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Microorganisms Nov 2023The upsurge in havoc being wreaked by antibiotic-resistant bacteria has led to an urgent need for efficacious alternatives to antibiotics. This study assessed the...
The upsurge in havoc being wreaked by antibiotic-resistant bacteria has led to an urgent need for efficacious alternatives to antibiotics. This study assessed the antibacterial efficacy of two isobutyl cyanoacrylate nanoparticles (iBCA-NPs), D6O and NP30, against major bacterial pathogens of fish. In vivo tests on rainbow trout were preceded by in vitro tests of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). NP30 exhibited higher efficacy than D60, but both iBCA-NPs demonstrated dose-dependent and species-specific in vitro antibacterial properties against the bacterial isolates. Generally, Gram-negative bacteria were more resistant to the iBCA-NPs. , , and were particularly sensitive to both iBCA-NPs. Administered to rainbow trout at 3571.4 mg (iBCA-NP)/kg feed, the iBCA-NPs produced a relative gain rate and survival rates comparable to the control ( > 0.05). The condition factor and the hepatosomatic and viscerosomatic indices of fish were indifferentiable ( > 0.05) between the iBCA-NP groups and the control. The iBCA-NPs caused no alteration in stress, oxidative stress (superoxide dismutase, SOD), plasma complement titer, or lysozyme activity. This study presents the first report of antibacterial activity of iBCA-NPs against Gram-negative bacteria. The results of this study suggest that D60 and NP30 may contribute to reducing the amounts of antibiotics and chemotherapeutic agents used in aquaculture.
PubMed: 38138020
DOI: 10.3390/microorganisms11122877 -
Foods (Basel, Switzerland) Dec 2023Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause...
Cold-smoked salmon are ready-to-eat products that may support the growth of pathogenic during their long shelf-life. Consumption of such contaminated products can cause fatal listeriosis infections. Another challenge and potential risk associated with CS salmon is their high levels of sodium salt. Excess dietary intake is associated with serious health complications. In the present study, anti-listerial bacteriocin (nisin), P100 bacteriophages (Phageguard L, PGL) and fermentates (Verdad N6, P-NDV) were evaluated as commercial bio-preservation strategies for increased control of in standard (with NaCl) and sodium-reduced (NaCl partially replaced with KCl) CS salmon. Treatments of CS salmon with nisin (1 ppm) and PGL (5 × 10 pfu/cm) separately yielded significant initial reductions in (up to 0.7 log) compared to untreated samples. Enhanced additive reductions were achieved through the combined treatments of nisin and PGL. Fermentates in the CS salmon inhibited the growth of Listeria but did not lead to its eradication. The lowest levels of during storage were observed in nisin- and PGL-treated CS salmon containing preservative fermentates and stored at 4 °C, while enhanced growth was observed during storage at an abusive temperature of 8 °C. Evaluation of industry-processed standard and sodium-replaced CS salmon confirmed significant effects with up to 1.7 log reductions in levels after 34 days of storage of PGL- and nisin-treated CS salmon-containing fermentates. No differences in total aerobic plate counts were observed between treated (PGL and nisin) or non-treated standard and sodium-reduced CS salmon at the end of storage. The microbiota was dominated by but with a shift showing dominance of spp. and spp. in fermentate-containing samples. Similar and robust reductions in can be achieved in both standard and sodium-replaced CS salmon using the bio-preservation strategies of nisin, PGL and fermentates under various and relevant processing and storage conditions.
PubMed: 38137194
DOI: 10.3390/foods12244391 -
Biology Dec 2023Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and...
Salinity is an important environmental stress factor in mariculture. Shrimp intestines harbor dense and diverse microbial communities that maintain host health and anti-pathogen capabilities under salinity stress. In this study, 16s amplicon and transcriptome sequencing were used to analyze the intestine of under low-salinity stress (15 ppt). This study aimed to investigate the response mechanisms of the intestinal microbiota and gene expression to acute low-salinity stress. The intestinal tissues of were analyzed using 16S microbiota and transcriptome sequencing. The microbiota analysis demonstrated that the relative abundances of and decreased significantly, whereas , , , , , , , and became the predominant communities. Transcriptome sequencing identified numerous differentially expressed genes (DEGs). The DEGs were clustered into many Gene Ontology terms and further enriched in some immunity- or metabolism-related Kyoto Encyclopedia of Genes and Genomes pathways, including various types of N-glycan biosynthesis, amino acid sugar and nucleotide sugar metabolism, and lysosome and fatty acid metabolism. Correlation analysis between microbiota and DEGs showed that changes in , , , and were positively correlated with immune-related genes such as peritrophin-1-like and mucin-2-like, and negatively correlated with caspase-1-like genes. Low-salinity stress caused changes in intestinal microorganisms and their gene expression, with a close correlation between them.
