The role of dietary nucleotide on energy sources and growth function of common carp, Cyprinus carpio

Considering the effects of dietary nucleotides on growth and metabolism, this study was conducted to determine the effect of different levels of this nutrient on the sources of the body needed energy, and growth performance of common carp. Fish with average (±SD) weight of 7.5±0.2g were fed to five levels of dietary nucleotides containing 0, 0.1, 0.2, 0.3 and 0.4 percent for 8 weeks. Fish were fed 5 times daily according the satiation. After 56 days, the results showed that the level 0.2% nucleotide had the highest growth rate in terms of weight and length, but other parameters such as body weight, specific growth rate and feed conversion ratio, differences were not significantly changed. Biochemical analysis of serum parameters and proximate analysis showed that the physiological function of fish affected by different levels of nucleotides whereas in the energy supply sources, including glucose, triacyleglycerol, total protein and albumin there were no significant difference in cholesterol and lipid content of carcass. This study conveys a positive effect on the biosynthesis of dietary nucleotides on energy sources and growth functions, while the common carp has ability to synthesize this substance into the body, the level of 0.2% in the diet can affection *Corresponding author sufficient effect on growth and some biochemical indices

Effects of different starter diets on growth indices of Caspian Kutum, Rutilus frisii kutum larvae

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). The best performance was observed in fish fed Artemia nauplii. The survival rate was significantly different among the treatment (P<0.05) 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

Effects of lecithin on growth and hematological indices in juveniles of Siberian sturgeon (Acipenser baeri Brandet 1869)

This study was carried out to evaluate the effects of dietary lecithin on growth performance and hematological indices in juveniles of Siberian sturgeon (Acipenser baeri). Fish with initial average weight of 32.9±0.3 grams were fed five isoproteic and isolipidic formulated diets with different soybean lecithin levels including 0, 2.5, 5, 7.5 and 10% in triplicate groups for 8 weeks. Results showed that lecithin supplementation to 7.5% significantly increased some growth indices such as body weight increase (BWI), specific growth rate (SGR), feed conversion ratio (FCR ) final weight (Wf), condition factor (CF) and protein efficiency ratio (PER). Also, increasing dietary lecithin to the level of 10% significantly decreased growth indices. According to the results of hematological assays, hemoglobin (Hb) in treatments of 5% and 7.5% in comparison to other treatments had higher value. Hematocrit (Hct) in fish fed with 7.5% lecithin was higher than those fed with 0 and 2.5% lecithin in the diets. Other hematological indices such as WBC, RBC, MCV, MCH and MCHC showed no significant differences among the treatments. In conclusion, the results of this study indicated that Siberian sturgeon juveniles have a relatively moderate lecithin requirement (between 5 and 7.5 percent of the diet) and these levels of lecithin in diet induces increase of growth performance and improves health status of this species

Effect of different oxygen levels on growth performance, stress response and oxygen consumption in two weight groups of great sturgeon Huso huso

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) 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

The independent effects of ferrous and phosphorus on growth and development of Tetraselmis suecica; an in vitro study

Five treatments including Conway medium, media containing 0.1, 0.17, 0.3 and 0.5 mg l-1 ferrous (Fe; in the first experiment), media with 1, 1.26, 1.59, 2 mg l-1 concentrations of phosphorous (P; in the second experiment) and a pure sample of Tetraselmis suecica were cultured under laboratory conditions. Growth rate of the algae was determined using the optical density method at 750 nm and number of algal cells was counted with a hemocytometer. The results of the first experiment showed that the amount of Fe for maximum growth of this species was 0.3 mg l-1, while Fe concentration in Conway medium was 0.27 mg l-1 (P>0.05). The results of second experiment showed that 1.59 mg l-1 P caused the maximum growth of algae which was not significantly different from that of the control medium (with 1.6 mg l-1; Conway; P>0.05).These results showed that due to the lack of significant differences in maximum growth of this alga recorded in 0.3 mg l-1 Fe and that recorded in 1.59 mg l-1 P in Conway medium, increase or decrease of these doses will have a significant negative effect on algal growth

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

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

Determination of artificial propagation normative in Acipenser gueldenstaedtii

This study was carried out to determine artificial breeding normatives of Russian Sturgeon (Acipenser gueldenstaedti). In this research, which was conducted in Shahid Marjani Breeding Center in late winter, 27 female and 13 male broodstocks were used. All broodstocks were provided from Turkeman and Mianghaleh fishing ground in the Caspian Sea. After maintaining them at Kurinski ponds and determination of germinal vesicle in the oocytes, 15 female and 13 male broodstocks were injected by 60-75 and 40-55 mg of pituitary hormone, respectively. After maturity duration, 10 female and 5 male broodstocks showed response to the hormone injection. Some parameters such as maturity duration, number of oocytes per gram, oocyte diameter, weight and bodymass of oocyte, motility and density of spermatozoid, duration of reaching to 4 and 16 divisions, incubation duration, fertilization percentage in each stage, mortality rate during incubation, number of larvae resulted from each broodstock, number of larvae per gram, weight of each larvae as well as some morphometric parameteres and age for each broodstock were determined

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