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Frontiers in Physiology 2023This study explored the role of replacing fish meal protein with fermented soybean meal (FSBM) protein on the growth performance and intestinal morphology, immunity, and...
This study explored the role of replacing fish meal protein with fermented soybean meal (FSBM) protein on the growth performance and intestinal morphology, immunity, and microbiota of the pearl gentian grouper (). Three isonitrogenous and isolipidic diets with increasing levels of FSBM (0%, 20% and 40%; referred to as FM, FSBM20 and FSBM40 diets, respectively) as a replacement for fish meal were selected for this study. The pearl gentian grouper were fed these diets for 10 weeks. The findings revealed that the growth of fish fed the FSBM diets (FSBM20 and FSBM40) were remarkably lower than the fish fed the FM diet. Pathological manifestations of intestinal inflammation, such as shortened intestinal mucosal folds and thickened lamina propria, were observed in the fish fed the FSBM diets. Moreover, the gene expression levels of , , , and were remarkably upregulated in fish fed the FSBM40 diet, in contrast to the gene expression levels of and , which were remarkably downregulated ( < 0.05). The FSBM diets significantly affected the stability of the fish gut microbiota. was the dominant phylum in all experimental groups, and the proportion of these bacteria gradually decreased with increasing FSBM substitution. The composition of intestinal flora at the genus level was not the same in the three experimental groups, with a richer composition of intestinal bacteria detected in the FSBM20 and FSBM40 groups ( < 0.05). The correlation between intestinal flora balance and immune gene expression revealed that only was negatively correlated with the above upregulated genes, while other bacteria were positively correlated with these pro-inflammatory factors ( < 0.05). was positively correlated with the above downregulated genes, while other bacteria were negatively correlated with these anti-inflammatory factors ( < 0.05). In conclusion, high levels of substitution of FSBM for fish meal causes intestinal inflammation in pearl gentian grouper. This is likely associated with changes to the intestinal flora. More attention should be paid to the negative role of dietary FSBM on intestinal flora.
PubMed: 37469566
DOI: 10.3389/fphys.2023.1194071 -
Microbiology Spectrum Sep 2023Acute hepatopancreatic necrosis disease (AHPND), a high-mortality-rate shrimp disease, is caused by specific (Vp) strains with a plasmid encoding the PirAB toxins. As a...
Acute hepatopancreatic necrosis disease (AHPND), a high-mortality-rate shrimp disease, is caused by specific (Vp) strains with a plasmid encoding the PirAB toxins. As a bacterial pathogen, the invasion of AHPND-causing Vp might impose pressure on commensal microbiota in the shrimp gut, while the relationship between the pathogenesis of AHPND and the dysbiosis of gut bacterial communities remains unclear. Here we explored the temporal changes of shrimp gut microbiota in response to AHPND-causing and non-AHPND-causing Vp strains, with the non-infected controls as a baseline of the shrimp gut microbiota. The diversity and composition of bacterial communities from 168 gut samples (covering three treatments at seven time points with eight individuals per set) were investigated using 16S rRNA gene metabarcoding with high-throughput sequencing. The results showed that (i) species diversity of gut bacterial communities declined in Vp-infected shrimp, independent of the strain pathogenicity; (ii) taxonomic compositions of gut bacterial communities were significantly different between shrimp infected by AHPND-causing and non-AHPND-causing Vp strains; (iii) short-term (within 6 hours) compositional shifts in the gut microbiota were found only in AHPND-causing Vp-infected shrimp; (iv) the gut microbiota of AHPND-causing Vp-infected shrimp was enriched with genera and , with a decline in Bacilliplasma; and (v) functional predictions suggested the loss of normal metabolism due to compositional shifts in the gut microbiota. Our work reveals distinct features of community dynamics in shrimp gut microbiota, associated with pathogenic versus non-pathogenic infections, providing a new perspective of the pathogenesis of AHPND. IMPORTANCE Shrimp production is continually threatened by newly emerging diseases, such as AHPND, which is caused by specific Vp strains. Previous studies on the pathogenesis of AHPND have mainly focused on the histopathology and immune responses of the host. However, more attention needs to be paid to the gut microbiota, which acts as the first barrier to pathogen colonization. In this study, we revealed that shrimp gut microbiota responded differently to pathogenic and non-pathogenic Vp strains, with bacterial genera and enriched in pathogenic Vp-infected shrimp, and Bacilliplasma enriched in non-pathogenic Vp-infected shrimp. Moreover, functional predictions suggested that changes in taxonomic compositions would further affect normal metabolic functions, emphasizing the importance of sustaining an equilibrium in the gut microbiota. Several biomarkers associated with specific microbial taxa and functional pathways were identified in our data sets, which help predict the incidence of disease outcomes.
