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Animal Nutrition (Zhongguo Xu Mu Shou... Sep 2023Several reports have revealed the vital role that probiotics play in fish growth and health. However, few works are available for host gut-derived probiotics on the...
Host gut-derived probiotics supplementation improves growth performance, serum and liver immunity, gut health, and resistive capacity against infection in hybrid grouper ( × ♂).
Several reports have revealed the vital role that probiotics play in fish growth and health. However, few works are available for host gut-derived probiotics on the growth, immunity, and gut microbiota of fish, especially in hybrid grouper (♀ × ♂) due to their isolation difficulty and functional verification. This study aimed at assessing 3 host gut-derived species' effects on the growth, immune and antioxidant-biochemical responses, haematological parameters, intestinal morphology, immune-related gene expression, gut microbiota, and disease resistance against in hybrid grouper. A total of 480 hybrid grouper (initial weight = 9.03 ± 0.02 g) were randomly allotted into 4 groups, namely, the group fed a basal diet without probiotic inclusion (control, B0), the group fed the basal diet with GPSAK4 (BV), the group fed the basal diet with GPSAK9 (BS), and the group fed the basal diet with GPSAK2 (BT) strains at 1.0 × 10 CFU/g. After a 6-week feeding trial, the results revealed significant improvements ( < 0.05) in the growth performance, whole fish-body proximate composition, blood haematological parameters, serum, liver, and intestinal biochemical indexes, intestinal morphology, and protection against . pathogen in the probiotic-treated groups compared with the untreated. Additionally, the expressions of intestinal tight junction genes (occludin and ), pro- and anti-inflammatory genes, including , , , , , , and , were upregulated ( < 0.05) after species administration. Host gut-derived supplementation shaped the gut microbiota by significantly increasing ( < 0.05) the relative abundance of Proteobacteria, Bacteroidetes, Actinobacteria (except the BS group), Acidobacteria (except the BT group), Cyanobacteria (except the BV and BT groups), and Verrucomicrobia phyla, as well as known beneficial genera (, , , 1 and 13, , and ), but significantly decreased ( < 0.05) the abundance of Firmicutes, Chloroflexi, and Fusobacteria phyla, and purported pathogenic genera ( and ) compared with the control group. Collectively, the results suggest that . GPSAK4, . GPSAK9 (especially this strain), . GPSAK2 dietary supplementation at 1.0 × 10 CFU/g has positive effects on the intestinal health of hybrid grouper via microbial composition modulation, thus enhancing the assimilation and absorption of nutrients to boost fish growth, immunity, and disease resistance.
PubMed: 37448647
DOI: 10.1016/j.aninu.2023.05.005 -
Environmental Research Oct 2023Polycyclic aromatic hydrocarbons found in crude oil can impair fish health following sublethal exposure. However, the dysbiosis of microbial communities within the fish...
Polycyclic aromatic hydrocarbons found in crude oil can impair fish health following sublethal exposure. However, the dysbiosis of microbial communities within the fish host and influence it has on the toxic response of fish following exposure has been less characterized, particularly in marine species. To better understand the effect of dispersed crude oil (DCO) on juvenile Atlantic cod (Gadus morhua) microbiota composition and potential targets of exposure within the gut, fish were exposed to 0.05 ppm DCO for 1, 3, 7, or 28 days and 16 S metagenomic and metatranscriptomic sequencing on the gut and RNA sequencing on intestinal content were conducted. In addition to assessing species composition, richness, and diversity from microbial gut community analysis and transcriptomic profiling, the functional capacity of the microbiome was determined. Mycoplasma and Aliivibrio were the two most abundant genera after DCO exposure and Photobacterium the most abundant genus in controls, after 28 days. Metagenomic profiles were only significantly different between treatments after a 28-day exposure. The top identified pathways were involved in energy and the biosynthesis of carbohydrates, fatty acids, amino acids, and cellular structure. Biological processes following fish transcriptomic profiling shared common pathways with microbial functional annotations such as energy, translation, amide biosynthetic process, and proteolysis. There were 58 differently expressed genes determined from metatranscriptomic profiling after 7 days of exposure. Predicted pathways that were altered included those involved in translation, signal transduction, and Wnt signaling. EIF2 signaling was consistently dysregulated following exposure to DCO, regardless of exposure duration, with impairments in IL-22 signaling and spermine and spermidine biosynthesis in fish after 28 days. Data were consistent with predictions of a potentially reduced immune response related to gastrointestinal disease. Herein, transcriptomic-level responses helped explain the relevance of differences in gut microbial communities in fish following DCO exposure.
