Determining the amount of lysine required in the diet of Huso huso juvenile and its effect on growth performance

The amount of lysine required in the diet of juvenile Beluga Huso huso with an average initial weight of 2.45 g was evaluated based on growth response in 12 aerated aquariums in four treatments each with three replications for 40 days. Four diets were prepared based on fish meal with the same protein (39.32%), fat (15.78%) and carbohydrate (21.19%) with different levels of lysine (0, 0.75, 1.5 and 2.25% of dry weight). The diet without lysine was considered as the control diet. Each ration was given in proportion to 4% of body weight, in three equal portions, to groups of three with 10 fish in each replicate. The mean water temperature, dissolved oxygen and pH during the test period were 23.8 ºC, 6.27 mg/L and 7.32, respectively. The results showed a significant difference in the growth performance between the treatments. The maximum weight obtained (31.95 ± 0.84 g) and specific growth rate (7.01 ± 0.09%/day) were observed in the treatment with 2.25% lysine. Apart from the decreased growth in the fish fed the lysine-deficient diet, no signs of growth deficiency were observed in the other fish. Codition factor, food conversion ratio, protein efficiency ratio and survival rate were not significantly different among treatments. Finally, the optimal amount of lysine for this weight group of juvenile Beluga was estimated to be 2.25 g per 100 g of the dry weight of the diet

Antibacterial activities of bioactive compounds extracted from Marine algae Gracilaria salicornia against Aeromonas hydrophila

Herbal medicinal products have attracted significant research interest in recent years. Considering the efficiency of algae products in controlling pathogenic bacteria and also easy access to large resources of algae, this study was conducted to evaluate the effects of methanolic, chloroformic and aqueous extracts of Gracilaria salicornia against Aeromonas hydrophila, a heterotrophic, Gram-negative, rod-shaped bacterium found mainly in warm climate. Algae samples were collected from Qeshm Island coastlines and transferred to the laboratory. Standard methods were used to obtain the algae extract. Antibacterial activities of various extracts were tested against the bacterium using well diffusion assay method. Significant differences were observed in antibacterial activities of different extracts (P<0.05). The diameter of zone of growth inhibition varied in correlation with concentration of the extracts (50, 100, 200 and 300 mg.ml-1). The best inhibition zone was observed at 100, 200 and 300 mg.ml-1 methanolic and 300 mg.ml-1 aqueous extracts

Marine macro-algae as a bio-indicator of heavy metal pollution in the marine environments, Persian Gulf

357-363The northern parts of the Persian Gulf are more affected by pollutants because of their low depth, limited rotation, salinity, and high temperature. The anthropogenic and non-anthropogenic contaminations caused by organic and inorganic pollutants in aquatic ecosystems will eventually lead to increase pollution in water, sediments, and aquatic organisms. It seems that, algae are the most suitable indicator for soluble heavy metals (HMs) in both active and passive states. Samplings were carried out on a monthly basis in four different stations in Bushehr Province, northwest of the Persian Gulf from March 2016 to March 2017. ICP-mass spectrometry was used to determine Pb, Cu, Cd, As, Cr, Zn, Al, Mn, Co, V, Ni, Mg, S, Fe, and Ca concentrations in some macroalgae. In this study Padina gymnospora (brown algae) and Hypnea hamulosa (red algae) had the highest absorption, while the Cladophoropsis membranacea (green algae) showed the least absorption in all the sampling areas

Assessing some heavy metals pollutions in sediments of the northern Persian Gulf (Bushehr province)

Background: Land and water pollution by heavy metals is a universal issue. Although the pollution affects all countries, but its range and severity vary hugely. The pollution of the marine environment by heavy metals is a worldwide problem. Marine sediments can be sensitive indicators for monitoring contaminants in aquatic environments. Methods: The concentration of 10 elements (As, Cd, Cr, Cu, Al, Fe, Ni, Pb, Sb, and Zn) was determined in the sediments of four shoreline stations including Imam Hassan port, Ameri port, Bushehr port, and Nayband Bay at the west Persian Gulf from March to December 2017. The elements were measured by inductively coupled plasma mass spectrometry (ICP-MS). Data were analyzed using SPSS version 16. Results: The contamination of the sediments was assessed based on the geoaccumulation index (Igeo) and enrichment factor (EF). Spearman correlation matrix was calculated between all the trace metals and major elements as well as corresponding sampling regions. Statistically significant inter-elemental correlations (e.g., Cr-Fe, Cr-Al, Cr-Ni, Cr-Zn, and Cr-Cu) were found between some metals. High EF levels for Fe, Al, and Pb suggest that metals in the sediments of the northern Persian Gulf could have originated from anthropogenic sources. Conclusion: The contamination pattern of sediments is affected by factors such as sedimentation patterns, physical and chemical properties of the sediments. For example, sediments with fine-grained and high surface area-to-volume ratio can act as good absorbents for many pollutants. Keywords: Heavy metals, Geologic sediment, Persian Gulf, Busheh

