فصلنامه فیزیولوژی و بیوتکنولوژی آبزیان
سال نهم شماره 1 (بهار 1400)

Sea anemones (order Actiniaria) are among the most diverse and successful members of class Anthozoa, subclass Hexacorallia. According to the wonderful role of sea anemones as a benthic suspension feeding community and their ecological success by a propensity for engaging in symbiotic relationships and also their recent applications in biotechnology and the extraction of active biological substances and drug compounds, a study of internal structure of this aquatics is necessary. In this study, the histological sections with 5 µm thick were prepared from two species Anthopleura buddemeieri and Stichodactyla haddoni and stained with hematoxylin and eosin. By investigation of light microscope images, in both species the body wall and gastrovascular cavity were easily visible. Body wall significantly contained 3 layers of epidermis, mesoglea and gastrodermis and gastrovascular cavity structure included mesentery, longitudinal retractor muscles and parietobasilar muscles. In the species A. buddemeieri with making a histological section from all of the gastrovascular cavities of this animal, actinopharynx and siphonoglyphs were observed and the types and numbers of mesenteries were determined. Also in both species the longitudinal retractor muscles were stronger and wider attached to the end of primary and secondary mesenteries than pareitobasilar muscles placed near the body wall.

In this study, growth, carcass composition and fatty acid profile were evaluated in Hediste diversicolor fed faeces and food of beluga in open and semi-closed systems. This research was carried out based on three treatments in three replicates consisting of treatment 1: Nereis worm fed by beluga wastewater and using recycling water (semi-closed), treatment 2: Nereis worm fed by beluga wastewater without recycling water (open) and treatment 3: Nereis worm fed by concentrated food. Results showed that growth indices and survival rate in worms fed by concentrated food were higher than in comparison with other treatments (P<0.05). The highest content of SPUFA and w-3/w-6 ratio were observed in Nereis worms fed concentrated food (P<0.05). Reared worms in semi-closed system had the maximum content of SMUFA and DHA/EPA ratio (P<0.05). Significant differences were recorded in protein and lipid of carcass and TSS contents of worm tanks outlet (P<0.05). According to the results, because of having high content of protein as well as suitable ratios of DHA/EPA and w-3/w-6, these worms have high nutritional value for sturgeons and shrimp broodstocks. Economically, because of the lack of expense on food, the worm can be exploited as secondary product.

The aim of this study was to investigate the effect of a diet containing golder powder (Otostegia persica) on blood parameters, antioxidant and immunological responses in common carp (Cyprinus carpio). For this purpose, fish with a mean weight of 28.32±2.12g were distributed in aquariums and were fed with 0 (control), 0.5 (T1), 1 (T2) and 1.5% (T3) of golder powder for 45 days. At the end of the period, blood samples were collected from fish and immunological parameters and antioxidant enzymes evaluated. The results showed that the addition of plant powder to the diet did not cause significant changes in hematological indices (RBC and WBC count and hematocrit) and RBC indices (MCV, MCH and MCHC) between experimental treatments (P>0.05). Also, liver enzymes alanine transaminase (ALT), alkaline phosphatase (ALP) and aspartate transaminase (AST) were not significantly different (P>0.05). The highest total protein was observed in fish fed with T2 and the control group has the lowest level, and there was a significant difference between treatments containing 1 and 1.5% of plant powder and other treatments (P<0.05). Albumin, triglyceride and cholesterol of fish fed with golder powder were not significantly different at the end of the experiment with control treatment (P>0.05). Catalase, glutathione peroxidase and superoxide dismutase had the highest levels in fish fed with diets containing 1 and 1.5% of golder powder (P<0.05). The amount of malondialdehyde decreased significantly with increasing the amount of plant powder in the diet (P<0.05). Generally, golder powder has a positive effect on serum antioxidant parameters in this study.

