Effect of salinity on growth and chemical composition of the diatom Thalassiosira weissflogii at three culture phases | Efecto de la salinidad en el crecimiento y composición química de la diatomea Thalassiosira weissflogii en tres fases de cultivo (original) (raw)
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Latin American Journal of Aquatic Research, 2012
The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977) has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu), on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu) during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥35 psu). The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.
Latin American Journal of Aquatic Research, 2012
The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977) has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu), on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu) during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥35 psu). The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.
Aquacultura Indonesiana, 2023
A two-week batch experiment was conducted on three newly isolated Indonesian microalgal strains (Kb1-2 identified as Chaetoceros sp., Kb1-3 and Kb1-5) and Tisochrysis lutea to determine salinity effects upon the growth, proximate composition and ω-3, eicosapentaenoic acidand docosahexaenoic acid, (EPA and DHA) and ω-6 (arachidonic acid /ARA) fatty acids. Salinity within each strain growth of all microalgae tested. The highest cell densities were observed in Indonesian strains, Kb1-3 on day 8 at 25 psu and Kb1-5 on day 10 at 35 psu. Salinity significantly affected the lipid, protein and carbohydrate content in all microalgae cultured. The highest total lipid content was found in T. lutea cultured at 30 psu (28.3 %) followed by Kb1-2 cultured at 20 psu (25.0 %) and T. lutea at 35 psu (24.8 %). Kb1-3 produced highest protein when cultured at 20 and 25 psu, decreasing at higher salinities of 30 and 35 psu, 44.7 and 39.2 % to 31.5 and 32.6 %, respectively, similar to T. lutea. Kb1-5 had higher protein at both 25 and 35 psu but showed lower protein levels at 20 and 30 psu. Indonesian strains showed almost a similar content of carbohydrate across culture salinities similar to T. lutea. Although all Indonesian microalgae contained important ω-3 (EPA and DHA) and ω-6 (ARA) fatty acids, concentrations were low in comparison to T. lutea. All Indonesian microalgal strains also contained the dicarboxylic acid (DCA), phthalic acid, which was not present in T. lutea.
Marine Biology, 1975
Cultures of the marine diatom Coscinodiscus eccentricus Ehrenberg were grown at four salinities, namely 20, 25, 30 and 35~. The changes in the carbohydrate, protein, silicon and pigment concentrations of the cells were studied throughout the growth cycles in these salinities. The carbohydrate content, expressed as a percentage of the cell dry weight, increased in all cultures during the lag and early log phases. It later fell, sharply at first, as it was used up faster than it was produced. It was not stored during the stationary phase. The protein percentage composition built up to a peak at different stages during the exponential or stationary growth stages, depending on the salinity, but was later respired. The silicon percentage of the dry weight usually decreased during the log phase, as the cells were dividing before becoming fully silicified, and remained low in the stationary phase due to an increase in the volume of the cells. The changes in the frustular thickness were also calculated. The values ranged from 0.24 to 0.35 bm (at the beginning and end of the experiments) to O.15 ~um during the log growth phase. The pigment content was always low. The lipid composition of the cells was calculated by difference. It was usually low during the exponential growth phase, but was accumulated during the stationary phase. The point at which this accumulation began was associated with the time when protein respiration started.
Microalgae are playing a very important role as live food for fish and shrimp larvae in marine hatcheries. In this study; three diatom species; Skelatonema Costatum (2-5 µm), Chaetoceros calcitrans (2-3 µm) and Detonulla confervacea (6-15 µm) were isolated from the Eastern Harbor of Alexandria, Egypt and evaluated as feed for shrimp larvae. Scanning electron microscope was used to support the identification process of the isolated diatom species. Effects of salinity, temperature, illumination and culture medium on growth of the three diatom species were conducted. The optimum salinity for highest growth rate of S. costatum, C. calcitrans and D. confervacea was achieved at 35 ppt, 30 ppt and 35 ppt, respectively; optimum temperature was achieved at 20 ºC, 25ºC and 20ºC respectively; and optimum illumination (light duration and light intensity) was 24 h Light / 750 Lux for all species. C. calcitrans showed the highest growth rate with a modification of vitamin amount (Di-F/2 standard vitamin) and silicate amount (Tri-F/2 standard silicate). Mass culture in outdoor tanks for the three species was conducted at high temperature (27-34ºC) in summer season. D. confervacea showed the highest growth rate compared with other diatom species. The three diatoms were evaluated as feed for marine shrimp larvae Penaeus japonicus from the first protozoa stage to the first postlarvae stage. D. confervacea resulted in an equal survival, development and metamorphosis of penaeid shrimp larvae Penaeus japonicus, when compared with other diatoms. These results suggest that D. confervacea can be used as feed for marine shrimp larvae Penaeus japonicus, especially at high temperaturein summer season.
