Sustainable Aquaculture and Health Management Journal
Volume:7 Issue: 1, Winter and Spring 2021

The parasites that normally cause fish disease under farming condition possess a direct life cycle with no need to intermediate hosts for dissemination. The ensuing infection can therefore spread rapidly inducing more damaging lesions in the external parts of host especially the gills. In this study, in order to isolate and identify foreign parasites of phytophagous fish in Guilan province, 4 farms were selected by cluster method from Silver Carp breeding farms around Rasht and 16 pieces of fish in 6 stages for 6 months from April to September 2020. The fish transported live to fish health lab, underwent individual clinical observation of their skin, fins and gills with at least 10 moist extended samples prepared for each part.  Isolation and morphometric identification of samples were carried out via microscopic examinations. The collected data were statistically analysed using Excel version 2010 and SPSS 20 software. All the diagrams and table contents representing the intended parameters including frequency and the means were processed by Chi-square critical value of percentage 5. The results of the study showed a similar infestation outbreak of  L. Trichodina on the fish fins and gills with no significant difference (P>0.05). Dactyl gyrus spp was more prevalent in fish gills and fins than on skin (P<0.05) but the prevalence rate of Dactylogyrus spp, chilodonellosis, cryptobia and Ichthyophthirius on the gills of phytophagous breeders were more than the rest of examined areas showing a significant difference with that of skin and gills (P<0.05).

Three species of fish including, macroscopic scaled fish  as Otolithes ruber, microscopic scaled sturgeon as Huso huso and free scaled cat fish as  Pangasius hypophthalmus were prepared and specimen of dorsal of head and caudal peduncle were carried out. Routine procedures of tissues preparation followed and paraffin sections stained with (H&E) and (PAS). Results showed, epidermis formed non keratinized stratified squamous epithelium with epidermis, lymphocytes, goblet cells, taste bud and club cells. The epidermis thickness of the head skin was higher than that of the caudal peduncle, as demonstrated by image analysis using light microscopy. Goblet cells were along the superficial cells layers and their distributions were varied. In histomorphometric studies by PAS staining the highest number of these cells were seen in head of O. ruber and the lowest were seen in the caudal peduncle of P. hypophthalmus. Most of them were seen from the middle to surface layer of the epidermis. Club cells, with large nucleus, mostly evident in the deep and middle layer of the epidermis, being the largest cells within the epithelium. The highest numbers of these cells (61.8 ± 2.16) were found in head region of P. hypophthalmus. Taste buds as a sensory organ were not seen in caudal peduncle of O. ruber and H. huso. Based on the results of this study, epidermis had similarities in cell type and differences in their numbers that could be justified by the presence or absence of scales.

Microalgae contain many valuable biological compounds, so their commercial production is of great importance. One of the important challenges in microalga production is their high cost associated with their harvesting processes. Therefore, finding efficient and cost-effective technologies for algae biomass separation is essential for achieving an operational process. The study was conducted to find the influence of pH variation from 4 to 11 on harvesting efficiency and fatty acids component of marine microalgae Thalassiosira sp under laboratory condition. The NaOH and HCl were added to adjust pH value in each treatment. Data was presented as mean ± SD. Comparison between treatments was performed using one-way analysis of variance ANOVA. The results showed that with increasing the pH up to 10, flocculation processes (92%) and concentration factor (20) increased significantly. While, lowering the pH from 8.2 to 4 was not effective in isolating algal biomass. In the next stage, the biomass fatty acids content was measured by both alkaline pH induction method and the centrifuge method. Analyzes showed that the percentage of lipid and saturated and unsaturated fatty acids in biomass collected by alkaline pH induction technique was lower than the centrifugation method. In general, the results of the present study showed that clotting in alkaline pH up to 10 can be suggested as a suitable method for harvesting of Thalassiosira sp microalgae, and if the production of polyunsaturated acids is considered, of consuming high amounts of sodium hydroxide should be avoided.

Algae can be used as indicator for water quality, which could be a benefit for fish health. In this study, algae and water samples were taken from three selected stations from Keban Dam Lake Gülüşkür Region were investigated for six months between March 2015 and August 2015. A total of 48 taxa belonging to Chlorophyta were recorded during the study. Members of Chlorophyta showed their best growth in July and August, when light and temperature increased. Species belonging to Scenedesmus, Pediastrum, Ankistrodesmus and Oocystis genera were the most important members of phytoplankton with their frequency of occurrence and the size of the populations they formed.

This research was conducted to evaluate the effect of different levels of Alphamune prebiotic on growth performance and blood chemistry of rainbow trout (Oncorhynchus mykiss) juvenile. Rainbow trout with an initial weight of 16.46±0.09 g were randomly assigned to four dietary treatments for eight weeks. The dietary treatment was: 0 (ALP0), 1 (ALP1), 1.5 (ALP1.5), and 2 (ALP2) g of Alphamune prebiotic/kg of basal diet. The results showed that there was no significant difference in survival rate and SGR at the end of the trial. A significant difference was observed in the final weight and weight gain, and the highest one was obtained in ALP1.5 treatment (p<0.05). Food conversion rate (FCR) was affected by Alphamune levels and the lowest FCR was observed in ALP1.5 treatment. Blood biochemistry assay revealed that glucose, triglyceride, and cholesterol were not influenced by Alphamune's different levels. There were significant differences in IgM and total protein and the highest value was obtained in ALP2. These results showed that 1.5% Alphamune prebiotic (ALP1.5) had a positive effect on growth performance and biochemical parameters of rainbow trout juveniles.

Today, nanotechnology is considered as a priority and strategic technology for all countries due to its wide range of applications. The present study was performed to evaluate the effects of various levels of dried Aloe vera extract nanoparticles on some hematological parameters, liver enzymes and immune responses of Siberian sturgeon (Acipencer baerii). Three hundred sixty Acipenser baerii (with mean weight of 10.95 ± 0.04 g), were randomly divided into three treatment groups including 0.5%, 1% and 1.5% of nanoparticles of dried Aloe vera extract and one control group (without any additive), each in three replicates, stored in twelve tanks of 500-liter fiberglass with 350 liters water. Water physicochemical parameters were recorded daily. Nanoparticles of dried A. vera extract in a ratio of 0.5%, 1%, and 1.5% were added to the treatment groups diet for 2 months. At the end of the first and second months of rearing, the necessary samplings for hematology and serology studies were done. The results of this study showed that the amounts of RBC, Hb, Hct, MCV, WBC, lysozyme, ACH50 and IgM were significantly different in the treatment groups compared with the control group at the end of the study (p<0.05). There were no significant differences in liver enzymes including ALT, AST and ALP between treatments and control groups (p>0.05). In conclusion the results have shown that use of nanoparticles of dried A. vera extract had the impact of immune function booster and the usage of this nanoparticle mainly at the level of 1% in the diet can be used as a safety stimulant for Siberian sturgeon.