AQUATIC PHYSIOLOGY AND BIOTECHNOLOGY
Year:2019 | Volume:6 | Issue:4|Papers Count:9

This study was conducted to determine the profile of Epeorus genetic diversity along the Gamasiab River. The sampling was done from four stations ranged source of the river downward, about 500 meters from each other, in four seasons with three replications from the middle and riverside of the river by the Surber sampler. After isolation and fixation of the Epeorus, the DNA extraction steps were performed and the quality of DNA was investigated on the electrophoresis gel. After gene amplification using specific cytochrome oxidase subunit I (COI) primers, PCR products were sequenced. Sequencing was performed with MEGA 6 software. Molecular investigations indicated that the reduction of genetic diversity at station 2 exposed to wastewater and trout farm effluents, especially in the seasons which are associated with decreasing water charge.

The present study was to investigate the effect of various dietary levels of unsaturated fatty acids (HUFA and PUFA) on some morphometric features of duodenum in newly weaned rainbow trout larvae. Therefore, eight different experimental diets consisted of various dietary levels of HUFA (0, 0. 5, 1 and 2 percent) at a fixed dietary PUFA of 20 percent (the first experiment) and various dietary PUFA levels (10, 20, 30 and 40 percent) at a fixed dietary HUFA of 8 percent (the second experiment) were formulated. The stocking density of larvae was 100 larvae per each container and the experiments lasted for six weeks. At the end of the experiments, six fish were randomly taken and the proximal intestine was dissected out and fixed for classical histological studies. In the first experiment concomitant with any increase in dietary HUFA content, epithelial thickness and villous height significantly decreased (P<0. 05) and according to the results the appropriate HUFA level could be 0. 5 percent of the dietary lipid moiety. However, in the second experiment, only villous height of duodenum was affected by experimental diets (P<0. 05) and villous height was the highest (207. 2± 10. 3µ m) at PUFA level of 20 percent of the total dietary lipid. In conclusion, it is recommended that in the case of using vegetable oils in feed formulation (to replace marine lipid sources) led to higher PUFA levels, dietary HUFA levels could be increased to eight percent for keeping normal intestine morphometry.

Rotifers are important as being alive food for fish larvae aquaculture and as bio-indicator for evaluating the water quality of wetland ecosystems. In the present study, the sampling of rotifers carried out in three regions of the Anzali wetland including Pirbazar, Sheyjan and Bahambar, during 2016-2017. In this investigation, 29 genera of rotifer from 17 families belonging to the two subclasses of Monogononta and Bdelloidea were identified in the sampled region. The highest and lowest abundance of rotifers observed in Pirbazar during summer and in Bahmbar during winter, respectively. Results of CCA revealed a positive correlation between rotifers’ density and temperature, pH, total phosphorus and total nitrogen and also a negative correlation with dissolved oxygen in Pirbazar region. The abundance of some rotifer genera such as Filinia, Brachionus and Polyarthra showed a positive correlation with temperature and Keratella abundance had a negative correlation with dissolved oxygen. Based on the TRIX index, the water of Pirbazar region was richer than Sheyjan and Bahmber regions.

This experiment was conducted to evaluate the effect of different levels of supplementation of algae Sargassum ilicifolium on the growth performances, feed indices, body composition and digestive enzymatic activities of grey mullet (Mugil cephalus )for 60 days. The experiment was conducted in a completely randomized design with 120 of grey mullet (with average weight of 11. 77± 1. 07g )divided in 4 treatments and 3 replicates (n=10 in each replicate ) and included: 0, 5, 10 and 15 g algal extract per Kg diet. The results showed that at the end of experiment, the highest final weight (FW ), specific growth ratio (SGR ) and protein efficiency rate (PER ) were observed in treatment 4 (15g/Kg ). The highest crude protein, moisture and amylase, lipase, protease activities the lowest crude lipid were observed in treatment 4. However no significant difference were observed in amylase activity, between 10 and 15g extract per Kg diet (P>0. 05 ). Overall, the results of the experiment revealed that grey mullet fed with 15g S. ilicifolium per Kg diet showed better growth performance, feed utilization, body composition and digestive enzymatic activities than control group, and could suggest for grey mullet.

The growth and development of aquatic plants depends to environmental factors such as light, temperature, dissolved oxygen, pH, organic and mineral materials. The purpose of this study was to investigate some physiological responses of Azolla filiculoides Lam. to the pH, electrical conductivity, salinity and dissolved oxygen in different aquatic habitats of Babolsar city. Azolla in green and red colors was collected from the canal around the rice field and rice field in Ojaksar area and Azizak wetland in four replicates and transferred to the laboratory. The study of water parameters showed the pH level among the habitats was slightly but significantly different and the rice field had significantly higher electrical conductivity, salinity and lower soluble oxygen content than the other habitats. The results showed the content of pigments, protein and peroxidase activity in both Azolla collected from rice field were significantly higher than those of other two habitats. Although the percentage of dry matter, protein, anthocyanin, total nitrogen and phosphorus content of red Azolla in all tree habitats were significantly higher than the green Azolla and it seems the red Azolla has probably a higher ability to absorb the essential elements and synthesize organic compounds than the green Azolla.