Aquaculture, 2005
The marine diatom Chaetoceros cf. wighamii has been investigated for its potential use as food in mariculture. In this work, we investigated temperature (20, 25, and 30 8C), salinity (25 and 35) and carbon dioxide addition (air and air + CO 2) effects on growth and biochemical composition of C. cf. wighamii, under laboratory conditions. C. cf. wighamii growth and biomass was primarily affected by carbon dioxide addition and to a lesser extent by temperature and salinity. In general, lipid and carbohydrate content were higher at lower temperatures (20 and 25 8C) while protein was unaffected. Carbon dioxide addition increased protein and lowered carbohydrates, but had no effect on lipid content. Carbohydrates were enhanced while lipids and protein decreased at the highest salinity (35). These results should be taken into consideration when evaluating the nutritional value of this microalga for marine invertebrate larvae.
Aquaculture International, 2012
Bio-floc shrimp culture systems have been investigated in an attempt to optimize water use and prevent the discharge of effluent into the environment. The importance of microalgae in maintaining water quality and nutrition of the shrimp is well known in conventional systems; however, its maintenance amid bio-flocs and its role in the shrimp performance in this system are still poorly understood. The aim of this study was to evaluate the contribution of diatoms in the performance of Litopenaeus vannamei reared during the nursery phase in intensive system with minimal water exchange. Shrimp (0.31 ± 0.10 g) were reared among diatoms, bio-flocs and the combination of the two forming the mixture medium. The survival of shrimp was high in all treatments (90-97%). However, the shrimp reared among diatoms showed higher weight gain (P \ 0.05) and feed conversion ratio significantly more efficient, reaching a value of 0.47. The results indicate the importance of diatoms in bio-floc culture systems and points out to future research in an attempt to maintain a constant presence of these microalgae in culture medium without requiring successive inoculations.
Journal of Experimental Marine Biology and Ecology, 2001
The present study was designed to understand how carbohydrate CBH and protein metabolism are related in the penaeid shrimp Litopenaeus Õannamei. With this information, we obtained a comprehensive schedule of the protein-carbohydrate metabolism including enzymatic, energetic, and functional aspects. We used salinity to determine its role as a modulator of the protein-carbohydrate metabolism in shrimp. Two experiments were designed. The first experiment evaluated the effect of CBH-salinity combinations in growth and survival, and hemolymph glucose, protein, and ammonia levels, digestive gland glycogen, osmotic pressure, and glutamate dehydrogenase Ž. GDH of L. Õannamei juveniles acclimated during 18 days at a salinity of 15‰ and 40‰. The second experiment was done to evaluate the effect of dietary CBH level on pre-and postprandial Ž. oxygen consumption, ammonia excretion, and the oxygen-nitrogen ratio OrN of juvenile L. Õannamei in shrimps acclimated at 40‰ salinity. We also evaluated the ability of shrimp to Ž. carbohydrate adaptation. We made phosphoenolpyruvate carboxykinase PECPK and hexokinase activity measurements after a change in dietary carbohydrate levels at different times during 10 days. The growth rate depended on the combination salinity-dietary CBH-protein level. The maximum growth rate was obtained in shrimps maintained at 15‰ salinity and with a diet
Journal of Applied Phycology, 2018
Salinity is an important factor affecting microalgal production yield especially under the uncontrollable environments of outdoor cultivation systems. Elucidating the optimal salinity range for algal biomass and high-value biochemical production might help to increase the production potential and reduce cultivation cost. This study examined the effects of salinity changes from that of normal seawater level (30 ppt) to various salinities from 10 to 60 ppt on growth, biomass, photosynthesis, morphology, biochemical composition, fatty acid composition, and volumetric productivity of the marine microalga Tetraselmis suecica. The optimal salinity for biomass production of T. suecica was in the range from 20 to 60 ppt. Severe growth inhibition, alterations in cell morphology, and reduction of photosynthetic rate were found at low salinity of 10 ppt, suggesting that the algal cells suffered from osmotic and ionic imbalance. Total protein, carbohydrate, and lipid content were not significantly affected under the different salinities, although the increase in salinity from 30 to 50 and 60 ppt improved the total lipid productivity by nearly 22%. Fatty acid composition and content remained unchanged over the range of salinities. The predominant fatty acids were of C16 to C18 chain lengths, whereas eicosapentaenoic acid (EPA) was the major long-chain polyunsaturated fatty acid (LC-PUFA). Together these results demonstrate that a wide range of salinities are suitable for cultivation of in T. suecica without a compromise in biomass yield and biochemical composition.
Journal of Applied Aquaculture, 2008
Salinity and preferred nutrient composition of Chaetoceros affinis and Skeletonema costatum were tested. Salinity was tested at 12, 16, 23, 28, and 32 ppt. Three compositions of nitrogen (N), phosphorus (P), and potassium (K) and two on-farm low-cost alternative media sources, cow urine (CU) and hatchery waste water (HWW), were tested to find the suitable NPK ratio and to determine the efficacy of the on-farm media respectively. Chaetoceros affinis preferred 23 ppt salinity, while Skeletonema costatum preferred both 28 and 32 ppt. Among the NPK treatments, higher cell density was observed in 4:1:1 followed by 4:2:1 ratios. Significant differences in maximum cell density of both species were observed in the NPK treatments while only S. costatum showed significant difference in CU and HWW.