Journal of Aquaculture Development
Year:2016 | Volume:10 | Issue:2|Papers Count:12

Nitrate and phosphate are abundance in urban wastewater. To evaluate the efficiency of nitrate and phosphate removal from wastewater by Chlorella vulgaris and its use as a medium for Chlorella vulgaris, samples collected from the effluent of central wastewater treatment in the Gorgan. This experiment included 3 treatments and 6 replications that effluent with 100%, 50% and 0% were diluted. The results showed that Chlorella vulgaris could well be grown in wastewater and 100% Phosphate (group C0) and %99.37 nitrate (group C50) was removed. The highest biomass production (0.25 grams per liter), the amount of chlorophyll a (3.34 mg per liter), the number of cells (1.4 × 106 cells per ml) was observed in the group C0. Considering the results of this study, it seems that the algae can be used to remove phosphates and nitrate and algal biomass in municipal wastewater filtration systems before entering the environment. The municipal wastewater can be used as culture medium for mass production of algae.

This survey was conducted on 775 specimens of Acipenser gueldnstaedtii. A number of 27 specimens were identified from viewpoint of external lesions and samples were studied for bacterial agent's isolations. It was determined the most content of lesions was related to scutes with abundance of 81.48% After that, skin (37.04%) and fin (7.4%), respectively. The most lesions were in ventral skin and scute. In bacteriological experiments, Genera of Aeromonas, Acinetobacter, Pseudomona, Enterobacterand Proteus were detected. Acinetobacter (42.11%) had the most abundant and proteus and Enterobacter (each one 5.6%) the least abundant from total bacteria. Existence of lesion in ventral surface can be because of benthivorous feed behavior. With regards to a relation between isolated bacteria in this study and known species in water, health management is mandatory to preserve water quality, prevention of increase of organic load and providing of suitable density and reduction of handling in order to control of bacterial agents.

Great sturgeon, Huso huso, is one of commercially important sturgeon species in the Caspian Sea, but little studies have been reported about oxygen requirements of this species. The effect of water dissolved oxygen on spleen of great sturgeon was examined histopathologically in two weight classes (initial weight 280.9±49.2g and 1217.9±138.1g). Oxygen treatments (8 weeks) included hypoxia (2-3 mg/l), normoxia (5-6 mg/l) and hyperoxia (9-10 mg/l). Tissues were collected and fixed by immersion in Bouin’s fluid, then processed by routine methods, sectioned by microtome in 7 mm thickness, stained with hematoxilin & eosin (H & E) and observed by light microscopy. In hypoxia treatment both weight classes showed congestion. In lower weight class cell swelling, piknotic nuclei and loss of cytoplasm were observed. In hyperoxia in both weight classes cell swelling and vacuolation of cytoplasm were found. In both weight classes significant differences were found in the weight of fish and the spleen (P<0.05). Due to a significant reduction in spleen weight to body weight and observation of congestion and rich red blood cell areas in the hypoxia treatment, it can be included that great sturgeon spleen released red blood cells in the hypoxia condition and thereby helps fish to tolerate the lack of oxygen.

The effects of salinity on growth performance spats Pinctada radiata collected from the natural environment by collect hypnotics constructed around the Henduraby Island in the Persian Gulf. On 5 different salinity treatments with different salinity of 25, 30, 35, 40 and 45 with microalgae Isochrysis aff galbana culture medium with F / 2, Studied. Spats in a Total of adaptation were sampled and measurements of the length Ventral (DVM) and heel length (HL), thickness (Th) mm and weight (W) 20 liter container containing 15 g per liter of seawater filter data recording.All statistical and analysis were Performed using the SPSS 16 and Excel software package.5 salinity treatments showed that the maximum length of 18.14±0.93, the heels 19.26 ± 0.65, thickness 5.52 ± 0.30 and weight of 0.96 ±0.10 salinity of 35. Nevertheless, no significant differences were observed in the treatments in terms of total length, heel length and thickness (P>0.05). But there was a significant difference in weight between treatments (P<0.05).The results showed that the best salinity for Pinctada radiate growth was 35 ppt.

