1,721,081 research outputs found
Contribution of bacteria to the Artemia diet
Full text linkThe aim of this study was to determine the dietary role of bacteria in Artemia culture. In the first study, bacteria associated in Artemia culture were isolated and fed to germ-free Artemia nauplii under gnotobiotic cultutre condition (with a known flora) in 6 days experimental period. The results showed that among nines isolated (HT1-HT9), some bacteria could be a food source when offered as a sole food. Among nine isolates, HT3 and HT6 fed Artemia had higher survival and growth, for this reason HT3 and HT6 was included in the second study where mixed diets between bacteria and microalgae were fed to Artemia under gnotobiotic culture condition. In this study, 15N stable isotope was used to label on microalgae in the mixed diet. After 24 h feeding period, 15N accumulated in the Artemia tissue from microalgae were analyzed. The results show that, when bacteria were offered as food together with microalgae there may be enhanced assimilation of nitrogen from microalgae, as compared to the algal mono-diet. In the last study, heterotrophic bacteria were enhanced to grow by sucrose addition from day 2 after hatching (DAH2) onwards within the Artemia culture vials. The assimilation of bacteria by Artemia was evaluated with different depressive feeding regimes: standard feeding regime (SF), half of SF regime (SF1/2), one third of SF regime (SF1/3) and one fourth of SF regime (SF1/4). 15N stable isotope and fatty acids were used as study tools to follow the assimilation of bacteria by Artemia. The results at DAH15 showed that, Artemia biomass production increased in all sucrose addition treatments as compared to the control culture without sucrose addition. Particularly, the Artemia biomass production in the SF1/3 regime with carbon addition treatment was equal to that obtained in the SF regime treatment (without carbon addition). The results of fatty acids level and 15N accumulation in Artemia tissue showed that Artemia fed on bacteria, especially in the algae-limited conditions. Our results, however, still remain to be confirmed in pond culture conditions
Effects of environmental factors on cyst hatching and on larval quality of the brine shrimp Artemia sp. (Anostraca: Branchiopoda)
Full text linkPurple bacteria as microbial protein source : technology development, community control, economic optimization and biomass valorization
No full textAbstract: \u200bFood production is a cornerstone in contemporary industrial societies. Its production requires land, water and enormous amounts of fertilizers. These precious fertilizers enter the linear food chain and suffer from a cascade of inefficiencies, resulting in detrimental effects to the environment. A radical transforming of the current food production chain is, therefore, essential to guarantee a sustainable future for humanity. \u200bThis thesis has studied the production of microbial protein (i.e. single-cell protein), which is the use of microorganisms such as yeast, fungi, algae and bacteria as protein ingredient for animal feed. The type of microorganisms targeted in this thesis were purple non-sulfur bacteria (PNSB). These bacteria are an extremely heterogenic group that contain photosynthetic pigments and are able to perform anoxygenic photosynthesis. The core focus of the thesis was technology development for the production of PNSB as a source of microbial protein on wastewater and fresh fertilizers. In the final stage of this research, it was the objective to explore the potential of PNSB as a nutritious feed ingredient for shrimp. \u200bOverall, this work has provided the building blocks to transform the conventional food production chain. The findings show that PNSB production and biomass valorization is within reach. Further pilot implementation and cost reduction will facilitate the introduction of PNSB production in future\u2019s wastewater treatment plants and the valorization of the biomass as nutritious animal feed ingredient.\u200
Genetic diversity of Artemia populations in Lake Urmia, Iran
No full textUrmia Lake is one of the largest permanent hypersaline lakes in the world, located in northwestern Iran. It is one the permanent habitats for the genus Artemia. This thesis deals with the study of the genetic diversity of the Artemia population in the lake. It was assumed that the information obtained by conducting several genetic and life span characterization studies can provide better insight into the Artemia population in Urmia Lake. Additionally the aim of this study was to assess and improve molecular analyses as a tool to describe inter- and intraspecific diversity of the Artemia populations from Iran. In this thesis, a new molecular marker was developed to identify the parthenogenetic strain co-occurring with bisexual Artemia in Urmia Lake. In addition, in order to investigate the temporal population diversity of Artemia from Urmia Lake, subfossil cyst samples were recovered from the sediment which was dated to 5000-6700 YBP and identified as parthenogenetic Artemia. Another study of this thesis describes the population diversity among Artemia samples, originating from different areas of Urmia Lake, using a mtDNA molecular marker and various phenotypic characteristics. The experimental data bring us to the conclusion that only combined efforts in which selectable molecular markers are joined with phenotypic traits, covering representative numbers of populations, can provide sufficient complementary information for a maximal understanding of the biodiversity of the genus Artemia in Urmia Lake
Isolation and identification of quorum quenching bacteria and assessment of their inhibitory effect on quorum sensing-dependent pathogenicity of Yersinia ruckeri
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High density production of fairy shrimp Branchinecta orientalis G. O. Sars 1901 in fish pond effluents
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