PubMed: 38132328
DOI: 10.3390/biology12121502 -
Food Research International (Ottawa,... Jan 2024Fresh fish is a highly perishable product and is easily spoiled by microbiological activity and chemical oxidation of lipids. However, microbial spoilage is the main...
Fresh fish is a highly perishable product and is easily spoiled by microbiological activity and chemical oxidation of lipids. However, microbial spoilage is the main factor linked with the rapid fish sensorial degradation due to the action of specific spoilage organisms (SSOs) that have the ability to dominate over other microorganisms and produce metabolites responsible for off-flavours. We explored the microbial dynamics in fresh anchovies stored in different packaging (air, modified atmosphere, under vacuum) and temperatures (0, 4 and 10 °C) using shotgun metagenomics, highlighting the selection of different microbial species according to the packaging type. Indeed, Pseudoalteromonas nigrifaciens, Psychrobacter cryohalolentis and Ps. immobilis, Pseudomonas deceptionensis and Vibrio splendidus have been identified as the main SSOs in aerobically stored anchovies, while Shewanella baltica, Photobacterium iliopiscarium, Ps. cryohalolentis and Ps. immobilis prevailed in VP and MAP. In addition, we identified the presence of spoilage-associated genes, leading to the potential production of biogenic amines and different off-flavors (HS, TMA). In particular, the abundance of microbial genes leading to BA biosynthesis increased at higher storage temperature, while those related to HS and TMA production were enriched in aerobically and VP packed anchovies, suggesting that MAP could be an effective strategy in delaying the production of these compounds. Finally, we provided evidence of the presence of a wide range of antibiotic resistance genes conferring resistance to different classes of antibiotic (β-lactams, tetracyclines, polymyxins, trimethoprims and phenicols) and highlighted that storage at higher temperature (4 and 10 °C) boosted the abundance of ARG-carrying taxa, especially in aerobically and MAP packed fish.
Topics: Animals; Food Packaging; Anti-Bacterial Agents; Food Microbiology; Food Preservation; Genomics; Microbiota
PubMed: 38129066
DOI: 10.1016/j.foodres.2023.113788 -
Microbial Genomics Dec 2023This study presents the assembly and comparative genomic analysis of luminous strains isolated from the light organs of 12 fish species using Oxford Nanopore...
This study presents the assembly and comparative genomic analysis of luminous strains isolated from the light organs of 12 fish species using Oxford Nanopore Technologies (ONT) sequencing. The majority of assemblies achieved chromosome-level continuity, consisting of one large (>3 Mbp) and one small (~1.5 Mbp) contig, with near complete BUSCO scores along with varying plasmid sequences. Leveraging this dataset, this study significantly expanded the available genomes for and its subspecies , enabling a comparative genomic analysis between the two lineages. An analysis of the large and small chromosomes unveiled distinct patterns of core and accessory genes, with a larger fraction of the core genes residing on the large chromosome, supporting the hypothesis of secondary chromosome evolution from megaplasmids in Vibrionaceae. In addition, we discovered a proposed new species, sp. nov., isolated from an acropomatid host, with an average nucleotide identify (ANI) of 93 % compared to the and strains. A comparison of the and lineages revealed minimal differences in gene content, yet highlighted the former's larger genome size and potential for horizontal gene transfer. An investigation of the operon, responsible for light production, indicated congruence between the presence of and host family, challenging its role in differentiating from . Further insights were derived from the identification of metabolic differences, such as the presence of the NADH:quinone oxidoreductase respiratory complex I in as well as variations in the type II secretion system (T2S) genes between the lineages, potentially impacting protein secretion and symbiosis. In summary, this study advances our understanding of genome evolution, highlighting subtle differences between closely related lineages, specifically and . These findings highlight the benefit of long read sequencing for bacterial genome assembly and pangenome analysis and provide a foundation for exploring early bacterial speciation processes of these facultative light organ symbionts.
Topics: Animals; Photobacterium; Symbiosis; DNA, Bacterial; Genomics; Genome, Bacterial
PubMed: 38112751
DOI: 10.1099/mgen.0.001161 -
Effects of plant-based proteins and handling stress on intestinal mucus microbiota in rainbow trout.Scientific Reports Dec 2023Via 16S rRNA gene amplicon sequencing, this study explores whether the gut mucus microbiota of rainbow trout is affected by the interaction of a plant-protein-based diet...
