International Journal of Aquatic Research and Environmental Studies
Volume:2 Issue: 2, Summer-Autumn 2022

Super nutrients are nutrient compounds including fat dissolved vitamins, necessary minerals and growth promoters. Present research was carried out with the aim of determining super nutrients effect on some growth and biochemical indices in juvenile Acipenser baerii in International Sturgeon Research Institute during 6 months. Blood samples obtained in days 45 (stage I) and 90 (stage II) and plasma provided. Some plasma biochemical an ions levels were measured in VIRO MED laboratory in Rasht. The results showed that the mean final weight, final biomass, body weight increasing (BWI), specific growth rate (SGR), condition factor condition factor (CF) and daily growth rate (ADG) showed significant difference between control group with other treatments (p<0.05). Results showed that sodium, potassium and calcium ion levels showed no significant difference in various concentrations of super nutrients during rearing period (p>0.05). Based on obtained results, super nutrients adding in diet of Acipenser baerii caused to significant difference in growth indices and improved them. Therefore, it recommended using of super nutrients in Siberian sturgeon diet.

Tetraploidization of rainbow trout (Oncorhynchus mikiss) was induced by hyperthermia and designed in three treatments (28ºC for 10, 12 and 14 min), 7 h after fertilization. Immature fishes were anaesthetised using standard method in tank (Table 1). Blood samples were collected by caudal venipuncture using 2 mL syringes fitted with 0.5 x 35 mm (25 gauge) needles (Sima, Iran) pre-dosed with heparin (Caspian Tamin, Iran). Blood samples subjected to various conditions, were analysed by FC. Methodology was adapted from established protocols for human blood FC analysis, but modified as required due to the nucleated nature of fish erythrocytes. Blood sample evaluations by FC were performed in surface-deactivated polypropylene tubes to minimize cell-tube adhesion and associated quantitation error. Five millilitre 12 x 75 mm polypropylene Falcon tubes (Maxwell, Italy) were filled with a 4% solution of bovine serum albumin (BSA; Sigma, USA) in PBS and stored overnight at 4°C (Lecommandeur et al., 1994). Prior to use, the tubes were emptied and centrifuged at 2000 rpm for 5 min. For each treatment, we also measured the size of erythrocytes and genome size. Genome size was positively correlated with erythrocyte nucleus size and chromosome number when using PI as the fluorescent dye. This work provides new knowledge on Oncorhynchus mykiss genetics/genomics, important for future research in basic cellular/molecular mechanisms and for the development of molecular techniques in this species. However, further investigation is required to obtain a high percent tetraploid Rainbow trout population.

The study was carried out in the genetics and breeding resaerch canter of yasouj. All eye-stage eggs were used for the experiment using vertical hatching units to complete hatching. A standard commercial granule feed was used in all experimental groups. The experiment consisted of control treatment and one dose of hormone  17α-Methyltestosterone added to the diet at the rate of 3 mg per kg food by dissolving in 200 ml of 95% ethanol per kg feed.The use of oral administration of 17α-methyltestosterone (17MT) at 3 mg 17MT/kg of feed for 70 days following the onset of feeding to sex reverse rainbow trout (Oncorhynchus mykiss) to produce XX males is well established. Examination of the results showed that 17α- methyltestosterone was effective in sex riversed of rainbow trout. The results  has shown in nearly 100% of the treated animals being males. The GSI index in female and male fish of control group were  0.04±0.1   and 0.07±0.01, respectively (Fig.3) and significantly different (p≤5%). But  GSI index  of 100% sex riversed male fish of MT treated was 0.06±0.01 and hadn,t significantly differene (p≥5%) with treated group ( genetically male and female).

