جستجوی مقالات مرتبط با کلیدواژه "red algae" در نشریات گروه "شیلات"

Seaweeds are ecologically important and have many applications economically. Inorganic carbon, nitrogen and phosphorus are the main elements needed for photosynthesis and growth of seaweed. Different concentrations of urea and phosphate as fertilizers with the ratio of 1:10 urea to phosphate (P: N = treatment one = 0.2: 2, treatment two = 0.4: 4, treatment three = 6: 0.6 and treatment four = 0.8: 8 mg/l) made treatments and compared to control (without nutrient, as fifth treatment), and their effects on growth of red macro algae, Hypnea musciformis were evaluated in triplicates. Algae sampled from the tidal area of the Oman Sea offshore at the time of the maximum tide and cultured to get optimum biomass for running the experiment. The algae were inoculated into experimental units and cultured for 45 days. A transparent plastic tank containing 40 liters of filtered seawater considered as the experimental unit. At the end of the experiment, the highest and lowest daily growth rate recorded in treatments 2 and control at the rates of 3.3±0.04 and 2.19 ± 0.02 g/day, respectively (p <0.05). These rates in third and fourth treatments were 2.87 ± 0.01 and 2.8 ± 0.01 g/day, respectively, and had a significant increase on growth of algae in comparison to the control (p <0.05). The results indicated that the concentrations of urea and phosphate rates and their ratios in the medium affecting on growth of this alga under outdoor conditions, and at the concentration of 0.4: 4 mg/l and ratio of 1/10 of phosphate to urea algae had the highest growth.

The aim of this study was to investigate the effects of Caspian red algae (Laurencia caspica) as natural originated immunostimulant in common carp fry. Algae were collected from Caspian sea and supplemented to diet in different levels of 0, 1, 2, 3 and 4 percent for 60 days. Results of growth parameters indicated an increase in final weight, and specific growth rate in fish fed 2, 3 and 4% algae powder (AP) comparing to control (P<0.05). The numbers of white blood cells and red blood cells were higher in diet containing 3 and 4% AP than those of control and 1% AP. The highest levels of hemoglobin and hematocrit were found in fish fed diet containing 3 and 4% AP. Moreover, fish fed 2, 3 and 4% AP demonstrated lower cholesterol and higher total protein among groups. Hepatic enzymes such as aspartate transaminase, alanine transaminase and alkaline phosphatase displayed a decreasing trend by addition of AP. Alternative complement pathway improved by increasing AP level as the highest value observed in 3 and 4% AP. Also, diet containing 3% AP led to significantly increase lysozyme when compared to other diets. Fish bacterial challenging with A. hydrophila showed increasing survival (more than 40%) in fish received 2, 3 and 4% AP. Overall, administration of 3% L. caspica powder to diet of common carp fry is advised in order to improve growth performance, hematological and immune indices and resistance against A. hydrophila.
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this experiment was carried out to investigate the effects of supplementing two macroalgae Sargassum cristaefolium and Gracilaria pygmaea extracts in feed on some growth indices, hematology and blood constituents of juvenile rainbow trout (Onchorhynchus mykiss). Rainbow trout were randomly divided into four groups: a control group was fed with basal diet, and three treated groups fed with basal diet supplemented with 500 (mg/kg) S.cristaefolium (SA), 500 (mg/kg) G.pygmaea (GL) and 250 (mg/kg) S.cristaefolium + 250 (mg/kg) G.pygmaea (SA+GL) for 8 weeks. The fish were fed 4 times by hand to apparent visual satiation and water was changed every day. Results showed that growth factor such as final fish weight, specific growth rate (SGR), weight gain (WG) and condition factor (CF) were not significantly different among treated groups (P > 0.05). Hepatosomatic index (HSI) was significantly higher in fish fed control or SA diets (P < 0.05). Among the blood parameters, hemoglobin levels in fish fed diet containing gracilaria was significantly higher than the control group (P < 0.05). Among the biochemical composition of blood, group fed the control diet had higher triglycerides level compared to the groups fed diets containing sargassum or a mix of sargassum and gracilaria (P < 0.05). These results indicated that dietary supplementation of sargassum and gracilaria extracts in rainbow trout feed had not significant impacts on growth performance and blood parameters of this fish.

The speciemns of red algae “Gracilaria corticata” were collected from the rocky intertidal shores in Bostaneh Port in the Persian Gulf and Lipar in Oman Sea in May, June and August 2013. Anatomical, morphological structures, thallus of vegetative and reproductive samples were studied. Carpogonial and tetrasporangium stages were determined based on histological and morphological methods. The female thallus, the Cystocarp with hemispherical structure through out thallus were observed. The Spermatangial conceptacle was located deeper as the oval shape in male thallus. The tetrasporophytic stage of diploid samples was determined by the presence of tetrasporangium oval shape.

The effects of urea and TMRL media have been surveyed on the laboratory cultivation of Gracilaria corticata during 41 days in spring 2002, using sea water as control. We used nine 25 litre aquariums each containing 100 grams of the red algae. During the experiments, pH, salinity and water temperature were measured daily, airing was conducted continually, and 80% of the water in each aquarium was changed every other day adding the required culture media after the change.
Water pH ranged between 8.1±0.02 to 9.05±0.4, salinity was recorded between 37-41 ppm, and temperature range was 24.5±0.49 to 35.3±0.86 degrees centigrade. We measured daily growth rate, net production and final weight of the algae for urea and TMRL culture media which the TMRL culture media provided the highest growth rate and we spotted a change in colour of the algae treated with this medium ranging from dark brown to light brown and colourless phase.