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Michael R Hall - One of the best experts on this subject based on the ideXlab platform.
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the effects of pre digested protein sources on the performance of early mid stage Panulirus ornatus phyllosoma
Aquaculture, 2015Co-Authors: Michael R Hall, Jessica A Conlan, David S Francis, Steven Gamble, Igor Pirozzi, Chaoshu ZengAbstract:Phyllosoma of the tropical spiny rock lobster, Panulirus ornatus, possess a rudimentary digestive system with a limited capacity to digest large protein molecules. As such, to foster the successful aquaculture of this species, research into dietary requirements should place a focus on feed ingredients aligned with digestive capacity. Thus, the aim of the present study was to assess the effects of two protein pre-digestion treatments: acid denaturation and enzyme hydrolysis, on a regular fishmeal ingredient in a novel formulated diet for early–mid stage P. ornatus phyllosoma (Stages III–VIII). Three iso-nitrogenous, iso-lipidic and iso-energetic diets were formulated with 100% of protein originating from intact fishmeal (IFM), acid-denatured fishmeal (DFM) or enzyme hydrolysed fishmeal (HFM) and fed to early–mid stage phyllosoma for a period of 35-days. Growth performance metrics were all significantly higher in phyllosoma receiving the HFM treatment compared to the DFM and IFM treatments. Phyllosoma fed the HFM diet also had the most advanced development stages, with a significantly greater proportion of individuals reaching Stage VII (2). No significant differences were detectable in either the protein-bound or FAA composition of phyllosoma across all treatments, suggesting that the superior growth performance of the HFM fed phyllosoma was the result of an increased abundance of intermediate, shorter chain dietary peptides. The present study suggests that enzyme hydrolysed fishmeal is a superior protein ingredient for artificial diets and most closely resembles the requisite dietary protein format for P. ornatus phyllosoma.
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changes in the nutritional composition of captive early mid stage Panulirus ornatus phyllosoma over ecdysis and larval development
Aquaculture, 2014Co-Authors: Michael R Hall, Jessica A Conlan, Paul L Jones, Giovanni M Turchini, David S FrancisAbstract:Abstract Elucidation of the key nutritional requirements for complete larval development of the tropical spiny rock lobster, Panulirus ornatus, presents a major challenge for the development of robust commercial aquaculture for this crustacean. As a foundation study in this area, the chemical composition of early–mid stage P. ornatus phyllosoma (Stages I–VI) receiving a novel formulated diet was analysed immediately prior and post-ecdysis to provide insight into the crude nutritional trends during the larval development cycle. From the onset of moulting, cyclical patterns were evident in the proximate composition of phyllosoma, resulting in substantial restructuring between the pre- and post-moult stages of the moult cycle. Proportions of protein, lipid and ash were high at the premoult stage, reflecting growth and nutrient accumulation over the intermoult period, and reduced at the post-moult stage, reflecting the large uptake of water to facilitate subsequent growth. Polar lipid was the dominant lipid class, accounting for > 90% of the total lipid content. Conversely, triacylglycerol concentrations were low (
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identification of an antagonistic probiotic combination protecting ornate spiny lobster Panulirus ornatus larvae against vibrio owensii infection
PLOS ONE, 2012Co-Authors: Evan F. Goulden, Michael R Hall, Lily Pereg, Lone HojAbstract:Vibrio owensii DY05 is a serious pathogen causing epizootics in the larviculture of ornate spiny lobster Panulirus ornatus. In the present study a multi-tiered probiotic screening strategy was used to identify a probiotic combination capable of protecting P. ornatus larvae (phyllosomas) from experimental V. owensii DY05 infection. From a pool of more than 500 marine bacterial isolates, 91 showed definitive in vitro antagonistic activity towards the pathogen. Antagonistic candidates were shortlisted based on phylogeny, strength of antagonistic activity, and isolate origin. Miniaturized assays used a green fluorescent protein labelled transconjugant of V. owensii DY05 to assess pathogen growth and biofilm formation in the presence of shortlisted candidates. This approach enabled rapid processing and selection of candidates to be tested in a phyllosoma infection model. When used in combination, strains Vibrio sp. PP05 and Pseudoalteromonas sp. PP107 significantly and reproducibly protected P. ornatus phyllosomas during vectored challenge with V. owensii DY05, with survival not differing significantly from unchallenged controls. The present study has shown the value of multispecies probiotic treatment and demonstrated that natural microbial communities associated with wild phyllosomas and zooplankton prey support antagonistic bacteria capable of in vivo suppression of a pathogen causing epizootics in phyllosoma culture systems.
