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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 -
Cryo Letters 2023Chitin is the second largest carbon source on the earth, and chitosan oligosaccharides produced by its degradation have good application prospects in medicine,...
BACKGROUND
Chitin is the second largest carbon source on the earth, and chitosan oligosaccharides produced by its degradation have good application prospects in medicine, cosmetics, and agricultural production.
OBJECTIVE
The discovery of a chitinase with high efficiency, high stability and clear degradation mechanism is of great help to promote the research of chitin derivatives and the development of the industrial chain.
MATERIALS AND METHODS
In this experiment, a low-temperature chitinase-producing strain Photobacterium sp. LG-29 was isolated from deep-sea mud in the Bohai Sea, and studied by means of molecular biology, biochemistry and bioinformatics.
RESULTS
Purification of chitinase yielded an enzyme solution with a concentration of 0.918 mg per mL and a specific activity of 21.036 U per mg. The optimum action temperature is 35 degree C, and it is still active at 4 degree C, showing low-temperature enzymatic activity, and also has certain thermal stability. The optimum pH is 8.0, and it maintains more than 70% of the enzyme activity at pH 11, which is very stable in an alkaline environment. Mn, Ca, and Mg are the main activators of enzymes, while Fe, Zn, etc. have extremely significant inhibitory effects on enzymes. The Km and Kcat of chitinase were determined to be 269.05 μmol/L and 0.49 min, respectively. Chitinase PbCHI5 has both endonuclease and exonuclease activity. The theoretical pI of the enzyme is 4.16, which is a stable hydrophilic protein.
CONCLUSION
This experiment laid a theoretical foundation for the development and utilization of new low-temperature chitinases. Doi.org/10.54680/fr23510110212.
Topics: Chitinases; Temperature; Photobacterium; Cryopreservation; Chitin; Cloning, Molecular
PubMed: 38032308
DOI: No ID Found -
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 -
International Journal of Food... Jan 2024Zoonotic nematodes of the family Anisakidae are highly common in many marine fish species, which act as paratenic hosts for the third larval stage. In the fish, these...
Zoonotic nematodes of the family Anisakidae are highly common in many marine fish species, which act as paratenic hosts for the third larval stage. In the fish, these parasites may migrate from the fish's gastro-intestinal tract (GI-tract) further to the coelomic cavity and muscles, making them a possible contamination source of bacteria they carry on their cuticle and in their GI-tract. A previous study revealed no apparent effect of Anisakis simplex on spoilage of fish, but the equally common anisakid species Pseudoterranova decipiens has a larger body surface potentially increasing the bacterial load brought into the fish muscle upon migration. As the presence of shelf-life reducing spoilage bacteria in the microbiome of this anisakid species has been demonstrated, the objective of the present study was to assess the potential shelf-life reducing effect of P. decipiens in fresh fish fillets stored in a domestic refrigerator. Atlantic cod was used as a model since members of the cod family are the third most consumed marine fish globally and it has the highest prevalence of P. decipiens infections. Infected and non-infected codfish fillet portions were collected and microbiologically analyzed at day 0 and day 4 of storage in a domestic fridge. Three isolation media were used to enhance maximum bacterial recovery and isolates were identified using MALDI-TOF MS and 16S rRNA gene sequencing. In parallel to the microbiological examination, sensory analysis was performed daily on the cod fillets to evaluate the freshness of the fish. Results revealed the presence of typical spoilage bacteria (e.g., Pseudomonas sp., Photobacterium sp.) in all fish, but based on the total viable counts, total HS-producing bacteria, and sensory analysis, there were no objective indications to assume an increased fish spoilage rate by the presence and migration P. decipiens. Additionally, a beta-diversity comparison revealed no significant differences in microbiota composition between infected and non-infected fish parts, though individual heterogeneity in microbiome composition among Atlantic codfish individuals was found. As total viable counts did, however, exceed the guideline limits for fresh fish, further research should now focus on the role of the candling step as a potential source of post-harvest contamination. As such, anisakid infection might still accelerate fish spoilage, though now in an indirect way.
Topics: Animals; Gadus morhua; RNA, Ribosomal, 16S; Ascaridoidea; Fishes; Anisakis
PubMed: 37977078
DOI: 10.1016/j.ijfoodmicro.2023.110426 -
Fish & Shellfish Immunology Dec 2023Galectins, as members of lectin families, exhibit a high affinity for β-galactosides and play diverse roles in biological processes. They function as pattern...