The present study was to investigate the effect of dietary conjugated linoleic acid (CLA ) at various inclusion levels of lecithin on immune indices of rainbow trout. To do so, 600 rainbow trout with an average body weight of 100± 10g were randomly allotted into 10 distinct treatments comprised of various combinations of three dietary inclusion levels of lecithin (2, 3 and 4% )and CLA (1, 2 and 3% )along with a control group (devoid of CLA and lecithin ) for 70 days. At the end of the experiment, immune parameters including lysozyme activity, complementary pathway, total antibody, lymphocyte proliferation and phagocytic power of the neutrophil (NR assay )were assayed. Lysozyme activity, complement pathway and total antibody content of serum of those fish fed diet containing 4% lecithin were affected by dietary CLA level to extent that lysozyme activity was the highest at 1% of CLA, while complement pathway and total antibody content of serum were the highest in diets containing 2% CLA (P<0. 05 ). Lymphocyte proliferation of those fish fed diet containing at least 3% lecithin along with 2% CLA was the highest (P<0. 05), and NR was significantly increased in those fish received diet included with at least 2% lecithin and 1% CLA (P<0. 05 ). In conclusion, dietary incorporation of at least 1% CLA along with 3% lecithin could improve immune parameters of rainbow trout.

The bio-availability of phosphorus for primary producers is reduced mainly due to the formation of complex with cations and organic matter in warm-water fish ponds. Therefore, the most important new approaches for increasing watersoluble phosphate that are consistent with the principles of sustainable agriculture are the use of phosphate solubilizing and mineralizing bacteria (PSB ). For this purpose, sampling of the sediment of warm-water fish ponds in central regions of Mazandaran province was carried out. Isolation and identification of bacteria were performed using by National Botanical Research Institute (NBRIP ) medium and 16s rRNA gene sequence. The ability of strains to grow in the range of environmental parameters of warm-water fish ponds was also evaluated. In the present study, a total of 64 PSB strains were isolated, among these, 11 stronger PSBs were including Pseudomonas taiwanensis (Persian1 and Persian2 ), P. putida (Persian3 ), P. umsongensis (Persian4 and Persian5 ), P. kilonensis (Persian6 ), P. frederiksbergensis (Persian7, Persian8 and Persian9 ), P. deceptionensis (Persian10 ) and Acinetobacter lactucae (Persian11 )had the best performance in solubilizing insoluble phosphates. The results showed that these strains have a high ability to dissolve insoluble phosphate compounds and grow well under the environmental parameter of warm-water fish ponds.

Silver nanoparticles (Ag NPs ) have been widely used in various industries, thus inevitably released into the aquatic ecosystem. Microalgae have important role in aquatic ecosystem, so in this study, the effect of different concentrations of Ag NPs (0, 1, 5, 10, 25 and 50 mg/L ) investigated on Nannochloropsis oculata. The results showed that the growth rate and the content of chlorophyll a significantly decreased in algal cells treated with Ag NPs compared to control. Also, the content of carotenoids significantly increased, while the phenolic compounds significantly decreased in response to Ag NPs. Increase of carotenoids probably is a defensive response in this microalga under stress condition. The TEM images of algae cells treated with Ag NPs showed that NPs damaged the algal cell wall.

The aim of this study was to evaluate the effects of food supplements Pediococcus acidilactici probiotic and Agaricus bisporus prebiotic separate and together (synbiotics ) on the expression of immune-mediated genes (TNF-1α , IL-8 and LYZ-c ) in common carp exposed to silver nanoparticles. For this aim, 180 carp with an average weight of 29. 6± 0. 4g were divided into four groups of probiotic, prebiotic, combined and control (feeding with no supplements ) and were fed for 8 weeks. After the end of feeding period, the fish were exposed to the concentration of sub-acute nano-silver (1mg/L ) for 14 days. Sampling from the intestinal tissue was performed to measure the expression of these genes during days 1, 7 and 14. The expression of TNF-1α gene increased significantly with probiotic and periotic dietary supplementation during increasing days of exposure to nano-silver (P<0. 05 ). The expression level of this gene was increased in the 14 days treatments (1. 61 )compared to other treatments. Expression of IL-8 and LYZ-c genes was highest on 1st day of exposure. However, on the 7 th th and 14 days of exposure to the nano-silver, the expression of these two genes decreased significantly (P<0. 05 ). However, in spite of the use of synbiotics supplementation in diet, it was not superior to their separate use. Separate or combined use of P. acidilactici as a probiotic and A. bisporus as a prebiotic in the diet can increase the relative expression of TNF-1α gene in common carp exposed to nanosilver. Also, these supplements did not affect the expression of IL-8 and LYZ-c genes.