The species Capoeta aculeata (Valenciennes, 1844) is one of the most important freshwater species endemics to Iran. However, the investigation of a population genetic structure of this species is limited by the low number of molecular markers currently described. In this study, we implemented next generation sequencing technology to identify polymorphic microsatellite markers and investigate the population genetic structure of C. aculeata sampled from three geographical sites in Iran. We sequenced 60 individuals from three populations occurring in the Zagros basin. We characterized and developed 36 novel polymorphic microsatellite markers and these loci were examined in 120 individuals from three populations occurring in the Zagros basin. The average number of alleles per locus varied from 1.7 to 16.  (average=7.89). The results showed that, the polymorphism information content (PIC) of these SSR loci varied from 0.254 to 0.888. The observed heterozygosity (Ho) per locus ranged from 0.170 to 0.881, while the expected heterozygosity (He) per locus was from 0.170 to 0.881. Among these SSR loci, 20 loci deviated significantly from the Hardy–Weinberg equilibrium after Bonferroni correction (p<0.05). These microsatellite markers could provide a valuable tool for future population and conservation genetics studies of C. aculeate populations and other closely related species.

Better management of tilapia hatcheries depends on effective factors on spawning and is affected by different factors. Nile tilapia Oreochromis niloticus were held at a water salinity of 11.5ppt, a temperature of 27±0.5°C. Fish were fed a 40% protein food. Absolute fecundity varied between 50 and 2600 (mean 853±25) eggs per clutch. Relative fecundity varied from 0.29 to 6.8 (mean 2.77±0.13) eggs/g of female. Mean of wet weight of egg clutches was 4.98±0.31g during the study period, increasing with size of female (p<0.05). Mean wet weight of each egg was 0.0062±0.0001g. Diameter of the eggs varied between 1.8 to 3.5mm and its mean was 2.58±0.009mm increasing with average length and weight of spawners. The impact of sex ratio, stocking density, photoperiod, water salinity and replacement period on spawning performance of Oreochromis niloticus were investigated. Sex ratios 1:1, 1:4 and 1:7 (Male: Female), stocking densities 2, 3.5 and 5 fish/m3, photoperiods 6:18, 12:12 and 18:6 (Light: Dark) hours, water salinities 0, 4, 8 and 12 ppt, also 10- and 15-days replacement of breeders were studied. Fecundity, breeder and egg per day, spawning intervals, egg diameter and weight were investigated. Results showed stocking density 5 fish/m3, photoperiod 12:12 h, 8 ppt water salinity and 10 days replacement had better performance.

Feed preparation is the most expensive part of the aquaculture industry. In recent years, studies have been conducted on the utilization of plants’ wastes and by-products (such as peel, pulp, and kernels) as phytogenetic materials and sources of protein and nutrients for preparing feed in the aquaculture industry, which have yielded promising results. These wastes are recycled by processing as feed additives and returned to the feed chain, and because they are waste products of plants and fruits, prepared phytogenic feed additives cannot be regarded as feed sources for humans. In the future, there will be large quantities of fruit and vegetable waste, which have the potential to be recycled and returned to the feed chain by being processed as additive feed for aquatic animals. Phytogenics encompass a wide range of substances that can be classified based on plant origin, the processing method, and composition but generally found in the form of herbs and spices, or as plant extracts, essential oils, and oleoresins. The phytogenic properties of plants are related to the various secondary metabolites produced by them. These metabolites are used as growth and appetite stimulants. Furthermore, these metabolites induce the secretion of bile and other digestive enzymes. They are not a threat to the environment, and their benefits as substitutes for antibiotics have been promising. The antioxidant, anti-cancer, analgesic, antimicrobial and antiparasitic effects of these products have been proven so far but the main function reported for these compounds in the host is to improve gastrointestinal microbiota and immune function (modulating cytokine production by epithelial cells). However, the mechanisms of action of these products are not yet completely understood, and further studies are needed to divulge the potential side effects of phytogenic substances on the host, the environment, and on gastrointestinal microbiota. Understanding these mechanisms will ensure us about the safety of these herbal additives for fish, consumers, and the environment. Despite some applications of plant materials in aquaculture, their widespread use for feed preparation is still limited due to the lack of sufficient knowledge on the mechanisms of action of phytogenic materials. So, a better understanding of the effects of these compounds, which are derived from plant and fruit wastes, on the host’s physiology will provide us with the opportunity to use these substances more widely in the aquaculture industry. In the present review, we discuss the studies conducted on the use of phytogenic materials as feed additives for aquatic animals, as well as their effects, advantages, and disadvantages.