Background: Enteric red mouth disease and Saprolegniasis, which are caused by the bacteria
Yersinia ruckeri
and
the oomycete
Saprolegnia parasitica
, respectively, are important illnesses that affect salmonid farming. Sanitary
problems in farms are addressed by the prevention of disease outbreaks or by the treatment of diseases with
chemicals. Environmental and governmental restrictions, toxicity and high treatment costs limit the use of
drugs. Marine organisms, such as algae, sponges and corals, have developed an antimicrobial defense strategy
based on the production of bioactive metabolites. Among these organisms, seaweeds offer a particularly rich
source of potential new drugs. Hence, many pharmacologically active substances have been isolated from
seaweeds. In the
Ceramium genus,
Ceramium rubrum has been emphasized by several authors for its antimicrobial
properties. Based on this background, the present study focused on the antimicrobial activity of a lipophilic extract
of
C. rubrum on
Y. ruckeri and
S. parasitica.
Results: The alga, collected from the Pacific coast of Chile, underwent an ethanol extraction, and the concentrated
extract was partitioned between water and dichloromethane. From the dichloromethane extract, fatty acids,
fatty acid esters, one hydrocarbon and phytol were identified by Gas Chromatography–Mass Spectrometry
(GC/MS) analysis. The antimicrobial study showed that the whole extract was more active than the individual
components, which suggests a strong synergistic effect among the components.
Conclusions: These results may constitute a basis for promising future applied research that could investigate the
use of
C. rubrum seaweed as a source of antimicrobial compounds against fish pathogens.
