Journal of Aquatic Ecology

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Microalgae as a source of saturated and unsaturated fatty acids, pigments, pharmaceutical and food metabolites, has received more focus by biological researchers at last decades. The amount and composition of fatty acids produced by microalgae depended on biomass production and environmental factors such as changes in salinity, light and nutrient availability. In this study, the green microalgae Dunaliella bardawil isolated from Chabahar Bay was cultured under different salinities (35, 70 and 105 g/L) using Conway medium. All treatments with air pump at 25±2 ° C and 12L: 12D (h) photoperiod and aerated. Effect of different salinity on the growth rate, lipid production and fatty acid composition of algal biomass were examined. ANOVA results showed that the highest growth rate and lipid content in the salinity of 70 g/L was obtained which are 933 and 206 milligrams per liter, respectively. Maximum and minimum lipid content of D. bardawil measured, 24.5 and 19 percent, at 105 and 35 ppt, respectively. Due to reduced cell density in 105 grams of salt per liter of fat produced per unit volume decreased to 65mg/L. The results show that D. bardawil purification from Chabahar Bay with degree unsaturation between 95-73 has great potential for biodiesel production.

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 In this study, the effects of salinity on the hematological parameters in Mesopotamichthys sharpeyi were investigated within 21 days. One hundred and twenty fish weighing 300-350g were divided randomly to four treatments of urban water and following 3 salinities: 4, 8 and 12 g/lit and blood samples were taken in following days of experiment: 1th, 3th, 7th, 14th and 21th.Hematological parameters were measured: white blood cell count (WBC), red blood count (RBC), Hb, RBC index (MCHC, MCH, MCV) and cortisol hormone.At the end of the experiment, compare of treatments with control group showed significant decrease in the total count of red blood cells in the salinity of 12 g/l (p<0.05). But no significant difference was observed in other hematological indices (p>0.05). Cortisol hormone showed significant variation among different treatments in different days (p<0.05). At the end of the experiment, the highest cortisolrates were observedin salinity of 4 gr/L (45.25±3.8) and the lowest cortisolrateswere observed in salinity of 8 gr/L (19.75±1.53).The results suggested that hematological parameters and cortisol hormone can be affected by salinity environment.

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Nutrition and the use of valuable nutrients is one of the most important issues in the aquaculture industry. In this study, the algal species I. galbana and P. lutheri alone and in combination with C. mulleri were incorporated in the diet of white leg shrimp larvae (L.vannamei) and the survival and growth rate of shrimp were investigated. This research was carried out in Persian Gulf & Oman sea Ecological research institute in July 2016. The experiment was carried out from nauplii 6 stages to PL10 and the shrimp were fed six times a day over 16 days.  Six treatments including single species of I. galbana, P. lutheri, and in combination with C.mulleri (as control) were in 3 replicates. At the end of the feeding period, the results of the experiment indicated that C treatment had the highest survival (72%) and the lowest survival was observed in B treatment (47%). There were significant differences among treatments (P≥ 0/05). The maximum (8.02mm) and the minimum (7.23mm) length were observed in F and B treatments, respectively. However, there was no significant difference among treatments (P≤ 0/05). The highest survival rate in salinities 45 and 53 was observed at 98% in E treatment and 95% in F treatment.  No significant differences were observed in survival among treatments. Thus C.mulleri is an essential main species for feeding white leg shrimp larval stage and I.galbana can also be supplemented for increasing nutritional value that could be suitable to improve quality and growth factor of shrimp larvae.

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