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Sakata N, Mantani Y, Nakanishi S, Morishita R, Yokoyama T, Hoshi N. Histological study of diurnal changes in bacterial settlement in the rat alimentary tract. Cell Tissue Res 2022; 389:71-83. [PMID: 35403967 DOI: 10.1007/s00441-022-03626-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 03/30/2022] [Indexed: 11/28/2022]
Abstract
The composition of fecal bacteria is reported to change throughout the day, whereas the circadian rhythmicity of indigenous bacteria that settle on the epithelium is mostly unknown. The present study aimed to clarify the diurnal changes in the settlement of indigenous bacteria in the rat alimentary tract using histological analysis. The settlement of indigenous bacteria on the mucosal epithelium throughout the day and the diurnal changes in settlement levels were observed in the esophagus, the nonglandular area of the stomach, and the ileum. The peak of zeitgeber time (ZT) in the settlement level differed by segment: ZT 12 in the esophagus, ZT 6 in the nonglandular area of the stomach, and ZT 0 in the ileum. Moreover, 16S rRNA amplicon sequencing using tissue sections revealed that the compositions of the indigenous bacteria in the ileum differed among ZT. In the intervillous spaces of the ileum, the formation level of the mucus layer, one of the most fundamental host defenses against bacteria, was lowest at ZT 0. Bacteria were preferentially adjacent to the villous epithelium in the area without coverage by the mucus layer at ZT 0. These findings collectively suggest that the settlement level and possibly the composition of the indigenous bacteria changed diurnally in various segments of the alimentary tract, and the formation of the mucus layer might be the most likely to lead to such diurnal changes in indigenous bacteria, at least in the ileum.
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Affiliation(s)
- Nanami Sakata
- Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Youhei Mantani
- Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan.
| | - Satoki Nakanishi
- Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Rinako Morishita
- Laboratory of Histophysiology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Toshifumi Yokoyama
- Laboratory of Animal Molecular Morphology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
| | - Nobuhiko Hoshi
- Laboratory of Animal Molecular Morphology, Department of Bioresource Science, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo, 657-8501, Japan
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Ramos LRV, Pedrosa VF, Mori A, Andrade CFFDE, Romano LA, Abreu PC, Tesser MB. Exogenous enzyme complex prevents intestinal soybean meal-induced enteritis in Mugil liza (Valenciennes, 1836) juvenile. AN ACAD BRAS CIENC 2017; 89:341-353. [PMID: 28198920 DOI: 10.1590/0001-3765201720160446] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 09/20/2016] [Indexed: 11/22/2022] Open
Abstract
Four soybean meal-based diets containing increasing levels of an enzyme complex (E50, E100, E150 and E200 at 50, 100, 150 and 200 g ton-1, respectively) and one soybean meal-based diet without the enzyme complex (E0) were fed in triplicate to M. liza juveniles in a semi-static flow system with 20 fish per tank for 75 days. There were no differences between the treatments for animal performance parameters, but fish fed the enzyme complex treatment exhibited significantly (P<0.05) higher values of calcium bone retention compared with control fish. Although there was no relationship between bacterial counts in different sections of the gastrointestinal tract or enzyme levels, filamentous bacteria were increased in E50 compared with E150. All of the treatments resulted in higher bacterial counts in the stomach than in intestinal segments. Histological screening showed serious to moderate infiltration of inflammatory cells, modification in villus morphology and necrosis in some cases in fish fed the E0 diet. In addition, fish from the E0 treatment exhibited significantly (P<0.05) lower lipid deposition in the peritoneal cavity. Therefore, the use of low levels of exogenous enzyme is recommended in diets for M. liza when soybean meal is used as the main source of protein.
