AQUATIC PHYSIOLOGY AND BIOTECHNOLOGY
Year:2019 | Volume:7 | Issue:1|Papers Count:9

The present study aimed to determine the effects of 4 experimental diets including diets contain astaxanthin, turmeric and spirulina (100mg per Kg diet) and diet without adding pigment, on growth, hematological and immunological parameters and coloration of the tiger oscar (Astronotus ocellatus). For this purpose, 120 fingerlings of tiger oscar, with a mean weight of 7. 5± 0. 5g, were fed with experimental diets for 8 weeks. At the end of this period, fish were sampled to measure the parameters. The results of data statistically analysis showed that there was a significant difference between the treatment fed with astaxanthin and other treatments in WG, FCR, SGR, BWI, length increase and lysozyme activity (P<0. 05). However, there was no significant difference between treatments in other immunological parameters (total immunoglobulin, IgM), hematological parameters and total carotenoids (P>0. 05). The results of this study showed that the pigments used can improve the growth, immunity and coloration factors of the tiger oscar. Among these pigments, astaxanthin has a better performance than other pigments.

In situ hybridization is a powerful tool to localize a specific sequence of nucleic acids in heterogeneous cell population. Therefore, the aim of this study was to apply this technique for localization of Vasa mRNA expression in testicular tissue of Caspian trout (Salmo caspius). In this study, a digoxigenin-labeled RNA probe was synthesized using the plasmid pGEM-T carrying a Caspian trout Vasa cDNA fragment as a template. The RNA labeling was performed through in vitro transcription reaction with DIG labeling mix. For in situ hybridization of tissue sections, Caspian trout testes were fixed and dehydrated. After rehydration and treatment with proteinase K, sections were incubated with hybridization buffer containing Vasa antisense riboprobe for 16h. After washing with SSC solution and incubation with anti-Dig-digoxigenin Antibody, the sections were treated with NBT/BCIP. The results of in situ hybridization using a Vasa antisense riboprobe showed that all developmental stages of male germ cells (spermatogonial stem cells to spermatozoa) expressed this gene, but the expression level was different among germ cells. Therefore, Vasa gene is introduced as a specific marker to identify germ cells and in situ hybridization can be used as a technique to evaluate the localization and expression level of gene mRNA in testicular tissue. These findings may provide important information to help understand the formation and development of germ cells in this valuable species of Caspian Sea.

The aim of this study was to evaluate the toxicity of iron oxide nanoparticles on the gill antioxidant defense system of juvenile common carp (Cyprinus carpio). The juveniles (17± 0. 6g) were exposed to different concentrations (10, 30 and 50. 0 mg. L-1 ) of waterborne iron oxide nanoparticles for 0, 1, 7 and 14 days and then the levels of antioxidant enzymes activities including superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and malondialdehyde (MDA) were evaluated in gills. The results showed that exposure to nanoparticles led to a significant increase in MDA levels and timerelated changes in antioxidant enzyme activities (P<0. 05). Therefore, the biomarkers such as antioxidant enzymes and MDA level can be used as a suitable index for monitoring oxidative stress in carp.

Effects of adding various carbon sources in biofloc system on growth, feeding performance and water quality in common carp (mean weight of 11± 0. 89g) culture during 56 days in five feeding treatments including control (no extra carbon source), second treatment with molasses, third treatment with wheat flour, fourth treatment with bagasse and fifth treatment with corn flour, each with 3 replicates, was investigated. According to the results, growth and feeding indices were not significantly different among the treatments (P>0. 05) but the body weight gain, survival, specific growth rate and protein efficiency ratio was higher and the food conversion ratio was better in the second treatment. TSS and FV amounts were lowest in control and highest in the second treatment, while TAN and nitrite showed an opposite trend. The changes trend in TAN and nitrite was correspondent with that of TSS and FV indicating the positive performance of flocs in biofloc system in reducing harmful nitrogenous compounds and converting it to an unharmful range for cultured common carp. In conclusion, the use of carbon sources especially molasses in the biofloc system could be recommended to improve water quality, growth and feeding performance in common carp culture.

