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۱Effects of different starter diets on growth indices of Caspian Kutum, Rutilus frisii kutum larvae
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، يازدهم،شماره۱، Jan ۲۰۱۲، سال
تعداد صفحات: ۱۹
Six different diets including two rainbow trout starters, Gammarus dry powder, shrimp dry powder, egg yolk dry powder and newly hatched Artemia were used in feeding of Caspian Kutum larvae. During a 4–week trial, larvae with a mean weight of 17.5 ± 4.7 mg were fed with three replicates and growth parameters were measured at the end of the experiment. Thirty fish in each experimental unit with 3 L volume were fed 6 times daily according to their satiation. Results showed that there were significant differences in the final weight, final length, body weight increase, voluntary feed intake and specific growth rate for weight and length among the treatments (P0.05), but not in the condition factor (P>0.05). The best performance was observed in fish fed Artemia nauplii. The survival rate was significantly different among the treatment (P0.05) which the highest (75.6 ± 3.8%) and lowest (22.2 ± 11.7%) were observed in fish fed Artemia nauplii and Coppens, respectively. According to obtained results, it appears that except Artemia, the most suitable and inexpensive diet is egg yolk powder, which can results in high growth performance and survival rates. The results of this study suggested that using dry non–live diets with good composition could be replaced with Artemia that had suitable growth and survival rate in Caspian Kutum during larval 0 .

۲Effect of different oxygen levels on growth performance, stress response and oxygen consumption in two weight groups of great sturgeon Huso hus
نویسنده(ها): ، ،
اطلاعات انتشار: IRANIAN JOURNAL OF FISHERIES SCIENCES، دوازدهم،شماره۳، Jul ۲۰۱۲، سال
تعداد صفحات: ۱۷
In the present study, different oxygen levels were examined in two weight groups of great sturgeon Huso huso including small size (with initial weight 280.9 ± 49.2 g) and large size (with initial weight 1217.9 ± 138.1 g). The fish were kept in hypoxia (2–3 mg\l), normoxia (5–6 mg\l) and hyperoxia (9–10 mg\l) conditions for 8 weeks and then were individually placed in the tanks with oxygen level of 6 mg\l to levels causing sedate fish and subsequently dissolved oxygen level in water was measured every 30 minutes. No significant effects on blood cortisol and glucose levels were observed after 8 weeks (P>0.05), but there were significant differences in cortisol concentrations between treatments (P0.05) after stress. Significant differences were found in cortisol and glucose levels in pre and post stress conditions in small size, but no significant differences were observed (P>0.05) in large size. There were no significant differences in oxygen consumption among treatments (P>0.05). Results revealed that dissolved oxygen had a significant effect on growth of H. huso and also a low level of oxygen accompanied by reduction in feed intake resulted in lower growth and changes in stress response.

۳Bioaccumulation of copper nanoparticle in gill, liver, intestine and muscle of Siberian sturgeon (Acipenser baerii) juvenile
اطلاعات انتشار: Caspian Journal of Environmental Sciences، چهاردهم،شماره۲، ۲۰۱۶، سال
تعداد صفحات: ۱۱
Copper (Cu) is an essential element required by all living organisms, since at least 30 enzymes are known to use Cu as a cofactor. Cu is also toxic in excess and liver and gills are known to be target organs for it. In the present study, 240 Siberian sturgeon juvenile (with initial weight 29.2 ± 3.1 g and initial length 21.8 ± 1.4 cm) were randomly distributed in 12 fiberglass tanks at 4 different copper nanoparticle (Cu–NPs) treatments with 3 replicates. Treatments included control (T0 = no added Cu–NPs), 50 (T50), 100 (T100), 200 (T200) µg.l–1 Cu–NPs (mean primary particle size of 2 – 6 nm) in a semi–static waterborne exposure regime. Water exchanged were 20% daily with re–dosing after each change. The experimental period lasted 28 days, 14 days exposure to Cu–NPs and 14 days as recovery time. Fish liver, gill, intestine and muscle were sampled at days 0, 7, 14, 21 and 28. Samples were weighed, dried (100 ◦C for 48 h) then digested in concentrated nitric acid in a water bath, cooled, and analyzed for Cu concentration in the tissues with graphite furnace atomic absorption spectroscope. Most of the Cu–NPs were accumulated in the intestine, gill, liver and muscle. The accumulation of NPs in tissues was increased in all treatments from day 7 through 14. In the recovery period, Cu–NPs in tissues decreased but it was still higher than the control treatment. The current findings indicate that preventing the entry of Cu–NPs into the aquatic environment would seem to be essential.
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