Sirwe Ghaderpour, Nasrollah Ahmadifard, Naser Agh, Zakaria Vahabzadeh, Alicia Estevez,
Volume 10, Issue 3 (9-2021)
Abstract
Despite the positive role of rotifers in many hatcheries for feeding the early stages of aquatic larvae, the lower mineral content of zinc (Zn) is one of the disadvantages of rotifer compared to copepods. Therefore, it is necessary to increase its amounts through enrichment. For this purpose, in the present study, a combination of algae Isochrysis aff. galbana and Nannochloropsis oculata were enriched with zinc sulfate for 1 and 3 hours. Due to obtaining better results in 1 hour, its effects on the growth and enrichment of rotifer were surveyed. The 1: 1 alga composition was enriched with zinc sulfate at concentrations (45, 90, and 135 mg/l). The highest amount of zinc was observed in the mixed algal enriched with 90 mg/l for 1 h, which had the highest copper amount and there was no significant difference with the control group. Also, the manganese amount was higher than the other treatments except for the control group. After feeding the rotifers with enriched algae for 1 hour, the best treatment was 45 mg/l, which also contained the second level of zinc and the first level of manganese, copper, potassium, and sodium. On the other hand, this treatment had the highest number of eggs on the peak day of reproduction treatments (third day) and its population density in the last days was not significantly different from the control group (p <0.05). Zn-enriched rotifers can be used to feed marine fish to meet the nutritional needs of aquatic larvae.
Saeid Vahdat, Manizheh Biabani Asrami,
Volume 12, Issue 1 (12-2022)
Abstract
Bacteria are used directly by zooplankton as a food source. The purpose of this study is to use straw as a substrate for the proliferation of bacteria in geomembrane pools and its effects on the production and biochemical compositions of Artemia. One week before Artemia culture, the pools inoculated with Dunaliella sp. and straw (particles less than 200 microns) as follows: treatment 1= geomembrane pool containing Dunaliella sp. (one week of algae cultivation), treatment 2 = geomembrane pool containing Dunaliella sp. and 0.5 grams per liter of straw (one-week algae cultivation and adding straw from the second week), treatment 3 = geomembrane pool containing Dunaliella sp. and 0.5 g/l of straw (algae cultivation and adding straw from the first week) and treatment 4= geomembrane pool containing 0.5 g/l of straw (adding straw from the first week). Artemia was cultured for 18 days and fed based on a turbidity depth of 15 cm. The highest growth rate was observed at the end of day 18 in treatment 3 (P<0.05). The highest amount of protein was obtained in treatment 1 (P<0.05). The highest amount of biomass was observed in the control and T3 groups (P<0.05). The presence of straw in Artemia pools decreased EPA fatty acid by 5-7 times less than the control (P<0.05). Artemia can grow while feeding on environmental bacteria. Applying straw in Artemia cultivation can lead to an increase in PUFA fatty acids with 18 carbon chains.
Mohammad Shamsaei, Zahra Ghasemi, Zahra Amini Khoei,
Volume 14, Issue 1 (2-2025)
Abstract
Using nutrient-rich aquaculture effluent as a growth medium for cultivating microalgae can help reduce dependence on chemical culture media. In a 14-day study, the effect of replacing a standard culture medium (control) with shrimp farming effluent (10%, 25% and 50%) on the cell growth of microalgae Nannochloropsis oculata was investigated. The results showed that in the early days (up to the sixth day), different concentrations of wastewater increased cell growth more than the control medium. From the eighth to the tenth day, the amount of cell growth in 10% concentration with 2190 cells per milliliter (day ten) was similar to the control medium, but in higher concentrations of 25% and 50%, a significant decrease in cell growth was observed (p˂0.05). On the twelfth day, the cell growth rate in the effluent concentration of 10% was higher than the control medium (p˂0.05). This shows the potential of shrimp farm effluents for microalgae cultivation in different concentrations, although the optimization of ratios is necessary to avoid the negative effects of toxic substances. Also, the results showed that with the passage of time, the ability of shrimp farming effluent to stimulate cell growth varies. In general, the findings emphasize the importance of using wastewater as a source of cell culture and can lead to the optimization of culture conditions and commercial applications in the cultivation processes of microorganisms.
