Laboratory-controlled challenges of streptococcosis in Nile tilapia using the oral route (infected-feed) for infection.
Fish Shellfish Immunol
; 120: 295-303, 2022 Jan.
Article
en En
| MEDLINE
| ID: mdl-34871760
The study aimed to evaluate the oral infected-feed, intragastric-gavage, and intraperitoneal routes of the Streptococcus agalactiae infection in Nile tilapia (Oreochromis niloticus). For this purpose, 270 juveniles of Nile tilapia, with an average weight of 2 g, were distributed in 18 experimental units of 90 L, acclimatized, and raised for 55 days, until reaching 50 g (median weight). The experimental design was entirely randomized in six treatments, three of which were composed by bacterial infection routes: intraperitoneal 100 µL fish-1 [108 CFU], intragastric 100 µL fish-1 [108 CFU], feed inoculum 100 µL g feed-1 [109 CFU], and three respective control groups. Clinical signs were observed, and mortalities monitored until reaching 50% in the infected groups. Then, tissue samples from the spleen, liver, intestine, brain, and blood were collected from 20 fish per treatment for histopathological and hemato-immunological analyses. In addition, a related mortality curve was established at the end of the experimental challenge. The intraperitoneal and intragastric routes were more aggressive than the oral inoculum, causing greater brain damage, acute hemato-immunological response, and early mortality. While the orally fed inoculum, fish presented brain lesions with less intensity, and a chronic haemato-immunological response, the mortalities occurred twice as long as the other routes. The present research demonstrated that the S. agalactiae oral (feed inoculum) administration can be an innovative methodology to future experimental challenges in aquaculture research.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Infecciones Estreptocócicas
/
Cíclidos
/
Enfermedades de los Peces
Límite:
Animals
Idioma:
En
Revista:
Fish Shellfish Immunol
Asunto de la revista:
BIOLOGIA
/
MEDICINA VETERINARIA
Año:
2022
Tipo del documento:
Article
Pais de publicación:
Reino Unido