Journal of Aquaculture Development
Year:2016 | Volume:10 | Issue:1|Papers Count:12

This study was conducted to determine the effects of the long period of protein restriction on growth performance and body composition of rainbow trout (Oncorhynchus mykiss) in during of eight weeks. Experimental diets were formulated to contain protein restriction 30% and control diet of 45% protein levels. The experiment was a completely randomized design consisted of three treatments in triplicates and fish with initial weight of 12.73±72 g were randomly assigned and distributed at a density 10 fish per tank (80 L). The control treatment fed with 45% protein during the period, treatment 2 with 30% protein with 3 weeks restriction and treatment 3 with 30% protein with 4 weeks restriction were fed at during the eight weeks. At the end of experiment, treatment 2 obtained highest body weight and highest specific grows rate (SGR) among of the protein restriction treatments. Statistical analysis indicated that there was not significantly differences (P>0.05) between amounts of FCR, PER, FI and SV protein restriction treatments and control treatment. Thus at the end of experiment compensatory grow obtained in treatment 2.

Increase of the need of fish culture and reproduction workshops for the use of anaesthetics, requires the study of new anaesthetics efficiency in order to introduce and substitute a substance which has the least disadvantage or stress for the fish. This study considers the influence of three anaesthetics including: 2-phenoxy ethanol, clove oil and PI222 on the stress indicator (glucose and cortisol hormones) on silver carp fish (Hypophthalmichthys molitrix). At first, 120 fish were anesthetized by best dosage of each anaesthetic based on causing induces anesthesia in fish in less than 5 minutes and recovery in less than 3 minutes (indicating 300 ppm as the best dosage for 2-phenoxy ethanol, and 50 ppm as the best dosage for clove oil and PI222). And their blood samples were taken on 0, 6 and 24 hours post recovery. The level of their glucose and cortisol hormones was evaluated hematologically to identify the stress amount they had received during unconsciousness. Results indicated that 2-phenoxy ethanol increased glucose meaningfully (p<0.05) so it was identified as a stressful anaesthetic; and clove oil and PI222 were identified as proper anaesthetics because they did not cause meaningful changes in these hormones.

In this research we studied the effect of pink Leucantin on white Oscar (Astronotusocellatus) skin omit.72 individual fish by the weight of 9.37±0.025 g and the length of 8.24±0.012 cm in two treatments and a control group which contained three replicates feed by the food contained 200 mg/kg of food pink leucantin. Each tank or replicate held 12 fish. After 27 day 6 randomly selected fish photographed digitally in a constant condition of light. Then color changes evaluated by Photoshop software (CS6). Final colorimetric survey showed that fishes feed diet contained pink Leucantin were significantly different from controls (P=0.00). So the red color content in pictures of leucantin treated fishes compared the control increased significantly.

This study was carried out to produce and evaluate biofloc for application in zero water exchange tanks of Litopenaeus vannamei culture. Three fiber glass containers with 200 liters volume of water were filled with filtered seawater (salinity 32ppt) for four weeks and for production of biofloc, organic carbon material (bran, wheat flour, Molasses), shrimp food, sieved clay and fertilizer urea were calculated and added to each of the tanks. By adding mentioned compounds, development of the bacteria were promoted and led to the formation of microbial Floc (bioflocs). Dissolved oxygen and pH parameters decreased during the study by adding of organic carbon materials. Density of heterotrophic bacteria increased during the study and the minimum (1.533±0.057´103 CFU.lit-1) and maximum heterotrophic bacteria (3.36±0.15´107 CFU.lit-1) were observed at the beginning and at the end of the experiment, respectively. The deposited suspended solids (Bioflocs volume) increased with a gentle slope and reached to the amount of0.46 and 12.33 mg.lit-1 at the beginning and at the end of the experiment, respectively. Organisms related to floc constituted the ratio of 73.47, 20.53, 3.33 and 2.67 percent for hairy and flagellate protozoans, microalgae, nematodes and other suspended organisms in floc, respectively. The results reveal that with zero- water exchange system and by adding organic compounds, the density of heterotrophic bacteria and the development of floc could be increased and the produced floc could be used as stock bacterial in zero- water exchange system.