In this study, for enhancing the efficacy of exogenous protease, a chitosan nanoparticles (0. 25%) nanoencapsulation-based delivery system was developed. An experiment was conducted for 45 days to evaluate nanoencapsulated protease (NCP) (0. 01% and 0. 02%) along with 0. 25% chitosan nanoparticles against a control diet on growth, hepato-somatic index, body composition, blood biochemical factors and activity of intestinal protease of beluga (Huso huso) with mean body weight 10. 2± 0. 3. In different treatments, CF were not significantly different (P>0. 05), but WGP, SGR, PER and hepatosomatic index were significantly higher in NCP groups than other groups (P<0. 05). The best FCR was in NCP groups and it was significantly lower than other groups (P<0. 05). The highest body protein was observed in 0. 01% NCP group and it was significantly higher than control group (P<0. 05). No difference was observed in blood glucose (G), albumin (A) and A/G ratio (P>0. 05). Blood total protein and globulin were significantly higher in NCP groups compared to the control group (P<0. 05). Blood BUN was significantly higher in 0. 02% NCP group compared to control group (P<0. 05). The highest activity of intestinal trypsin was observed in 0. 01% NCP group (P<0. 05). The result of this study showed that the supplementation of nanoencapsulated trypsin to feeds could improve the growth performance of beluga by increasing activities of digestive enzymes.

In this study, the effect of zeotene, was studied on some growth parameters, carcass composition and immunity of common carp fingerlings. 180 fish (mean weight 20. 3± 0. 1g) were randomly divided into 4 treatments and fed for 8 weeks, with diets containing 0 (control), 2, 4 and 8g/Kg zeotene. At the end of the experiment, the average of final weight, condition factor, feed efficiency ratio, protein efficiency ratio, hepatosomatic index and viscerosomatic index increased and FCR decreased in treatments 2 and 4 grams of zeotene (P<0. 05). The highest carcass moisture content and the lowest carcass fat were related to treatments 2 and 4 grams of zeotene (P<0. 05). Carcass ash in treatment 8 grams of zeotene was the highest (P<0. 05). Among serum biochemical parameters, the amounts of globulin, lysozyme, complement and IgM in treatment 4 grams of zeotene was significantly higher than control and treatment 8 grams of zeotene (P<0. 05). The lowest and the highest numbers of WBCs were seen in 8 and 2 grams of zeotene, respectively. The highest and the lowest percentage of lymphocytes and neutrophils were seen in 2 and 4 grams of zeotene, respectively. In conclusion, 4 grams of zeotene per kilogram diet can improve growth factors, carcass quality and immune parameters of common carp.

The scope for growth as a proportion of the energy absorbed and is а measure of the efficiency with which the food is converted into body tissues. It is mentioned in both net and gross growth efficiency. In this study, the scope for growth and growth efficiency of the bivalve Azumapecten ruschenbergerii have been investigated at Chabahar Bay before and after summer monsoon, as a laboratory experiment. Monsoonal climate dominates the northern Indian Ocean, and its effects felt in summer and winter with stronger winds in summer. According to this, the study on the energy budget of mentioned bivalve at 19 to 33 ° C showed that the average of both indices has significant increase after summer monsoon (P<0. 001). The results indicated that A. ruschenbergerii is opposed to better condition and less stress after the monsoon.

Large scale biodiesel production from renewable sources like microalgae is an appropriate option to replace nonrenewable fuels. The biodiesel production procedure from microalgae involves costly and energy consuming processes such as harvesting and drying of microalgae and oil extraction. The expansion of effective commercially oil extraction processes is considered as one of the most requirements for large scale production. Thus, in this study, oil extraction conditions from Haematococcus pluvialis, including temperature and solvent mixture content, was optimized by applying response surface method. Optimum points were obtained at 42. 6° C and 17. 23 mL for temperature and solvents content, respectively. The algal oil was extracted in optimized and unoptimized conditions and fatty acid profile of these extracted oils was compared together. Results showed that the optimization has positive effects on the extracted fatty acids profile which can be used to produce biodiesel with higher quality.

The present study aims to develop a new nanoparticle-based system. The natural polymer chitosan for nanoparticles and luteinizing hormone releasing hormone analogue (LHRH-A2) were used as a hormone which utilizes for fish artificial propagation. The ionic gelation method was applied to prepare the chitosan nanoparticles. The design in the present study was an experimental D-optimal response-surface method. The variables were the concentration of the hormone, the concentration ratio of chitosan/tripolyphosphate and hormone-chitosan solution pH. The nanoparticles were determined morphologically through the scanning electron microscopy (SEM). In order to check the size, the zeta and PdI particles, dynamic light scattering instrument, and infrared spectroscopy were used. Moreover, regarding the nanoparticles’ structure formation and detection of thermal resistance, the differential scanning calorimetry was applied. The results displayed the nanoparticles optimal size was 108 nm, the zeta potential was 16. 2μ V and the particle size distribution index was 0. 274. The result of the in vitro release of the prepared nanoparticles revealed that the percentage of released hormone from the nanochitosan was 80. 14% within 48 hours. The SEM image showed the segregated and non-aggregated nanoparticles in sub-spherical smooth morphology. Furthermore, it is revealed that the high thermal stability of hormone nanoparticles at a temperature up to 400° C. This system can be used as a suitable injection carrier for slow-release hormone system in induction of various species of fish such as sturgeons.