جستجوی مقالات مرتبط با کلیدواژه « specific growth rate » در نشریات گروه « علوم پایه »

Due to the increasing use of nanoparticles in human activities, as well as its role in reducing the adverse effects of heavy metals on living organisms, at this study the effects of sub-lethal concentrations of copper nanoparticles were discussed on growth factors and biochemical composition carcass of common carp.

82 carp with an average weight of 42 ± 2 g was prepared and after adaptation for the laboratory condition, were exposed at 42 days at three treatments (10, 40, 80 ppm) and three replicates respectively, also a control group were prepared with three replications under the affect of sub-lethal concentrations of copper oxide nanoparticles.

Analysis of growth indices showed that all growth indices had significantly different (P<0/05) with metal treatments in compared to the control group. So the control group had the highest average body weight, percent of body weight, SGR rate, and feed conversion efficiency with averaging 2.93. The lowest specific growth rate and the highest rate of conversion were related to the treatment number three (80 ppm), respectively. The amount of ash, fat, protein and maximum moisture was observed at the control group. The highest percentage of protein and fat was at treatment (3) and concentration of 80 milligrams per litre of copper oxide nanoparticles that in this regard showed significant differences (P<0.05) with the control group.

The results indicate that the presence of copper oxide nanoparticles in aquatic ecosystems have negative effects on growth and biochemical composition of fish carcasses even at sub-lethal concentrations, that by increasing the concentration of the nanoparticles in aquatic ecosystems, the influence of these effects will become clearer.

Rotifers is frequently used as indicator test animals of water pollutants due to their sensitivity and ecological importance. In present study, population response of rotifer B. calyciflorus to six different concentrations of carbaryl (0, 1, 10, 100, 200 and 400 µg/l(parts per billion)) with three replicates per concentration was studied for 6 days. Rotifer density and specific growth rate were calculated daily in the control and treatments containing carbaryl. Result showed that, rotifer population growth decreased significantly (p< 0.05) with increasing carbaryl concentration in the medium. The maximum density in six day belongs to control (49.15± 0.05 ind/ml) and minimum density belongs to treatments containing concentration of 400 µg/l carbaryl (6.28± 0/1 ind/ml). Also, the rotifer specific growth rate decreased significantly (p< 0.05) (from 0.71± 0/006 in control group to 0.37± 0/003 in concentration of 400 µg/l) with increasing concentration of this pesticide. The results showed that the pesticide carbaryl even at very low concentrations can highly affect the population rotifer B. calyciflorus.

Reuse of unconventional waters, such as wastewater, is very important in point of environmental principles view. The main objectives of the present study was to survey feasibility of the growth and survival performance of two species of silver carp and common carp at different concentrations of wastewater, and also investigation of the effects of presence of these two species on improving the quality parameters of wastewater BOD, COD, TSS, TDS, nitrate and phosphate parameters in the Mahdishahr wastewater treatment plant (active sludge method) in the Semnan province. For this study, five wastewater treatments were considered as control treatment (without wastewater) and treatments of 25, 50, 75 and 100% wastewater with triplicate in 80 liter reservoirs. In each tank, 10 common carp and 10 of silver carp were introduced with average weight 30± 5 gr. In one month, the growth performance and survival rate of fish were compared in different treatments. Also, changes in different wastewater parameters in the 100% wastewater treatment with presence of fish and without of fish (control) were also investigated during the 10-day intervals. According to the results, the highest growth (WG) (18%) and specific growth rate (SGR) (0.23) were related to the 75% and 100% of wastewater treatments. Also, in the treatment of 100% of wastewater in the presence of fish compared to the control (without fish) during the study period, BOD, COD, TSS, nitrate and phosphate parameters decreased significantly (P≤0.05) during the research period, while the trend for the TDS parameter was increasing in the treatment. The results showed that urban wastewater without water mixing also has the potential for reuse in aquaculture of resistant species such as Cyprinidae family species. Also, the presence of aquatic species with regard to diet has a significant effects on the improving the quality parameters of the wastewater.

