نشریه آبزیان زینتی
سال هفتم شماره 2 (تابستان 1399)

,Different variations of Aplysia have been appealing options in medical and pharmaceutical researches for years. Persian Gulf’s sea hare—Aplysia dactylomela—is a species native to Persian Gulf and can be evaluated in various areas. In this research, carried out in 2019 in Persian Gulf University’s Research Centre, the antibacterial potential of the ink of this species has been measured against three pathogenic bacteria in aquatics, namely Yersinia rukeri, Streptococcus iniae, and Vibrio Harvey. The purple ink was extracted out of ten sea hares of Aplysia dactylomela species, the ink has then been applied in raw form against the above-mentioned bacteria in an anti-bacterial test. The measurement of the antibacterial properties has been done through disc diffusion method and the minimum inhibitory concentration(MIC) and the minimum bacterial concentration(MBC) have been determined with serial dilution. Gentamicin and Tetracycline antimicrobial discs have been used as positive evidence. The average inhibitory zone for V.harvey turned out to be 19/24 millimetres, the MIC  was 200 milligrams in millilitre and the MBC was 400 milligrams  in millilitre. The inhibitory zone for S.iniae turned out to be 21/72 millimetres; the MIC was 50 milligrams in millilitre and the MBC was 200 milligrams in millilitre. Accordingly, the inhibitory zone for Y.rukeri turned out to be 22/36 millimetres; the MIC was 50 milligrams in millilitre and the MBC was 100 milligrams in millilitre.The ink of Persian gulf’s sea hare  in this research revealed antibacterial effect in reaction to all the three bacteria.

A new and suitable breeding method for inducing asexual or sexual reproduction (opium pneumonia) of Daphnia Magna is described in the laboratory. Drying and dehydration cause the production of epiphium epiphium with rapid hatching. In the present study, the effect of many different parameters such as pesticides, light periods and light intensity, sediments, culture oxygen levels, dark period, and ultraviolet rays, and The effect of temperature on Daphnia production was reviewed. In the present study, it was shown that the prerequisite for finding the optimal conditions and the highest hatch rate and obtaining the optimal breeding technique need to the present studies more. But in general, in the optimal laboratory method, dormant eggs of cladoceran need a dark period of about 2 weeks (different in different species) and then drying, and then to revive that, light and oxygen conditions and free of herbicides are required.

The present work was conducted to study the biological characteristics of giant snakehead, Channa micropeltes, a popular ornamental species in the world. This species is native to Southeast Asia and also is distributed in Thailand, Laos (Mekong Basin), Vietnam, Malaysia, Sumatra (Bangka and Belitung Islands), Kalimantan and northern Java. Among the environmental characteristics, vegetation plays an important and key role in the habitat suitability of this species. This vicious predator has been introduced to other countries such as China, Philippines, Singapore, Italy and the United States. So far, many reports have been recorded on ecological consequences of introducing this invasive species, including the Philippines and Malaysia. Experts believe that introducing of giant snakehead to breeding cages will reduce the populations of other fish, including Chinese carp and tilapia, and thwart their breeding project. The information presented in this study can be a good guide for researchers and ichthyologists to study the biological and ecological characteristics of giant snakehead (C. micropeltes) in Iran.

In this study the effect of paprika pepper powder on the blood parameters of Zebrafish was evaluated. A total number of 480 zebrafish with 0.05g initial body weight and total length of 1.71 mm were randomly to 4 treatments (with three replications) and were divided into 12 aquariums. For this purpose, experimental diets with control group without any additive (control diet), 1(treatment 1), 2 (treatment 2), and 3 (treatment 3) percent of paprika powder were reared for 56 days. At the end of the experiment period, the results showed that some blood parameters did not significantly differ among treatments (P>0.05). However, the highest number of white blood cells was recorded in treatments 2 and 3 compared to other groups (P<0.05). Also, the differential count of leukocytes showed that the highest percentage of lymphocytes and monocytes were observed in 2 and 3 % treatments compared to the control group (P<0.05). In general, oral administration of paprika powder, especially at 3% can improve some blood parameters of zebrafish.

In recent years, the use of medicinal plants to prevent disease has become a common alternative to antibiotics in aquaculture. Herbal products have attracted more attention due to their special properties, such as less damage to the environment, availability and cheapness, as well as the possibility of large-scale cultivation. Increasing bacterial resistance to commercial antibiotics has increased the tendency to use plants to stimulate the immune system. Medicinal plants play an important role in strengthening the function of the aquatic immune system and effectively reduce the cost of Fish farming with antiviral and antibacterial activities. In this review article, we review the role of medicinal plants in the immune system of fish, during which several related articles have been evaluated in recent years.

It is important to know the nutritional requirements of ornamental fish to achieve better growth and production performance. In recent years, nutritional information has been obtained about some aquarium species. Also, in some cases, the diet information of these fish can be extracted from the results obtained from farmed fish. Having the right dietary formula for the complementary needs of aquarium fish improves the digestibility of nutrients, meets metabolic needs, and reduces maintenance costs and water pollution. And at the same time feeds the complete formula of sustainable aquaculture goals.  In addition, a complete diet follows the goals of sustainable aquaculture. So far, a variety of foods such as milk powder, flakes, slaughterhouse waste, dry food and a variety of live foods including rotifers, Artemia nauplii, Moina, daphnia, Ceriodaphnia and algae have been widely used to feed aquarium fish; each has its own nutritional and production value. Considering that the coloring of ornamental fish species is important in the trade of these fish, it is recommended to add pigments and carotenoids to the diet of aquarium fish. The aim of this study was to investigate the specific nutritional requirements to improve production and thus more economical fish farming.