Effect of aerobic
Gram-positive heterotrophic bacteria associated with Artemia franciscana
cysts on the survival and development of its larvae
C. Orozco-Medina, A.M. Maeda-Martínez, A. López-Cortés-2002
Aquaculture, 213(1-4): 15-29
Abstract:
The study of bacterial interaction with crustaceans
used in aquaculture, such as the brine shrimp Artemia, is gaining
importance. It is presumed that some bacteria provide nutritional elements,
and/or have the capacity to function as probiotics. In this work, aerobic
Gram-positive heterotrophic bacteria associated with commercial Artemia
cysts were isolated. According to molecular analyses, these bacteria
corresponded to the genera Microbacterium and Exiguobacterium.
No previous record of these bacteria in association with Artemia
cysts exists, nor are there studies of their effect on Artemia
culture. In this study, nauplii of Artemia franciscana Kellogg, 1906
were challenged in 6-day-monoxenic cultures with three bacteria strains: Microbacterium
sp. A, Microbacterium sp. B, and Exiguobacterium sp. Also, a
putative pathogenic strain of Vibrio parahaemolyticus was tested for
comparative purposes. Our objective was to evaluate the effect of these
bacteria on the survival, growth, and development of Artemia larvae. Microbacterium
sp. B and V. parahaemolyticus negatively affected Artemia
larvae (survival <17%). Microbacterium sp. A and Exiguobacterium
sp. were harmless, having no impact on survival, growth, and development of
the larvae when compared with the control treatment (survival >80%).
However, the mixture of the harmless bacteria in a dixenic culture had a
significant positive effect on the growth and development of Artemia
larvae. On the basis of these results, it is suggested that Microbacterium
sp. A and Exiguobacterium sp. are potential candidates as probiotic
bacteria for the culture of Artemia larvae.
The results of the challenge tests demonstrated that
the protocol to obtain and culture bacteria-free Artemia larvae,
using autoclaved baker's yeast as food, was a useful standardized tool to
evaluate the effect of bacteria strains on the survival and development of
this crustacean. The method was an in vivo, small-scale (monoxenic or
dixenic) test, which was in line with the rationale for the search for
probiotics in aquaculture.
(Centro de Investigaciones Biológicas del Noroeste,
S.C. Apdo. Postal 128, La Paz, Baja California Sur, 23000, Mexico, e-mail of
A.M. Maeda-Martínez: almaeda@cibnor.mx)