Galectins, as members of lectin families, exhibit a high affinity for β-galactosides and play diverse roles in biological processes. They function as pattern recognition receptors (PRRs) with important roles in immune defense. In this study, galectin-1, designated as SpGal-1, was identified and characterized from silver pomfret (Pampus argenteus). The SpGal-1 comprises an open reading frame (ORF) spanning 396 base pairs (bp) and encodes a deduced amino acid (aa) sequence containing a single carbohydrate recognition domain (CRD). Sublocalization analysis revealed that SpGal-1 was mainly expressed in the cytoplasm. The mRNA transcripts of SpGal-1 were ubiquitously detected in various tissues, with a higher expression level in the intestine. In addition, when exposed to Photobacterium damselae subsp. damselae (PDD) infection, both the liver and head kidney exhibited significantly increased SpGal-1 mRNA expression. The recombinant protein of SpGal-1 (named as rSpGal-1) demonstrated hemagglutination against red blood cells (RBCs) from Larimichthys crocea and P. argenteus in a Ca or β-Mercaptoethanol (β-ME)-independent manner. Notably, rSpGal-1 could bind with various pathogen-associated molecular patterns (PAMPs) including D-galactose, D-mannose, lipopolysaccharide (LPS), and peptidoglycan (PGN), with highest affinity to PGN. Moreover, rSpGal-1 effectively interacted with an array of bacterial types encompassing Gram-positive bacteria (Staphylococcus aureus and Nocardia seriolae) and Gram-negative bacteria (PDD and Escherichia coli, among others), with the most robust binding affinity towards PDD. Collectively, these findings highlight that SpGal-1 is a crucial PRR with involvement in the host immune defense of silver pomfret.
Topics: Humans; Animals; Galectin 1; Gene Expression Regulation; Immunity, Innate; Base Sequence; RNA, Messenger; Phylogeny
PubMed: 37944682
DOI: 10.1016/j.fsi.2023.109209 -
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 -
Animals : An Open Access Journal From... May 2023This study aims to assess the effects of different dietary n-6/n-3 long-chain polyunsaturated fatty acid ratios and CHO content in the immune response of gilthead...
This study aims to assess the effects of different dietary n-6/n-3 long-chain polyunsaturated fatty acid ratios and CHO content in the immune response of gilthead seabream. For that purpose, gilthead sea bream juveniles (initial body weight = 47.5 g) were fed for 84 days with four isoproteic (47% crude protein) and isolipidic (18% crude lipids) diets with high (20%) or low (5%) level of gelatinized starch (HS or LS diets, respectively) and included approximately 2.4% ARA or DHA. At the end of the trial, the DHA-enriched groups presented increased red blood cell (RBC) count, hemoglobin, plasmatic nitric oxide (NO) content, and antiprotease and alternative complement activities. The ARA groups had increased thrombocyte count, and plasmatic bactericidal activity against was lower in the fish fed the ARA/LS diet. After the feeding trial, the fish were challenged with an intraperitoneal injection (i.p.) of killed subsp. () and sampled at 4 and 24 h after the challenge. At 4 h after i.p., the ARA groups presented increased plasma total immunoglobulins (Ig) and bactericidal activity against . In addition, the fish fed the ARA/LS diet presented lower white blood cell (WBC) and alternative complement activity. At 24 h after i.p., the ARA groups presented increased RBC, WBC, and thrombocyte numbers, total IG, plasma peroxidase activity, and casp3 expression in the distal intestine. The HS groups presented increased plasma NO content and bactericidal activity against and decreased protease, antiprotease activity, and bactericidal activity against . In conclusion, high dietary DHA levels seemed to improve the immune status of unchallenged gilthead sea bream juveniles, while high dietary ARA levels improved the fish immune response to a bacterial challenge. The energy provided by dietary starch seems to be important to promote a fast response by the fish immune system after a challenge.
PubMed: 37889635
DOI: 10.3390/ani13111770 -
International Journal of Systematic and... Oct 2023A Gram-stain-negative, facultative anaerobic, rod-shaped strain, named SDRW27, was isolated from offshore seawater collected near Qingdao. Strain SDRW27 was able to grow...