Artemia urmiana nauplii were used as a vector in bioencapsulation processing to carry blends of five probiotic bacilli called Protexin aquatic,including Bacillus circulans, B. subtilis, B. licheniformis, B. laterosporus and B. Polymyxa to digestive system of Beluga Huso huso larvae. Nauplii were bioencapsulated with three concentrations of 1×105 (T1), 2×105 (T2) and 3×105 (T3) bacteria per mililiter in suspension and were fed to Beluga larvae for 10 hours. The larvae were fed on the base of the 50% of their body weight for 6 times a day in a completely randomized design and the results were compared with control group (unbioencapsulated Artemia nauplii) in fourteenth day of experiment. The results suggest a positive effect of probiotic bacillus on growth of Beluga larvae compared to the control group. The highest weight was obtained in fish fed by bioencapsulated Artemia with a concentration of 1×105 bacteria/mL. . Food conversion rate significantly decreased in experimental treatments. The probiotic bacilli had significant positive effects on the specific growth rate, relative gain ratio, survival rate, average daily growth and thermal growth coefficient in comparison with control (P<0.05). However, condition factor did not show any significant difference (P>0.05). The results showed that probiotic bacilli have the highest ability in increasing the growth of Beluga larvae and fish fed by bioencapsulated Artemia with a concentration of 1×105 bacteria/mL had the best results.

The aim of this study was to investigate the effect of different dietary crude protein/energy ratios on growth indices and body composition of Bester juveniles. Triplicate groups (60 individuals per group) of fish (average weight ± SD, 358.4 ± 13.37g) were fed with three diet (D1, D2 and D3) including 31.67%, 35.54% and 40.86% of crude protein and 4377, 4800 and 5344 kcal of energy/kg, respectively, during eight weeks based on 1.5% of biomass per day. The result showed different significant of growth parameters (P<0.05). Body weight increase, condition factor, specific growth rate, average daily growth, protein productive value, and feed conversion ratio (FCR) improved in D2 and D3 treatment groups compared with D1. Comparison of the carcass composition of examined fish showed significant different between treatment groups (P<0.05). Therefore, the highest moisture, lipid and ash level of carcass gained in fish fed with diet D2 (P<0.05). Also highest carcass crude protein recorded in fish fed with diet D3 (P<0.05). These results suggested that the diet including 35.54% of crude protein and 4800 kcal of energy/kg is economic and suitable for culture of juvenile Bester.

Pigments such as Chlorophyll and Carotenoid are of particular interest due to their antioxidant and therapeutic properties. Spirulina is a great source to commercial pigments production due high pigment percentage and simple extraction processes. The aim of this study was chlorophyll and carotenoid optimization of spirulina biomass by innovative photobioreactor. In this experimental study, by designing and constructing an innovative photobioreactor for the elimination of some defects of commercial open cultures, spirulina combined culture was investigated. Using RSM-CCD method, the effect of circulation cycle factors, control volume, and irradiance intensity on total value of pigments were evaluated. The data were analyzed by SPSS 16, using linear regression. The highest amount of total Chlorophyll (3.63mg/l) was obtained in Test No. 7 with the shortest circulation cycle (2hr) and control volume of 30%. In this situation, total carotenoid was 0.90mg/l and the whole amount of two pigments was maximum. But, the highest amount of total carotenoid (1.59mg/l) was obtained in the least control volume (20%), circulation cycle of 9.5hr, and light intensity of 10500Lux. In order to attain the highest level of chlorophyll, the optimal irradiance intensity to increase the biomass and the short-range circulation cycle to increase content are the top priority. But, to attain the maximum level of carotenoid, long-range circulation cycle to increase biomass and irradiance intensity at high level to increase content is predominate. The importance of the effect of increasing irradiance intensity on the increase of carotenoid content as well as the reduction of the circulation cycle on the increase of chlorophyll content is greater than its negative effect on the dry weight of biomass and results in an increase in the pigmentation.