PubMed: 37750710
DOI: 10.1128/spectrum.01180-23 -
Immunity, Inflammation and Disease Jan 2024This study was designed to analyze the structural characteristics of the intestinal flora of elderly Uygur patients with sarcopenia, thereby providing new ideas for...
OBJECTIVE
This study was designed to analyze the structural characteristics of the intestinal flora of elderly Uygur patients with sarcopenia, thereby providing new ideas for clinical treatment.
METHODS
Firstly, fecal samples were collected from 40 elderly Uygur patients with sarcopenia (Sarcopenia group) and 40 healthy people (Control group). Next, significant differences in the intestinal flora between the two groups were analyzed based on 16S rDNA high-throughput sequencing. The linear discriminant analysis effect size (LEfSe) was used to estimate the magnitude of the effect of each component (species) abundance on the differential effect. Additionally, an analysis was also performed on the relationship between the intestinal flora and the cytokines in the peripheral blood of patients with sarcopenia.
RESULTS
The results of β diversity showed that there were differences in the structure of the intestinal flora between the two groups. Besides, the phylum level of intestinal flora between the two groups was not significantly different. However, the difference was significant in the intestinal flora at the order, family, and genus levels between the two groups. Among them, Lachnoclostridium, Photobacterium, Anaerobic Bacillus, Hydrogenophilus, and Eubacterium were enriched in the Sarcopenia group; Prevotella 9, Firmicutes FCS020 group, Streptobacillus, Aggregatibacter, Corynebacterium, Clostridium Difficile, and Haloanaerobium were enriched in the Control group. The LEfSe outcomes further showed that Lachnoclostridium was highly enriched in the Sarcopenia group; Prevotella 9 and Firmicutes FCS020 group were significantly enriched in the Control group. Furthermore, the relative abundance of Lachnoclostridium and Streptobacillus were significantly different in patients with high and low IL-6 levels.
CONCLUSION
In conclusion, Lachnoclostridium is significantly enriched in the intestines of elderly Uygur patients with sarcopenia; the increase in Lachnoclostridium abundance and the decrease in Streptobacillus abundance are associated with high levels of IL-6. Therefore, abnormal intestinal flora is related to inflammatory reflexes in patients with sarcopenia.
Topics: Aged; Humans; Gastrointestinal Microbiome; Interleukin-6; Sarcopenia; Cytokines; Feces
PubMed: 38270306
DOI: 10.1002/iid3.1097 -
FEMS Microbiology Ecology Feb 2024The skin of fish contains a diverse microbiota that has symbiotic functions with the host, facilitating pathogen exclusion, immune system priming, and nutrient...
The skin of fish contains a diverse microbiota that has symbiotic functions with the host, facilitating pathogen exclusion, immune system priming, and nutrient degradation. The composition of fish skin microbiomes varies across species and in response to a variety of stressors, however, there has been no systematic analysis across these studies to evaluate how these factors shape fish skin microbiomes. Here, we examined 1922 fish skin microbiomes from 36 studies that included 98 species and nine rearing conditions to investigate associations between fish skin microbiome, fish species, and water physiochemical factors. Proteobacteria, particularly the class Gammaproteobacteria, were present in all marine and freshwater fish skin microbiomes. Acinetobacter, Aeromonas, Ralstonia, Sphingomonas and Flavobacterium were the most abundant genera within freshwater fish skin microbiomes, and Alteromonas, Photobacterium, Pseudoalteromonas, Psychrobacter and Vibrio were the most abundant in saltwater fish. Our results show that different culturing (rearing) environments have a small but significant effect on the skin bacterial community compositions. Water temperature, pH, dissolved oxygen concentration, and salinity significantly correlated with differences in beta-diversity but not necessarily alpha-diversity. To improve study comparability on fish skin microbiomes, we provide recommendations for approaches to the analyses of sequencing data and improve study reproducibility.