A Gram-stain-negative, facultative anaerobic, rod-shaped strain, named SDRW27, was isolated from offshore seawater collected near Qingdao. Strain SDRW27 was able to grow at 16-37 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 6.0) and in the presence of 1-7 % (w/v) NaCl (optimum, 3 %). Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SDRW27 was most closely related to H01100410B (97.89 % sequence similarity), H01100409B (97.89 %) and ATCC 25521 (97.82 %). The predominant fatty acids were summed feature 3 (C ω7 and/or iso-C 2-OH), summed feature 8 (C 7 and/or C 6) and C. The polar lipids of strain SDRW27 comprised phosphatidylglycerol, phosphatidylinositol dimannoside, phosphatidylcholine, phosphatidylethanolamine and three unidentified lipids. The major respiratory quinone was ubiquinone-8. The G+C content was 47.71 mol%. The genome size was 5.84 Mbp, including 85 contigs with an N50 value of 223 542. The average nucleotide identity (ANI) values of SDRW27 with its three most similar strains, H01100410B, H01100409B and ATCC 25521, were 71.36, 71.58 and 72.23 %, respectively (all lower than the 95-96 % ANI threshold), and the DNA-DNA hybridization (DDH) values were 20.4, 20.8 and 20.4 % (all lower than the 70 % DDH threshold). The obtained results of polyphasic analysis demonstrate that strain SDRW27 represents a novel species, for which the name sp. nov. is proposed. The type strain is SDRW27 (=MCCC 1K06286=KCTC 82892).
Topics: Fatty Acids; Photobacterium; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Base Composition; Bacterial Typing Techniques; DNA, Bacterial; Sequence Analysis, DNA
PubMed: 37889564
DOI: 10.1099/ijsem.0.006096 -
Journal of Hazardous Materials Jan 2024In chemical membrane cleaning, the challenge is to efficiently remove irreversible fouling while minimizing the impact on membrane materials. Particularly, traditional...
In chemical membrane cleaning, the challenge is to efficiently remove irreversible fouling while minimizing the impact on membrane materials. Particularly, traditional hypochlorite cleaning will further lead to the generation of toxic halogenated by-products. To address these issues, a combined system composed of peroxymonosulfate and chloride (PMS/Cl) was applied to clean irreversible-humic-acid-fouled polyethersulfone (PES) membranes. After fouled membranes were soaked for 1 h in a PMS/Cl solution (10 mM/15 mM) at 25 °C under neutral conditions, 94% flux recovery and 96% resistance removal were realized. Surface properties of virgin and cleaned membranes were very similar, confirming the effectiveness of the PMS/Cl solution in removing irreversible foulants. The stability of membrane separation performance during multiple fouling and cleaning cycles further confirmed the minimal impact on membrane materials. Rapid diminution of the peaks centered in the region of fulvic-like and humic-like components, monitored under 3D-fluorescence for the cleaning solution, was attributed to PMS-catalyzed chlorination, thereby revealing the primary foulant detachment mechanism. Crucially, the approach exhibited lower toxicity than hypochlorite, as evidenced by reduced halogenated by-products and lower acute toxicity to Photobacterium phosphoreum T3. Overall, this novel cleaning system is promising for the efficient and environmentally friendly removal of irreversible organic foulants in practical water-treatment.
PubMed: 37879274
DOI: 10.1016/j.jhazmat.2023.132827 -
Environmental Microbiome Oct 2023Coral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic...
BACKGROUND
Coral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic microbiome, including bacteria, archaea, viruses and eukaryotic microbes, are referred to coral holobionts. Among them, coral diseases, mainly caused by Vibrio spp., have significantly contributed to the loss of coral cover and diversity. Habitat filtering across the globe has led to a variety structure of marine bacterial communities. Coral species, quantity and characteristics are significant differences between the Xisha Islands and Daya Bay (Guangdong Province). Thus, the Vibrio communities may be distinct between coral rich and poor areas.
RESULTS
Through comparison of Vibrio dynamics between coral-rich (Xisha Islands) and coral-poor (Daya Bay) locations, we uncovered differences in Vibrio abundance, diversity, community composition and assembly mechanisms associated with corals. The higher abundance of Vibrio in coral rich areas may indicate a strong interaction between vibrios and corals. V. campbellii, Paraphotobacterium marinum and V. caribbeanicus were widely distributed in both coral rich and poor areas, likely indicating weak species specificity in the coral-stimulated growth of Vibrio. Random-forest prediction revealed Vibrio species and Photobacterium species as potential microbial indicators in the coral rich and coral poor areas, respectively. Ecological drift rather than selection governed the Vibrio community assembly in the Xisha Islands. Comparatively, homogenizing selection was more important for the Daya Bay community, which may reflect a role of habitat filtration.
CONCLUSION
This study revealed the different distribution pattern and assembly mechanism of Vibrio spp. between coral rich and poor areas, providing the background data for the research of Vibrio community in coral reef areas and may help the protection of coral reef at the biological level. The main reasons for the difference were different number and species of corals, environmental (e.g., temperature) and spatial factors. It reflected the strong interaction between Vibrio and corals, and provided a new perspective for the investigation of Vibrio in coral reef ecosystem.
PubMed: 37872593
DOI: 10.1186/s40793-023-00532-7