Carotenogenesis of five strains of the algae Dunaliella sp. (Chlorophyceae) isolated from Venezuelan hypersaline lagoons. We evaluated discontinuous cultures (Algal medium at 0.5 mM of NaNO 3 , and 27% NaCl) of five strains of Dunaliella sp. isolated from Venezuelan hypersaline lagoons (Araya, Coche, Peonía, Cumaraguas, and Boca Chica) and one strain from a reference collection (Dunaliella salina, LB1644). Cultures were maintained to 25±1 °C, with constant aeration, photoperiod 12:12, and two light intensities (195 and 390 µE.m -2 .s -1 ) during 30 days. Cell count was recorded on a daily basis using a Neubaüer camera. Totals of chlorophyll a and carotenoids were measured at the end of the experiment. The largest cellular densities were measured during the smallest light intensities. The strain with the largest cellular density was isolated from Boca Chica (8 x10 6 and 2.5 x10 6 cel.ml -1 a 390 and 195µE.m -2 .s -1 , respectively). The increment of light intensity produced a significant reduction of growth rates in all strains. Totals of carotenoids by volume were as large as 390 µE.m -2 .s -1 . Strains LB1644, from Coche and Araya were those that produced the largest amount of carotenoids (38.4; 32.8 and 21.0 µg.ml -1 , respectively). Differences total carotenoids by cell between treatments were significant. The largest concentration was 390 µE.m -2 .s -1 . The strains LB1644 and Coche produced the highest values of carotenes (137.14 and 106.06 pg.cel -1 , respectively). Differences in the relation carotenoid:chlorophyll a between the strains at various light intensities was significant. Strains LB1644 presented the largest value of the relation carotenoids:chlorophyll a (20:1) at 195 µE.m -2 .s -1 . No significant differences were detected in the strain Coche (15:1). All the other strains showed relations lower than one. Our results suggest that the strains of Coche and Araya show potential to be used in the biotechnology of carotenoids production. Rev. Biol. Trop. 53(3-4): 331-337. Epub 2005 Oct 3.
The changes of the distribution patterns of some dinoflagellates considered as biological indicators showed the development of the 1982–1983 El Niño. During El Niño conditions the density of dinoflagellates was diminished, but there was a larger number of species, many of which are rarely found in this region. Protoperidinium obtusum, an indicator of cold coastal waters, disappeared almost completely during El Niño 1982–1983, but it was very abundant when the conditions returned to normal. Ceratium breve, an indicator of equatorial surface waters, during normal conditions is restricted to the northern area up to 5°S; during El Niño it was distributed up to 15°S. Several species indicators of warm waters were widely distributed during El Niño 1982–1983 but are very rare or absent during normal conditions.
The fattening of bluefin tuna is a very important economic activity for Spanish aquaculture, and mainly for the Mediterranean area. The feeding is supplied exclusively by bait consisting of complete copies of small pelagic fish and cephalopods like squid. The amount of bait needed to feed these animals is very considerable, since it is estimated between 2 and 10%. The D. G. Livestock and Fisheries within Epidemiological Surveillance Pilot Program in Aquatic Animal Inland Murcia Region started in 2006, provides for the realization of a series of regular checks on the bait used on tuna farms in Murcia´s coast. The objective is to evaluate in a practical way possible transmission of viral diseases to the local wildlife and the rest of aquaculture farms located in the area. In this paper reflects the results of the first four years of this monitoring program.
Evaluación económica de tres niveles de calcio y fósforo en dietas de cuyes (Cavia porcellus) durante la gestación y lactancia Economic evaluation of three levels of calcium and phosphorus in diets of guinea pigs (Cavia porcellus) during pregnancy and breastfeeding
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