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pathogenicity and infection cycle of vibrio owensii in larviculture of the ornate spiny lobster Panulirus ornatus
Applied and Environmental Microbiology, 2012Co-Authors: Evan F. Goulden, Michael R Hall, David G Bourne, Lily Pereg, Lone HojAbstract:The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organism Artemia (brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeled V. owensii DY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection. V. owensii DY05 is a marine enteropathogen highly virulent to P. ornatus phyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.
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patterns of larval growth lipid composition and fatty acid deposition during early to mid stages of development in Panulirus ornatus phyllosoma
Aquaculture, 2012Co-Authors: Greg Smith, Michael R HallAbstract:The tropical spiny lobster, Panulirus ornatus, is a commercially important Palinurid marine lobster species of high market value with wild populations distributed throughout the tropical and sub-tropical Indo-Pacific region. As wild populations of P. ornatus has been over-exploited, so there is interest in the development of this lobster aquaculture to meet current and rising market demand for supply. However, a major challenge for closed-life cycle production of Palinurid lobsters is the development of a commercially viable hatchery technology. There is minimum knowledge of larval nutrition, and in particular, the lipid requirements. The current study focused on investigations into the growth pattern and ontogenetic changes of lipid composition for early–mid stage P. ornatus (stages I–VI) under controlled laboratory conditions. Body wet weight (WW), dry weight (DW) and total body length (TBL) increased exponentially with the number of stages. There were large increases in WW, DW and TBL between stages I and VI, with increases of 4092%, 3864% and 504%, respectively. The greatest increase in DW and WW was noted between stages III to IV while the greatest specific growth rate (SGR) was noted during stages I to II. The lipid class profile of phyllosoma was dominated by phospholipids (PL) for all early stages (I–V) despite the high triacylglyceride (TG) content of Artemia; which was the primary food source. The newly hatched phyllosoma contained higher percentages of total saturated fatty acids (SFA), 20:5n3 (EPA), 22:6n3 (DHA) and total highly unsaturated fatty acids (HUFA) compared to that found in all other stages. From stages II to V, the total lipid, lipid class and fatty acid profile of phyllosoma resembled those of their diet with the exception of 20:4n6 (ARA). The increase in ARA concentration during phyllosoma development (stages II–V) suggested that mid-stage phyllosoma (IV and V) had a higher requirement compared to that noted in early-stage (II and III) phyllosoma. It was noted that early-stage (II and III) phyllosoma preferentially sequestered and accumulated a higher proportion of EPA and DHA compared to that present in their diets. These data indicate that early–mid stage P. ornatus phyllosoma have an ability to preferentially sequester, store or modify their dietary lipid composition to support normal growth and development. These results provide important morphometric date useful in the evaluation of larval feed and culture conditions as well as, providing baseline larval lipid nutrition data required for the development of artificial diets for P. ornatus phyllosoma.
David S Francis - One of the best experts on this subject based on the ideXlab platform.
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the effects of pre digested protein sources on the performance of early mid stage Panulirus ornatus phyllosoma
Aquaculture, 2015Co-Authors: Michael R Hall, Jessica A Conlan, David S Francis, Steven Gamble, Igor Pirozzi, Chaoshu ZengAbstract:Phyllosoma of the tropical spiny rock lobster, Panulirus ornatus, possess a rudimentary digestive system with a limited capacity to digest large protein molecules. As such, to foster the successful aquaculture of this species, research into dietary requirements should place a focus on feed ingredients aligned with digestive capacity. Thus, the aim of the present study was to assess the effects of two protein pre-digestion treatments: acid denaturation and enzyme hydrolysis, on a regular fishmeal ingredient in a novel formulated diet for early–mid stage P. ornatus phyllosoma (Stages III–VIII). Three iso-nitrogenous, iso-lipidic and iso-energetic diets were formulated with 100% of protein originating from intact fishmeal (IFM), acid-denatured fishmeal (DFM) or enzyme hydrolysed fishmeal (HFM) and fed to early–mid stage phyllosoma for a period of 35-days. Growth performance metrics were all significantly higher in phyllosoma receiving the HFM treatment compared to the DFM and IFM treatments. Phyllosoma fed the HFM diet also had the most advanced development stages, with a significantly greater proportion of individuals reaching Stage VII (2). No significant differences were detectable in either the protein-bound or FAA composition of phyllosoma across all treatments, suggesting that the superior growth performance of the HFM fed phyllosoma was the result of an increased abundance of intermediate, shorter chain dietary peptides. The present study suggests that enzyme hydrolysed fishmeal is a superior protein ingredient for artificial diets and most closely resembles the requisite dietary protein format for P. ornatus phyllosoma.
