbutryn accumulated in C. vulgaris provoked a decrease in the feeding rate ofBrachionus sp. cultures fed with these microalgae with respect to control cultures. After this treatment period, all the rotifer populations, except those fed with 500 nM terbutryn-exposed microalgae, showed recovery patterns when they were returned to fresh medium containing herbicide-free microalga. Taking into account the results obtained, uptake of pesticides by phytoplankton can directly affect higher trophic levels.Xunta de Galicia; PGIDIT04RFO103946P

Toxicity induced by three antibiotics commonly used in aquaculture on the marine microalga Tetraselmis suecica (Kylin) Butch

Aquaculture facilities are a potential source of antibiotics to the aquatic ecosystems. The presence of these compounds in the environment may have deleterious effects on non-target aquatic organisms such as microalgae, which are often used as biological indicators of pollution. Therefore, the toxicity induced by chloramphenicol (CHL), florphenicol (FLO) and oxytetracycline (OTC), three antibiotics widely used in aquaculture, on the marine microalga Tetraselmis suecica was evaluated. Growth inhibition and physiological and biochemical parameters were analysed. All three antibiotics inhibited growth of T. suecica with 96 h IC50 values of 11.16, 9.03 and 17.25 mg L−1 for CHL, FLO and OTC, respectively. After 24 h of exposure no effects on growth were observed and cell viability was also unaffected, whereas a decrease in esterase activity, related with cell vitality, was observed at the higher concentrations assayed. Photosynthesis related parameters such as chlorophyll a cellular content and autofluorescence were also altered after 24 h of antibiotics addition. It can be concluded that T. suecica was sensitive to the three antibiotics tested