نشریه علوم آبزی پروری ایران
سال پنجم شماره 1 (بهار و تابستان 1396)

Induction of triploidy is one of the biotechnological methods in aquaculture used for genetic manipulation. The aim of this study was to evaluate the effect of triploidy on growth factors and body deformities of koi fish (Cyprinus carpio). In this experiment, induction of triploidy was performed by heat shock. For thermal shock three shock variables (38, 40 and 42°C), initiation time of shock (1, 2, 4, 6 and 8 min after fertilization) and shock duration (1, 2 and 3 min) were examined. The method of red cell nucleus measurement was used to identify the triploid fish. In order to evaluate the effect of triploid on growth factors, the initial and final weight and length of fish were measured. Growth factors, including weight gain, specific growth rate, condition factor and feed conversion ratio were then evaluated. Also, at the end of the experiment, the number of fish with body deformities was studied. The results showed no significant difference in FCR and SGR between diploid and triploid fishes. In addition, there were no significant difference in WG and CF between two groups (P>0.05). According to the results of the experiment, there were no significant difference in relation to body shape deformities between the diploid and triploid fish (P>0.05).

Rotifers are microscopic aquatic animals of phylum Rotifera, which live in a diverse range of aquatic habitats. They are important in ecology of freshwater ecosystems by recycling nutrients and can alter trophic dynamic of planktonic communities. These features have also been used as indicators of the environmental conditions in aquatic habitats. Considering the important roles of this group of animals in the trophic chains of aquatic environments and the need to explore their biodiversity, this study was planned with the aim of analyzing patterns of rotifer community structure in Kani-Brazan and Bohlul-Kendi water bodies located in northwest Iran. Samples were collected seasonally between October 2007 and November 2008. Temperature, pH, DO, conductivity, salinity and rotifer abundance were measured. In total, 28 rotifer species were identified from the two studied sites. In each site, rotifer species diversity differed seasonally. Canonical correspondence analysis (CCA) was used to estimate the relationship between environmental variables and abundance of rotifer taxa. The clusters showed strong correlation with dissolved oxygen and electrical conductivity for shaping the rotifer assemblages in both Kani-Brazan and Bohlul-Kendi reservoirs.

In this study, 147 common carp for two weeks were kept in the aquarium condition. LC50 / 96h of Vertimec was calculated as 1.243 and on this bais three lethal concentration 2, 3, 6 ppm were considered for this study. Isomaltooligosaccharide prebiotic was spereyed to the food as 1 g / kg. The results showed that after induction of isomaltooligosaccharide to the treatments that were exposed to vertimec, histopathological disorders such as vacuolization latest, bleeding, necrose, degeneration of the epithelium, loss of intestinal villi in the intestinal tissue was observed.  Concentration of 6, 3 and 2 ppm had severe effects on intestinal tissue, respectively. Isomaltooligosaccharide could not decrease the histopathological effects tissue due to vertimec exposue. Since tis prebiotic is absorbed via intestinal tissue and can show its positive effect of this organ, but the results did not show significant and positive effect in the intestinal tissue.

Using of the standard methods for the production of unicellular algae have high harvesting costs and in many cases is not affordable. Therefore chemical fertilizers could be considered as an appropriate alternative for the production of unicellular algae. In this regards, Haematococcus pluvialis, were transferred to each of the 3-liters container. The results showed that the specific growth rate, the cell division per day, carbon dioxide fixation efficiency, biomass and total biomass efficiency was significantly higher and lower in treatment 7 and 1 respectively (P<0.05). The highest protein (17.35%), fat (15.46%) and carbohydrate (6.42 and 8.01) content was observed in treatments 6, 7, 2 and 3, respectively (P<0.05). the highest chlorophyll a (44.60 mg/g FW) in treatment 5 and chlorophyll b (62.19 mg/g FW) carotenoid (152.73 mg/g FW) in treatment 3 (P<0.05).

This study was conducted to survey population variation of Capoeta heratensis in Hari River and Dasht-e Kavir basins of Iran using geometric morphometric technique. For this purpose, 3 populations of C. heratensis, with 30 specimens for each population, were collected from the Aal, Hari and Bidvaz rivers. The specimens were fixed into buffered formalin after anaesthetizing and transported to the laboratory. The left side of each specimen was photographed using digital camera and fifteen landmark points were digitized on 2D images using TpsDig2. The landmark data after generalised procrustes analysis were analyzed using PCA, CVA and cluster analysis using Past and MorphoJ softwares. CVA analysis displayed significant differences among three studied populations. Based on the results, Bidvaz population showed greater differences compared to two other populations. The observed differences can be attributed to the diversity of habitat and feeding habits of the studied populations as well as geographical separation.

Fish are very sensitive to a wide range of chemicals, including herbicides, which can pollute water sources not only through deliberate drainage into the waterways, but also through spraying farms in conventional farming practices which also jeopardizes aquatic ecosystems and living organisms. Roundup is a very useful herbicide in present case study was aimed to investigate the effect of its sub-lethal toxicity on blood indices of silver carp. For this purpose, first with determination of some poison concentration for LC50 calculation, mortality was monitored at 24, 48, 72 and 96 hours and lethal concentarion was measured 9.9 mg/l with probit analysis. Then, a separate experiment was designed according to the LC50 data where fish were put in 4 treatments with triplicate (control group and 12.5, 25 and 50% of LC50 96h) in two periods of 4 and 8 days and after exposure to the herbicide some blood hematological parameters such as hematocrit, hemoglobin, RBC indices, RBC, WBC and differential count of white cells were studied. Results of hematological indices found a significant decrease in RBC, WBC, hematocrit and hemoglobin and also an increase in the number of neutrophils showed by increasing the concentration of the herbicide. The results of this study showed that hematological indices are a sensitive indicator and can be useful to evaluate the effect of herbicides on aquatic organisms.