This study was carried out with the aim of measuring steroid hormones levels residue including 17b- estradiol (E2), 17a- hydroxy progesterone (17a-OHP), testosterone (T) and gonadotropine hormones (GTH I and GTH II) in farmed Persian (Acipenser persicus) and Siberian (Acipenser baerii) sturgeon in International Sturgeon Research Institute (Areo). 10 gram of eggs weighed and centrifuged at 3000 rpm per 10 minutes after homogenizing for extract. Results showed that maximum level of testosterone was 13.2±0.97 ng/ml in Acipenser persicus and showed significant difference compared to Acipenser baerii. Maximum level of progesterone and E2 were 2.9±0.1 and 1.4±0.6 ng/ml in Acipenser persicusand showed significant difference compared to Acipenser baerii (P<0.05). Based on results, sex steroid hormone residue observed in sturgeon eggs so that steroid hormones levels residue was more than gonadotropin I and II level and was different depended on hormone type and species.

This experiment was conducted to the survey of performance and change of the carcass color with firethorn fruit (Pyracantha Coccinea) in rainbow trout (Oncorhynchus mykiss) feeding with four treatments, three replicates and 240 pieces of fish in completely randomized block design. Treatments consisted of basal diet (control), basal diet + five percent of firethorn fruit powder, basal diet + ten percent of firethorn fruit powder, and basal diet + fifteen percent of firethorn fruit powder. Functional traits (feed intake average, weight gain average and feed conversion ratio average) were examined weekly and in entire period. Carcass components and carcass characteristics, total length, fork length and colorimetric of meat and fish skin at the end of the period was examined. weight gain average and feed conversion ratio averaged in entire period, the relative weight of the carcass, offal and liver to live weight, total length and fork length of fish, the indicator of meat brightness (L*), the indicator of meat red / green (a*), the indicator of meat yellow / blue (b*), the indicator of skin brightness (L*), the indicator of skin red / green (a*), the indicator of skin yellow / blue (b*) and percent of mortality were not significant (P>0.05). The most of feed intake Average in entire period was in control treatment that it had statistically significant different with other treatments (P<0.05).

The current study deals with the optimal design of rectangular rearing ponds of cold-fish water like trout based on hydraulic efficiency for investigating the hydrodynamic flow mixing. The hydraulic efficiency criterion is defined by the residence time distribution curve of the pond. In this study, ten artificial rectangular rearing ponds with 120 m2 area and different aspect ratios (form 0.13 to 20.83) have been considered. In order to calculating the hydraulic efficiency, depth averaged hydrodynamic numerical model, Smagorinsky turbulence model and convective-diffusive equation using finite volume technique on unstructured triangular mesh have been applied. According to the findings of the study, choosing a minimum aspect ratio of 2 (hydraulic efficiency more than 50%) is essential for having an acceptable level of water mixing. However, it is recommended to choose a minimum aspect ratio of 7.5 (hydraulic efficiency more than 75%) for high level of water mixing. In cases of physical limitations for constructing rectangular pond with the minimum aspect ratio of 7.5, the minimum aspect ratio can be considered as 5 by improving the geometry of the inlet part and reducing dead zones.

Vitamin groups composed of different natural compounds that can be used as an essential supplement in food dietary for fish and shrimp health, growth and reproduction. In this study fingerling common carp (Cyprinus carpio) feed on with food meals SFC containing different levels of Vitamin B2 (7, 15 and 20 mg/kg). Also, a control group was fed with diets containing SFC without vitamin supplements. According to the biometrical parameters results and growth indices in dietary food treatments containing different levels of riboflavin vitamin shows that in biometric characteristics and percentage of weight increasing in body weight (BWI %) in different treatments have a significantly difference (P£0.05). Maximum growth rate was found in treatment number 3 (21.52±0.55g) and minimum growth rate was observed in control treatment (18.03±0.72). According to blood hematology factors and biochemical parameters results there was a statistically significant different in MCH value in different groups in different dietary treatments shows that these treatments according to all accessed and evaluated parameters except (P£0.05). Based on the obtained results, the optimal proportion of Vitamin B2 in fish meal for fingerling common carp is 20mg/kg.