An experiment was conducted to evaluate the effect of phosphorus on biomass production, chlorophyll a, total carotenoid, total protein and carbohydrate content of Cyanobactrium, Nostoc calcicolaat during growth. Three levels of phosphorus, as 100, 200 and 400 mg/l were analyzed triplicate groups for 12 days. The results revealed that content of phosphorus have significantly (P<0.05) effect on biomass production, chlorophyll a and total carotenoid at during growth. At investigation of protein and carbohydrate content, result shown that protein content increased at day 6, 8 and 10 of culture. Different between 400 mg P/L with other treatment was significant (P<0.05), but was no significantly different between 100 with 200 mg P/L. at 100 mg P/L, maximum of protein content was 372.4±20.1 mg g DM-1 at 6 day of culture. For 200 mg P/L, maximum of protein content was 386.33±34.05 mg g DM-1 at 8 day of culture. At 6 day of culture for 400 mg P/L treatment, maximum of protein content was 434.47±39 mg g DM-1. Protein content for 400 mg P/L treatment was higher other treatment until 10 day of culture. In addition to, we observed P content had no significantly effect on carbohydrate content at different days of culture. According these results, N.calcicolais a species that increasing P can increase biomass, protein and carotenoid such as valuable pigment.

Rutilus frisiialthough is an important commercial fish species in the Caspian Sea, however few studies have been conducted on its immune system in the nature and during its migration from brackish water of the Caspian Sea to river freshwater and vice versa. In this study, 23 fish (12 female and 11 male) were caught in the Caspian Sea (salinity=7.52 ppt and pH=8.9) and 23 fish (12 female and 11 male) from the Khoshkrood River (salinity=0.11 ppt. and pH=8.7) from October 2011 through September 2012. Variations in non-specific immune responses of female and maleR. frisii under the influence of migration between brackish and freshwater and its subsequent effects on the activities of blood serum lysozyme and skin mucus lysozyme were examined. Lysozyme activity assay was performed using Micrococcus lysodiecticus suspension based on the amount of light absorbed by means of ELISA reader. There was no significant difference in lysozyme activities of blood serum as a non-specific immune response between males and females, however a significant reduction in blood serum lysozyme activity was observed in correlation with decrease in salinity. The highest blood serum lysozyme activity ((U/mL/min)) was observed in the sea (39.09±7.03) and the lowest in the river (7.75±1.36). On the other hand lysozyme activity in skin mucus of females increased during migration to the river (145.45±7.02) in comparison to those caught in the Sea (101.55±16.53, p<0.05). Skin mucus sampling was not possible in males due to widespread presence of breeding tubercles on body surface and deficiency of mucus excretion. The study revealed an effective association between lysozyme activities with salinity. There was no significant correlation between lysozyme activity and fish sex. Lysozyme activity was much higher in the skin mucus as compared to blood serum lysozyme.

This study was carried out to examine allometric growth and morphometric changes in Corydoras aeneus, an ornamentally-important fish species from hatching through 51 days later.140 samples were taken and their morphologic and ontogenic changes in the first stages of life were studied daily. The morphometric data was achieved from ImageJ software and allometric growth pattern was measured as power function of total length by using unchanged data in Y=aXb formula. The results showed that the mouth and vent were opened in the day 3 and the yolk sac was absorbed in the day 7 after hatching. The growth patterns of mouth and tail were first positive allometric and then changed to isometric. The length of trunk was first negative allometric and then changed to isometric. According to these findings, the growth of this species was divided to four stages including 1) Eleuthero -embryo, 2) Propterygio-larval, 3) Pterygio-larval and Juvenile.

In comprehensive hydrobiological and hydrological investigation in Yamchi Dam coastal, investigating the status of plankton community as a basic study in aquaculture have been conducted. This study carried out in 4 station during winter 2010 to autumn 2011. The plankton sampling method was designed to measure, Phytoplankton were collected for a liter of water directly, for Zooplankton samples 30 liter of water were filtered by 30 micron zooplankton net. Samples were preserved with Formaldehyde at % 4 concentration for analyses in the laboratory. In the present phytoplankton study 4 phyla and 33 genera were identified. The maximum density of Phytoplankton belongs to Phylum Bacillariophyta with generaCyclotella, Synedra, Achnanthes and Nitzschia. This Phylum observed during the year, and had %92.2 total abundance in the year. Chloropyta were the second major phylum, with generaCoelastrums, pediastrum and Oocystis had %7.4 total abundance, Cyanophyta, and Euglenophyta respectively %0.3 and %0.1 next level. Zooplankton study revealed 6 phyla and 29 genera, maximum density of zooplankton belongs to the subkingdam Protozoa with phylum Ciliophora (%66) and Rhizopoda (%6) with generaArcella and Difflugia (totality %72), Arthropoda were the second major phylum, In class Copepoda with generaCyclops and their Nauplious, and order Cladocera withBosmina had totality %14 abundance in the year. Phylum Rotatoria with genera Cephalodella, Rotariaand Coulrella. This phylum was observed during the year and had %11 zooplankton total abundance. The results of plankton survey showed that the river planktonic population and diversity is suitable for aquaculture extension.