Morphological comparison of western and eastern populations of Caspian kutum, Rutilus kutum (Kamensky, 1901) (Cyprinidae) in the southern Caspian Sea

This study aimed to investigate morphological differences of western and eastern populations of Caspian kutum Rutilus kutum in the southern Caspian Sea and its providing length-weight relationships and condition factor (CF). A 13-landmark based morphometric truss network system was used to investigate the hypothesis of population fragmentation of western and eastern populations of this species. The studied populations were differentmorphologically based on pre anal, body height, distance from pectoral fin to ventral fin, distance from pectoral fin to anal fin, caudal peduncle length, head length, pre orbital, pre ventral, and dorsal length. The results also revealed a negative allometry (b<3) of length-weight relationships for both sexes. Maximum condition factors was found in March. The results suggest distinct stocks in the western and eastern of Caspian Sea for fisheries management

Evaluation of antimicrobial properties of diethyl ether and methanol extracts of Scenedesmus dimorphus against bacterial Micrococcus lutesus and Aeromonas hydrophila

Antimicrobial properties of diethyl ether and methanol extracts of algae Scenedesmus dimorphus against Gram positive bacterium Micrococcus lutesus and Gram negative becterium, Aeromonas hydrophila were evaluated. The algae was pure cultured and once the required volume and number of cells achieved coli using agar well diffusion method diethylether and hexane extracts of the algae cells were extracted. Antibacterial properties of the extracts were evaluated using well diffusion method. The results showed inhibitory activities of methanol and ether extracts of Scenedesmus dimorphus against M. luteus and A. hydrophila with 11-13 mm and 13-21 mm diameters of inhibition zone, respectively. In case of diethyl ether extracts also the inhibitory activity observed with diamaters of inhibition zone in the range of 9-23.7 mm and 21.6-6.3 mm respectively against M. luteus and A. hydrophila. Gas chromatography mass spectrophotometry was used to identify different substances within diethyl ether and methanol extracts with hydrocarbon and ester with highest perentage among other substances. The results confirmed antimicrobial activities of extracts from S. dimorphus against bacteria used in this study

Distribution of benthic centric diatom Pleurosira laevis (Compère, 1982) in different substrate type and physical and chemical variables

Abstract: Aim This contribution reports the first regional occurrence of Pleurosira laevis in the Masuleh River, Iran and additionally describes the pattern of occurrence along the Masuleh River and among four substrate types. The aim of this study was to assess the effects of substrate type and physical and chemical variables on distribution of centric diatom P. laevis. Methods At each station, triplicate samples were collected from 4 substrata. Epilithic (assemblages on rock), epidendric (assemblages on wood), epipsammic (assemblages on sand), and epipelic (assemblages on mud) diatom and water quality sampling was done four times at 5 stations. Physical and chemical variables including total nitrate, total phosphate, silicate, Fe2+, EC, and pH were also determined. Samples preserved in 2% for formalin solution and transferred to the laboratory, boiled with acid (HNO3: H2SO4; 2:1), centrifuged, identified, and counted. Cluster analysis was performed to indicate the main differences and similarities in diatom abundance amongst substrates sampled and amongst sampling stations. Results The highest (12.54 ± 1.54) and lowest (0.74 ± 0.10) abundance was obtained from wooden and muddy substrates at stations S5 and S4, respectively. The highest abundance was observed in the wooden substrate among all of sampling stations where showed significant differences (P 0.05). Conclusion We conclude that wood substrata can be substituted for one another during field surveys. Results from this study demonstrate that the type and roughness of the substrate both influence the attachment of P. laevis and its subsequent growth conditions

Seasonal succession of phytoplanktons in relation to physcio-chemical factors in Yamchi dam reservoir, Ardabil province

The seasonal succession of phytoplankton communities in Yamchi dam constructed on Balikhli River, Ardabil province was studied from October 2014 to November 2015. Monthly sampling was carried out in three stations at the depths of 0, 5 and 10 m in station number 1 and the depths of 0 and 5 m in stations number 2 and three. In this survey, 41 species belonging to 35 genera, 8 classes and 6 phylla of algae were studied. The phyla Chlorophyta and Bcillariophyta contained the highest number of species (14 and 13 species, respectively). The highest density of phytoplanktons was observed in station 1 at the depth of 10 m in September (2.4 × 104 cell.ml -1) and the lowest density was identified at station 1 at the depth of 5 m in May (2 × 103 cell.ml -1). In total, the highest densities belonged to Chlorophyta with the maximum densities in spring and summer (the highest was 1.2 × 103 cell.ml -1). In studying the seasonal succession, diatoms were dominant in autumn and early spring assemblages. In summer, green algae and dinoflagellates and in late summer cyanobacteriae were the  most dominant groups. The seasonal succession observed in Yamchi dam reservoir is characteristic of eutrophic alkaline lakes. Results of ordination analysis (PCA) revealed that the temperature, silicate, sulphate and BOD, and COD were the main factors affecting phytoplankton assemblages in this lake