Special properties and various applications of Spirulina species have led to the growing focus of biotechnology to the cost effective cultivation. Open ponds used in the most commercial cultivation have many deficiencies such as risk of contamination, lack of light penetration, inefficient mixing and low productivity. In this study, an innovative reactor was designed and manufactured. By adding a control area, it was possible to control some environmental conditions for a limited amount of open pond volume. The conventional pumping system was replaced by a new elevator system to reduce the damage of to the fragile cells. The baffles structure and aeration from bottom, contributed to better mixing system. The effect of tree factors (Circulation Cycle (Cir. Cyc.), Control Volume (Con.Vol.) and Irradiance Intensity (Irr. Int.) in units of hours, percentage and Lux respectively) on the quantity of biomass (Specific Growth Rate (SGR, day-1) and fifth and seventh day dry weight (g/L)) were evaluated using RSM-CCD. The maximum biomass dry weight (0.915 g/L) was achieved in longest circulation cycle (12 hours), 30% Con. Vol. and 7000 Lux light intensity. The optimal irradiance intensity to achieve the highest biomass was 8700 Lux. According to the results, due to the great influence of Con. Vol. and Cir. Cyc., it is possible to increase the productivity and enhance the culture dry weight by controlling a limited amount of ponds volume (20%), subject to economic considerations. These successful results can provide the context using a control zone for several open ponds to improve the overall efficiency.

Feeding frequency and stocking density are important factors affecting growth and maturation of cultured fishes. The aims of this investigation were to determine the effects of stocking density (10, 20, 30 and 40 fish per aquarium) and feeding frequency (2, 3 and 4 times per day) on growth parameters and hematocrit of the Rutilus rutilus caspicus. The experiment was continued for 45 days in two replicates. The results of this study showed that growth parameters, including weigh gain (WG), feed conversion ratio (FCR) and specific growth rate (SGR) were affected significantly by stocking density (P0.05). The highest WG and SGR were recorded with the lowest stocking density (10 fish / aquarium). The least FCR was obtained in density of 10 fish/aquarium, FCR value was significantly higher with high stocking density (P0.05). Density and feeding frequency hand no significant effect of hematocrit concentration (P>0.05). On the other hand, interactions between stocking density and feeding frequency significantly affected hematocrit levels (P

This research evaluated the effects of dietary supplementation of commercial Bactocell and D-Pro probiotics on growth performance, survival and carcass composition in giant freshwater prawn Marcrobrachium rosenbergii postlarvae (PL) in a 60 day feeding trial. A total of 600 PLs with mean initial weight of 0.090± 0.004 g were assigned to five treatments each with three replicates in a completely randomized design experiment with 40 PL in each 50 L tank. . Experimental groups including control diet (without probiotic), 0.3 g Bactocell (treatment 1), 0.6 g Bactocell (treatment 2), 0.4 g D-Pro (treatment 3) and 0.8 g D-Pro per kg diet (treatment 4). After feeding trial, growth indices, dietary factors and proximate compositions were analyzed. The results showed that final weight, weight gain, condition factor, survival, specific growth rate and protein efficiency ratio were significantly higher in prawns fed with probiotics compared to control (p<0.05). The highest level of growth parameters and the lowest level of feed conversion ratio were observed in treatment 4. Proximate composition was significantly different among treatments. The highest levels of protein and lipid were observed in treatment 4. According to the results, the application of diets supplemented with Bactocell and D-Pro probiotics can promote growth and dietary factors and proximate composition in cultured giant fresh water prawn PLs.