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changes in the nutritional composition of captive early mid stage Panulirus ornatus phyllosoma over ecdysis and larval development
Aquaculture, 2014Co-Authors: Michael R Hall, Jessica A Conlan, Paul L Jones, Giovanni M Turchini, David S FrancisAbstract:Abstract Elucidation of the key nutritional requirements for complete larval development of the tropical spiny rock lobster, Panulirus ornatus, presents a major challenge for the development of robust commercial aquaculture for this crustacean. As a foundation study in this area, the chemical composition of early–mid stage P. ornatus phyllosoma (Stages I–VI) receiving a novel formulated diet was analysed immediately prior and post-ecdysis to provide insight into the crude nutritional trends during the larval development cycle. From the onset of moulting, cyclical patterns were evident in the proximate composition of phyllosoma, resulting in substantial restructuring between the pre- and post-moult stages of the moult cycle. Proportions of protein, lipid and ash were high at the premoult stage, reflecting growth and nutrient accumulation over the intermoult period, and reduced at the post-moult stage, reflecting the large uptake of water to facilitate subsequent growth. Polar lipid was the dominant lipid class, accounting for > 90% of the total lipid content. Conversely, triacylglycerol concentrations were low (
David G Bourne - One of the best experts on this subject based on the ideXlab platform.
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pathogenicity and infection cycle of vibrio owensii in larviculture of the ornate spiny lobster Panulirus ornatus
Applied and Environmental Microbiology, 2012Co-Authors: Evan F. Goulden, Michael R Hall, David G Bourne, Lily Pereg, Lone HojAbstract:The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organism Artemia (brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeled V. owensii DY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection. V. owensii DY05 is a marine enteropathogen highly virulent to P. ornatus phyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.
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Microbiological aspects of phyllosoma rearing of the ornate rock lobster Panulirus ornatus
Aquaculture, 2007Co-Authors: David G Bourne, Lone Hoj, Nicole S. Webster, Matthew S Payne, Mette E. Skindersoe, Michael Givskov, Michael R HallAbstract:Abstract Rock lobsters of the Palinuridae are the most valuable wild fisheries sector in Australia and are currently target aquaculture species. Significant challenges exist however to produce commercial scale quantities of post-larvae due to an extended larval phase which acerbates a high rate of larval attrition caused by inadequate nutrition and a challenging microbial environment. Here we investigate a diverse and varied bacterial community in four compartments of the larval-rearing system: the water column, the biofilm, live feeds and the phyllosomas themselves. External fouling of phyllosoma by filamentous Thiothrix sp. was documented by scanning electron microscopy (SEM) and fluorescence in situ hybridisation (FISH). Internal proliferation of bacteria coinciding with mass mortality of phyllosoma was observed in histopathological analysis and identified as Vibrio sp. by specific labelling of sectioned hepatopancreas tissue using FISH. Of particular interest in relation to larval mortalities was a range of Vibrio species, isolated from the four rearing compartments, closely affiliated with V. alginolyticus, V. parahaemolyticus, and V. harveyi. The presence of bacterial quorum sensing signal molecules within the system was demonstrated in both biofilm and phyllosoma environments during a larval-rearing run. Interestingly, a large increase in quorum sensing signal molecules was detected in phyllosoma corresponding with mass mortality.
