90 research outputs found
Logarithmic entropy--corrected holographic dark energy with non--minimal kinetic coupling
In this paper, we have considered a cosmological model with the non--minimal
kinetic coupling terms and investigated its cosmological implications with
respect to the logarithmic entropy-- corrected holographic dark energy
(LECHDE). The correspondence between LECHDE in flat FRW cosmology and the
phantom dark energy model with the aim to interpret the current universe
acceleration is also examined.Comment: 11 pages, 2 figures; Can. J. Phys. Vol. 90, 201
Effects of supplemental dietary L-carnitine on growth and body composition of beluga (Huso huso) juveniles
The effect of feed supplemented with L-carnitine at four levels of 0, 300, 600 and 900mg kg-1 on growth performance and body composition of beluga, H. huso, juveniles were evaluated in two separate trials. In the first trial, 180 juveniles (525±9gw) were fed with the test diet for a period of 71 days, and the trial extended to another 126 days in the second phase by randomly selecting 120 juveniles (870.7±32g) and rearing them with similar diets. All trials, in triplicates, were conducted in circular fiberglass tanks (200cm diameter, 40cm height).The fish were fed 4 times daily to apparent satiation. In the first phase, L-carnitine did not significantly affect mean final weight, feed conversion ratio (FCR) or specific growth rate (SGR) of the fish, however, the fish receiving 900mg kg-1 L-carnation showed better growth increment, SGR and feed efficiency (FE) than those in control group (p³0.05); neither did it significantly affect protein, lipid, moisture or ash as well as leptosomatic index (HSI) (p³0.05). The protein efficiency ratio (PER) was significantly affected by L-carnitine supplemented diet, particularly at 900mg kg-1(p£0.05). In the second phase, fish fed L-carnitine-supplemented diets produced significantly higher W2, SGR and PER than the control group (p£0.05), but HSI decreased significantly (P£0.05). At the end of the trial, the whole body composition of fish did not differ significantly among experimental treatments, but slightly reduced lipid content was observed at 600 and 900mg kg-1 L-carnitine (p£0.05).The results of this study indicated that supplementation of diets with 300-600mg carnitine kg-1 improved growth rate, feed utilization and stimulated protein-sparing effect in this species
Proximate composition and fatty acids profiles of Artemia cysts and nauplii from different geographical regions of Iran
Artemia has been widely used in aquaculture as a suitable live food. The presence of highly unsaturated fatty acids is a key factor that determines the nutritional value and marketing of Artemia for shrimp, marine larvae, sturgeon and ornamental fish industries. To determine the variation in nutritional content in cysts, decapsulated cysts and nauplii of Artemia from three different biotopes of Iran, were tested for their protein, lipid, energy, and fatty acid profiles, particularly essential fatty acids. The cysts collected from Urmia, Maharlou and Meighan lakes, were rinsed, processed, decapsulated, hatched and then analyzed for proximate and fatty acid composition using standard methods. Statistical comparisons of the results revealed significant differences not only in proximate composition but also in fatty acid contents (p<0.05). The highest mean (±SD) level of protein (60.5±3.3%), lipid (18.60±1.1%) and energy contents (5448.3±10.4 Kcal/kg) were observed in Instar I nauplii hatched from Urmia Lake cysts, Instar I nauplii hatched from Maharlou Lake cyst and Instar I nauplii hatched from Urmia Lake decapsulated cyst, respectively. The highest content of DHA (0.78 mg/g DW) was observed in nauplii of cysts from Urmia Lake whereas it was around zero in other samples. The highest level of EPA (24.24 mg/g DW) was measured in nauplii from Maharlou Lake decapsulated cysts and the lowest (0.24 mg/g DW) was observed in Urmia lake cysts. The results revealed that the nauplii from decapsulated cysts of Maharlou Lake Artemia contained significantly higher levels of EPA and n-3 HUFA compared to others. Therefore, it is recommended to use it in aquatic larviculture
Utilization of poultry by product meal as an alternative protein source for Huso huso within growth period
