Study on survival and growth rate of three Artemia species fed with Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata

In recent years, Artemia has proven to be one of the easiest to prepare and the most nutritious food available to aquaculture. In this research, the process of hatching of Artemia cyst into larval stage using algae as a diet was investigated. The cysts used for this experiment belonged to three species Artemia urmiana, Artemia parthenogenetica and Artemia franciscana. The algae species used for the feeding of the Artemia included Dunaliella tertiolecta, Tetraselmis suecica and Nannochloropsis oculata. The effect of algae feeding on growth rate and survival of the Artemia species from hatching to maturation during 15 days was investigated. The results showed that A. franciscana had better growth rate and survival compared to the other two species

Evaluation of some biofilter substrates in freshwater recirculation system

The nitrifying bacteria acting on various biofilter substrates including: scoria, P.V.C., marble and zeolite were evaluated. The experiment started with manufacture of a recirculation system with 130 liter fresh water volume in 7 l.min-1 flow rate in 3 replicate for every treatment. The volume of each biofilter was 60×40×30cm and after achievement to stable environmental conditions the nitrifying bacteria at a concentration of 105 ml-1were inoculated in each biofilters. Daily 3-10mg.l-1 of NH4Cl was added to biofilters. The procedure was conducted by exposure of Ammonium and Nitrate concentrations and pH in biofilters. The results showed that the Scoria can be reliable substrate as biofilter, in which provide the best substrate for the growth and attachment of the nitrifying bacteria which can reduce the retention time of a biofilter from 40-60 to 15 days

Comparative study on some physiologic, biometrics, nutritional value and molecular characteristics of Mighan Lake’s Artemia (Arak)

Due to the importance of identifying the major characteristics of Artemia populations, in this study some physiologic, biometric, nutritional and genetic characteristics of one Artemia population from Iran named Arak’s Artemia (Mighan Lake) was studied. The hatched larvae of Artemia were reared in the saline water of 80 g/l with standards method in which percentage of survival and growth were evaluated on days 3, 7, 11 and 15 of culture period. In order to study the morphometric characteristics of Artemia, diameter of full cysts as well as 11 more morphological parameters of adult Artemia were measured. The fatty acid profile was analyzed by gas chromatography. The Genetic characteristics were compared with other Artemia populations by sequencing after PCR amplification of Hsp 26 gene. According to the results, the diameter of cysts and nauplii instar were 276.28 and 544.66 micron, respectively. The growth and survival of brine shrimp Artemia, in comparison with other populations, reflected good growth and survival of this population. The results of fatty acids profile also showed higher amounts of polyunsaturated fatty acids in this Artemia compared to other populations cultured under identical conditions. The morphometric characteristics and genetic study of Hsp 26 gene showed great affinity of this population with the parthenogenetic brine shrimp Artemia. However, individual differences could be used to characterize this population

First report of Kazachstania sp. intestinal flora of cultured rainbow trout

Yeasts, single-celled organisms in the intestinal flora of fish are useful due to their probiotic properties such as production of some antibiotics and vitamins. According to research, great population and species diversity of these unicellular yeasts can be anticipated in the intestine flora. In present study, along with study on species diversity of Saccharomyces genus as natural intestines flora of Rainbow trout, several new species similar to Saccharomyces genus were detected. Identification of the yeasts flora of rainbow trout by molecular techniques of PCR as well as diffraction media could characterize not only some strain of Saccharomyces genus but also a new genus of Kazachstania in cultured rainbow trout

Comparative effects of manipulated beaker's yeast and Lansy PZ on fatty acid composition of adults in Artemia urmiana and A. franciscana

Recently, due to the high costs and a decrease in producing of Lansy PZ, various researches have been conducted to the baker's yeast (Saccharomyces cerevisiae) as a substitute for Lansy PZ in Artemia culture technologies. In this study, the effects of six feeding regimes: Lansy PZ (as control), enriched yeast with HUFA, enriched yeast with HUFA and without mannoproteins in wall cells, yeast without mannoproteins in wall cells, industrial yeast 100 %, and industrial yeast 50 % replaced with alga were respectively examined on the fatty acid composition of two Artemia species (Artemia urmiana and A. franciscana) at a salinity of 80 ppt and a density of 500 nauplii per liter in culture conditions. Results showed that the enrichment of baker’s yeast with HUFA had increasing trend on the EPA and DHA contents of baker yeast (19.11 and 34.51%, respectively). The yeast type had significant effect on the fatty acid composition of the two species of Artemia. The highest content of HUFA obtained when Artemia fed the Lansy PZ. Our results recommended that the Artemia fed with HUFA enriched yeast and enriched yeast with HUFA without mannoproteins in wall cells induced higher contents of essential fatty acid (especially DHA) compared to other treatments. On the basis of the present investigation, the enrichment of Artemia with yeast enriched HUFA can be substitute to Artemia fed with Lanzy PZ

SNP detection in Na/K ATP-ase gene alpha(1) subunit of bisexual and parthenogenetic Artemia strains by RFLP screening

In order to find a marker for differentiating between a bisexual and a parthenogenetic Artemia strain, Exon-7 of the Na/K ATPase alpha(1) subunit gene was screened by RFLP technique. The results revealed a constant synonymous SNP (single nucleotide polymorphism) in digestion by the Tru1I enzyme that was consistent with these two types of Artemia. This SNP was identified as an accurate molecular marker for discrimination between bisexual and parthenogenetic Artemia. According to the Nei's genetic distance (1973), the lowest genetic distance was found between individuals from Artemia urmiana Gunther 1890 and parthenogenetic populations, making the described marker the first marker to easily distinguish between these two cooccurring species