الفهرس 
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Abstract
This study is an attempt to provide a use of Artemia in aquaculture in Egypt, a substitute for imported high-cost Artemia types, using a comparative study of some of local and imported Artemia species, and access to more economic results in this field.
The study included three experiments:
The experiment I was designed to investigate the morphological charac-ters including:- cyst diameter, Artemia morphology (total body length), biological characters including:- hatchability at different incubation tem-peratures according to Sorgeloos et al., (1986).
The experiment II was designed to investigate the effect of two different feed (oat and baby food) on growth survival rate and proximate composi-tion of local, Lake Qarun Artemia (LQA), compared to imported, Great Salt Lake Artemia (GSLA).
The experiment III was conducted to determine the nutritional value of Qarun Artemia (LQA) compared to Great Salt Lake Artemia (GSLA) as a sole diet at two different stocking densities (100 and 150 nauplii/ fish) for goldfish, Carassius auratus fry. All conditions of the experimental evalu-ation in the present study were apparently satisfactory and fell under the optimal standards defined for evaluations in goldfish.
The experiments were carried out in static glass tanks in fish nutrition lab, fish research station, EL-Kanater El-Khayria, National Institute of Oceanography and fisheries (NIOF), Cairo, Egypt.
The results showed that, the mean value of the diameter of non-decapsulated cysts for LQA ranged from 212 to 230μm, while for the GSLA cysts it varied from 183 to 201 μm. With regard to sex, LQA rec-orded higher length in both female and male than GSLA. GSLA recorded higher hatching efficiency than LQA. Hatching curve revealed that the hatching started after 15 and 13 h for LQA and GSLA, respectively, and reached T10 and T90 at (17, 15 h) and (22, 21 h), respectively. GSLA had significant higher hatching % than LQA, incubation period for 48h recorded significant (p<0.05) higher hatching % than 24h and the effect of incubation temperature showed that the higher one (30 ºC) had higher significant (p<0.05) hatching % than the lower (25 ºC) incubation temperature. The highest hatching % (p<0.05) was recorded for LQA cyst hatched for 48 hour at 25ºC (96.30 %). However, the worst cyst hatching % was recorded for LQA hatched for 24 hour at 25ºC (56.3%).
The highest percentage (p<0.05) of nauplii were recorded for LQA fol-lowed by GSLA incubated for 48 hour at 25 ºC. The highest percentage (p>0.05) of cysts and umbrella percentages were recorded for LQA fol-lowed by GSLA incubated for 24 hour at 25 ºC. GSLA showed higher % of nauplii (p<0.05) and cysts (p>0.05), but lower umbrella (p<0.05) than LQA. Moreover, both longer incubation hours and higher incubation tem-peratures recorded higher significant (p<0.05) nauplii % and lower (p<0.05) umbrella and cysts %.
The highest survival % value was recorded for LQA followed by GSLA fed oats at 4th day. However, LQA fed baby food recorded the lowest survival % value after 11 days. Differences between treatments were significant (p<0.05). No significant differences (P>0.05) were found among either the different Artemia or inert food sources as main effects on survival%. Survival % gradually decreased (p<0.05) as days after hatch increased.
The highest Artemia length (mm) value was recorded for GSLA fed on baby food at 11 days after hatch. GSLA recorded length (p<0.05) higher than LQA. Baby food results higher (p<0.05) length than oats.
Chemical composition showed that LQA had higher moisture (p<0.05), crude protein (p<0.05), EE and ash (p>0.05) than GSLA. Artemia fed on baby food recorded higher moisture (p<0.05), crude protein and EE (p>0.05) than oats. LQA fed on baby food recorded the highest crude protein and EE content (p<0.05).
The final fish length, final Body weight, and survival % were significantly affected by Artemia strains and level of Artemia. However, weight gain, and specific growth rate (mg/days) were insignificantly affected.