• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.2
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• pp.133-141
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• 2012

Effects of temperature and salinity on the growth of the toxic dinoflagellate $Alexandrium$ $tamarense$ and $A.$ $catenella$ isolated from the southern coast of Korea were examined in the laboratory. Growth experiment was conducted under the following combinations of temperature and salinity; 10, 15, 20, 25 and $30^{\circ}C$, 10, 15, 20, 25, 30 and 35 psu at a constant irradiance of 300 ${\mu}mol$ photons $m^{-2}s^{-1}$. Temperature and salinity conditions for maximum growth rate were indicated as follows: temperature $15^{\circ}C$ and salinity 30 psu (0.31 $d^{-1}$) in $A.$ $tamarense$, temperature $25^{\circ}C$ and salinity 30 psu (0.36 $d^{-1}$) in A. catenella. Temperature and salinity ranges for optimum growth condition of two species were $10{\sim}20^{\circ}C$, 25~35 psu and $120{\sim}30^{\circ}C$, 25~35 psu, respectively. The result of two-factor ANOVA indicated significant effects (P<0.001) of temperature and salinity on the growth rate, and two species were more effected by a temperature than a salinity on the growth. In addition, prediction equations were obtained through the multiple regressions of the specific growth rates as ${\mu}=0.04+0.0193T-0.0339S- 0.0005T^2+0.0021S^2+0.00073TS-0.000022T^3-0.000038S^3+0.00000086TS^2-0.0000255T^2S$ in $A.$ $tamarense$ and ${\mu}=1.01-0.1288T-0.0778S+0.0067T^2+0.0038S^2+0.00204TS-0.0001T^3-0.000059S^3-0.0000131TS^2-0.0000392T^2S$ in $A.$ $catenella$. Correlation coefficient between experimental values and simulated values was highly indicated. These results seem to provide information for understanding the spreading mechanism of $A.$ $tamarense$ and $A.$ $catenella$.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1722-1727
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• 2006

The nutritive value of 4 straws, obtained after thrashing of seeds from fodder crops, was assessed as complete feed for ruminants. Sixteen male Murrah buffaloes (liveweight 365.8${\pm}$19.5 kg), were divided into 4 equal groups and offered ad lib. straw of either Trifolium resupinatum, Trifolium alexandrium, Medicago sativa or Lolium perenne, supplemented with minerals and vitamin A, for 40 days in a completely randomized design. Simultaneously, each straw was offered to 3 rumen fistulated male buffaloes in order to assess the biochemical changes in the rumen. Compared to other straws M. sativa straw had higher (p<0.05) organic matter (OM), crude protein (CP), acid-detergent fiber (ADF) and cellulose content. L .perenne had the highest (p<0.05) hemicellulose and lowest (p<0.05) CP and acid-detergent lignin (ADL) content. T. resupinatum had the lowest concentration of cell wall constituents (CWC). The digestibility of nutrients of T. resupinatum and L. perenne straw was similar, but higher (p<0.05) than that of other straws. M.sativa straw showed highest (p<0.05) digestibility of CP. The highest OM digestibility of T. resupinatum and CP digestibility of M. sativa were responsible for highest (p<0.05) total volatile fatty acids and trichloroacetic acid precipitable nitrogen in the strained rumen liquor. The digestible crude protein (DCP) was highest (p<0.05) in M. sativa followed by that in T. alexandrium. The total purine derivatives excreted in urine varied from 0.22-0.32 mmol/kg $W^{.75}/d$. The efficiency of microbial protein synthesis indicated that OM of straws of M. sativa and that of T. alexandrium was used more (p<0.05) efficiently. The microbial protein synthesized was highest in T. resupinatum, but statistically similar to other groups. The values for N-retention and apparent biological value were highest for L. perenne, though comparable with that of M. sativa and T. alexandrium. The available metabolizable energy (ME) was highest (p<0.05) in T. resupinatum followed by that in L. perenne and lowest in M. sativa. It was concluded that all the straws, supplemented with minerals and vitamin A, could be fed exclusively to adult ruminants with no adverse affect, as animals were able to maintain body weight (372${\pm}$20.1 kg).

• Korean Journal of Environmental Biology
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• v.24 no.3
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• pp.275-281
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• 2006

We examined effects of water temperature, salinity, irradiance, and different media on the growth of the toxic dinoflagellate Alexandrium tamarense (HYM9704), which was isolated from Jinhae Bay, Korea. The ranges of temperature and salinity in which the strain was able to grow were $10{\sim}20^{\circ}C$ and $20{\sim}34$ psu, respectively. These values were in accordance with those observed in situ. The maximum growth rates of axenic A. tamarense (HYM9704) was $0.25d^{-1}$ at $15^{\circ}C$, 30 psu, and $100{\mu}Em^{-2}s^{-1}$. The temperature affected the growth rates of axenic A. tamarense more significantly than the salinity. The type of culture media did not affect the growth rates of axenic A. tamarense. The strain in N-limited and P-limited media went into the stationary phase faster than that in T1 and T1/2 medium.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.175-184
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• 2012