With regard to increasing the fish meal price, utilization of hygienic and analyzed poultry by product meal as an alternative protein source in diets for Huso huso within growth period were investigated. Six test diets isonitrogenous and isocaleric (contain 42% protein and 20 Mj kg-1 energy) were prepared. Fish meal was substituted by poultry by product at 20% (PBM20), 40% (PBM40), 60% (PBM60), 80% (PBM80) and 100% (PBM100) in base diet, respectively. A total of 180 Huso huso with average (±SD) weight of 107.89±5.9gr were stocked in 18 fiberglass tanks (Voloum:2000 lit,Temperature:20±2C 0) and fed satiation to 18 weeks. No significant differences were detected between final weight (FW),weight gain (WG) and specific growth rate of fish fed (PBM0), (PBM20), (PBM40), (PBM60) and (PBM80) respectively. The Highest protein belonged to fish fed PBM20 (%16.97±0.36) with significant difference with PBM40 (% 15.41 ± 0.67), respectively. Body lipid fish fed PBM80 and PBM100 (%6.63±0.016) (%7.49±0.17) were significantly lower than other treatments. The Synchronic hepatosomatic index increased with increasing poultry by product in diets and highest rate were found in fish fed PBM 100 , but except PBM20, visceral index in fish fed other treatments was same. The result showed that up to 80% fish meal could be replaced by poultry by product with no adverse effect on growth and feed conversion ratio for Huso huso within growth period
The evaluation of input costs contribution to sturgeon fish farming in 2006 in Iran
Culture of sturgeon species is of great economic and ecological importance for those countries such as Iran whose natural stocks have declined. This species has shown a good growth performance in many types of production systems and in tanks with different sizes. Recently, sturgeon species is also offering good prospects for aquaculture in north of Iran, including: Guilan, Mazandaran and Golestan provinces. Several species of sturgeon are now considered attractive candidates for whole-cycle production in Iran. Production analysis may help manager of a sturgeon farm in decision making and in adjusting to changes. Economic assessment provides a basis not only for decision making among farm managers but also for formulating government aquaculture policies. Over the period 2006, based on previous experiments with cultured cam, shrimp and trout farming, total costs, total income, profitability and the contribution of production costs for sturgeon farming were determined by completing questionnaires. Among the various expenditures in the year 2006, labor costs had the greatest share and averaged 25% of the total costs. Feed costs averaged more than 17% of the Costs and fingerling costs averaged 10% of the costs. Results show, on average, total cost per kg production of sturgeon was IR Rials 40,587 (US 7.57), and profitability per kg production of sturgeon meat also averaged IR Rials 27,944 (US$ 3.11). The results suggest that farmers are doing more efficiently and have better conditions in Mazandaran, resulting in higher farm income per kg, followed by Guilan province
Stability analysis of agegraphic dark energy in Brans-Dicke cosmology
Stability analysis of agegraphic dark energy in Brans-Dicke theory is
presented in this paper. We constrain the model parameters with the
observational data and thus the results become broadly consistent with those
expected from experiment. Stability analysis of the model without best fitting
shows that universe may begin from an unstable state passing a saddle point and
finally become stable in future. However, with the best fitted model, There is
no saddle intermediate state. The agegraphic dark energy in the model by itself
exhibits a phantom behavior. However, contribution of cold dark matter on the
effective energy density modifies the state of teh universe from phantom phase
to quintessence one. The statefinder diagnosis also indicates that the universe
leaves an unstable state in the past, passes the LCDM state and finally
approaches the sable state in future.Comment: 15 pages, 12 figure
Study and evaluation of economical and hygienic effects of aflatoxin B1 in cultured Huso huso
In the present study, the impacts of various concentrations of Aflatoxin B1 (AFB1) on Beluga, Huso huso, under controlled conditions were investigated. Belugas (120±10 g) were fed diets containing 0, 25, 50, 75, and 100 ppb AFB1/kg of diet for 3 months. Results showed that various levels of AFB1 do not significantly affect the specific growth ratio (SGR) (p< 0.05) of fish in different treatments. However, weight gain and food conversion ratio (FCR) varied significantly (p< 0.05 between control and treatments with diets contaminated with 75 and 100ppb AFB1/kg after 90 days). The increase in level of AFB1 did not affect the percent of survival rate (SR) and no mortality was observed in treatments (SR=100%). Various levels of AFB1 under experimental conditions of the present study affect some growth factors, such as, weight gain and FCR but have no significant impact on SGR. Histopathological studies showed that different level of AFB1 can cause broad range of changes in liver, kidney, spleen and gills tissues, particularly at concentration