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microbial diversity within early stage cultured Panulirus ornatus phyllosomas
Applied and Environmental Microbiology, 2007Co-Authors: Michael R Hall, Matthew S Payne, L I Sly, David G BourneAbstract:A thorough understanding of the microorganisms and pathogens associated with the larval stage of the tropical ornate rock lobster, Panulirus ornatus, is required to overcome disease outbreaks that currently block aquaculture attempts. This study used microscopy in addition to culture and molecularly based microbiological techniques to characterize the bacterial community associated with cultured, developmental stage PI to PII P. ornatus phyllosomas. Scanning electron microscopy demonstrated colonization of phyllosomas by filamentous, rod-shaped, and coccus-shaped bacteria. A clone library constructed from dead phyllosomas sampled from the larval rearing tank on day 10 was dominated by Thiothrix-affiliated sequences (56% of clones). A comparable library from live phyllosomas also contained Thiothrix-affiliated sequences, though these only represented 19% of clones within the library. Fluorescent in situ hybridization (FISH) confirmed identification of the filamentous bacteria as Thiothrix sp., being present on dead phyllosomas. FISH also identified Leucothrix sp. and Vibrio sp., as well as a range of other rod- and coccus-shaped bacteria, colonizing both live and dead phyllosomas. The development of the microbial community associated with phyllosomas was monitored through a standard larval rearing run using denaturing gradient gel electrophoresis (DGGE). Vibrio sp.-affiliated bands dominated the profiles of live animals through the rearing period and dead phyllosomas sampled on selected days. The population of Vibrio sp. associated with phyllosomas was monitored with culture-based analysis on selective media and demonstrated to increase significantly on day 7, coinciding with the beginning of the larval molt. An isolated Vibrio harveyi strain demonstrated an identical 16S rRNA sequence with retrieved DGGE and clone library sequences. Colonization of phyllosomas with filamentous bacterial species potentially hinders the ability of the animals to molt and, combined with the added stress of the molt process, likely results in reduced immune function, allowing opportunistic pathogenic Vibrio sp. to cause larval mortalities.
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biofilm development within a larval rearing tank of the tropical rock lobster Panulirus ornatus
Aquaculture, 2006Co-Authors: David G Bourne, Lone Hoj, Nicole S. Webster, Jennie Swan, Michael R HallAbstract:Abstract The role of bacterial biofilms in disease processes is becoming increasingly recognised in both clinical and environmental settings. Biofilm development within a rearing tank of the tropical rock lobster Panulirus ornatus was studied to evaluate if the biofilm is a reservoir for potentially pathogenic bacteria that cause mass larval mortalities. Within a 5000 L larval rearing tank, fiberglass microscope slides were systematically distributed during a standard rearing attempt to assess biofilm development. Culture-based counts for two media types, TCBS and Marine Agar (MA), demonstrated increased bacterial densities until days 11 and 13 respectively. For both media types, a drop in the plate counts was followed by a subsequent increase towards the end of the experiment. Scanning electron microscopy (SEM) confirmed that cell densities decreased between days 13 and 17, most likely due to sloughing of the biofilm into the water column. SEM images revealed distinct changes in dominant morphologies reflecting a succession of bacterial populations. A dynamic succession of microbial species during biofilm development was also demonstrated using denaturing gradient gel electrophoresis (DGGE) profiling of bacterial 16S rRNA genes in combination with statistical ordination analysis. Prominent changes in the DGGE profiles coincided with the decrease in bacterial numbers observed by SEM and plating on MA between days 13 and 17. Fluorescence in situ hybridization (FISH) identified α- Proteobacteria as being numerically abundant in the biofilm. This was supported by results from DGGE analysis, which retrieved only sequences affiliated with α- and γ- Proteobacteria . DGGE bands affiliated with Vibrio became dominant towards the end of the larval run (days 21 to 24). A Vibrio harveyi strain isolated from the biofilm late in the larval rearing trial (day 24) demonstrated increased larval mortality in small scale phyllosoma survival studies. The detection of Vibrionaceae at the end of the larval trial coincided with mass phyllosoma mortality and show that the biofilm is a reservoir for potentially pathogenic bacteria.
