Proximate composition and fatty acids profiles of Artemia cysts and nauplii from different geographical regions of Iran

Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p<0.05). The highest mean (±SD) level of protein (60.5±3.3%), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture

The study of possible biotechniques and normative to production some species of Anostraca (Phallocryptus spinosa)

This project was carried out in order to determine the hatching conditions and laboratory culture methods of Fairy Shrimps (Phallocryptus spinosa). Physico- chemical factors and phytoplankton of natural habitat of this organism was investigated in Khasellou region around Azarshahr – East Azarbaijan province. The results showed that occurance and growth of fairy shrimps in their habitates were beginning from early Aprill and their survival was decreased with increasing temperature, precipitation and increasing the salinity of their culture medium. Then they disappeared. Their habitat phytoplankton contained 3 phylla and 10 genera, from which green algae enjoyed the greatest density in May. The pool salinity was around 20-17 g/l, when metanauplii was observed in early spring. In the pool containing and without fairy shrimps the oxygen concentration was high (9 mg/l) and low (2.9 mg/l), respectively. In 9 prawn ornamental fish genera, feeding with fairy shrimp showed a significant higher fecundity and hatching percentage compared to manual diets (cow liver, spinach). In all groups fed with fairy shrimp the duration of spawning time were reduced from 15 to 8-10 days and the color was enhanced. The means of cyst number per captured female also, cyst, decapsulated cyst and Naupilli diameters were mesured 142.9±19.0 cysts, 273.2±4.9µ, 242.4±3.8µ and 542.6±27.0 µ, respectively. The hatching rate was increased by reducing temperature and salinity of their culture mediums from 25 to 15 ◦C , and 28 to 18 g/l, respectively. The highest hatching was observed on 5th day at 15 ◦C and 18 g/l (5, 33 %). In addition, low but multiple hatching was observed. Therefore, water temperature and salinity affected hatching rate in this species. The hatching success of Phallocryptus spinosa cysts was better when collecting cysts together with dry sediments of their habitat without separation sensitive cysts. In addition to cold keeping and freezing, the hydration – dehydration method caused more diapause deactivation for hatching induction. The laboratory results revealed that the survival of fairy shrimps were highest at 15 ◦C (42%) and lowest at 25◦C (26%), respectively. Also, their life was inhibited in 30◦C. In different salinities, the mean survival rate were 26% (Salinity= 15 g/l) and 20% (Salinity= 25 g/l), respectively. The mean survival percentage of Phallocryptus spinosa cultured in natural habitat water (64.3%) was higher than aerated tap water (23, 3 %). Also, feeding with Nanochlorepsis caused higher survival rates. On the other hand, Beakers yeast caused higher mortality rates. Therefore, regarding to relatively high sensitivity of these species to physico– chemical and nutritional conditions of their culture medium, it is better to culture these species with expansion of their natural habitat in order to preserve their biodiversity, culture and increase stocking density with regard to environmental considerations