اهلی سازی و تولید انبوه لارو کرم پرتار دریایی

The aim of this research was to create a pilot plant for the production of larvae and worm stocking from wild worms of their natural habitats, as well as the evaluation of the biochemical composition of the Nereis worm from the diets containing vegetable oils, and the determination of the N. diversicolor density (individual/m2) in the culture system. In this study, stoching worm were collected from its natural habitat (Anzali lagoon) and stored in 14 tanks (500 L) containing sandy loam with air and water system installed and adapted to growth conditions. The breeding and maturity of worms took place at necessary conditions, and the larvae migrated to the surface of the sediments. The results of this study showed that domestication and adaptation of wild worms to artificial conditions for breeding worms could occur. Effect of seven formulated diets containing different vegetable oils from n-3 and n-6 fatty acids (including canola oil, soybeans, sunflower and corn oils, and a mixture of canola oils, corn and soybeans, sunflower), and each of these was performed in three replicates to feed the larval and the young N. diversicolor. After the end of the raring period, growth indices in each treatment included increasing total biomass, L3 length, specific growth rate (SGR), body weight gain (BWI), and survival rate in the basis on standard formulas. The results showed that there was no significant difference in the growth performane of worm from diets containing different oils with control treatment (worms fed from diet of without oil). The final biomass, the increase in biomass and weight gain in the treatment of worms fed with diets containing canola oil, sunflower, and mixtur of canola and corn increased compared to other treatments. Biochemical composition including total protein, total fat and fatty acid profile of diets and Nereis body carcass were analyzed according to standard methods. The results indicate that the fat in the diet has no effect on the growth of the worms, but the presence of these vegetable oils in carcass composition was important. The results of this study showed that all saturated and unsaturated fatty acids in the diet, except of the control treatment in the N. diversicolor, were higher than their dietary levels. In the present study, N. diversicolor, which fed from diet containing of canola oil, had the highest n-3 fatty acids. Worms fed from diets containing soy had higher survival rates than other treatments. But among the seven treatments, the value of n-6 / n-3 was 0.39 that was within the recommended range for humans (0.2-1%). Larvae fed dietary of containing canola and corn oil had higher levels of DHA compared to other groups, while the control group (non-oil-based diet) and soy oil-based diet had a lower level of DHA than the other groups. The highest EPA levels in the worms fed by the canola oil diet (5.2 ± 0.05 mg/g) were much higher than the same diet (0.3 ± 0.01 mg/g). The results showed that the amount of eicosapentaenoic acid (EPA) was 17 times higher and docosa pentaenoic acid (DHA) was 3.5 times higher than that in the diet of Nereis. The results of the ratio of ⍵-3 / ⍵-6 in the diet showed that its amount in worm was 2 times higher than dietary. Experiments on the effects of different densities on growth and survival of worm were performed in 6 treatments and 3 replicates with 1000, 2500, 5000, 7500, 10000, and 15000 individual/m2 in 6 months. After the end of raring period in each group, based on the total weight, specific growth rate (SGR), body weight gain (BWI) and survival rate were calculated by the growth indices formula. According to the statistical results it was observed that there was no statistical difference between treatments 1 and 2 in survival, and on the other hand, because treatment 2 (density 2500 m2 / m2) had the highest biomass compared to other treatments, it can be concluded that treatment 2 as the worst worm density is recommended.Key word: Nereis diversicolor, Diet, Density, Growth, Survival, Fatty acid profile