This study aimed to investigate erosion of various fins in different weight groups of rainbow trout Oncorhynchus mykiss. Weight, standard length (SL), length of pectoral, ventral, dorsal, anal and caudal fins in four weight groups of fish including 20, 50, 100 and 400 g were measured and relative fin length to SL were determined for all fins. The results showed significant differences for all weight groups in most relative indexes exclude relative right and left pectoral fins to SL. The highest significant relationship of fins length with weight was observed in fish weight of 50 and 100 g, while there was no relationship in those measured parameters in weight group of 400 g. The results of this study demonstrated that higher sensitivity of fin erosion in fish weight of 50 g, but the highest fin erosion was observed in higher weight groups which revealed the positive relationship of fin erosion with fish weight. So that, this index could be a useful indicator for evaluation of fish welfare and quality in rearing condition.

The effect of probiotics bacteria Bacillus subtilis isolated from the intestine of common carp at two levels of concentration of 1×103, 1×106 CFU / ml (cells per ml) mixed with food by young fish carp (weighted average 56.54±1 g) were fed. Project was carried out in a completely randomized design with three replications for 8 weeks. Feed rate were done based on 2% of body weight and 2 times a day. Determination the length and weight of fish every 14 days once was carried out. At the end of the experiment, a group of fish that were given probiotic, growth and feed efficiency, such as weight gain, specific growth rate, protein efficiency were found a higher level and better feed conversion efficiency as compared to their diet without fish probiotics (p<0.05). The highest above indices was obtained at 1×106 CFU/ml per kg diet. Only viscerosomatic index did not display any significant difference among the treatments 1×103 CFU/ml compared to controls (P<0.05). The highest survival rate of young fish in the treatment 1×103 CFU/ml compared to controls was observed that this difference was significant (p<0.05). The results showed that the probiotic Bacillus subtilis to feed young fish common carp at a rate of 1×106 CFU / ml per kg diet has positive effects on the growth parameters and nutrition indices.

Silver pomfret, Pampus argenteus, is a commercially high-value species and a good candidate for aquaculture development which is now under environmental pressure due to overfishing and other ecological changes. In the present study, population structure of silver pomfret from Oman Sea and Persian Gulf were investigated using 7 microsatellite loci and restriction fragment length polymorphisms (RFLP) of the mitochondrial ND-2 gene region. For this purpose 100 samples were collected from 4 locations (kuwaiti waters, khozestan, Bushehr and Chabahar). By using 16 restriction enzymes, the estimates of mtDNA haplotype and nucleotide diversity were (h=0.0875±0.00143, p=0.001238±0.0000004). The result for testing of homogeneity in haplotype frequencies by montecarlo test was (c2=68.8, P>0.05) which showed that a monophylitic population lives in Oman Sea and Persian Gulf. However, the average of observed and expected heterozygosity was 0.53 and 0.67 respectively. After appling the Hardy-Weinberg Equilibrium (HWE)*tests, most of loci were found to deviate significantly from HWE in some populations in which deficiency of heterozygosity was apparent. Pairwse Fst valus showed significant difference between all studied populations (P<0.01). Results indicated that microsatellite markers are more powerful than PCR-RFLP in determination of genetic diversity and population structure in this species.

Due to the un-sufficient information about susceptibility of Caspian roach (Rutilus caspicus) to environmental ammonia, in the present study mortality rate, clinical and histological signs of this fish in acute exposure situation to un-unionized ammonia have been studied. To this 180 fingerling with average weight of 6.5±1 were divided in 18 aquaria (10 fish per aquarium) and acclimatized for 2 weeks. After adaptation 5 treatment groups and one control group with three replicates for each one were considered. Fish of treatment groups were exposed to different concentration including 2.5, 5, 10, 15 and 20 mg/l of total ammonia which were equal to 0.34, 0.66, 1.32, 1.98 and 2.66 mg/l of ununionized ammonia. No ammonia exposure was happened in control group. According to the results 96 h median lethal concentration (LC50) of unionized ammonia in fingerlings Caspian roach calculated as 1.62 mg/l. Congestion in the kidneys and petechial haemorrhage in basal part of eyes were the typical clinical signs. Histological studies were characterized by congestion in kidney, oedema and epithelial lifting in secondary lamella in gill tissues and diffused degeneration in kidney tubules. No mortality and abnormal clinical and histological change were observed in fish of control groups. According to the present study maximum sub lethal concentration of unionized ammonia has calculated as 0.162 mg/l for Caspian roach fingerling.