AQUATIC PHYSIOLOGY AND BIOTECHNOLOGY
Year:2017 | Volume:4 | Issue:4|Papers Count:7

Heat shock proteins (Hsp) are an important group of chaperones that are responsible for controlling proper protein folding in the cell. The heat shock protein 90 (Hsp90) are one of the most important members of them as they are the most abundant protein found in a cell (1-2% of total protein). Hsp90 is also responsible for other cellular tasks such as cell signaling. In the present study, the Hsp90 of the Caspian kutumRutilus frisii kutum was investigated. Since there were no data available on the sequence of the desired gene, nucleotide sequence analysis of this protein was carried out using PCR technique after cDNA synthesis by using of RNA extracted from the fish liver tissue. The results showed high homology with some species such asCyprinus carpio and Gobiocypris rarus (97% of sequence similarity). Data also showed that the desired protein has 727 amino acids and the gene encoding the protein includes 2181 nucleotides.

Among aquatic animal pathogens, viruses have the most sensible role and cause higher mortalities than other pathogens due to the high infectivity, difficult diagnosis and high severity. In this study, antiviral activity of silver nanoparticles (Ag-NPs) against Rhabdovirus carpio, the etiological agent of spring viraemia of carp (SVCV), in epithelium a papulosum cyprini (EPC) cell line was monitored. Cytotoxic concentration 50% (CC50) of Ag-NPs in EPC cells was determined and the concentration 0.5 CC50 was used. Viral exposure to Ag-NPs was performed using simultaneous and delayed inoculation of the virus and Ag-NPs onto EPC cells. The inoculated cells were monitored for six days for any cytopathic effects and mortalities. According to the results, the CC50 of Ag-NPs was determined 62mg/L. In addition, mortalities of simultaneous and delayed inoculated cells were recorded 39% and 26% respectively, while in the meantime 100% of the cells inoculated with pure SVCV were died. Thus, it could be concluded that Ag-NPs have an appropriate antiviral activity against SVCV in their less toxic concentrations and could be employed as an antiviral agent in aquaculture.

Probiotics are generally defined as live microbial food supplement which improve the balance of the host animal’s intestinal flora and the absorption of nutrients from the intestine. The aim of this study was to evaluate the effect of different levels of Lactobacillus casei (PTCC1608) on some digestive enzymes of rain bow trout (Oncorhynchus mykiss) fingerlings. Four thousand eight hundred fingerlings (average weight 32.6±5.5g) were randomly divided into 4 groups with three replicates (each with 400 fish). The control group fed with basal diet and the other groups were fed with 5×106 (A), 5×107(B) and 5×108(C) CFU/mL L. caseifor 60 days. Activities of digestive enzymes were examined at 0 and 60 days of study. Results showed significantly increased intestine enzymes (a-amylase, trypsin, chemotrypsin) of rainbow trout (P<0.05) at 5×106CFU/ml concentration on day 60 compared to the control group, however on day 60, no difference between other treatments and control group was observed (P>0.05). Alkaline phosphatase, lipase and protease activity at 5×106 and 5×107CFU/mL concentration on day 60showed significantly difference compared to the control group (P<0.05). These results suggest that dietary supplementation of food with L. casei at 5×106CFU/mL concentration is suitable for enhancing the digestive enzymes activity of O. mykissbut higher concentrations of these probiotics have negative effects on O. mykiss.

During the last decade studying of adaptive markers in contrast to neutral types, have been welcomed. The most famous member of these genes, MHC, along with 8 microsatellites was analyzed in spatial groups (138 individuals) of silver carp from different provinces including Golestan, Mazandaran, Guilan, Khouzestan in addition to line samples imported from China. Mean allelic richness, expected heterozygosity and Shannon Index estimated for microsatellites as 5.04, 0.682 and 1.32, and MHC as 4.21, 0.674 and 1.23, respectively. About 2% and 3% of differentiation among populations was observed for microsatellites and MHC respectively. No significant bottleneck signals were detected in all of studied populations. Given to significant excess heterozygosity revealed in both of MHC and microsatellites in contrast to hardy-Weinberg model and proportional higher degrees of differentiation between populations in MHC, a balancing selection function can be attributed to this locus. Finally, it can be concluded that studied populations in this research have been able to maintain their genetic diversity in these loci through several stages of propagation in the hatcheries. Higher allelic richness of MHC-DAB loci in Chinese samples beside high levels of heterozygosity and diversity within population can be considered as the strength of this group.

