THE EFFECT OF DIET ON THE EFFECT OF DIET ON DMSP ACCUMULATION AND DMSP ACCUMULATION AND TASTE IN SOUTH AFRICAN TASTE IN SOUTH AFRICAN ABALONE (ABALONE (Haliotis midaeHaliotis midae))
Deborah Robertson-Andersson1; A. J.
Smit2; S. Peall3 and Bolton J. J1
1Botany Department, UCT
2School of Biological and Conservation Sciences,
UKZN
3Hearshaw and Kinnes Analytical Laboratory, UCT,
Deborah Robertson-Andersson1; A. J.
Smit2; S. Peall3 and Bolton J. J1
1Botany Department, UCT
2School of Biological and Conservation Sciences,
UKZN
3Hearshaw and Kinnes Analytical Laboratory, UCT,
What do DMSP and abalone taste have What do DMSP and abalone taste have to do with each other?to do with each other?What do DMSP and abalone taste have What do DMSP and abalone taste have to do with each other?to do with each other?
Abalone farming and the importance of macroalgal feeds
The effect of macroalgae on abalone growth
The problem
DMSP
Our studies
Work in progress and the future
Abalone farming and the importance of macroalgal feeds
The effect of macroalgae on abalone growth
The problem
DMSP
Our studies
Work in progress and the future
Integrated abalone-macroalgal Integrated abalone-macroalgal cultivationcultivationIntegrated abalone-macroalgal Integrated abalone-macroalgal cultivationcultivation
number of benefits:
Increased growth rates,
Improved vigor
and stress resistance
number of benefits:
Increased growth rates,
Improved vigor
and stress resistance
6
8
10
12
14
16
18
20
22
24
26
28
30
Aug-02
Sep-0
2
Oct-0
2
Nov-02
Dec-0
2
Jan-
03
Feb-0
3
Mar
-03
Apr-03
May
-03
Mea
n w
et w
eig
ht
(g)
Mixed diet
Rotation
Fresh Kelp
Fresh Kelp + formulated feed
Formulated feed
(Naidoo et al., in press)
Benefits of a mixed algal diet
KELP ONLY DIET
MIXED ALGAL DIET
However…..However…..However…..However…..
Two farms which feed Ulva and Gracilaria exclusively experienced that their abalone developed an ‘off’ taste and sulphur-like smell after the canning process
Two farms which feed Ulva and Gracilaria exclusively experienced that their abalone developed an ‘off’ taste and sulphur-like smell after the canning process
Abalone Mariculture Operations in South AfricaAbalone Mariculture Operations in South Africa
Durban
Port ElizabethCape Town
I&J Abalone Atlantic FishingSea Plant Products
Roman Bay
Marine Growers
HIK Farm
AbagoldAquafarm Development
Avuca AbaloneFish Bay Mariculture
Jacobsbaai Sea Products
West Coast Abalone
Port Nolloth Sea Farms
Wild Coast Abalone
Abaseed
Questions…Questions…Questions…Questions…
What is the cause of the problem?
What can be done about it?
What is the cause of the problem?
What can be done about it?
Preliminary investigations Preliminary investigations Preliminary investigations Preliminary investigations
Methionine (mg.g-1 protein)
Cysteine (mg.g-1 protein)
Ecklonia 18.5 29.1
Ulva 15.7 13.3
Gracilaria 16.8 28.1
Methionine, cysteine? No…
Hill et al. (2000; 2004) mentioned a similar problem in tridacnid clams and implicated DMS (produced from DMSP)…
Do abalone receive DMSP in their diet?
Methionine, cysteine? No…
Hill et al. (2000; 2004) mentioned a similar problem in tridacnid clams and implicated DMS (produced from DMSP)…
Do abalone receive DMSP in their diet?