In this study, the effects of four different concentrations of lead (0, 15, 48.6 and 150 µg/L) and four different concentrations of cadmium (0, 1.2, 3.7 and 6.2 µg/L) with low (2×105 cell/ml) and high (6×105 cell/ml) algal concentrations of Scenedesmus quadricauda on the density, specific growth rate )SGR( and doubling time (Dt) of fresh water cladoceran Daphnia magna were investigated. The experiment was carried out as a completly random design for 21 days with three replications. Results showed that the density and SGR were increased when concentrations of lead and cadmium decrease significantly (p

Rotifers due to their relatively short lifespan, high fecundity and high rate of population increase are ideal for chronic toxicity tests. Mercury is one of the heavy metals highly toxic to aquatic organismsparticulary freshwater zooplankton of which rotifers are an important group. In peresentstudy, population response of rotifer B. calyciflorus to six different concentrations of mercury (0.0005, 0.001, 0.002, 0.004, and 0.008 mgL-1) with three replicates per concentration was studied for 12 days. Rotifer density and specific growth rate was calculated daily in the control and treatments containing mercury. Result showed that, rotifer population growth decreased significantly (p

Freshwater rotifer B. calyciflorus is one of the major zooplanktic species that is important in aquaculture, aquatic ecosystem foodchain and environmental monitoring. nickel is one of the stable environmental contaminants since it cannot be chemically degraded or destroyd. In present study, population response of rotifer B. calyciflorus to six different concentrations of nickel (0.025, 0.05, 0.1, 0.2, and 0.4 mg/l) with three replicates per concentration was studied for 8 days. Rotifer density and specific growth rate were calculated daily in the control and treatments containing nickel . Result showed that, rotifer population growth decreased significantly (p

The present study provides information of the effect of three culture media, viz. Tamiya, Trenkenshu and Guillard (f/2) on specific growth rate and cell density in alga Scenedesmus obliquus Kützing. The alga was isolated from the south cost of the Caspian Sea (the beach of Noor Town) and then it was purified and cultured in three media with three replications for each. Cell count was daily conducted with three replications by a hemocytometer and growth curves were plotted by excel. After calculating the specific growth rate, the one-way ANOVA was used to compare obtained values. The results of the present study showed that the highest density of cells (17×106 cell per mile liter) was in Trenkenshu culture medium, and the lowest density of cells (7×106 cell per mile liter) was in Guillard medium.

A 33-day feeding experiment was conducted to assess the effects of supplemented diets with sturgeon intestinal bacteria as probiotics in feeding of silver carp (Hypophthalmichthys molitrix) larvaewith average weight 200 ± 10 mg. These probiotics were isolated from gut of ten healthy fingerlings of Beluga (Huso huso) with average weight of (5.51 ± 0.31 g). Four diets (S1¡ S2¡ S3 and S4) were prepared containing similar ingredient composition and were supplemented with blend of three probiotics (Bacillus licheniformis¡ Bacillus subtilis and yeast of Saccharomyces cerevisiae) at four different levels (0¡ 1.5×106¡ 3×106¡ 4.5×106 cells per 100 g of diet¡ respectively). At the end of experiment¡ the Silver carp larvae fed probiotic supplemented diet had an improved and growth feeding performance compared to fish larvae not fed probiotics. Rearing of silver carp with feeding by experimental diets of¡ S2 and S3 (3×106 and 4.5×106 cells 100 g) resulted in better growth and feeding parameters in compared with the control. These probiotics resulted in a significant increase (P