This study was conducted to evaluate the effect of replacement of fish oil (FO) by vegetable oils on liver histology and serum hepatic enzymes of rainbow trout, Oncorhynchus mykiss. Four experimental diets were formulated with complete replacement of FO (treatment 1) with soybean oil (treatment 2), sunflower oil (treatment 3), and canola oil (treatment 4). Twenty five fish (65.12±1.13g mean weight) were allotted for each treatment tanks in duplicates groups at random and were fed for 50 days. There were no significant differences in the final weight of fish in any treatment. The results showed that serum AST, ALT and LDH levels were higher in fish fed the FO diet than the other fish. Hepatic lesions in liver tissue of all fish were characterized as hydropic degeneration, hepatocytes hypertrophy, necrosis, congestion and bleeding. Besides, liver tissues of treatment 1 (control) showed higher degree of liver lesions. These results indicate that oxidation of fish oil can cause hepatic lesions and increasing of serum hepatic enzymes in rainbow trout. In conclusion, mix of vegetable oils and fish oil can replace the sole use of fish oil in rainbow trout diet. Also, when using fish oil in the diet should be a lot of attention to its quality.

Biopersevation technology can reduce the use of chemical preservatives in food products and promote the organoleptic properties of food. In this study, the microbiological and sensory quality of minced meat produced from silver carp (Hypophthalmichtys molitrix) were investigated under the influence of essential oils, salt, nisin and acetic acid in refrigerated storage for 12 days. The treatments were including control, oregano essential oil (EO), marjoram EO, dill EO (0.2, 0.4, 0.6, 0.8 and 1%), salt, nisin and the combined groups (marjoram- oregano<oregano-acetic acid<marjoramacetic acid). According to the results, marjoram EO showed the highest diameter of inhibition zone and the greatest impact against L. monocytogenes. The MIC and MBC of marjoram EO against L. monocytogenes were 2.5mL/mL and 3.75mL/mL, respectively.All sensory sample indices decreased during preservation and more decrease was observed in the control group compared to samples treated with essential oils. In turbidity test, the results of this experiment show that the effect of treatment and time is significant and more turbidity was shown in the control group in comparison to other samples. The lowest turbidity was related to acid treatment. Therefore, application of nisin with herbal essential oils is appropriate to promote seafood safety.

This study was to evaluate the effect of emerging pollutant nanoparticles of zinc oxide (ZnO) and safety effects of vitamin C on the DNA breakage in the liver and gill cells of rainbow trout (Oncorhynchus mykiss). Fish were exposed to nanoparticles on three levels (0, 40 and 80 mg/L) and three levels of vitamin C (0, 400 and 800 mg/Kg) in 9 treatments with 3 replications. Fish with average weight 170 ± 10 gr were treated in 10 days. Liver and gill tissues were sampled in the fifth and tenth days at summer 2015. After the isolation, target samples were stored in microtubes contain alcohol 96%. DNA extraction was run with gel electrophoresis. At the end of the test, it was photographed with Gel-doc.Breakage of DNA was determined using the weighted average. According to the results, in liver and gill, the effect of zinc oxide nanoparticle, vitamin C and interaction with time-concentration were quite significant on the level of DNA damage. Most damages on liver and gill tissues in 80 mg/L of zinc oxide nanoparticles were on the 5th day. Also in both tissues, DNA breakage rate was on the 10th day. However, vitamin C has reduced DNA breakage.