Browsing by Author "Esteves, Liliana Sofia Ferreira"
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- Bioburden in aquafeeds designed for echinoderms production in PortugalPublication . Esteves, Liliana Sofia Ferreira; Viegas, Carla Sofia Costa; Pombo, Ana Margarida Paulino ViolanteThe aquafeeds can be a route of contamination for animals produced in aquaculture and, consequently, for humans. For this reason, it is imperative to identify the bioburden present in aquafeeds, in order to know the threat that may represent for human health. Extruded and jellified pellets and frozen microalgae were specifically designed for the potential production, in Recirculating Aquaculture Systems, of two species of echinoderms, the sea cucumber Holothuria tubulosa and the sea urchin Paracentrotus lividus. Thus, diet samples were collected to characterise their bioburden. Furthermore, water samples and sponge filter samples were also collected to identify their proliferation to water and the efficiency of filtration process used, respectively. All samples were collected 90 days after the start of the experiment. Culture-based methods were used for the characterisation of bioburden, in which mesophilic bacteria and total coliforms were enumerating for bacterial evaluation, while filamentous and xerophilic fungi were counting and identifying through micro and macroscopic characteristics for fungal assessment. Aspergillus sections were investigated through molecular method Real-Time Polymerase Chain Reaction. Mycotoxin analysis was carried out utilising Liquid Chromatography-Mass Spectrometry system. For mesophilic bacteria, the results reveal some spoilage activity. The results for total coliforms were actually minimal. Fusarium verticillioides was identified in one jellified pellet and in one frozen microalgae and F. culmorum was identified in the same frozen microalgae. Aspergillus sections were not detected in any sample. Mycotoxins were detected in the extruded pellets and in one jellified pellet, but the quantification only was possible in the extruded pellets. However, the most part of the findings of this study were below to the limits defined as harmless. So the diets used in the production systems evaluated seem to be safe to be used for feeding the studied echinoderms.
- Bioburden in aquafeeds designed for echinoderms production in PortugalPublication . Esteves, Liliana Sofia Ferreira; Viegas, Carla; Pombo, Ana MargaridaABSTRACT - The aquafeeds can be a route of contamination for animals produced in aquaculture and, consequently, for humans. For this reason, it is imperative to identify the bioburden present in aquafeeds, in order to know the threat that may represent for human health. Extruded and jellified pellets and frozen microalgae were specifically designed for the potential production, in Recirculating Aquaculture Systems, of two species of echinoderms, the sea cucumber Holothuria tubulosa and the sea urchin Paracentrotus lividus. Thus, diet samples were collected to characterize their bioburden. Furthermore, water samples and sponge filter samples were also collected to identify their proliferation to water and the efficiency of the filtration process used, respectively. All samples were collected 90 days after the start of the experiment. Culture-based methods were used for the characterization of bioburden, in which mesophilic bacteria and total coliforms were enumerating for bacterial evaluation, while filamentous and xerophilic fungi were counting and identifying through micro and macroscopic characteristics for fungal assessment. Aspergillus sections were investigated through molecular method Real-Time Polymerase Chain Reaction. Mycotoxin analysis was carried out utilizing a Liquid Chromatography-Mass Spectrometry system. For mesophilic bacteria, the results reveal some spoilage activity. The results for total coliforms were actually minimal. Fusarium verticillioides were identified in one jellified pellet and in one frozen microalgae and F. culmorum was identified in the same frozen microalgae. Aspergillus sections were not detected in any sample. Mycotoxins were detected in the extruded pellets and in one jellified pellet, but the quantification only was possible in the extruded pellets. However, most parts of the findings of this study were below the limits defined as harmless. So the diets used in the production systems evaluated seem to be safe to be used for feeding the studied echinoderms.