Probiotic Applications in Crustaceans - Aquaculture Nutrition: Gut Health, Probiotics and Prebiotics - page 317

(Gomez-Gil et al. 1998; Ziaei-Nejad et al. 2006; Immanuel et al. 2007). Ziaei-Nejad et al.
(2006) demonstrated that delivering a Bacillus probiotic to shrimp larvae through Artemia was
more efficient than direct administration in the water in order to increase the probiotic level
in the GI tract. Venkat and colleagues (2004) assessed the dietary application of two Lacto-
bacillus strains in live and formulated feeds fed to post larval M. rosenbergii . It was observed
that the growth of the probiotic fed groups was greater than the control group and that encap-
sulation of Lactobacillus sporogenes into live feed produced the greatest increase in weight
gain, feed efficiency and protein gain compared to the formulated feed. This may indicate that
bioencapsulation of probiotics into live feed vectors would be the optimal administration route
during the early life stages of crustaceans.
In the same way, several authors have suggested that probiotic treatments might be more
efficient if first applied at the larval stages, particularly before the opening of the mouth.
Rodríguez etal. (2007) assessed the Ili probiotic strain ( V.alginolyticus )on L.vannamei larvae
and post larvae challenged with WSSV and showed that when administered during larvicul-
ture, the probiotic confers an enhanced level of protection and a subsequent higher survival
rate of shrimps under farm conditions. Similarly, in their study, Ziaei-Nejad etal. (2006) exam-
ined the effects of a commercial Bacillus probiotic on digestive enzyme activity, survival and
growth of F. indicus , from nauplii to post larval stages, and reported that the improvement in
growth parameters was higher when larvae received the probiotic from the zoea stage.
11.4.2 Main benefits in juveniles and sub-adults
11.4.2.1 Overview
In the case of advanced post larvae stages or juveniles and sub-adult crustaceans, experiments
are usually run in small scale tanks or in aquaria. A summary of the most relevant scientific
studies is presented in Table 11.2.
Studies have assessed probiotic administration via the diet or directly into ponds. In many
cases, in vitro inhibitory assays toward pathogenic bacteria were generally performed (even if
not presented) and in vivo infection challenges with pathogens were achieved (Castex 2009).
Experimental challenges focused on vibriosis even though the effect of probiotics on the sus-
ceptibility to WSSV has now received more attention (Antony et al. 2011). An important
consideration with challenge trials is the duration of the experiment as studies are usually
conducted over a quite short period (few weeks) and long-term effects should be addressed.
As previously mentioned, the data available suggest an optimal probiotic bacteria level in
the gut between log 4 and log 6 CFU g -1 in the intestine of penaeid shrimps whatever the
probiotic species/strain considered. This information is of particular interest from practical
perspectives in order to adjust the probiotic concentration in the feed depending on the feeding
regime (Castex et al. 2011). More studies are required in order to design adaptive probiotic
feeding programs depending on the shrimp species, size and feeding regime. Additionally
more attention should in future be paid to the evaluation of a selected probiotic strain(s) under
different culture systems, specifically closed recirculating system, as such data are presently
lacking.
Finally, to our knowledge, the use of probiotics for broodstock has never been documented
in crustaceans but this topic does merit some interest. Indeed, it has been demonstrated that
broodstock conditioning has a great influence on reproductive performance and larval quality
(Racotta et al. 2003). Therefore probiotic effects, especially at the nutritional level, could have