Preliminary investigations Preliminary investigations Preliminary investigations Preliminary investigations
Methionine (mg.g-1 protein)
Cysteine (mg.g-1 protein)
DMSP (μg.g-1 fresh mass)
Ecklonia 18.5 29.1 0.5 - 46.1
Ulva 15.7 13.3 4101 - 7961
Gracilaria 16.8 28.1 1.6 - 48.6
Do abalone receive DMSP from their feed?
Van Alstyne et al. (2003) - Ulva… yes!
Do abalone receive DMSP from their feed?
Van Alstyne et al. (2003) - Ulva… yes!
Background: DMSP and DMS in algaeBackground: DMSP and DMS in algaeBackground: DMSP and DMS in algaeBackground: DMSP and DMS in algae
Some algal species contain high concentrations of intercellular DMSP
Produced in response to freezing temperatures and fluctuating salinity
hypothesised function as osmolyte
DMSP is oxidised in the presence of OH-, O3- or H2O2
reaction with reactive oxygen species implies role as antioxidant
Enzymatic cleavage of DMSP leads to DMS and acrylate
Some algal species contain high concentrations of intercellular DMSP
Produced in response to freezing temperatures and fluctuating salinity
hypothesised function as osmolyte
DMSP is oxidised in the presence of OH-, O3- or H2O2
reaction with reactive oxygen species implies role as antioxidant
Enzymatic cleavage of DMSP leads to DMS and acrylate
DMSP and DMSDMSP and DMSDMSP and DMSDMSP and DMS
COO-
CH3
CH3
S+
DMSP lyase
CH3
CH3
S COO-
H
CH2
H++ +
Dimethylsulphoniopropionate Dimethylsulphide Acrylate
• Produced by algal or bacterial DMSP lyase
• Thermal decomposition of DMSP
• Highly volatile• Distinct taste and
odor• Noticeable at 0.03 -
0.045 μg.ml-1 in water
• Produced by algae• Accumulated by
grazers
• Taste - and odorless
Do abalone contain
DMSP?
Do abalone contain
DMSP?
If they contain DMSP, where is it If they contain DMSP, where is it accumulated?accumulated?If they contain DMSP, where is it If they contain DMSP, where is it accumulated?accumulated?
Top of foot
foot
Epipodial frill
Epipodial frill
AM
BF F
TF
0
5
10
15
20
25
30
35D
MS
P (
g
.g-1)
DMSP values from various tissue types in mixed diet cultivated
abalone diet (25% Ulva; 1 year)
DMSP values from various tissue types in mixed diet cultivated
abalone diet (25% Ulva; 1 year)
Preliminary investigations Preliminary investigations Preliminary investigations Preliminary investigations
AM Abductor muscle
BF Bottom of foot
F Epipodial frill
TF Top of foot
In Tridacnidae, siphonal mantle not abductor muscle had high
concentrations (Hill et al. 2000)
Oysters and mussles have highest concentrations in abductor
muscle (Iida et al. 1986)
In Tridacnidae, siphonal mantle not abductor muscle had high
concentrations (Hill et al. 2000)
Oysters and mussles have highest concentrations in abductor
muscle (Iida et al. 1986)
Abductor muscle preparationAbductor muscle preparationAbductor muscle preparationAbductor muscle preparation
Step 1
Step 4Step 3
Step 2
DMSP diet experimentDMSP diet experimentDMSP diet experimentDMSP diet experiment
Values for fish, crustaceans and other molluscs usually below 1800 μg.g-1 (Hill et al. 2000)
Previous recorded highest DMSP accumulation in tridacnids with zooxanthellae (Hill et al. 2004)
Abalone about 25 % higher
Values for fish, crustaceans and other molluscs usually below 1800 μg.g-1 (Hill et al. 2000)
Previous recorded highest DMSP accumulation in tridacnids with zooxanthellae (Hill et al. 2004)
Abalone about 25 % higher
DMS content in canned abaloneDMS content in canned abaloneDMS content in canned abaloneDMS content in canned abalone
DMS in cans up to 44 μg.ml-1
Taste threshold of DMS in water about 1000 times lower
DMS in cans up to 44 μg.ml-1
Taste threshold of DMS in water about 1000 times lower
DepurationDepuration experiment experimentDepurationDepuration experiment experiment
Variation is consistent with that found in bivalve mollusks (Hill et
al. 1995)
Variation is consistent with that found in bivalve mollusks (Hill et
al. 1995)
0 100 200 300 400 500 600 700 800Time (days)
0
50
100
150
200
250
DM
SP
re
ma
inin
g (
g.g
-1)
smal
lest
smal
l
med
ium
larg
e
0
250
500
750
1000
1250
1500
DM
SP
(µg
.g-1
)Wild abaloneWild abaloneWild abaloneWild abalone
Smallest 10 -20 g
Small 100 -200 g
Medium250 – 750
g
Large > 1 000 g
Effect of DMS content on taste/odour of the product (quality control)?
