نشریه علوم آبزی پروری پیشرفته
سال هفتم شماره 1 (بهار و تابستان 1402)

In this study, a comparison of the efficiency of Perfish 5% solution (Peracetic acid and Hydrogen peroxide) with Bronopol 50% on fungal contamination control in rainbow trout (Oncorhynchus mykiss) eggs during the incubation stage was conducted. Some 24000 fertilized eggs were used in each vertical incubator (8000 fertilized eggs in each replication). Also, two treatments of 75 ppm Perfish and 300 ppm Bronopol (as the control group) were examined with three replications. Disinfection of eggs was conducted 48 hours after fertilization every other day for 30 minutes. The percentage of eyed eggs, hatching rate and larva deformity showed no significant difference between the experimental and control treatments. Therefore, due to the lower price of Perfish 5% compared to Bronopol 50% and also the need for the less amount of this disinfectant solution, Perfish 5% solution (Peracetic acid and hydrogen peroxide) can act as a suitable alternative composition to fungal contamination control of rainbow trout eggs in the incubation stage.

Nowday, with the progress of science and the spread of various diseases, mankind is looking for a big natural source of food-pharmaceutical and medical bioactive compounds. The sea environment is a very rich source of animals and plants containing bioactive compounds with unique applications in various fields. In addition, every year, during the processing of aquatics in various fishery products, large amounts of waste are produced, which are thrown away in many cases and provide a basis for creating environmental problems. These wastes can be a very suitable source for extracting bioactive compounds such as collagen connective tissue protein. The results of this research showed that collagen obtained from marine sources is widely used in the fields of nutrition, biomedical and other various industries. Also, collagen peptides (biologically active peptides) produced by collagen hydrolysis have biological properties such as antioxidant, anti-aging, anti-tumor, anti-coagulant, anti-inflammatory, anti-freeze, anti-microbial, anti-hypertensive, antidiabetic, wound healing, etc. The purpose of this research is to investigate the importance of using bioactive compounds extracted from aquatic wastes and to express the different uses of marine collagen and to prevent environmental pollution.

Using cryopreservation techniques are so important in conducting brood stock selection programs, species protection, and accessibility to the spermatozoa throughout the year. Normally, in the conventional method in Iran, the formulation based on egg yolk and DMSO has been employed to freeze the sturgeon sperm. In the present study, the MT extender (Modified Tsvetkova’s) which consists of the main components of methanol, sucrose, potassium chloride, and Tris has been used for the preservation of Acipenser stellatus spermatozoa, without using chemical substance DMSO and egg yolk. Our results demonstrated that the frozen sperm had at least 30% motility after one year of storage in nitrogen tank. The results of this research show that this extender could be used to preserve Acipenser stellatus spermatozoa. Since the sperm’s concentration of sturgeon species are similar, the usage of the MT extender can be suggested for other species of the sturgeons.

Aquaculture environments are always risky for diseases outbreak because of high density of aquatics and environmental conditions. Fish farmers need to use medicines, disinfectants and detergents to prevent and control of disease.Medicines selection and their concentration are affected by water physico-chemical parameters as well as farming conditions. For example, many chemicals in water are affected by water quality parameters such as pH, temperature and organic materials and may change the efficacy of the chemicals. Aquaculture medications are administered in three routs of oral, injection and bath treatments. In oral medication, aquatics are fed medicate food. This rout has the minimum stress, but inappetence in diseased aquatics is the main problem. In injections, the specific levels of medicine is entered the fish body, but is stressful and impossible to apply in high-density facilities. The most common rout of medicines is bath treatments that applies in several ways. Because of adding medicines in water, environmental requirements are carefully regarded. In medicine usage some subjects should be considered: the most important are registering of documentaries in all process of chemotherapy, medicine withdrawal time, veterinarian medicine prescription, usage of plastic containers for medicine preparation or handling, evaluation of drug impacts on environment and administration of bath treatment in early morning.

In an introduction to various types of tilapias, dietary requirements, and breeding methods, we become acquainted with a group of freshwater fish known as tilapia. These fish are cultivated worldwide due to their diverse characteristics. Different types of tilapias have distinct environmental conditions, dietary needs, and breeding methods. The dietary requirements of tilapia include protein, fats, and vitamins such as vitamin C and D, which can be sourced from various means. Breeding methods for tilapia encompass various environments, including freshwater ponds, lakes, and recirculating water systems. In each method, precise water condition management, proper nutrition, and disease control are of paramount importance. Overall, familiarizing oneself with the different types of tilapias and the principles of their cultivation is crucial as a valuable food source and for the sustainable development of aquatic resources.

Asian seabass (Lates calcarifer) is one of the important and commercial species. Due to its fast ‎growth, easy reproduction, high salt tolerance and ability to accept formula food, it has been ‎considered as one of the best farmed fish in the world in recent years This fish is cultivated in ‎different ways. The present research was conducted in order to investigate the effect of density on ‎the growth indicators and the survival rate of Asian seabass fry in 9 round assembled tanks with a ‎diameter of 10 Meter and a height of 2 meters and a volume of 150 cubic meters of water for 120 ‎days‏.‏‎ ‎In this research, the number of 29,500 pieces of Asian seabass fry with an average weight of ‎‎42.00±0.03 grams in a completely randomized design in 3 treatments and 3 replications with ‎densities of 15, 20 and 25 pieces per cubic meter respectively in treatments A, B and C are ‎stuocked. 44% were fed with special salmon pellet food at the rate of raw breeding. The results ‎showed that the highest specific growth rate was 6.3±0.02, survival was 93.56±3.22, and the ‎highest final weight was 800.10±0.40 in treatment A, and the highest food conversion ratio was 1.6 ‎in treatment C with the lowest weight. The final was recorded‏.‏‎ This study showed that the density ‎has a significant effect on the growth and survival indicators of Asian seabass fry, so that the ‎stocking density of 15 pieces per cubic meter in the recirculation system for seabass has the highest ‎growth and is recommended.‎