To investigate the feasibility of using poultry waste oil as an energy source in rainbow trout (Oncorhynchus mykiss) diets, an experiment designed by a completely randomized plan with three treatments and three replications for each treatment in a semi-closed aquaculture system, with an average temperature of 19.1±2.11°C (Mean±‌ SD). The experimental units consisted of fiberglass tanks with a useful volume of 100 liters by 1.5 liter per minute water replacing. Fattened fish weighted average 21.67±0.38 g were fed for eight weeks, with three of the same chemical composition and different fat sources diets (including 100% fish oil (control), 50% of poultry waste oil and 50% fish oil (treatment 1) and 100% of poultry waste oil (treatment 2)). The results of the experiment, showed significant difference in final weight, protein efficiency ratio, established protein, rate of muscle protein, condition factor, SGR and FCR between the experimental groups. Usage of treatment by 50% replacement led to fish in this experimental group, compared with the other groups on measures such as: feed conversion ratio, established protein, specific growth rate and condition factor was significantly superior (p>0.05). Overall findings indicate that the combined use of fish oil and poultry waste oil with equal proportion can be a good way to provide energy and fatty acids for rainbow trout.

Regarding the importance and selection of phytoplankton culturing for feeding marine zooplankton and fishes, under simple and practical conditions, two species of an unicellular green alga, Dunaliella sp. (isolated from Iran) and D.bardawil-UTEX 2538, were cultured and their growth characteristics were studied under different environmental light intensities (50µE and 150µE) and salt concentrations (0.1,0.5,1,1.5, 2 and 3M NaCl).Dunaliella sp. was different from D.bardawil because of having the longer logarithmic growth phase, higher number of cells (19×106 cells.ml-1) in 0.1M and 0.5M at light intensities of 150µE and 50µE respectively, higher chlorophyll and carotenoid contents, bigger size of cells (307.16±87.95µm3) and higher dry weight at 0.5M on 8th day from the beginning of experiment under 150µE, than those in D.bardawil. Protein content from the cells increased in both strains on 8th day but the maximum amount was belonged to D.bardawil under 150µE. The highest specific growth rate (SGR) and the lowest doubling time (DT) were seen under 50µE at 0.1 M and 0.5 M (Iranin species and D.bardawil, respectively) and under 150µE in 0.5M (Iranian species) and 1M and 1.5M (D.bardawil). The highest SGR and the lowest DT of D.bardawil was at 50µE and for Dunaliella sp. was at 150µE (both at 0.5M). Increasing in light intensity from 50 µE to150µE, caused decrease in chlorophyll and carotenoid contents and conversely increase in protein content (also the highest amount of fresh weight on 8thday) in most of the samples. Overall, Iranian species at lower salt concentrations showed better growth and higher efficiency.

Present study aims to determine suitable dose of inulin in Piaractus brachypomus fry diet and its effect on growth, survival and some hematologic indices in this species. In this research, one basic diet as control and three experimental diets including three levels of 1, 2 and 3% inulin each with three replicates were considered. Fish with mean initial weight of 2.31±0.14g were fed with experiment diets for 8 weeks. Results showed that the level of 2% prebiotic inulin in diet caused the increase of final weight gain and specific growth rate and improved food conversion rate (P

Temperature and photoperiod are important parameters in zooplankton culture, particularly in cladoceran culture due to their significant effect on growth and reproduction. Effects of temperature and photoperiod on the growth and fecundity of a cladoceran, Moina macrocopa was examined by culturing and feeding it with green algae Scenedesmus quadricauda in 500 ml conical flasks. Treatments used for temperature (0C) and photoperiod were 25, 30, 35 (0C) and 12:12, 24:0 and 0:24(light:dark hours), respectively. The maximum population density (310.5 individuals/flask), maximum specific growth rate (SGR) (0.387 individuals /day), shortest population doubling time (Dt) (1.79days) and highest fecundity (8.5 offsprings/ female) obtained at 30(0C). Correspondingly, the maximum population density (320.7 ind/flask), maximum SGR (0.538 ind/day), shortest Dt (1.28 days) and highest fecundity (7.54 offsprings/ female) determined at 24:0 light:dark photoperiod. Overall, this research showed that growth and reproduction of M. macrocopa at 30 (0C) and 24:0 light:dark photoperiod gave significant performance (P<0.05) compared to other examined treatments. Mass culture of this species under the mentioned conditions of temperature and photoperiod could provide suitable live food for use in fish larvaiculture.