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microbial diversity within the water column of a larval rearing system for the ornate rock lobster Panulirus ornatus
Aquaculture, 2006Co-Authors: Michael R Hall, Matthew S Payne, L I Sly, Raymond Bannister, David G BourneAbstract:The ornate tropical rock lobster, Panulirus ornatus has substantial potential as an aquaculture species though disease outbreaks during the animal's extended larval lifecycle are major constraints for success. In order to effectively address such disease-related issues, an improved understanding of the composition and dynamics of the microbial communities in the larval rearing tanks is required. This study used flow cytometry and molecular microbial techniques (clone libraries and denaturing gradient gel electrophoresis (DGGE)) to quantify and characterise the microbial community of the water column in the early stages (developmental stage I–II) of a P. ornatus larval rearing system. DGGE analysis of a 5000 L larval rearing trial demonstrated a dynamic microbial community with distinct changes in the community structure after initial stocking (day 1 to day 2) and from day 4 to day 5, after which the structure was relatively stable. Flow cytometry analysis of water samples taken over the duration of the trial demonstrated a major increase in bacterial load leading up to and peaking on the first day of the initial larval moult (day 7), before markedly decreasing prior to when > 50% of larvae moulted (day 9). A clone library of a day 10 water sample taken following a mass larval mortality event reflected high microbial diversity confirmed by statistical analysis indices. Sequences retrieved from both clone library and DGGE analyses were dominated by γ- and α-Proteobacteria affiliated organisms with additional sequences affiliated with β- and e-Proteobacteria, Bacteroidetes, Cytophagales and Chlamydiales groups. Vibrio affiliated species were commonly retrieved in the clone library, though absent from DGGE analysis.
Jessica A Conlan - One of the best experts on this subject based on the ideXlab platform.
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the effects of pre digested protein sources on the performance of early mid stage Panulirus ornatus phyllosoma
Aquaculture, 2015Co-Authors: Michael R Hall, Jessica A Conlan, David S Francis, Steven Gamble, Igor Pirozzi, Chaoshu ZengAbstract:Phyllosoma of the tropical spiny rock lobster, Panulirus ornatus, possess a rudimentary digestive system with a limited capacity to digest large protein molecules. As such, to foster the successful aquaculture of this species, research into dietary requirements should place a focus on feed ingredients aligned with digestive capacity. Thus, the aim of the present study was to assess the effects of two protein pre-digestion treatments: acid denaturation and enzyme hydrolysis, on a regular fishmeal ingredient in a novel formulated diet for early–mid stage P. ornatus phyllosoma (Stages III–VIII). Three iso-nitrogenous, iso-lipidic and iso-energetic diets were formulated with 100% of protein originating from intact fishmeal (IFM), acid-denatured fishmeal (DFM) or enzyme hydrolysed fishmeal (HFM) and fed to early–mid stage phyllosoma for a period of 35-days. Growth performance metrics were all significantly higher in phyllosoma receiving the HFM treatment compared to the DFM and IFM treatments. Phyllosoma fed the HFM diet also had the most advanced development stages, with a significantly greater proportion of individuals reaching Stage VII (2). No significant differences were detectable in either the protein-bound or FAA composition of phyllosoma across all treatments, suggesting that the superior growth performance of the HFM fed phyllosoma was the result of an increased abundance of intermediate, shorter chain dietary peptides. The present study suggests that enzyme hydrolysed fishmeal is a superior protein ingredient for artificial diets and most closely resembles the requisite dietary protein format for P. ornatus phyllosoma.
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changes in the nutritional composition of captive early mid stage Panulirus ornatus phyllosoma over ecdysis and larval development
Aquaculture, 2014Co-Authors: Michael R Hall, Jessica A Conlan, Paul L Jones, Giovanni M Turchini, David S FrancisAbstract:Abstract Elucidation of the key nutritional requirements for complete larval development of the tropical spiny rock lobster, Panulirus ornatus, presents a major challenge for the development of robust commercial aquaculture for this crustacean. As a foundation study in this area, the chemical composition of early–mid stage P. ornatus phyllosoma (Stages I–VI) receiving a novel formulated diet was analysed immediately prior and post-ecdysis to provide insight into the crude nutritional trends during the larval development cycle. From the onset of moulting, cyclical patterns were evident in the proximate composition of phyllosoma, resulting in substantial restructuring between the pre- and post-moult stages of the moult cycle. Proportions of protein, lipid and ash were high at the premoult stage, reflecting growth and nutrient accumulation over the intermoult period, and reduced at the post-moult stage, reflecting the large uptake of water to facilitate subsequent growth. Polar lipid was the dominant lipid class, accounting for > 90% of the total lipid content. Conversely, triacylglycerol concentrations were low (
Lone Hoj - One of the best experts on this subject based on the ideXlab platform.
