Feasibility of mass cultivation on Nannochloropsis oculata microalgae in tubular culture system

The presnt study has been carried out to evaluate the Nannochloropsis oculata culture performance in 100L columnar plastic bags under two chemical media (TMRL and CONWAY) and 3 light regimes in the controlled conditions. Algae used for the experiment has been provided through culture of primitive stock and by transferring it to 2 L glassy erlenmeyer and 15 L plastic containers (as intermediate stage) using CONWAY media respectively. Daily evaluation of algae concentration was carried out during the 18 days culture period. At the end of the study produced algae has been sedimented to be used for evaluation of the dried matter and algae biomass. Results of the study showed that the concentration of the algae culture was 22±3.34×106 cells. ml^-1, at 8th day, and reached the concentration of 26.58±4.02×106 cells. ml^-1 at the final day of the culture course. Although the results revealed the possibility of achievement of acceptable concentration for the N.oculta by the method adopted in the present study, but the achievement was not such favourable to be considered as an altenative for the common method. Nevertheless it could be considered as an alternative for the constrained situations. Moreover according to the results there was no significant algae concentration difference between light regimes (P>0.05). Similar results were observed for the interaction effect of chemical media and light regimes. Meanwhile the ratio of dried matter obtained from algae under the TMRL media was significantly (P0.05) affect the algae production. Finally it could be concluded that the N.oculata algae could be successfully cultured in plastic columnar bags under the controlled conditions but the method adopted in the present study could be applicable in the improper conditions

Compensatory growth of Sobaity (Sparidentex hasta) and yellowfin seabreams (Acanthopagrus latus) relative to feeding rate during nursery phase

A 60‐day study was conducted to investigate the compensatory growth (CG) responses of sobaity (Sparidentex hasta) and yellowfin (Acanthopagrus latus) seabreams to restricted feeding ration and normal feeding ration phases during the nursery period. Fry stage of S. hasta and A. latus with initial weight (BWi) of 1 and 0.8 g, respectively, were fed a commercial diet at five ration levels (RL) including 2%, 4%, 6%, 8% and 10% of their BWi over a period of 30 days (restricted‐ration phase) and then re‐fed up to visual satiation for another 30 days (normal‐ration period). According to the second‐degree polynomial relationship between specific growth rate and RL, the maintenance, optimum and maximum feeding rates for SGR in S. hasta were estimated to be 0.5%, 3.5% and 8.2%; meanwhile in A. latus, they were 0.3%, 4% and 8%, respectively. At the end of the normal‐ration phase, final body weight (BWf) of S. hasta fed at 10% RL was higher than the other treatments. In addition, A. latus fed at 6% and 8% RL showed full CG regarding BWf compared with fish fed at 10% RL. The findings of this study confirmed partial CG in S. hasta and full CG in A. latus after re‐feeding period.info:eu-repo/semantics/acceptedVersio