Topics: Animals; Water; Phylogeny; Reproducibility of Results; Skin; Microbiota
PubMed: 38366921
DOI: 10.1093/femsec/fiae021 -
Microorganisms Sep 2023The use of antibiotics in open-water aquaculture is often unavoidable when faced with pathogens with high mortality rates. In addition, seasonal pathogen surges have...
The use of antibiotics in open-water aquaculture is often unavoidable when faced with pathogens with high mortality rates. In addition, seasonal pathogen surges have become more common and more intense over the years. Apart from the apparent cost of antibiotic treatment, it has been observed that, in aquaculture practice, the surviving fish often display measurable growth impairment. To understand the role of gut microbiota on the observed growth impairment, in this study, we follow the incidence of subsp. in a seabass commercial open-water aquaculture setting in Galaxidi (Greece). Fish around 10 months of age were fed with feed containing oxytetracycline (120 mg/kg/day) for twelve days, followed by a twelve-day withdrawal period, and another eighteen days of treatment. The fish were sampled 19 days before the start of the first treatment and one month after the end of the second treatment cycle. Sequencing of the 16S rRNA gene was used to measure changes in the gut microbiome. Overall, the gut microbiota community, even a month after treatment, was highly dysbiotic and characterized by very low alpha diversity. High abundances of alkalophilic bacteria in the post-antibiotic-treated fish indicated a rise in pH that was coupled with a significant increase in gut parasites. This study's results indicate that oxytetracycline (OTC) treatment causes persistent dysbiosis even one month after withdrawal and provides a more suitable environment for an increase in parasites. These findings highlight the need for interventions to restore a healthy and protective gut microbiome.
PubMed: 37764146
DOI: 10.3390/microorganisms11092302 -
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 -
Microorganisms Feb 2024Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of...
Spotted sea bass () is a high-economic-value aquacultural fish widely distributed in the coastal and estuarine areas of East Asia. In August 2020, a sudden outbreak of disease accompanied by significant mortality was documented in reared in marine cage cultures located in Nanhuang island, Yantai, China. Two coinfected bacterial strains, namely, NH-LM1 and NH-LM2, were isolated from the diseased for the first time. Through phylogenetic tree analysis, biochemical characterization, and genomic investigation, the isolated bacterial strains were identified as and subsp. , respectively. The genomic analysis revealed that possesses two circular chromosomes and six plasmids, while subsp. possesses two circular chromosomes and two plasmids. Furthermore, pathogenic genes analysis identified 587 and 484 genes in and subsp. , respectively. Additionally, drug-sensitivity testing demonstrated both and subsp. exhibited sensitivity to chloramphenicol, ciprofloxacin, ofloxacin, orfloxacin, minocycline, doxycycline, tetracycline, and ceftriaxone. Moreover, antibiotic resistance genes were detected in the plasmids of both strains. Extracellular product (ECP) analysis demonstrated that both and subsp. can produce hemolysin and amylase, while additionally can produce caseinase and esterase. Furthermore, infected fish displayed severe histopathological alterations, including infiltration of lymphocytes, cellular degeneration and necrosis, and loose aggregation of cells. Artificial infection assays determined that the LD of subsp. was 3 × 10 CFU/g, while the LD of was too low to be accurately evaluated. Furthermore, the dual infection of and subsp. elicits a more rapid and pronounced mortality rate compared to single challenge, thereby potentially exacerbating the severity of the disease through synergistic effects. Ultimately, our findings offer compelling evidence for the occurrence of coinfections involving and subsp. in , thereby contributing to the advancement of diagnostic and preventative measures for the associated disease.