The genetic diversity of golden mullet species (Liza aurata) in the southern coasts of the Caspian Sea by D-Loop gene sequencing from the Gilan (Anzali) and Mazandaran (Sari) provinces coasts was investigated. Total DNA from the samples was extracted by ammonium acetate method and the quality and quantity of the extracted DNA were assessed by spectrophotometery and electrophoresis. Polymerase Chain Reaction (PCR) was conducted on the target DNA and then DNA sequencing was carried out. D- loop region in mitochondrial DNA (mtDNA) of golden mullet contained 900 base pairs (bp). Phylogenetic relationships by Tahjima’s test, using MEGA software version 5.05 among golden mullet was estimated. The results obtained from this study revealed that there were high genetic differences among sample locations. The genetic distance recorded between sample locations was calculated at 0.435. The high levels of FsT were observed between sample locations which indicates that genetic differences exist among present populations. Based on the results obtained from the south Caspian Sea, probably two different populations ofLiza aurata are living in the sample locations of Gilan and Mazandaran Provinces.

Motivation is one of the most powerful forces in the teaching-learning process, so that richest and best training and educational programs will fail in the absence of motivation. Present study was conducted to examine the effect of educational and social motivators on motivation for choosing aquaculture major in M.sc students’ in Tehran branches (Science and Research and North, in Tehran) of Islamic Azad University during 2012-2013. Statistical population were included all 56 M.Sc. students of Aquaculture engineering of the mentioned universities. Data were collected by a two-part questionnaire including personal information and motivational factors in the viewpoint of educational and social aspects influencing on choose of aquaculture major. Validity and reliability of the questionnaire were determined based on the content validity and Test-etest methods, respectively (r=0.9). Results showed that possibility of continuing education (3.04±0.84) and importance of the University place (2.88±0.93) had the most effect on the students’ motivation in the educational aspect for M.sc students in aquaculture major. In addition, having a career in relation to aquaculture major (1.96±0.43) and better social status (1.52±0.59) in the value aspect, also employment in this field (2.84±0.85) and the importance of the field than other major in agriculture and natural resources (2.57±1.11) in the job aspect were the most important factors in motivating students to study this major in social aspect. In general, results of present study suggest that the educational and social aspects affect to choose aquaculture major, so that most of the scores are associated to factors related to inner motivation due to achieving to values and career desires and interest to being successful is the main factor lead to students’ activity.

The purpose of this study is identifying effective factors on production and evaluating the production function and cost function, calculating related elasticities, efficiency, total factor productivity and net present value of units. The data used in this study were obtained by random sampling and answering 45 questionnaire by warm water aquaculture units in Rasht. Also according to the Allen partial elasticities all inputs are substitutes for each other. The average total factor productivity was 81 percent and the average of technical efficiencies according to CRS method was 84 percent and according to VRS was 92 percent. Also, more than 50 percent of units had more than 90 percent efficiency that shows good situation of warm water aquaculture units in this district.

This study was carried out about 15 months to determine suitable locations for the development of aquaculture across the Gamasiab river of Hamedan province in 2006 - 2007. Physicochemical parameters and macro benthic invertebrates fauna15 and 13 stations respectively every 45 days and seasonally fish identify in 8 stations were performed according standard methods. The average water temperature was 12.8±3.7cod, minimum and maximum dissolved oxygen were 2.6 and 12.5 mg/lit respectively during the study. The pH range was between 7.5-8.8, the minimum and maximum Ec was 250 and 750 mmos/cm in Mehr and Tir. The transparency range was recorded about 1-103 F.T.U. The under factors such as amount of suspended materials: 0.01-0.1 mg/l, amount of BOD5: 0.05-6.2 mg/l and COD: 30 (minimum) and 70.57 (maximum) were recorded. The total solids material (T.S.S) were less than 1 mg/lit. Totally 37 groups of bentic organisms were identified which 11 groups of them were appertained to pollution-sensitive orders containing Ephemeroptera, Trichoptera and Plecoptera.During fish population studied 21 species belonging 5 family were identified. Based on obtained results of biological, ecological, economic and social parameters, 10 sites in 7 areas were suitable identified for fish rearing and 12 aquaculture programs (10 plan for fish rearing and 2 plan for increasing fish production of (Onchorhynchus mikiss).The minimum and maximum production capacity in mentioned places was estimated about 1675 and 3850 tons respectively.