BACKGROUND: The aim of this study was to isolate and identify algicidal bacterium that tends to kill the toxic dinoflagellate Alexandrium catenella, and to determine the algicidal activity. METHODS AND RESULTS: Among of four algicidal bacteria isolated in this study, NH-12 isolate was the strongest algicidal activity against A. catenella. NH-12 isolate was identified on the basis of biochemical characteristics and analysis of 16S rRNA gene sequences. The isolate showed 97.67% homology with Pseudoalteromonas prydzensis ACAM $620^T$ (U85855), and was designated Pseudoalteromonas sp. NH-12. The optimal culture conditions of this isolate were $25^{\circ}C$, initial pH 8.0, and 3.0% (w/v) NaCl concentration. The algicidal activity of NH-12 was significantly increased to maximum value in the late of logarithmic phase of bacterial culture. As a result of 'cell culture insert' experiment, NH-12 is assumed to produce secondary metabolites, as an indirect attacker. When 10% culture filtrate of NH-12 was applied to A. catenella, over 99% of algal cells were destroyed within 24 h. In addition, the killing effects were increased in dose and time dependent manners. CONCLUSION(S): Taken together, our results suggest that Pseudoalteromonas sp. NH-12 could be a candidate for controlling of toxic algal blooms.

• ALGAE
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• v.33 no.3
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• pp.279-290
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• 2018

Microalgae have been utilized in diverse industries including aquaculture. Among the microalgae, dinoflagellates are known to have various bioactive compounds, and thus the interest in their application to industry has increased. In order to test their potential as food materials for aquaculture animals, the crude protein contents and compositions of amino acids of six dinoflagellates Heterocapsa rotundata (family Heterocapsaceae), Ansanella granifera (Suessiaceae), Alexandrium andersonii (Ostreopsidaceae), Takayama tasmanica (Brachidiniaceae), Takayama helix, and Gymnodinium smaydae (Gymnodiniaceae) belonging to diverse families were analyzed. The percentage of the amount of the crude protein relative to dry weight of T. tasmanica was the highest (65%) and that of A. andersonii was the lowest (26%). However, the highest percentage of total detected amino acids in crude protein was found in A. andersonii (98.2%). In all six dinoflagellates, glutamic acid was the most dominant amino acid in crude protein. However, the second main amino acid was aspartic acid for H. rotundata, A. granifera, T. helix, and G. smaydae, but were arginine and leucine for A. andersonii and T. tasmanica, respectively. Furthermore, T. tasmanica and T. helix did not have taurine and gamma-aminobutyric acid, whereas the other dinoflagellates possessed them. The percentages of essential amino acid contents of the dinoflagellates met the requirement levels for juvenile shrimps. In addition, the dinoflagellates were not toxic to the brine shrimp Artemia salina. Compared with the other microalgae reported so far, H. rotundata and A. andersonii can be used for arginine-rich diets, T. tasmanica for valine and leucine-rich diets, A. granifera for histidine-rich diets, T. helix for threonine-rich diets, and G. smaydae for lysine-rich diets. Therefore, based on their biochemical composition and toxicity to Artemia, the dinoflagellates could be used as essential amino acid sources for cultivating animals in the aquaculture industry.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.9
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• pp.1252-1261
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• 2008

Twenty-four yearling Boer$\times$Spanish goats were used in a crossover design experiment to determine effects of tethering on forage selection, intake and digestibility, grazing behavior and energy expenditure (EE) with forage high in nutritive value and low to moderate in mass. Objectives were to determine if tethered goats could be used as a model for study of unrestrained animals and to characterize tethering as a production practice. Four 0.72-ha pastures of wheat (Triticum aestivum) and berseem clover (Trifolium alexandrium) were grazed in December and January. Each pasture hosted six animals, three with free movement and three attached to a 4.11-m tether for access to a circular area of $53.1m^2$. Tethering areas were moved each day. One animal of each treatment and pasture was used to determine forage selection, fecal output or grazing behavior and EE; therefore, there were eight observations per treatment. Mass of forage DM before grazing in Tethered areas averaged 1,280 and 1,130 kg/ha in periods 1 and 2, respectively. The CP concentration in ingesta was greater ((p<0.05) 239 and 209 g/kg; SE = 8.0) and the NDF level was lower (p<0.05) for Free vs. Tethered animals (503 and 538 g/kg; SE = 12.0); in vitro true DM digestion was similar between treatments (0.808 and 0.807 for Free and Tethered, respectively; SE = 0.0096). Intakes of DM (1,013 and 968 g/d; SE = 78.6), NDF (511 and 521 g/d; SE = 39.9) and ME (10.9 and 10.7 MJ/d; SE = 0.90) were similar between treatments, but CP intake was greater (p<0.05) for Free vs. Tethered animals (241 and 203 g/d; SE = 17.2). There were small treatment differences in in vivo apparent digestibility of OM ((p<0.05) 0.780 and 0.814; SE = 0.0049), CP ((p<0.05) 0.800 and 0.817; SE = 0.0067) and NDF ((p<0.09) 0.777 and 0.760 for Free and Tethered, respectively; SE = 0.0078). There were no treatment effects on time spent ruminating or grazing (346 and 347 min/d for Free and Tethered, respectively; SE = 42.5), but EE was considerably greater (p<0.05) for Free vs. Tethered animals (571 and 489 kJ/kg $BW^{0.75}$; SE = 8.9). In conclusion, with forage of high nutritive value and low to moderate in mass, tethering can offer a production advantage over free grazing of less energy used for activity despite similar grazing time. With forage removal considerably less than that available for grazing, effects of tethering on chemical composition of selected forage were small and less than needed to markedly affect digestion. Tethering may offer a means of studying some aspects of grazing by ruminants, but would not seem suitable for energy metabolism.