Data/hora: 09/06/2024 09:38:17

Provedor de dados: 	5	
País: 	France	
Título: 	Utilisation de bactéries lactiques probiotiques pour prémunir les poissons d'élevage contre des vibrions pathogènes

The use of lactic acid bacteria to protect the fish farmed against pathogenic Vibrio	
Autores: 	Lamari, Faouzi.	
Data: 	2014-04-22	
Ano: 	2014	
Palavras-chave: 	Probiotiques; Microflore intestinale; Réponse immunitaire; Stress oxydatif; Malformations vertébrales; Ossification; Oxidative stress; Vertebral malformations; Dicentrarchus labrax; Artemia; Vibrio; Probiotic; Intestinal microflora; Immune response.	
Resumo: 	Diseases cause major production losses in fish farms. Bacteria of the genus Vibrio are known as opportunistic pathogens, and have been associated with mass-mortality episodes. To cope with these disease outbreaks, fish farmers often resort to the use of antibiotics. However, preventive overuse has led to the emergence of resistant strains and frequent treatment failures. Probiotic lactic acid bacteria are increasingly used to improve the quality of seed production in aquaculture, while limiting antibiotic treatments. Microbial strains must fulfil several criteria to be evaluated as potential probiotics.In a first step, we selected and characterized 55 strains of lactic acid bacteria isolated from fish hatchery. The first selection criterion focused on the in-vitro inhibition of pathogenic Vibrio strains. Lactic acid bacteria with antagonistic properties were tested for biofilm formation. The strains were characterised with the phenotypes, based on enzymatic and physiological tests, and identified by genotyping. In-vivo challenges with Vibrio aligonlyticus were then performed on Artemia. Lactobacillus casei X2 was thus selected, due to the best combination of the attributes that are required for probiotics. The strain showed antagonistic activity, adhered strongly to polystyrene plate, and secured Artemia with the best protection against V. alginolyticus. In a second step, La. casei X2 and a commercial strain of probiotics (Bactocell, Pediococcus acidilactici) were tested on European sea bass larvae, with a view to assess the effects on alevin quality, immune response and associated microbiota. Both of the lactic acid bacteria, La. casei and P. acidilactici, decreased the bacterial load and Vibrio in sea bass larvae. P. acidilactici changed significantly the profile of the bacterial community associated with fish larvae, compared to the control group. La. casei did not affect the structure of the bacterial community, although the strain was detected at high concentration in the larvae at 40 day post hatch (dph). Both probiotic treatments increased fish larval growth in body mass at 20 dph, and in length at 30 and 45 dph. Two physiological markers for gene expression suggested that P. acidilactici was more efficient than La. casei for the regulation of oxidative stress in sea bass at 41 dph. P. acidilactici induced some delay in bone development, and inflammatory signs were observed in the larvae at 20 dph. Though La. casei accelerated the early ossification process in the larvae by 20 dph, the histopathological study revealed a high incidence of vertebral malformations at 62 dph. In contrast, the treatment with P. acidilactici produced the highest proportion of fish with normal and complete ossification.	
Tipo: 	Text	
Idioma: 	Francês	
Identificador: 	https://archimer.ifremer.fr/doc/00498/60943/64336.pdf

https://archimer.ifremer.fr/doc/00498/60943/	
Editor: 	Université de Bretagne occidentale	
Formato: 	application/pdf	
Fonte: 	info:eu-repo/semantics/openAccess

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