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Garlic
Garlic ( Allium sativum ) dosed at 0.5 and 1.0 g/100 g of feed led to a stimulation in
growth, feed conversion and protein effi ciency, and marked reduction in mortalities
(RPS = 95 %) in rainbow trout after challenge with Aer. hydrophila with the mode of
action refl ecting the stimulation of the number of erythrocytes and leucocytes,
higher haematocrit and increase in anti-protease, bacteriocidal, lysozyme, phagocytic and respiratory burst activities (Nya and Austin 2009a ). Of course, natural
plant products are likely to contain many bioactive components, therefore, identifi -
cation of the active ingredients(s) is likely to be challenging. Allicin, a component
of garlic, was used separately as a feed additive dosed at 0.5 and 1.0 ml/100 g/feed
for the control of Aer. hydrophila with great success, i.e. the RPS was 90–100 %.
Again, there was evidence of immunomodulation, specifi cally increased phagocytic
and serum lysozyme activities (Nya et al. 2010 ).
Ginger
Success occurred with ginger ( Zingiber offi cinale ), which again led to immunomodulation and protection against Aer. hydrophila (Nya and Austin 2009b ).
Lupin, Mango and Stinging Nettle
Lupin ( Lupinus perennis ), mango ( Mangifera indica ) and stinging nettle ( Urtica
dioica ) were added to feed to 1 % (w/v) for 14 days, and protected rainbow trout
against challenge with Aer. hydrophila, with the mode of action considered to
involve immune stimulation, principally enhancement in lysozyme respiratory burst
and serum bacteriocidal activity, increases in the number of red and white blood
cells in the blood (Awad and Austin 2010 ), upregulation of cytokine gene, i.e. IL-8,
IL-1ß and TGF-ß] expression (Awad et al. 2011 ). The benefi t of stinging nettle was
reinforced by Ngugi et al. ( 2015 ), who noted growth, improvements, imunostimulation and protection of Victoria labeo ( Labe victorianus ) against challenge.
Neem
Dried neem leaf powder was incorporated into feed at 5 g neem/kg of diet, and fed
to common carp leading to immunostimulation (enhanced superoxide anion production, lysozyme activity, serum protein and albumin levels) and reduced mortalities after challenge (35 % died compared to 85 % of the controls) (Verma and Kumari
( 2013 )). As a further example, 4 g azadirachtin/kg, which is a secondary metabolite
of neem ( Azadirachta indica ) seeds, was effective at immunomodulation (enhanced
nitroblue tetrazolium and lysozyme activities, protein profi les, and leukocyte
counts) and disease protection (RPS = 42.6 %) in goldfi sh ( Carassius auratus ) when
dosed for 28-days (Kumar et al. 2013 ).
Aeromonas hydrophila
Garlic
Garlic ( Allium sativum ) dosed at 0.5 and 1.0 g/100 g of feed led to a stimulation in
growth, feed conversion and protein effi ciency, and marked reduction in mortalities
(RPS = 95 %) in rainbow trout after challenge with Aer. hydrophila with the mode of
action refl ecting the stimulation of the number of erythrocytes and leucocytes,
higher haematocrit and increase in anti-protease, bacteriocidal, lysozyme, phagocytic and respiratory burst activities (Nya and Austin 2009a ). Of course, natural
plant products are likely to contain many bioactive components, therefore, identifi -
cation of the active ingredients(s) is likely to be challenging. Allicin, a component
of garlic, was used separately as a feed additive dosed at 0.5 and 1.0 ml/100 g/feed
for the control of Aer. hydrophila with great success, i.e. the RPS was 90–100 %.
Again, there was evidence of immunomodulation, specifi cally increased phagocytic
and serum lysozyme activities (Nya et al. 2010 ).
Ginger
Success occurred with ginger ( Zingiber offi cinale ), which again led to immunomodulation and protection against Aer. hydrophila (Nya and Austin 2009b ).
Lupin, Mango and Stinging Nettle
Lupin ( Lupinus perennis ), mango ( Mangifera indica ) and stinging nettle ( Urtica
dioica ) were added to feed to 1 % (w/v) for 14 days, and protected rainbow trout
against challenge with Aer. hydrophila, with the mode of action considered to
involve immune stimulation, principally enhancement in lysozyme respiratory burst
and serum bacteriocidal activity, increases in the number of red and white blood
cells in the blood (Awad and Austin 2010 ), upregulation of cytokine gene, i.e. IL-8,
IL-1ß and TGF-ß] expression (Awad et al. 2011 ). The benefi t of stinging nettle was
reinforced by Ngugi et al. ( 2015 ), who noted growth, improvements, imunostimulation and protection of Victoria labeo ( Labe victorianus ) against challenge.
Neem
Dried neem leaf powder was incorporated into feed at 5 g neem/kg of diet, and fed
to common carp leading to immunostimulation (enhanced superoxide anion production, lysozyme activity, serum protein and albumin levels) and reduced mortalities after challenge (35 % died compared to 85 % of the controls) (Verma and Kumari
( 2013 )). As a further example, 4 g azadirachtin/kg, which is a secondary metabolite
of neem ( Azadirachta indica ) seeds, was effective at immunomodulation (enhanced
nitroblue tetrazolium and lysozyme activities, protein profi les, and leukocyte
counts) and disease protection (RPS = 42.6 %) in goldfi sh ( Carassius auratus ) when
dosed for 28-days (Kumar et al. 2013 ).
Aeromonas hydrophila