Topics: Animals; Gastrointestinal Microbiome; Gadus morhua; Petroleum; Fishes; Microbiota; Water Pollutants, Chemical
PubMed: 37399986
DOI: 10.1016/j.envres.2023.116516 -
Food Chemistry: X Jun 2023Sea urchin gonads have high nutritional value and degenerate rapidly during storage. Previous assessment of the freshness of sea urchin gonads was based on experience...
Sea urchin gonads have high nutritional value and degenerate rapidly during storage. Previous assessment of the freshness of sea urchin gonads was based on experience without valid biochemical indicators. Thus, the current study is to find biochemical indicators representing the freshness of sea urchin gonads. Results showed that the dominant genera of sea urchin gonads were changed from , , and to , , and . The differential metabolites of sea urchin gonads were mainly produced through amino acids metabolism. Among them, GC-TOF-MS based differential metabolites had the greatest enrichment in the valine, leucine and isoleucine biosynthesis pathway, while LC-MS based differential metabolites had the greatest enrichment in the alanine, aspartate and glutamate metabolism pathway. The growth of dominant genus () had a great influence on the production of differential metabolites. These results will provide valuable information for accurately judging the freshness and shelf life of sea urchin gonads.
PubMed: 37397197
DOI: 10.1016/j.fochx.2023.100727 -
Applied and Environmental Microbiology Jul 2023Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is...
Coral reefs are among the most biodiverse ecosystems, providing habitats for various organisms. Studies on coral bleaching have been increasing recently, but little is known about the distribution and community assembly of coral pathogenic bacteria (e.g., several species). We elucidated the distribution pattern and interaction relationships of total bacteria and spp. in sediments from the Xisha Islands, which are characterized by their high coverage and diversity of coral resources. spp. showed significantly higher relative abundance values in the Xisha Islands (1.00 × 10 copies/g) than in other areas (approximately 1 × 10 to 9.04 × 10 copies/g), indicating that the coral bleaching event of 2020 may have promoted the bloom of vibrios. A spatial shift in community composition was observed between the northern (Photobacterium rosenbergii and Vibrio ponticus) and southern (Vibrio ishigakensis and Vibrio natriegens) sites, accompanied by a clear distance-decay pattern. The spatial distance and coral species (e.g., and ) had much greater correlations with the community than did environmental factors. However, complex mechanisms may exist in the community assembly of spp. due to the large proportion of unexplained variation. Stochastic processes may play an important role, as shown by the neutral model. Vibrio harveyi had the highest relative abundance (77.56%) and niche breadth, compared to other species, and it was negatively correlated with Acroporidae, likely reflecting its strong competitive ability and adverse effects on specific corals. Our study provides insights into the bloom and underlying assembly mechanisms of sedimentary vibrios in the Xisha Islands, thereby contributing to identify the potential indicator of coral bleaching and provide inspiration for the environmental management of coral reef areas. Coral reefs exert important roles in maintaining the sustainability of marine ecosystems but decline worldwide due to various drivers, especially pathogenic microorganisms. Here, we investigated the distribution pattern and interactions of total bacteria and spp. in the sediments from Xisha Islands during the coral bleaching event of 2020. Our results showed that the abundances of (1.00 × 10 copies/g) were high across the whole sites, indicating the bloom of sedimentary spp. Coral pathogenic species were abundant in the sediments, likely reflecting adverse effects on several kinds of corals. The compositions of the spp. were separated by geographical location, which was mainly attributable to the spatial distance and coral species. Overall, this work contributes by providing evidence for the outbreak of coral pathogenic vibrios. The pathogenic mechanism of the dominant species (especially V. harveyi) should be comprehensively considered by laboratory infection experiments in the future.