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screening of marine bacteria with bacteriocin like activities and probiotic potential for ornate spiny lobster Panulirus ornatus juveniles
Fish & Shellfish Immunology, 2014Co-Authors: Van Duy Nguyen, Thu Thuy Pham, Thi Hai Thanh Nguyen, Thi Thanh Xuan Nguyen, Lone HojAbstract:Bacteriocins are ribosomally synthesized antimicrobial peptides, which have been found in diverse bacterial species of terrestrial origins and some from the sea. New bacteriocins with new characteristics, new origins and new applications are likely still awaiting discovery. The present study screened bacteria isolated from marine animals of interest to the aquaculture industry for antimicrobial and bacteriocin-like activities in order to uncover biodiversity of bacteriocin producers, and explore the potential application in aquaculture. In total, 24 of 100 screened isolates showed antimicrobial activities and 7 of these exerted bacteriocin-like activities. Sequencing of 16S rRNA genes identified the isolates as members of the six genera Proteus, Providencia, Klebsiella, Alcaligenes, Bacillus and Enterococcus. In some cases, further analysis of housekeeping genes, rpoB for Proteus and recA for Klebsiella, as well as biochemical tests was necessary for identification to species level, and some of the Proteus isolates may represent novel species. The seven bacteriocinogenic isolates showed a wide antimicrobial spectrum against foodborne and animal pathogens, which opens the way to their potential use as marine drugs and probiotics in food, aquaculture, livestock and clinical settings. As a case study, the protective effect of shortlisted bacteriocinogenic isolates were tested in aquaculture-raised spiny lobster (Panulirus ornatus) juveniles. A single-strain (Bacillus pumilus B3.10.2B) and a three-strain (B. pumilus B3.10.2B, Bacillus cereus D9, Lactobacillus plantarum T13) probiotic preparation were added to the feed of Panulirus ornatus juveniles, which were subsequently challenged with the pathogen Vibrio owensii DY05. Juveniles in the probiotic treatments displayed increased growth and reduced feed conversion rates after 60 days, and increased survival rate after pathogen challenge relative to the control. This study represents the first evidence of bacteriocin production by bacteria associated with lobster, tiger shrimp, snubnose pompano and cobia and the first description of V. owensii as a pathogen in P. ornatus juveniles.
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identification of an antagonistic probiotic combination protecting ornate spiny lobster Panulirus ornatus larvae against vibrio owensii infection
PLOS ONE, 2012Co-Authors: Evan F. Goulden, Michael R Hall, Lily Pereg, Lone HojAbstract:Vibrio owensii DY05 is a serious pathogen causing epizootics in the larviculture of ornate spiny lobster Panulirus ornatus. In the present study a multi-tiered probiotic screening strategy was used to identify a probiotic combination capable of protecting P. ornatus larvae (phyllosomas) from experimental V. owensii DY05 infection. From a pool of more than 500 marine bacterial isolates, 91 showed definitive in vitro antagonistic activity towards the pathogen. Antagonistic candidates were shortlisted based on phylogeny, strength of antagonistic activity, and isolate origin. Miniaturized assays used a green fluorescent protein labelled transconjugant of V. owensii DY05 to assess pathogen growth and biofilm formation in the presence of shortlisted candidates. This approach enabled rapid processing and selection of candidates to be tested in a phyllosoma infection model. When used in combination, strains Vibrio sp. PP05 and Pseudoalteromonas sp. PP107 significantly and reproducibly protected P. ornatus phyllosomas during vectored challenge with V. owensii DY05, with survival not differing significantly from unchallenged controls. The present study has shown the value of multispecies probiotic treatment and demonstrated that natural microbial communities associated with wild phyllosomas and zooplankton prey support antagonistic bacteria capable of in vivo suppression of a pathogen causing epizootics in phyllosoma culture systems.
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pathogenicity and infection cycle of vibrio owensii in larviculture of the ornate spiny lobster Panulirus ornatus
Applied and Environmental Microbiology, 2012Co-Authors: Evan F. Goulden, Michael R Hall, David G Bourne, Lily Pereg, Lone HojAbstract:The type strain of Vibrio owensii (DY05) was isolated during an epizootic of aquaculture-reared larvae (phyllosomas) of the ornate spiny lobster (Panulirus ornatus). V. owensii DY05 was formally demonstrated to be the etiological agent of a disease causing rapid and reproducible larval mortality with pathologies similar to those seen during disease epizootics. Vectored challenge via the aquaculture live feed organism Artemia (brine shrimp) caused consistent cumulative mortality rates of 84 to 89% after 72 h, in contrast to variable mortality rates seen after immersion challenge. Histopathological examination of vector-challenged phyllosomas revealed bacterial proliferation in the midgut gland (hepatopancreas) concomitant with epithelial cell necrosis. A fluorescent-protein-labeled V. owensii DY05 transconjugant showed dispersal of single cells in the foregut and hepatopancreas 6 h postexposure, leading to colonization of the entire hepatopancreas within 18 h and eventually systemic infection. V. owensii DY05 is a marine enteropathogen highly virulent to P. ornatus phyllosoma that uses vector-mediated transmission and release from host association to a planktonic existence to perpetuate transfer. This understanding of the infection process will improve targeted biocontrol strategies and enhance the prospects of commercially viable larviculture for this valuable spiny lobster species.