Via 16S rRNA gene amplicon sequencing, this study explores whether the gut mucus microbiota of rainbow trout is affected by the interaction of a plant-protein-based diet and a daily handling stressor (chasing with a fishing net) across two genetic lines (A, B). Initial body weights of fish from lines A and B were 124.7 g and 147.2 g, respectively. Fish were fed 1.5% of body weight per day for 59 days either of two experimental diets, differing in their fish meal [fishmeal-based diet (F): 35%, plant-based diet (V): 7%] and plant-based protein content (diet F: 47%, diet V: 73%). No diet- or stress-related effect on fish performance was observed at the end of the trial. However, we found significantly increased observed ASVs in the intestinal mucus of fish fed diet F compared to diet V. No significant differences in Shannon diversity could be observed between treatments. The autochthonous microbiota in fish fed with diet V was dominated by representatives of the genera Mycoplasma, Cetobacterium, and Ruminococcaceae, whereas Enterobacteriaceae and Photobacterium were significantly associated with diet F. The mucus bacteria in both genetic lines were significantly separated by diet, but neither by stress nor an interaction, as obtained via PERMANOVA. However, pairwise comparisons revealed that the diet effect was only significant in stressed fish. Therefore, our findings indicate that the mucus-associated microbiota is primarily modulated by the protein source, but this modulation is mediated by the stress status of the fish.
Topics: Animals; Oncorhynchus mykiss; Plant Proteins; RNA, Ribosomal, 16S; Gastrointestinal Microbiome; Microbiota; Diet; Animal Feed
PubMed: 38110473
DOI: 10.1038/s41598-023-50071-x -
Heliyon Nov 2023is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes...
is a unique traditional Icelandic product and is obtained by fermenting and drying Greenland shark (). However, little is known about the chemical and microbial changes occurring during the process. In this small-scale industrial study, fresh and frozen shark meat was fermented for eight and seven weeks, respectively, and then dried for five weeks. During the fermentation, trimethylamine -oxide levels decreased to below the limit of detection within five weeks and pH increased from about 6 to 9. Simultaneously, trimethylamine and dimethylamine levels increased significantly. Total viable plate counts, and specific spoilage organisms increased during the first weeks of the fermentation period but decreased during drying. Culture-independent analyses (16S rRNA) revealed gradual shifts in the bacterial community structure as fermentation progressed, dividing the fermentation process into three distinct phases but stayed rather similar throughout the drying process. During the first three weeks of fermentation, was dominant in the fresh group, compared to in the frozen group. However, as the fermentation progressed, the groups became more alike with , and being dominant. The PCA analysis done on the chemical variables and 16S rRNA analysis variables confirmed the correlation between high concentrations of TMAO and and at the initial fermentation phase. During the final fermentation phase, correlation was detected between high concentrations of TMA/DMA and , and . The results indicate the possibility to shortening the fermentation period and it is suggested that the microbial community can potentially be standardized with starter cultures to gain an optimal fermentation procedure.
PubMed: 38074871
DOI: 10.1016/j.heliyon.2023.e22127 -
Scientific Reports Dec 2023The large use of fish meal/fish oil in carnivorous fish feeds is the main concern regarding environmental sustainability of aquaculture. Here, we evaluated the effects...
Growth performance, gut microbiota composition, health and welfare of European sea bass (Dicentrarchus labrax) fed an environmentally and economically sustainable low marine protein diet in sea cages.
The large use of fish meal/fish oil in carnivorous fish feeds is the main concern regarding environmental sustainability of aquaculture. Here, we evaluated the effects of an innovative diet, designed to be (1) environmentally sustainable by lowering the marine protein content while being (2) cost effective by using sustainable alternative raw materials with acceptable cost and produced on an industrial scale, on growth performance, gut microbiota composition, health and welfare of European sea bass (Dicentrarchus labrax), a key species of the Mediterranean marine aquaculture, reared in sea cages. Results show that the specific growth rate of fish fed the low marine protein diet was significantly lower than those fed conventional diet (0.67% vs 0.69%). Fatty acid profile of fillets from fish fed a low marine protein diet presented significant lower n-6 and higher n-3 content when compared to conventional ones. Then, a significant increase in the abundance of Vibrio and reduction of Photobacterium were found in the gut of fish fed with the low marine protein diet but effects on sea bass health needs further investigation. Finally, no major health and welfare alterations for fish fed the low marine protein diet were observed, combined with a potential slight benefit related to humoral immunity. Overall, these results suggest that despite the low marine protein diet moderately affects growth performance, it nevertheless may enhance environmental and economic sustainability of the sea bass aquaculture.