PubMed: 38543554
DOI: 10.3390/microorganisms12030503 -
PeerJ 2024Nanoplastics (NPs) are an abundant, long-lasting, and widespread type of environmental pollution that is of increasing concern because of the serious threats they might...
Nanoplastics (NPs) are an abundant, long-lasting, and widespread type of environmental pollution that is of increasing concern because of the serious threats they might pose to ecosystems and species. Identifying the ecological effects of plastic pollution requires understanding the effects of NPs on aquatic organisms. Here, we used the Pacific white shrimp () as a model species to investigate whether ingestion of polystyrene NPs affects gut microbes and leads to metabolic changes in . The abundance of Proteobacteria increased and that of Bacteroidota decreased after NPs treatment. Specifically, spp., spp., spp., and spp. increased in abundance, whereas spp. and spp. decreased. Histological observations showed that exposed to NP displayed a significantly lower intestinal fold height and damaged intestinal structures compared with the control group. Exposure to NPs also stimulated alkaline phosphatase, lysozyme, and acid phosphatase activity, resulting in an immune response in . In addition, the content of triglycerides, total cholesterol, and glucose were significantly altered after NP exposure. These results provided significant ecotoxicological data that can be used to better understand the biological fate and effects of NPs in .
Topics: Animals; Gastrointestinal Microbiome; Ecosystem; Microplastics; Alkaline Phosphatase; Bacteroidetes; Penaeidae
PubMed: 38188162
DOI: 10.7717/peerj.16743 -
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 -
Frontiers in Immunology 2024Modern fish farming faces challenges in sourcing feed ingredients, most related with their prices, 21 availability, and specifically for plant protein sources,...
INTRODUCTION
Modern fish farming faces challenges in sourcing feed ingredients, most related with their prices, 21 availability, and specifically for plant protein sources, competition for the limited cultivation space for 22 vegetable crops. In that sense, halophytes have the added value of being rich in valuable bioactive compounds and salt tolerant. This study assessed the inclusion of non-food fractions of in European seabass diets.
METHODS
Different levels (2.5%, 5%, and 10%) were incorporated into seabass diets, replacing wheat meal (diets ST2.5, ST5, and ST10) or without inclusion (CTRL). Experimental diets were administered to seabass juveniles (8.62 ± 0.63 g) for 34 and 62 days and subsequent inflammatory responses to a heat-inactivated subsp. () were evaluated in a time-course manner (4, 24, 48, and 72 h after the challenge). At each sampling point, seabass haematological profile, plasma immune parameters, and head-kidney immune-related gene expression were evaluated.
RESULTS
After both feeding periods, most parameters remained unaltered by inclusion; nonetheless, seabass fed ST10 showed an upregulation of macrophage colony-stimulating factor 1 receptor 1 ( and cluster of differentiation 8 ( compared with those fed CTRL after 62 days of feeding. Regarding the inflammatory response, seabass fed ST10 showed lower plasma lysozyme levels than their counterparts fed ST2.5 and ST5 at 24 h following injection, while 4 h after the inflammatory stimulus, seabass fed ST10 presented higher numbers of peritoneal leucocytes than fish fed CTRL. Moreover, at 4 h, fish fed ST2.5, ST5, and ST10 showed a higher expression of interleukin 1β (), while fish fed ST5 showed higher levels of ornithine decarboxylase ( than those fed CTRL. An upregulation of macrophage colony-stimulating factor 1 receptor 1 () and glutathione peroxidase () was also observed at 72 h in fish fed ST10 or ST5 and ST10 compared with CTRL, respectively.
DISCUSSION
In conclusion, incorporating up to 10% of the non-food fraction in feed did not compromise seabass growth or immune status after 62 days, aligning with circular economy principles. However, inclusion improved the leucocyte response and upregulated key immune-related genes in seabass challenged with an inactivated pathogen.
Topics: Animals; Bass; Interleukin-1 Receptor-Like 1 Protein; Macrophage Colony-Stimulating Factor; Diet; Photobacterium
PubMed: 38500885
DOI: 10.3389/fimmu.2024.1342144