Topics: Animals; Ecosystem; Coral Bleaching; Islands; Coral Reefs; Anthozoa; Vibrio
PubMed: 37314342
DOI: 10.1128/aem.00543-23 -
Microbiology Spectrum Aug 2023Scombrotoxin (histamine) fish poisoning is a common seafood-borne illness attributed to toxin production by histamine-producing bacteria (HPB) in fish tissues during...
Scombrotoxin (histamine) fish poisoning is a common seafood-borne illness attributed to toxin production by histamine-producing bacteria (HPB) in fish tissues during decomposition. In laboratory studies, growth of HPB and other bacterial species is affected by physical and chemical attributes, but natural communities of HPB are not well understood. To determine how environmental and water quality variables may affect density of HPB in the natural aquatic environment, we compared presence and abundance of HPB to ambient temperature, salinity, dissolved oxygen, fecal coliforms, male-specific coliphage, nutrient concentrations, carbon and nitrogen stable isotope ratios, and C:N in water samples collected from July 2017 to February 2018 along a natural salinity gradient in a tidal river on the coast of northern Gulf of Mexico. HPB in water samples were quantified using a real-time PCR, most probable number method. HPB species were identified via 16S rRNA gene sequences. Temperature and salinity were determined to be the main factors driving HPB presence and concentration. Canonical correspondence analysis revealed that different HPB were associated with different environmental conditions. Photobacterium damselae was found under warmer, higher-salinity conditions; Raoultella planticola was found at colder, lower-salinity conditions; Enterobacter aerogenes was found at warmer, lower-salinity conditions; and Morganella morganii was found at most sites, independent of environmental conditions. These results showed that naturally occurring HPB abundance and species composition can be affected by environmental conditions, which could manifest in various potentials for histamine formation and scombrotoxin fish poisoning risk based on environmental factors. This study determined the effects of environmental conditions on presence and abundance of naturally occurring histamine-producing bacteria in the northern Gulf of Mexico. Here, we show that HPB abundance and species composition are related to ambient temperature and salinity, with the magnitude of this effect dependent on the particular HPB species. This finding suggests that environmental conditions at fishing sites could affect the risk of human illness from scombrotoxin (histamine) fish poisoning.
Topics: Animals; Male; Humans; Histamine; Gulf of Mexico; RNA, Ribosomal, 16S; Water Quality; Bacteria; Foodborne Diseases
PubMed: 37310253
DOI: 10.1128/spectrum.04720-22 -
MSystems Jun 2023Facultative marine bacterial pathogens sense environmental signals so that the expression of virulence factors is upregulated on entry into hosts and downregulated...
