543
Better protection was reported with both bacteria administered together (Wang et al.
2013 ). Is this an example of a heterologous vaccine or a probiotic?
Bystander Effect A sublethal dose of V. anguillarum VIB1 given intraperitoneally
to rainbow trout led to the transfer of resistance by inter-animal communication of
one or more unknown signals to naive fi sh (= ‘bystander’ fi sh) that had never been
exposed to the pathogen. Thus, challenge with a lethal dose of V. anguillarum led to
less mortalities (60 %) over a longer time span than the controls (100 % mortalities).
The communication signal caused an abrupt and transient increase in intracellular
calcium and a corresponding decrease in clonogenicity in a reporter assay (Mothersill
et al. 2015 ).
Probiotics Putative Aeromonas and Vibrio , from halibut, have been found to
inhibit the growth of fi sh pathogenic Vibrio (Bergh 1995 ). The relative incidence of
microbial antagonists is indicated from a study of >400 bacterial isolates from the
gastro- intestinal tract and surface of turbot and fi sh food and water, in which 28 %
(mostly from the intestinal mucus) were inhibitory to V. anguillarum (Westerdahl
et al. 1991 ). An isolate of V. alginolyticus, previously used as probiotic in Ecuadorian
shrimp hatcheries, has been effective at controlling diseases caused by V. anguillarum (Austin et al. 1995b ). Vagococcus fl uvialis protected sea bass against vibriosis,
achieving an RPS of 42.3 % (Sorroza et al. 2012). Similarly, Pediococcus pentosaceus was fed to orange-spotted grouper ( Epinephelus coioides) leading to enhanced
growth, immunostimulation and protection against challenge (Huang et al. 2014 ).
Furthermore, Lactococcus lactis subsp. lactis was fed to Artemia nauplii, which in
turn were fed to European sea bass ( Dicentrarchus labrax) larvae for 5 consecutive
days leading to signifi cantly improved survival after challenge (survival = 81 %
compared to 24 % of the controls) (Touraki et al. 2013 ).
Dietary Supplements/Immunostimulants The use of bovine lactoferrin, dosed
orally at 100 mg/kg for 3 days enhanced the resistance of rainbow trout to subsequent challenge by V. anguillarum (Sakai et al. 1993 ). Peptidoglycan, derived from
Bifi dobacterium thermophilus, was administered in feed (fed at 3 % of body weight
daily) at 0.2 and 2 mg/kg to rainbow trout of 0.12 g average weight for 56 days
(Matsuo and Miyazono 1993 ). These doses were the equivalent of 6 or 60 μg of
peptidoglycan/kg body weight of fi sh/day. Sub-groups of the fi sh were challenged
on day 26 and 56 by immersion in V. anguillarum, with mortalities monitored over
a 21 day period. At the halfway point of the feeding trial, survival following challenge with V. anguillarum was markedly higher than among the controls. Yet at day
56, there was not any apparent difference in survival between the experimental
groups and controls. So, it would appear that the benefi ts of this approach were
short-lived, and in the long term were not benefi cial (Matsuo and Miyazono 1993 ).
Feeding 4 g of mannan oligosaccharides/kg of feed to European sea bass
( Dicentrarchus labrax) juveniles for 8-weeks before challenge led to a reduction in
mortalities from 66 % to 12.5 % (Torrecillas et al. 2012 ).
Vibrio anguillarum
Better protection was reported with both bacteria administered together (Wang et al.
2013 ). Is this an example of a heterologous vaccine or a probiotic?
Bystander Effect A sublethal dose of V. anguillarum VIB1 given intraperitoneally
to rainbow trout led to the transfer of resistance by inter-animal communication of
one or more unknown signals to naive fi sh (= ‘bystander’ fi sh) that had never been
exposed to the pathogen. Thus, challenge with a lethal dose of V. anguillarum led to
less mortalities (60 %) over a longer time span than the controls (100 % mortalities).
The communication signal caused an abrupt and transient increase in intracellular
calcium and a corresponding decrease in clonogenicity in a reporter assay (Mothersill
et al. 2015 ).
Probiotics Putative Aeromonas and Vibrio , from halibut, have been found to
inhibit the growth of fi sh pathogenic Vibrio (Bergh 1995 ). The relative incidence of
microbial antagonists is indicated from a study of >400 bacterial isolates from the
gastro- intestinal tract and surface of turbot and fi sh food and water, in which 28 %
(mostly from the intestinal mucus) were inhibitory to V. anguillarum (Westerdahl
et al. 1991 ). An isolate of V. alginolyticus, previously used as probiotic in Ecuadorian
shrimp hatcheries, has been effective at controlling diseases caused by V. anguillarum (Austin et al. 1995b ). Vagococcus fl uvialis protected sea bass against vibriosis,
achieving an RPS of 42.3 % (Sorroza et al. 2012). Similarly, Pediococcus pentosaceus was fed to orange-spotted grouper ( Epinephelus coioides) leading to enhanced
growth, immunostimulation and protection against challenge (Huang et al. 2014 ).
Furthermore, Lactococcus lactis subsp. lactis was fed to Artemia nauplii, which in
turn were fed to European sea bass ( Dicentrarchus labrax) larvae for 5 consecutive
days leading to signifi cantly improved survival after challenge (survival = 81 %
compared to 24 % of the controls) (Touraki et al. 2013 ).
Dietary Supplements/Immunostimulants The use of bovine lactoferrin, dosed
orally at 100 mg/kg for 3 days enhanced the resistance of rainbow trout to subsequent challenge by V. anguillarum (Sakai et al. 1993 ). Peptidoglycan, derived from
Bifi dobacterium thermophilus, was administered in feed (fed at 3 % of body weight
daily) at 0.2 and 2 mg/kg to rainbow trout of 0.12 g average weight for 56 days
(Matsuo and Miyazono 1993 ). These doses were the equivalent of 6 or 60 μg of
peptidoglycan/kg body weight of fi sh/day. Sub-groups of the fi sh were challenged
on day 26 and 56 by immersion in V. anguillarum, with mortalities monitored over
a 21 day period. At the halfway point of the feeding trial, survival following challenge with V. anguillarum was markedly higher than among the controls. Yet at day
56, there was not any apparent difference in survival between the experimental
groups and controls. So, it would appear that the benefi ts of this approach were
short-lived, and in the long term were not benefi cial (Matsuo and Miyazono 1993 ).
Feeding 4 g of mannan oligosaccharides/kg of feed to European sea bass
( Dicentrarchus labrax) juveniles for 8-weeks before challenge led to a reduction in
mortalities from 66 % to 12.5 % (Torrecillas et al. 2012 ).
Vibrio anguillarum