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Amoah K, Cai J, Huang Y, Wang B, Shija VM, Wang Z, Jin X, Cai S, Lu Y, Jian J. Identification and characterization of four Bacillus species from the intestine of hybrid grouper (Epinephelus fuscoguttatus♀ × E. lanceolatus♂), their antagonistic role on common pathogenic bacteria, and effects on intestinal health. FISH & SHELLFISH IMMUNOLOGY 2024; 152:109795. [PMID: 39069109 DOI: 10.1016/j.fsi.2024.109795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/11/2024] [Accepted: 07/25/2024] [Indexed: 07/30/2024]
Abstract
As an alternative to the criticized antibiotics, probiotics have been adopted for their eco-friendly nature and ability to enhance host growth and immunity. Nevertheless, reports suggest ineffectiveness in commercially available probiotics since most are from non-fish sources; thus, this study was envisaged to isolate and characterize new Bacillus spp. from the gut of hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂) which could serve as potential probiotics. The isolation and characterization were performed based on their morphological and biochemical properties, and 16S rRNA sequencing homology analysis. A subsequent 30-day in vivo biosafety feeding trial was conducted to ascertain isolates' non-pathogenicity, as well as their effects on fish growth, and intestinal mucosal microvilli via scanning electron microscopy (SEM) analysis. Four Bacillus spp. strains, namely, B. velezensis strain PGSAK01 (accession number OQ726606), B. stercoris strain PGSAK05 (accession number OQ726607), B. velezensis strain PGSAK17 (accession number OQ726601), and B. subtilis strain PGSAK19 (accession number OQ726605), were identified and characterized in the current study. The strains showed promising probiotic properties such higher adhesion capability, higher thermotolerance, displaying higher survivability to 0.5 % bile, lower pH tolerance, γ-haemolytic activity, and multispecies characteristics. Among the 24 antibiotics tested, while all isolates showed susceptibility to 21, the PGSAK01 strain showed resistance to furazolidone antibiotics. None of the isolates showed possession of i) virulence factor genes encoding enterotoxigenic (hblA, hblC, hblD, nheA, nheB, and entFM) and emetic (cereulide synthetase gene, ces) genes, and ii) streptomycin resistance gene (vat c), ampicillin-resistant genes (mecA and bla), and vancomycin-resistant gene (van B). Nevertheless, the PGSAK01 and PGSAK17 strains showed possession of tek K, cat, and ant(4')-Ia (adenylyltransferase) (except the PGSAK01) resistant genes. All isolates displayed better antimicrobial effects against pathogenic bacteria Streptococcus agalactiae, S. iniae, Vibrio harveyi, and V. alginolyticus. The in vivo biosafety trial involved hybrid grouper fish being grouped into five (average weight 32 ± 0.94 g), namely, the group fed the basal diet void of isolate's supplementation (control), and the remaining four groups fed the basal diet with 1 × 108 CFU/g diet of individual strain PGSAK01, PGSAK05, PGSAK17, and PGSAK19 supplementation. At the end of the study, a significantly higher WGR, K (except the PGSAK01 group), VSI; lysozyme (except PGSAK01 group), total antioxidant activity, alkaline phosphatase, superoxide dismutase enzyme activities; highly dense intestinal mucosal villi (based on the scanning electron microscopy analysis); and significantly lower malondialdehyde levels were witnessed in the isolated treated groups compared to the control, supporting the results obtained in the auto-aggregation and cell-surface hydrophobicity test. This work's results have provided thought-provoking targets; thus, studies involving extensive genome sequencing and functional annotation analysis will be explored to offer unfathomable insights into their mechanisms of action and potential health benefits, further establishing the four Bacillus strains' (PGSAK01, PGSAK05, PGSAK17, and PGSAK19) potential role in probiotic fields and functional foods.
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Affiliation(s)
- Kwaku Amoah
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China.
| | - Jia Cai
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Yu Huang
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Bei Wang
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Vicent Michael Shija
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China
| | - Zhiwen Wang
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Xiao Jin
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Shuanghu Cai
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Yishan Lu
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China
| | - Jichang Jian
- College of Fisheries, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, Guangdong Ocean University, Zhanjiang, 524000, China; Guangdong Key Laboratory of Control for Disease of Aquatic Animals of Guangdong Higher Education Institutes, Zhanjiang, 524088, China; Guangdong Provincial Engineering Research Centre for Aquatic Animal Health Assessment, Shenzhen, 327005, China.
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Deciphering Bacterial Community Structure, Functional Prediction and Food Safety Assessment in Fermented Fruits Using Next-Generation 16S rRNA Amplicon Sequencing. Microorganisms 2021; 9:microorganisms9081574. [PMID: 34442653 PMCID: PMC8401261 DOI: 10.3390/microorganisms9081574] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 01/02/2023] Open
Abstract
Fermented fruits and vegetables play an important role in safeguarding food security world-wide. Recently, robust sequencing-based microbial community analysis platforms have improved microbial safety assessment. This study aimed to examine the composition of bacteria and evaluate the bacterial safety of fermented fruit products using high-throughput 16S-rRNA metagenomic analysis. The operational taxonomic unit-based taxonomic classification of DNA sequences revealed 53 bacterial genera. However, the amplicon sequencing variant (ASV)-based clustering revealed 43 classifiable bacterial genera. Taxonomic classifications revealed that the abundance of Sphingomonas, which was the predominant genus in the majority of tested samples, was more than 85–90% among the total identified bacterial community in most samples. Among these identified genera, 13 low abundance genera were potential opportunistic pathogens, including Acinetobacter, Bacillus, Staphylococcus, Clostridium, Klebsiella, Mycobacterium, Ochrobactrum, Chryseobacterium, Stenotrophomonas, and Streptococcus. Of these 13 genera, 13 major opportunistic pathogenic species were validated using polymerase chain reaction. The pathogens were not detected in the samples of different stages and the final products of fermentation, except in one sample from the first stage of fermentation in which S. aureus was detected. This finding was consistent with that of ASV-based taxonomic classification according to which S. aureus was detected only in the sample from the first stage of fermentation. However, S. aureus was not significantly correlated with the human disease pathways. These results indicated that fermentation is a reliable and safe process as pathogenic bacteria were not detected in the fermentation products. The hybrid method reported in this study can be used simultaneously to evaluate the bacterial diversity, their functional predictions and safety assessment of novel fermentation products. Additionally, this hybrid method does not involve the random detection of pathogens, which can markedly decrease the time of detection and food safety verification. Furthermore, this hybrid method can be used for the quality control of products and the identification of external contamination.
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