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Affiliation(s)
- Leonardo R V Ramos
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
| | - Virgínia F Pedrosa
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
| | - Agnes Mori
- Adisseo Brasil Nutrição Animal, Avenida Maria Coelho Aguiar, 215, Bloco G, 1º andar, Jardim São Luis, 05804-900 São Paulo, SP, Brazil
| | - Carlos F F DE Andrade
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
| | - Luis A Romano
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
| | - Paulo C Abreu
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
| | - Marcelo B Tesser
- Programa de Pós-Graduação em Aquicultura, Universidade Federal do Rio Grande/FURG, Avenida Itália, Km 8, s/n, Bairro Carreiros, 96201-900 Rio Grande, RS, Brazil
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McCarthy Ú, Pettinello R, Feehan L, Ho YM, White P. Experimental transmission of segmented filamentous bacteria (SFB) in rainbow trout Oncorhynchus mykiss. DISEASES OF AQUATIC ORGANISMS 2016; 119:45-57. [PMID: 27068502 DOI: 10.3354/dao02977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Rainbow trout gastroenteritis (RTGE) has been the cause of acute mortality in farmed rainbow trout in Europe since 1992. Epidemiological analysis has indicated a strong association with high production levels and suggested an infectious aetiology. The condition is characterised by the presence of large numbers of segmented filamentous bacteria (SFB) in the intestine, but the role of these in the disease has not been confirmed, in part because the organisms cannot be cultured. Therefore, other approaches need to be developed to investigate the role of SFB in RTGE. Faecal material from clinically affected RTGE trout, either untreated or heat-inactivated, was administered to fish from a susceptible stock, to determine whether the SFB could be transferred artificially and survive in or colonise the new host. Using histology and nested PCR, SFB were detected in the pyloric caeca of fish 23 to 30 d after challenge with untreated faeces. Histological changes in the intestine and the presence of an unidentified Gram-negative coccus were also significantly associated with exposure to untreated faeces. Upregulation of IFN-γ, IL-17A/F and IL-22 gene expression in proximal intestine suggested a low-level immune response to the challenge.
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Affiliation(s)
- Ú McCarthy
- Marine Scotland Science, Marine Laboratory, Aberdeen AB11 9DB, UK
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Ronza P, Bermúdez R, Losada AP, Robles A, Quiroga MI. Mucosal CD3ε+ cell proliferation and gut epithelial apoptosis: implications in rainbow trout gastroenteritis (RTGE). JOURNAL OF FISH DISEASES 2011; 34:433-443. [PMID: 21488908 DOI: 10.1111/j.1365-2761.2011.01254.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Rainbow trout gastroenteritis (RTGE) is an emerging disease that has acquired new relevance in European rainbow trout, Oncorhynchus mykiss (Walbaum), culture, because of the economic losses it causes. Disease aetiology and pathogenesis remain unclear. The lesions appear restricted to the gastrointestinal tract where extensive mucosal detachment associated with high numbers of segmented filamentous bacteria (SFB) can be detected. In this study, an RTGE outbreak in north-western Spain was investigated, and findings observed in diseased trout were compared with control fish. PAS stain and immunohistochemical assays with anti-CD3ε and anti-active caspase-3 antibodies were performed. The results showed that CD3ε+ inflammatory infiltrates were present in the intestine of diseased trout both in the lamina propria-submucosa and within the epithelium. Moreover, an increased number of caspase-3+ cells in the intestinal mucosa and also strong anti-caspase-3 immunoreactivity in desquamated cells in the gut lumen were observed. Changes in the number of goblet cells were also found, resulting in an increase or depletion of mucous cells depending on the severity of the intestinal lesions. These findings suggest that T cells and apoptosis play an important role in the development and pathogenesis of RTGE.
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Affiliation(s)
- P Ronza
- Departamento de Ciencias Clínicas Veterinaria, Facultad de Veterinaria, Universidad de Santiago de Compostela, Lugo, Spain
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Abstract
Bacterial taxonomy has progressed from reliance on highly artificial culture-dependent techniques involving the study of phenotype (including morphological, biochemical and physiological data) to the modern applications of molecular biology, most recently 16S rRNA gene sequencing, which gives an insight into evolutionary pathways (= phylogenetics). The latter is applicable to culture-independent approaches, and has led directly to the recognition of new uncultured bacterial groups, i.e. "Candidatus", which have been associated as the cause of some fish diseases, including rainbow trout summer enteritic syndrome. One immediate benefit is that 16S rRNA gene sequencing has led to increased confidence in the accuracy of names allocated to bacterial pathogens. This is in marked contrast to the previous dominance of phenotyping, and identifications, which have been subsequently challenged in the light of 16S rRNA gene sequencing. To date, there has been some fluidity over the names of bacterial fish pathogens, with some, for example Vibrio anguillarum, being divided into two separate entities (V. anguillarum and V. ordalii). Others have been combined, for example V. carchariae, V. harveyi and V. trachuri as V. harveyi. Confusion may result with some organisms recognized by more than one name; V. anguillarum was reclassified as Beneckea and Listonella, with Vibrio and Listonella persisting in the scientific literature. Notwithstanding, modern methods have permitted real progress in the understanding of the taxonomic relationships of many bacterial fish pathogens.
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Affiliation(s)
- Brian Austin
- Institute of Aquaculture, Pathfoot Building, University of Stirling, Stirling FK9 4LA, Scotland, UK.
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