The effects of water-borne silver ions and nanoparticles on oxidative stress responses, plasma liver enzymes and some other biochemical characteristics of blood parrot fish were investigated. For this study, 60 parrot fishes (average weight 25.5±6.5g) were randomly distributed into three different treatments including control, silver nanoparticles (250 μg/L) and silver ions (250 μg/L) for 5 days, without feeding during stress. The results showed that the effect of silver ions on plasma oxidative indices and liver enzyme levels was significantly higher than silver nanoparticles, meanwhile, they were significantly higher than control (P<0.05). Silver ion and nanoparticles also induced significant elevation on plasma protein, albumin and globulin levels in comparison to the control, but the effects of both chemicals on the recently mentioned characteristics were the same (P>0.05). In general, the results showed that both nano silver and ion could affect some physiological aspects of the blood parrot, but silver ions showed the highest effects.

Caspian brown trout (Salmo trutta caspius) is one of the most valuable fishes in the Caspian Sea and has great value due to its marketability, appearance and taste of meat. This study was carried out to determine the effects of oxygen changes on survival, some stress indices and hematological and immunological factors in Caspian Sea salmon (Salmo trutta caspius). 210 fish (50 10g) were randomly selected and placed in tanks with aerator and oxygen capsule. Fish were divided in 3 treatments with 3 replications including treatment hypoxia (2-3 mg/L oxygen), treatment control or normoxia (7-8 mg/L oxygen) and treatment hyperoxia (12-14 mg/L oxygen). Blood sampling were performed for 12 and 24 hours. The results showed that fish had no mortality in the different oxygen treatments. The effect of oxygen showed that there were significant differences in WBC, RBC, hemoglobin, hematocrit, neutrophil, lymphocyte, cortisol, glucose, lactate, lysozyme, total immunoglobulin, IgM, albumin, and total protein (P<0.05). In general, 7-8 mg/L oxygen is the most favorable condition for Caspian brown trout. Because the most appropriate values of factors were observed more in this group, which showed a significant difference with other treatments.

Manipulation in the concentration of the nutrients of microalgae is one of the effective strategies to improve biomass and nutritional value. In this study, the effect of different concentrations of cobalt (0.001, 0.01 (control), 0.1, 1 and 10mg/L) on cell density, chlorophyll a and b, lipid, fatty acid profile, iodine and soap numbers of Isochrysis galbana were studied for two weeks. Adding 0.001 mg/L cobalt significantly improved chlorophyll a (3.2118mg/L) and b (2.001mg/L) and lipid (24.09%) and protein (53.91%) content of I. galbana compared to other treatments (P<0.05). The highest level of saturated fatty acid (47.83%) was observed in 10mg/L cobalt treatment, while the reduction of cobalt to 0.001mg/L caused an increase in monounsaturated fatty acid (MUFA) and polyunsaturated fatty acids (PUFA). Also, the maximum and minimum iodine and soap numbers were observed at concentrations of 0.001 and 10mg/L cobalt, respectively. Overall, a concentration of 0.001 mg/L cobalt provided the nutritional value of this microalgae in terms of chlorophyll a and b, protein, lipid and PUFA, although an alteration in the optimal concentration had a negative effect on biomass.

Regarding the negative impacts of using toxic antifouling paints to solve the problem of biofouling, the development of non-toxic paints from natural products and their application in marine industries has gain importance. In the present study, the antifouling properties of Zataria multiflora essential oil in antifouling epoxy paint were investigated. Antibiofouling activity of essential oil was proved by antibacterial, antimicroalgal, antibarnacel and antiartemia activities. The minimum inhibitory concentration was 0.125 and 0.250 mg/L against two bacteria Staphylococcus aureus and Escherichia coli, respectively. According to antimicroalgal adherence assay, essential oil had inhibited the average specific growth rate of Isochrysis galbana with effective concentration of 52.186±17.67mg/L and LC50 was 8.720±1.28 and 35.210±2.37mg/L against antibarnacel and antiartemia, respectively. The essential oil was added to epoxy paint and coated on the fiberglass panel exposed to seawater for three months. At the end of the first and second months, the coated panels containing 3% essential oil had the lowest weight (78.81±22.2 and 178.44±6.58 g, respectively) and lowest fouling cover percentage (63.52±1.92% and 92.05±3.34%, respectively) (P<0.05). Results showed that the effectiveness of antifouling activity of Z. multiflora essential oil depends on the amount of essential oil in the paint and its wash rate in seawater.