Effect of different carbon sources on nursery performance of Pacific white shrimp (Litopenaeus vannamei) cultivated in biofloc system was investigated. Shrimp postlarvae (98.47 AE 8.6 mg) were fed for 32 days in tanks with water volume of 130 L and density of 1 individual L À1 . One control treatment and four biofloc treatments (BFT1, BFT2, BFT3 and BFT4) with adding different carbon sources including molasses, starch, wheat flour and mixture of them, respectively, were considered at equal weight ratios. According to the results, salinity, dissolved oxygen and pH were not significantly different among the biofloc treatments (P > 0.05). Maximum pH (8.27) and maximum dissolved oxygen (6.35 mg L À1 ) were recorded in the control. Maximum (0.43 mg L À1 ) and minimum (0.09 mg L À1 ) ammonia were recorded in the control and BFT2, respectively (P < 0.05). Using simple carbohydrates (molasses and starch) lowered the ammonia concentration significantly. The highest increase in body weight (1640.43 AE 231.28 mg), growth rate, specific growth rate (8.97 AE 0.42% per day) and biomass (190.29 AE 26.83 mg) were found in BFT1 and the highest survival (90 AE 0.77%) was found in BFT4. The highest feed conversion (1.52 AE 0.23) and the lowest feed efficiency (66.81 AE 7.95) were observed in the control (P < 0.05). The proximate composition analysis revealed an increase in lipid and ash in biofloc treatments. Results indicated that using biofloc technology with zero-water exchange system and adding carbon sources could help to recycle waste and improve the water quality. Moreover, the type of carbonaceous organic matter as a substrate for heterotrophic bacteria would be effective in degradation and metabolization of ammonia and nitrite.

Zeolites are microporous crystalline hydrated aluminosilicates, which have found various applications because of their very unique physicochemical characteristics such as ion exchange and adsorption–desorption properties. Significant progress has been made in recent years on applications of these inorganic adsorbents in different industries including agriculture, aquaculture, water and wastewater treatment, air purification and petrochemicals. This review article intends to summarize the published reports on the applications of natural, synthetic and modified zeolites in aquaculture industry. Application of zeolitic materials for water quality improvement of fish farms and fish transportation tanks by selective capturing of ammonia and toxic heavy metals and zeolite application as feed additive to enhance fish growth and promote their health and nutritional parameters are the most important discussed areas. According to the technical data that are discussed in this review, natural and synthetic zeolites should be considered as materials with tremendous potential of applications in the aquaculture industry. Considerable amounts of research works are under way to explore other opportunities for application of zeolites to benefit aquaculture industry.

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The Caspian Sea, the largest inland closed water body in the world, has numerous endemic species. The Caspian brown trout (Salmo trutta caspius) is considered as endangered according to IUCN criteria. Information on phylogeography and genetic structure is crucial for appropriate management of genetic resources. In spite of the huge number of studies carried out in the Salmo trutta species complex across its distribution range, very few data are available on these issues for S. trutta within the Caspian Sea. Mitochondrial (mtDNA control region) and nuclear (major ribosomal DNA internal transcribed spacer 1, ITS-1, and ten microsatellite loci) molecular markers were used to study the phylogeography, genetic structure, and current captive breeding strategies for reinforcement of Caspian trout in North Iranian rivers. Our results confirmed the presence of Salmo trutta caspius in this region. Phylogenetic analysis demonstrated its membership to the brown trout Danubian (DA) lineage. Genetic diversity of Caspian brown trout in Iranian Rivers is comparable to the levels usually observed in sustainable anadromous European brown trout populations. Microsatellite data suggested two main clusters connected by gene flow among river basins likely by anadromous fish. No genetic differences were detected between the hatchery sample and the remaining wild populations. While the current hatchery program has not produced detectable genetic changes in the wild populations, conservation strategies prioritizing habitat improvement and recovering natural spawning areas for enhancing wild populations are emphasized.