disease control in aquaculture is, and...
TRANSCRIPT
210/5/2017
DISEASE CONTROL IN AQUACULTURE IS, AND WILL REMAIN, A FOCUS POINT
1960-1970 19901980 2000
Start
industrial
farming
2010 2020
Optimizing reproduction
protocols, nutrition and culture
systems
2017
310/5/2017
Walker and Mohan (2009)
20161970 19901980 2000
Start
commercial
farmingIHHNV
MBV
YHV
TSV
WSSV
GAVMSGS
IMNV EMS
EHP
vibriosis
DISEASES, A PROBLEM OF INCREASING INDUSTRIALISATION
Start
industrial
farming
410/5/2017
1960-1970 19901980 2000 2010 20202017
Optimizing reproduction
protocols, nutrition and culture
systems
Developing and optimizing disease
control strategies
Developing and optimizing disease
control strategies
DISEASES, A PROBLEM OF INCREASING INDUSTRIALISATION
510/5/2017
Walker and Mohan (2009)
20161970 19901980 2000
Start
commercial
farmingIHHNV
MBV
YHV
TSV
WSSV
GAVMSGS
IMNV
EHP
vibriosis
EARLY MORTALITY SYNDROME IN SHRIMP FARMING
EMS
610/5/2017
- Shrimp post-larvae
- 10 - 30 days after stocking in grow-out pond
- causes up to 100 % mortality
- 5-7 $ bn losses in Thailand (2011-2015); > 10 $ mln losses in
Mekong Delta in 2015
China (2009)
Vietnam (2010)
Malaysia (2011)
Thailand(2012)
Mexico (2013)
EARLY MORTALITY SYNDROME IN SHRIMP FARMING
EARLY MORTALITY SYNDROME IN SHRIMP FARMING
- Caused by Vibrio parahaemolyticus
- Contains plasmid with pirA and pirB toxin encoding genes
Xiao et al. (2017)
810/5/2017
INITIAL APPROACH OF MICROBIAL MANAGEMENT: USE OF ANTIBIOTICS TO CONTROL EMS
Only focus was on killing the bad bugs
PATHOGENHOST DISEASE
CULTURE SYSTEM
PATHOGEN + all other bacteria
“ANTIBIOTICS USE INTENDED TO REDUCE LOSSES DUE TO THE EARLY MORTALITY SYNDROME (EMS/AHPNS) IN SHRIMP FARMS IN VIET NAM” By Loc H. Tran et al. (2013)
Bacterial isolates in Vietnam were investigated for antibiotic resistance against oxytetracycline
97/9/2017
PRESENTATION WORLD AQUACULTURE SOCIETY -WAS 2013
EMS-causing V. parahaemolyticus
Non EMS-causing V. parahaemolyticus
2011/2012 0% resistant 0% resistant
EMS-causing V. parahaemolyticus
Non EMS-causing V. parahaemolyticus
2011/2012 0% resistant 0% resistant
2013 85,7% resistant 100% resistant
1010/5/2017
ANTIBIOTIC USE IN MEXICO TO CONTROL EMS
1110/5/2017
The evolution of bacteria on a “mega-plate” petri dish – Kishony Lab;
Harvard Medical School
WHAT HAPPENS WHEN WE USE ANTIBIOTICS?
1210/5/2017
BALANCED HEALTH TO MINIMIZE EMS RISK
RESILIENCE CHALLENGE
ON FARM
DISEASE
CHALLENGE
NUTRITION
IMMUNITY
GENETIC
RESISTANCE
- MINIMIZE “RED STACK” AND MAXIMIZE “GREEN STACK”
Vision
New approach of microbial management = control the presence and/or activity of bad bugs AND good bugs
137/9/2017
PATHOGEN
CULTURE SYSTEM
- Avoid entrance
and transmission
of the plasmid
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
1410/5/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
AVOIDING ENTRANCE INTO THE SYSTEM
- BIOSECURITY
Vision
1410/5/2017
Specific pathogen
free (SPF)
Disinfection protocol in Thailand
157/9/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
HOST
CULTURE SYSTEM
- Steer gut colonizationPATHOGEN - Use of bacteria
- Avoid entrance
and transmission
of the plasmid
1610/5/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
USE OF GOOD BACTERIA TO CONTROL BAD BACTERIA -PROBIOTICS
1710/5/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
PROBIOTICS
Mayo/Junio 2017 Vol. 22
1810/5/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
PROBIOTICS
Disease challenge test in collaboration with Can Tho University (Vietnam)
1910/5/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
PROBIOTICS
Munoz et al. 2014. Global Aquaculture Advocate. Sept-
Oct 2014, 50-52
207/9/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
HOST
CULTURE SYSTEM
- Steer gut colonizationPATHOGEN - Use of bacteria
- Avoid entrance
and transmission
of the plasmid
- Use of plant
components
2110/5/2017
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: USE OF PLANT COMPONENTS
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1 4 7 1013161922252831343740434649
OD
60
0n
m
Time (h)
Growth Streptococcus agalactiae in presence of plant compound 1
0
25
50
100
250
500
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49
Time (h)
Growth of Aeromonas salmonicida in presence of plant compound 3
0
25
50
100
250
500
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: USE OF PLANT COMPONENTS
Product applied in the culture water during 24h PL10 transport.
➢ Drastic reduction of Vibrio in transport water and shrimp.