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Microbiological aspects of phyllosoma rearing of the ornate rock lobster Panulirus ornatus
Aquaculture, 2007Co-Authors: David G Bourne, Lone Hoj, Nicole S. Webster, Matthew S Payne, Mette E. Skindersoe, Michael Givskov, Michael R HallAbstract:Abstract Rock lobsters of the Palinuridae are the most valuable wild fisheries sector in Australia and are currently target aquaculture species. Significant challenges exist however to produce commercial scale quantities of post-larvae due to an extended larval phase which acerbates a high rate of larval attrition caused by inadequate nutrition and a challenging microbial environment. Here we investigate a diverse and varied bacterial community in four compartments of the larval-rearing system: the water column, the biofilm, live feeds and the phyllosomas themselves. External fouling of phyllosoma by filamentous Thiothrix sp. was documented by scanning electron microscopy (SEM) and fluorescence in situ hybridisation (FISH). Internal proliferation of bacteria coinciding with mass mortality of phyllosoma was observed in histopathological analysis and identified as Vibrio sp. by specific labelling of sectioned hepatopancreas tissue using FISH. Of particular interest in relation to larval mortalities was a range of Vibrio species, isolated from the four rearing compartments, closely affiliated with V. alginolyticus, V. parahaemolyticus, and V. harveyi. The presence of bacterial quorum sensing signal molecules within the system was demonstrated in both biofilm and phyllosoma environments during a larval-rearing run. Interestingly, a large increase in quorum sensing signal molecules was detected in phyllosoma corresponding with mass mortality.
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biofilm development within a larval rearing tank of the tropical rock lobster Panulirus ornatus
Aquaculture, 2006Co-Authors: David G Bourne, Lone Hoj, Nicole S. Webster, Jennie Swan, Michael R HallAbstract:Abstract The role of bacterial biofilms in disease processes is becoming increasingly recognised in both clinical and environmental settings. Biofilm development within a rearing tank of the tropical rock lobster Panulirus ornatus was studied to evaluate if the biofilm is a reservoir for potentially pathogenic bacteria that cause mass larval mortalities. Within a 5000 L larval rearing tank, fiberglass microscope slides were systematically distributed during a standard rearing attempt to assess biofilm development. Culture-based counts for two media types, TCBS and Marine Agar (MA), demonstrated increased bacterial densities until days 11 and 13 respectively. For both media types, a drop in the plate counts was followed by a subsequent increase towards the end of the experiment. Scanning electron microscopy (SEM) confirmed that cell densities decreased between days 13 and 17, most likely due to sloughing of the biofilm into the water column. SEM images revealed distinct changes in dominant morphologies reflecting a succession of bacterial populations. A dynamic succession of microbial species during biofilm development was also demonstrated using denaturing gradient gel electrophoresis (DGGE) profiling of bacterial 16S rRNA genes in combination with statistical ordination analysis. Prominent changes in the DGGE profiles coincided with the decrease in bacterial numbers observed by SEM and plating on MA between days 13 and 17. Fluorescence in situ hybridization (FISH) identified α- Proteobacteria as being numerically abundant in the biofilm. This was supported by results from DGGE analysis, which retrieved only sequences affiliated with α- and γ- Proteobacteria . DGGE bands affiliated with Vibrio became dominant towards the end of the larval run (days 21 to 24). A Vibrio harveyi strain isolated from the biofilm late in the larval rearing trial (day 24) demonstrated increased larval mortality in small scale phyllosoma survival studies. The detection of Vibrionaceae at the end of the larval trial coincided with mass phyllosoma mortality and show that the biofilm is a reservoir for potentially pathogenic bacteria.
