a
Núcleo de Investigación en Producción Alimentaria/Escuela de
Acuicultura, Facultad de Recursos Naturales, Universidad Católica de
Temuco, Temuco, Chile
b Instituto de Patología, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
c Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Chile
b Instituto de Patología, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
c Centro FONDAP: Interdisciplinary Center for Aquaculture Research (INCAR), Chile
Abstract
The present study
aimed to evaluate the effects of a commercial phytopharmaceutical
preparation from herbal and macroalgal origin on the growth and immune
response of rainbow trout adapted to seawater and its susceptibility to
Piscirickettsia salmonis infection. Preliminary in vitro trials,
evaluated the effects of the commercial product Futerpenol® on the
expression levels of selected immune-regulatory genes and its protective
effect in a challenge against Piscirickettsia salmonis (LF89).
Subsequent in vivo feeding trials were conducted to corroborate fish
protection against Piscirickettsia salmonis. Control and treatment diets
(with or without the commercial product Futerpenol® at a concentration
of 1 kg/ton) were fed to triplicate groups of 50 fish (average weight:
100.1 ± 11.1 g) during 30 days. Fish from all dietary groups were
equally redistributed in three tanks and challenged by cohabitation with
fish infected with P. salmonis (shedders) at the end of the feeding
treatment, and mortalities were recorded over 80 days post-infection. A
cumulative mortality of 35.0 ± 4.3 and 15.0 ± 6.0% was registered when
challenged fish were previously fed during 30 days with the control and
treatment diets respectively. Futerpenol® dietary administration
preceding the cohabitation challenge gave significant protection from P.
salmonis as suggested by the Relative Percent Survival (RPS) values of
62.3 and 57.1% after 60 and 80 days post-infection, respectively. These
results suggest that dietary supplementation with Futerpenol® at 1
kg/ton do not affect growth performance and strengthen immunity of
Oncorhynchus mykiss against P. salmonis under the experimental
conditions applied during this study. Statement of relevance: This study
demonstrates that dietary supplementation with a phytopharmaceutical
preparation, rich in fucoidans and labdane diterpenes strengthen
immunity of O. mykiss against P. salmonis. The use of feed supplemented
with this kind of phytopharmaceutical preparations in anticipation to
potential infections or vulnerable stages of the production could be
useful as an alternative method to prevent and limit the outbreak of
salmonid rickettsial septicaemia (SRS) which constitutes one of the main
infectious diseases causing production problems and substantial loss in
salmonids and marine fish aquaculture worldwide. © 2015 Elsevier B.V.
Author keywords
Fucoidans; Immunostimulants; Labdane diterpenes; Oncorhynchus mykiss; Phytopharmaceuticals; Piscirickettsia salmonis
Indexed keywords
Species Index: Oncorhynchus mykiss; Piscirickettsia salmonis; Salmonidae