of 75 and 100 ppb AFB1/kg of diets after 60 days. No tumor formation observed. With regard to toxin concentration and time of exposure to AFB1 in experimental fish, different degree of skin lesions (simple hemorrhage to progressive wounds) were observed in different parts of body especially in vent, caudal peduncle, fins, and head. "Yellow sores" on head and trunk regions are considerable and led to deterioration of appearance. Prevalence of skin lesion in different treatments was 8 -53.3 %, which after stop feeding with toxic diets, 16-24 % healing observed. Haematological changes included chronic anemia and lymphocyteopenia. Also neutrophilia observed with increasing of skin lesions. Meat accumulation of AFB1 in different treatments is not so considerable and harmful for human consumption, but is significantly different with control fishes (P<0.01)
The effects of water temperature on weight and length growth in Bester
Hybrid Bester sturgeon (female Beluga x male Sterlet) was produced for the first time in Iran using sperm from a male Acipenser ruthenus and eggs of a female Huso huso in Shahid Marjani Sturgeon Porpagation Center (Agh Ghala, Golestan province). Bester fries and those of Beluga as control treatment weighed 490mg and 377mg respectively after about one month and were transported to International Sturgeon Research Institute (Rasht). All fishes were fed by artificial concentrated food (48-50% protein and 1547% fat) after a period of feeding on Artemia and Daphnia. Sorting was carried out according to weight increase for both fishes. Results showed that the weight increase in warmer months (water temperature 18-28°C) was higher than the colder months and ceased at 6-12°C. The trend in weight increase was of the same pattern for both fishes. There were no significant differences between fish length up to 5 months of rearing but afterwards, Bester showed a higher rate of length increase compared to that of the Beluga. The length increase rate for both fishes was sharper during the first year than the second year. Fish length increase was ceased at 6.841.4°C which coincided with the increase in fish weight
Analyze the types and methods suitable nutrition in introducing a variety of fish cages in the southern part of Caspian Sea
Regarding the fish farming in cages, taking into account all nutritional requirements appropriate to the needs of aquaculture is essential in order to minimize damage to the environment and achieve maximum growth. Fish nutritionists should be aware about the analysis of ability to digest and absorb nutrients in the diet to prepare and adjust the diet according to the needs of aquaculture. Food must also have appropriate physical properties for food intake with minimal loss of nutrients in the water. Inadequate resources with low quality or energy consumption within food, reduced the growth performance and increased the excretion of nitrogen in the environment. Food must be designed so that the balance of minerals in food will help maintain osmotic pressure within the body of fish in salty water. Food requirements and efficiency of food conversion ratio (FCR) is variable by changing environmental conditions (dissolved oxygen, temperature, water quality, flow rate, light intensity ,day length). The fish of cages are feeding by floating pellets which have the ability to stand in the water column. The floating pellets allows the fish to have sufficient time and opportunity for finding food. But sinking pellets pass rapidly from the cage and are inaccessible to fish. According to the Caspian sea conditions is better the extruded food equipped with Hygenizer to be used that a portion of it remains on the water surface and part of it moves gently down with an immersion mode in the water column (Softly deposited) for fish consumption. The amount, number and time of feeding are important factors to assess the nutritional activities. In general, fish feed from dry food between 2 to 3 percent of their body weight. Food consumption was also varied due to the quality of the food and fish physiological factors such as age, size, stage of life and stress level. Fish food distribution being fed manually or by means of demand, launcher and automatic feeding. The farm managers should pay attention to the things like water flows in the cage, wind, fish appetite, consolidated flows in the cage during food distribution as well as food storage in dry places with proper ventilation system to prevent the growth of fungi and insects activities to prevent loss of food. Also, adding antioxidants to the 100150 ppm when storing dry foods including the important cases particularly in prevention of fish liver lipoidosis disease is considered
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