فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال هفتم شماره 1 (بهار 1398)

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 analysis statistically 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 time-related 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.

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 productive efficiency, hepato-somatic index, body composition, blood biochemical factors and activity of intestinal protease of the beluga (Huso huso) with mean body weight 10.2±0.3. Different treatments of (CF) were not significantly different from each other (P>0.05), But (WGP), (SGR), (PER) and hepato-somatic index was 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 the control group (P<0.05). The highest body protein was observed in NCP groups (P<0.05). No difference was observed in Blood glucose, albumin 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).

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.