Topics: Animals; Bass; Gastrointestinal Microbiome; Diet; Fish Oils; Fatty Acids; Diet, Protein-Restricted; Animal Feed
PubMed: 38042956
DOI: 10.1038/s41598-023-48533-3 -
International Journal of Food... Jan 2024This study aimed to explore the diversity of fifty-four Photobacterium strains isolated from muscle tissue of European plaice (Pleuronectes platessa) caught at different...
Insight to the diversity of Photobacterium spp. isolated from European plaice (Pleuronectes platessa) based on phylogenetic analysis, phenotypic characterisation and spoilage potential.
This study aimed to explore the diversity of fifty-four Photobacterium strains isolated from muscle tissue of European plaice (Pleuronectes platessa) caught at different fishing seasons and stored 14-days under various conditions. Single phylogenetic markers (16S rRNA, gapA, gyrB and recA) and multilocus sequence analysis (MLSA) were employed to classify isolates at species level. Furthermore, intra- and interspecies variability in the phenotypic traits, maximum specific growth rate (μ) and spoilage potential of the Photobacterium isolates were investigated. The isolates were classified into the P. iliopiscarium (53.7 %), P. phosphoreum (40.7 %) and P. piscicola (5.6 %) clades using MLSA. Two housekeeping genes, gyrB and recA, exhibited a consistent phylogenetic relationship with MLSA, suggesting that they might be used as individual phylogenetic markers for the Photobacterium genus. Intra- and interspecies variability in the expression of phenotypic characteristics and the production of trimethylamine (TMA), inosine (HxR), and hypoxanthine (Hx) were observed. A growth optimum temperature for P. iliopiscarium was approximately 20 °C, while those for P. phosphoreum and P. piscicola were closer to 15 °C. All isolates exhibited the highest growth density at 1.5 % NaCl, followed by 0.5 %, 3 %, and 6 % NaCl. However, P. phosphoreum demonstrated a higher NaCl tolerance than the other two species. Although, the high CO atmosphere significantly inhibited the growth of all strains at 4 °C, P. phosphoreum and P. piscicola showed higher growth density at 15 °C than P. iliopiscarium. Notably, all strains demonstrated HS production. The μ varied considerably within each species, highlighting the significance of strain-level variability. This study demonstrates that P. iliopiscarium and P. piscicola, alongside P. phosphoreum, are efficient TMA-, HxR-, Hx-, and HS-producers, suggesting their potential contribution to synergistic off-odour generation and spoilage. Moreover, the Photobacterium isolates seem to exhibit diverse adaptations to their environments, resulting in fluctuated growth and spoilage potential. Understanding intra- and interspecies variability will facilitate modelling seafood spoilage in microbial risk assessments and developing targeted hurdles to prolong products' shelf-life.
Topics: Animals; Phylogeny; Flounder; Photobacterium; RNA, Ribosomal, 16S; Sodium Chloride; Seafood
PubMed: 37984214
DOI: 10.1016/j.ijfoodmicro.2023.110485 -
The ISME Journal Dec 2023The bioluminescent symbiosis involving the urchin cardinalfish, Siphamia tubifer, and Photobacterium mandapamensis, a luminous member of the Vibrionaceae, is highly...
The bioluminescent symbiosis involving the urchin cardinalfish, Siphamia tubifer, and Photobacterium mandapamensis, a luminous member of the Vibrionaceae, is highly specific compared to other bioluminescent fish-bacteria associations. Despite this high degree of specificity, patterns of genetic diversity have been observed for the symbionts from hosts sampled over relatively small spatial scales. We characterized and compared sub-species, strain-level symbiont diversity within and between S. tubifer hosts sampled from the Philippines and Japan using PCR fingerprinting. We then carried out whole genome sequencing of the unique symbiont genotypes identified to characterize the genetic diversity of the symbiont community and the symbiont pangenome. We determined that an individual light organ contains six symbiont genotypes on average, but varied between 1-13. Additionally, we found that there were few genotypes shared between hosts from the same location. A phylogenetic analysis of the unique symbiont strains indicated location-specific clades, suggesting some genetic differentiation in the symbionts between host populations. We also identified symbiont genes that were variable between strains, including luxF, a member of the lux operon, which is responsible for light production. We quantified the light emission and growth rate of two strains missing luxF along with the other strains isolated from the same light organs and determined that strains lacking luxF were dimmer but grew faster than most of the other strains, suggesting a potential metabolic trade-off. This study highlights the importance of strain-level diversity in microbial associations and provides new insight into the underlying genetic architecture of intraspecific symbiont communities within a host.
Topics: Animals; Phylogeny; Fishes; Perciformes; Operon; Bacteria; Symbiosis
PubMed: 37891426
DOI: 10.1038/s41396-023-01550-6