Ahmad Ahmadi, Nasrollah Ahmadifard, Ahmad Imani, Sajad Pirsa, Behrooz Atashbar,
Volume 10, Issue 4 (12-2021)
Abstract
In the present study, the effect of phytohormone gibberellin on some physiological parameters of Tetraselmis suecica microalgae was investigated. Algae culture was performed under standard conditions with Gillard culture medium, temperature 25 ± 2 C°, light intensity 16: 8 (light/dark), salinity 25 ± 2 mg / l, and 24-hour aeration for ten days. Concentrations of 10, 20, 40, and 60 mg / l were added to the algae culture medium. Growth factors, pigments, photosynthetic factors, and biochemical composition were measured in the log phase. Based on results, the highest rate of cell growth was observed in the treatment of 60 mg / l, although in other treatments there was a significant difference with the control (P <0.05). The highest amount of protein and carbohydrates was observed in the treatment of 60 mg / l (P <0.05). ). Total lipid content increased from 15.23 in control to 18.53 in 60 mg / l (P <0.05). Antioxidant potential, pigments, photosynthetic factors, and dry weight also showed a significant difference in the concentration of 60 mg / l compared to the control (P <0.05). The highest amount of chlorophyll a and chlorophyll b was observed at concentrations of 60 mg / l (P <0.05). Based on the results, gibberellin has a high potential for cell division, final density, antioxidant potential, cell size, and biochemical composition of Tetraselmis suecica. Also, Tetraselmis suecica can be a good candidate for marine aquatic larvae, drugs, antioxidants, and a rich source of compounds in biofuels.
Volume 18, Issue 1 (1-2016)
Abstract
This study was conducted to evaluate a temperature regime ranged from 15 to 30°C on survival, growth, life span and reproductive traits (reproductive period, clutch number, offspring number) of Phallocryptus spinosa from Iran. Newly hatched nauplii (N= 200 and 3 replicates per each treatment) were allocated into containers and maintained at various temperature regimes (at 15, 20, 25 and 30˚C). During trial, the larvae were fed with unicellular algae Dunaliella tertiolecta and Lansy PZ (lipid-enriched yeast). Survival and growth rate of P. spinosa with an interval of 3 days to 18 days were examined. After attaining adulthood, 16 pairs of adult P. spinosa were transferred from all culture vessels into separate containers supplied with 300 ml of brackish water (5 ppt) and similar temperatures to compare their life span and reproductive traits. Based on results obtained, maximum growth at shortest period (13.2±2.0 mm on day 12) was observed at 30°C; whereas, all P. spinosa died before reaching sexual maturity by day 15. Maximum survival (86%) was observed at 15°C; however, minimum growth also was obtained at the same temperature with none of P. spinosa reaching sexual adulthood. On the 18th day, P. spinosa reached sexual adulthood only at 20 and 25°C. Furthermore, a significant difference was observed in most of the reproductive traits especially in total egg production per female at 20°C. Thus, it seems that 20°C is the suitable temperature to rear this fairy shrimp. Future studies should be focused on the feasibility of mass production of this species as a valuable live feed in the aquaculture industry.
