Effect of long-term starvation and restricted feeding on growth performance and body composition of juvenile Siberian sturgeon (Acipenser baerii Brandt 1869)

The present study was designed and performed to investigate the eefect of long-term some feeding strategies (starvation, restricted feeding at rate of 1% biomass per tank and satiate feeding as control) on growth performance and body composition of juvenile Siberian sturgeon (Acipenser baerii Brandt 1869) for 8 weeks. In this regard, 270 juveniles Siberian sturgeon (average weight 54 ± 6/27 g and density 1.5 g/l) were distributed in three treatments (with three replicates) in 9 fiberglass tanks (1050 l). For all fish in each tank, body weight and total length were individually recorded at a biweekly interval. At the termination of the experiment period, five fish per replicate were caught randomly for proximate composition. Results showed that growth performance of Siberian sturgeon was affected significantly by starvation and restricted feeding periods. Moisture and lipid contents were differed significantly in all treatments; which the highest moisture and lipid contents were observed in starved and control fish, respectively. Protein content in starved fish was significantly lower than other groups, whereas ash contents were not significantly different among the treatments. In general, weight loss and other growth factors of juveniles siberian sturgeon during the food shortage were refered to mobilizing the body lipid reservesand then body protein sources and replacing with water. In fact, juvenile Siberian sturgeon can conserve body protein stores better than lipids during the food shortage period

Effects of dietary carbohydrate levels on growth, survival and body composition in Caspian Kutum (Rutilus frisii kutum, Kamenskii, 1901)

This study was carried out to evaluate the effects of dietary carbohydrate levels on growth performance and body composition of juveniles Caspian Kutum (Rutilus frisii kutum). Fish with initial average weight of 0.8±0.2g (±SD) were fed five isoproteic and isenergic formulated diets with different carbohydrate levels including 15, 20, 25, 30 and 35% in triplicate groups, 4 times daily according to their satiation for 10 weeks. Results showed that increasing the level of carbohydrate to 35% significantly increase some growth indices such as final weight (Wf), weight gain (WG), body weight increase (BWI), specific growth rate (SGR) and protein efficiency ratio (PER). In addition, result of body composition analysis showed that the increase in carbohydrate level lead to increase of protein level. So, the highest amount of protein was observed in fingerlings fed with diet containing 35% carbohydrate. In conclusion, the results indicate that increase in carbohydrate levels from 15 to 35% have not any negative effect on growth parameters and therefore, the level of 35% carbohydrate in the diet of 1-2g Caspian Kutum fingerlings can lead to better efficient in protein and desirable growth

Effects of different levels of vitamin C on hatching efficiency and survival of Maharloo Lake Artemia nauplii (Artemia parthenogenetica) at different temperatures

In this study, different levels of vitamin C (L-ascorbyl-2-polyphosphate) on the hatching efficiency and obtained Artemia nauplii survival were examined at different temperatures. In the first experiment, the effect of different amounts of vitamin C (0, 500, 1000 ppm) on hatching percentage of the Maharloo Lake Artemia cyst was examined with 6 replicates. Results of the first experiment showed that different amounts of vitamin C had no significant effect on hatching percentage. In the second experiment, the effect of different temperatures on the percentage of survival of Artemia nauplii was studied. In this experiment, obtained nauplii from first experiment were put in 3 different temperatures (1, 4, 16ºC) with 6 replicates for 48 hours, then percentage of survival of Artemia nauplii accounted. Result of the second experiment showed that interaction of vitamin C and different temperatures had no significant on the survival rate of Artemia nauplii. Different amounts of vitamin C (0, 500, 1000 ppm) had no significant difference on the percentage of survival of the Artemia nauplii, but different temperatures had significant effect on survival rate. Results of these experiments showed that increase of the amount of vitamin C had significant difference on hatching percentage of the Maharloo Artemia cyst, no significant effect on survival rate of Artemia nauplii. Also it is found that survival rate of Artemia nauplii in 16 ºC temperatures was more than 1 and 4 ºC temperatures

Changes of growth, food intake and plasma cortisol in juvenile common carp (Cyprinus carpio) following cortisol injection

The present study conducted to investigate the effect of cortisol injection on growth indices, food intake and plasma cortisol in juvenile common carp (Cyprinus carpio). After 2 weeks adaptation, 240 fish with 19.5 ± 0.2 g average weight were randomly distributed in to 12 fiberglass tanks with four treatments and three replicates (20 fish per tank). Based on body weight, cortisol (mixed with oil) was injected to treatments with different dosages at 0 (C0), 1 (C1) and 10 (C10) µg/g. At the end of 21 days, fish were weighed and growth parameters showed significant reduction in C10. No significant change was observed in hepatosomatic index among different treatments. Food intake were recorded daily during the experiment and showed significant reduction in days 1 to 8, 16 and 19 in C10 compared to control group . Blood was taken to determine plasma cortisol at the start, day 3, day 7 and day 21 of the experiment. Cortisol concentrations showed significant reduction in C10 compared to C0 group three days after the initiation of the experiment. The results showed that increasing of cortisol in a short time after injection, affected by changes of blood plasma cortisol and reduction of food intake could negatively have an effect on growth

Bioaccumulation of copper nanoparticle in gill, liver, intestine and muscle of Siberian sturgeon (Acipenser baerii) juvenile

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 redosing 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

Effect of dietary estradiol-17β on growth performance, body composition and blood indices in Stellate sturgeon, Acipenser stellatus

This study was investigated the effects of dietary estradiol-17β (E2) on growth, body composition and blood indices in Acipenser stellatus. Fish (40.9 ± 1.1 g average initial weight; n = 60 per group) were fed with three different diets containing 0 (control), 25 and 50 mg kg-1 dietary estradiol contents to apparent satiation for seven months. The results suggested that growth rate were decreased as the E2 level was increased. No significant difference was observed in condition factor among dietary treatments. The highest survival rate was observed in fish fed control diet, but was not significantly different among the treatments (P>0.05). Body composition did not show significant changes among dietary treatments. Number of white blood cells and red blood cells, hemoglobin and hematocrit values were significantly decreased as the E2 levels were raised (P<0.05). Plasma biochemical parameters including glucose, total protein, cholesterol, triglyceride, calcium, and phosphorus levels were dose dependent with the lowest levels in control with the highest levels in fish treated with 50 mg E2. The results of the present study revealed growth suppression of dietary E2 and changes of blood indices with providing some basic information on the effect of estrogen hormone on physiology of sturgeon

The effect of optical spectroscopy on incubation disorders of Iranian Acipenser persicus

Without abstract

Stress behaviour across human tooth by temperature gradient resulting of laser irradiation

The authors report the simulation of temperature distribution and thermally induced stress in the premolar tooth under ND-YAG pulsed laser beam. The Three-Phase-Lag (TPL) non-Fourier model is proposed to describe the heat conduction in the human tooth with nonhomogeneous inner structures. A premolar tooth comprising enamel, dentin, and pulp with real shapes and thicknesses are considered and a numerical method of finite difference was adopted to solve the time-dependent TPL bio-heat transfer, strain and stress equations. The surface heating scheme is applied for simulation of laser therapy. The aim of this laser therapy is that the temperature of pulp reaches to 47oC. The results are achieved as a function of laser heat flux showed when laser beam is irradiated downward (from the top of the tooth), the temperature and thermally induced stress increase as a function of time. The temperature increment is high on the top layers of tooth that is a result of strong absorption of beams by enamel. The thermal stress and strain in the enamel and dentin layers are more than the pulp layer that is a result of weak thermal expansion of them proportional to the pulp layer