Facultative marine bacterial pathogens sense environmental signals so that the expression of virulence factors is upregulated on entry into hosts and downregulated during the free-living lifestyle in the environment. In this study, we utilized transcriptome sequencing to compare the transcriptional profiles of subsp. , a generalist pathogen that causes disease in diverse marine animals and fatal infections in humans at NaCl concentrations that mimic the free-living lifestyle or host internal milieu, respectively. We here show that NaCl concentration constitutes a major regulatory signal that shapes the transcriptome and uncover 1,808 differentially expressed genes (888 upregulated and 920 downregulated in response to low-salt conditions). Growth at 3% NaCl, a salinity that mimics the free-living lifestyle, upregulated genes involved in energy production, nitrogen metabolism, transport of compatible solutes, utilization of trehalose and fructose, and carbohydrate and amino acid metabolism with strong upregulation of the arginine deiminase system (ADS). In addition, we observed a marked increase in resistance to antibiotics at 3% NaCl. On the contrary, the low salinity conditions (1% NaCl) that mimic those encountered in the host triggered a virulence gene expression profile that maximized the production of the type 2 secretion system (T2SS)-dependent cytotoxins damselysin, phobalysin P, and a putative PirAB-like toxin, observations that were corroborated by the analysis of the secretome. Low salinity also upregulated the expression of iron-acquisition systems, efflux pumps, and other functions related to stress response and virulence. The results of this study greatly expand our knowledge of the salinity-responsive adaptations of a generalist and versatile marine pathogen. IMPORTANCE Pathogenic species experience continuous shifts of NaCl concentration in their life cycles. However, the impact of salinity changes in gene regulation has been studied in a small number of species. In this study, we analyzed the transcriptional response of subsp. (), a generalist and facultative pathogen, to changes in salinity, and demonstrate that growth at 1% NaCl in comparison to 3% NaCl triggers a virulence program of gene expression, with a major impact in the T2SS-dependent secretome. The decrease in NaCl concentration encountered by bacteria on entry into a host is proposed to constitute a regulatory signal that upregulates a genetic program involved in host invasion and tissue damage, nutrient scavenging (notably iron), and stress responses. This study will surely inspire new research on pathobiology, as well as on other important pathogens of the family and related taxa whose salinity regulons still await investigation.
Topics: Humans; Animals; Virulence; Sodium Chloride; Salinity; Photobacterium; Iron
PubMed: 37288979
DOI: 10.1128/msystems.01253-22 -
International Journal of Food... Jul 2023The aim of this study was to investigate seasonal variations (September, December and April) in the initial microbial communities of skin and gills' external mucosal...
Photobacterium predominate the microbial communities of muscle of European plaice (Pleuronectes platessa) caught in the Norwegian sea independent of skin and gills microbiota, fishing season, and storage conditions.
The aim of this study was to investigate seasonal variations (September, December and April) in the initial microbial communities of skin and gills' external mucosal tissues (EMT) and muscle of European plaice (Pleuronectes platessa). Moreover, a potential relationship between EMT and fresh muscle microbiota was examined. The microbial community succession in plaice muscle as a function of fishing season and storage conditions was also investigated. The selected seasons for the storage experiment were September and April. Investigated storage conditions were; fillets packaged in either vacuum or modified atmosphere (70 % CO, 20 % N, 10 % O) and chilled/refrigerated conditions (4 °C). Whole fish stored on ice (0 °C) was selected as a commercial standard. Seasonal variations were detected in the initial microbial communities of EMT and plaice muscle. The highest microbial diversity was found in EMT and muscle of April-caught plaice, followed by December and September catch indicating the important role of environmental factors in shaping the initial EMT and muscle microbial communities. The EMT microbial communities were more diverse than fresh muscle samples. The low number of shared taxa between EMT and initial muscle microbial communities indicates that only a minor part of the muscle microbiota came from the EMT. Psychrobacter and Photobacterium were the predominant genera in the EMT microbial communities in all seasons. Photobacterium dominated the initial muscle microbial communities with a gradual seasonal reduction of its abundance from September to April. Storage time and storage conditions shaped a less diverse and distinct community compared to the fresh muscle. However, no clear separation was seen between the communities at the middle and end of storage time. Regardless of EMT microbiota, fishing season and storage conditions, Photobacterium dominated the microbial communities of stored muscle samples. The Photobacterium prevalence as the primary specific spoilage organism (SSO) could be attributed to its high relative abundance in the initial microbiota of muscle and its CO-tolerance. The findings of this study indicate the important contribution of Photobacterium to the microbial spoilage of plaice. Thus, the development of innovative preservation techniques addressing the rapid growth of Photobacterium could contribute to the production of high-quality and shelf-stable convenient retail plaice products.
Topics: Animals; Carbon Dioxide; Flounder; Food Microbiology; Food Packaging; Food Preservation; Gills; Microbiota; Muscles; Photobacterium; Seasons
PubMed: 37099863
DOI: 10.1016/j.ijfoodmicro.2023.110222