1,E+00
1,E+01
1,E+02
1,E+03
1,E+04
1,E+05
1,E+06
Postlarvae Water Postlarvae Water
Vibrio sp. Vibrio parahaemolyticus
CFU
/ml o
r p
ost
larv
ae Control
Plant compound
based product
2310/5/2017
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: USE OF PLANT COMPONENTS
Disease challenge test in collaboration with Can Tho University (Vietnam)
247/9/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
HOST
CULTURE SYSTEM
- Steer gut colonizationPATHOGEN - Use of bacteria
- Avoid entrance
and transmission
of the plasmid
- Use of plant
components
- Increase nutrition and
immunity
2510/5/2017
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: BOOSTER DIETS
• Optimal nutrition for postlarval shrimp• Contains immunostimulants• Neutralisation of EMS bacteria
• Partial replacement of nursery or grow-out diet during critical period
Improve overall resilience of the shrimp
2610/5/2017
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: BOOSTER DIETS
15% Booster diet
15% Booster diet
2710/5/2017
FUTURE MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
TREATMENTS UNDER INVESTIGATION: BOOSTER DIETS
Disease challenge test in collaboration with Can Tho University (Vietnam)
287/9/2017
CURRENT MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
HOST
CULTURE SYSTEM
- Steer gut colonizationPATHOGEN - Use of bacteria
- Avoid entrance
and transmission
of the plasmid
- Use of plant
components
ENVIRONMENT - Modify system
operational
parameters
- Increase nutrition and
immunity
2910/5/2017
NEW MICROBIAL MANAGEMENT STRATEGIES TO CONTROL EMS
MODIFICATION OF SYSTEM OPERATIONAL PARAMETERS
Based on knowledge on ecology of the pathogen…
Vibrio parahaemolyticus = Vibrio sp.Vibrio sp. = normal component of marine environments
opportunistic pathogens
… it is possible to modify the system and set-up selection regime to outcompete vibrios
neutral/beneficial bacteria
harmful bacteria (obligate pathogens)
potentially harmful bacteria
(opportunists)
What do we want???
- all bacteria are eliminated
In order to eliminate bad bacteria: disinfection
- but, new bacterial colonization starts: difference r-strategists ( ) and K-strategists ( )!!!!
ecological characteristics of
Importance for shrimp
Dangerous; opportunistic pathogens;
EMS causing bacteria
Generally harmless
Growth rate upon enrichment
HIGH LOW
Dominance? Unstable environmental conditions
Stable environmental conditions
K-strategist bacteriar-strategist bacteria
Initially: Low number of bacteria and a lot of nutrients
Stimulates r-strategist bacteria
Substrate per bacterium = HIGH; niches are openTime
What happens at the microbial level after
disinfection?
In the mean time:
K-strategist bacteria grow slowly
TimeSubstrate per bacterium = HIGH; niches are open
What happens at the microbial level after
disinfection?
SYSTEM DESIGN IN TIMES OF EMS
(Taw, 2017)
Prior to EMS
Time
What happens in the long run?
substrate/bacterium remains HIGH
Standard systems: a lot of nutrients and wash-out
r-strategist bacteria dominate
Timesubstrate/bacterium remains HIGH
Standard systems: a lot of nutrients and wash-out
r-strategist bacteria dominate
What happens in the long run?
Timesubstrate/bacterium remains HIGH
What happens in the long run?
introduction of animals: typically during massive microbial growth
4010/5/2017
- Industrial approach to control EMS in Asia
Minimize waste within the system (remove nutrients)Shrimp toilets
Minimize exchange of water with the external environmentRecirculation of the water
SYSTEM MANAGEMENT TO MINIMIZE DISEASE RISK
- Industrial approach to control EMS (Asia)
(Taw, 2017)
After EMS
SYSTEM MANAGEMENT TO MINIMIZE DISEASE RISK
Prior to EMS
Transition: High number of bacteria and less nutrients
Collapse of r-strategist bacteria
TimeSubstrate per bacterium = LOW; niches are taken
What happens at the microbial level because of RAS and
removal of excess waste?
Transition: High number of bacteria and less nutrients
K-strategist bacteria continue to grow
TimeSubstrate per bacterium = LOW; niches are taken
What happens at the microbial level because of RAS and
removal of excess waste?
r selection
K selection
Time
Consequence of alternative system operations implied by
shrimp farmers
Animals live in environment controlled for V. parahaemolyticus dominance, but also opportunists (e.g. Vibrio) in general
r selection
K selection
Time
Consequence of alternative system operations implied by
shrimp farmers
introduction of animals: typically during massive microbial growth
r selection
K selection
Time
Similar RAS methodology will also work for control of
vibrios in general, both in farm and in hatcheries
477/9/2017
HORIZONTAL TRANSFER OF EMS PLASMID AMONG BACTERIA
HORIZONTAL TRANSFER OF EMS PLASMID AMONG BACTERIA
487/9/2017
Problem of horizontal transfer implies the need to control not
only EMS-causing V. parahaemolyticus,
but Vibrio in general!!
SUMMARY
- BIOSECURITY IS KEY; AVOID ENTRANCE
- PROBIOTICS, BOOSTER DIETS AND PHYTOBIOTICS CAN CONTRIBUTE IN CONTROLLING EMS, HOWEVER ARE NOT THE ONLY SOLUTION!
- SYSTEM OPERATIONS SHOULD BE (RE)CONSIDERED TO MINIMIZE DISEASE RISK. KEY IS TO ENSURE MICROBIAL STABILITY
- COMBINATION OF THE ABOVE WILL MAXIMIZE THE SUCCESS OF SHRIMP CULTURE IN TIMES OF EMS
4910/5/2017
5010/5/2017