Important taste consequences in seafoods (Peavy & Riley, 1993; 1994) which limit cultivation e.g. tridacnids
Excessive DMS in cod is commercially problematic, but very low concentrations of DMS are part of the “valued flavor” of some clams and oysters (Ackman & Hingley, 1968; Iida & Toukuaga, 1986; Brooke et al. 1968; Hill et al. 2000)
Effect of DMS content on taste/odour of the product (quality control)?
Important taste consequences in seafoods (Peavy & Riley, 1993; 1994) which limit cultivation e.g. tridacnids
Excessive DMS in cod is commercially problematic, but very low concentrations of DMS are part of the “valued flavor” of some clams and oysters (Ackman & Hingley, 1968; Iida & Toukuaga, 1986; Brooke et al. 1968; Hill et al. 2000)
Continuing studies…Continuing studies…
The effect of DMSP on abalone physiology
Partitioning of DMSP – are there tissue properties that
specifically act to exclude DMSP?
May affect enzyme function (Karsten et al. 1996) therefore
have specialised enzymes developed to function in a high
DMSP environment (Hill et al. 2004)?
The effect of DMSP on abalone physiology
Partitioning of DMSP – are there tissue properties that
specifically act to exclude DMSP?
May affect enzyme function (Karsten et al. 1996) therefore
have specialised enzymes developed to function in a high
DMSP environment (Hill et al. 2004)?
The FutureThe Future
Physiology of DMSP production by macroalgae
Can the DMSP production in Ulva be reduced by altering the
cultivation conditions?
Evaluate the role of DMSP as antioxidant in algae by studying
its photophysiology (stress to photosystems)
Physiology of DMSP production by macroalgae
Can the DMSP production in Ulva be reduced by altering the
cultivation conditions?
Evaluate the role of DMSP as antioxidant in algae by studying
its photophysiology (stress to photosystems)
THANK YOU
ACKNOWLEDGEMENTS
I would like to extend special thanks to the following people and organizations without whose help this project
would be impossible:
Swedish and South African Collaborative Program
I & J Mariculture farm
JSP Mariculture farm
Wild Coast Abalone
Abagold
N R F JSP
A small experiment was instigated to see if DMS was detectable in
abalone.
1 – 2 g of tissue was removed from 5 abalone fed a mixed (kelp, Ulva and
Gracilaria) diet.
Samples were placed in 20 ml of Methanol
Measurement of DMS:
Quantitative conversion of DMSP to DMS through alkali hydrolysis
DMS analysis via gas chromatography
A small experiment was instigated to see if DMS was detectable in
abalone.
1 – 2 g of tissue was removed from 5 abalone fed a mixed (kelp, Ulva and
Gracilaria) diet.
Samples were placed in 20 ml of Methanol
Measurement of DMS:
Quantitative conversion of DMSP to DMS through alkali hydrolysis
DMS analysis via gas chromatography
Preliminary investigations Preliminary investigations Preliminary investigations Preliminary investigations
DMSP and DMS DMSP and DMS DMSP and DMS DMSP and DMS
Ever notice the salty sea smell when you're out on or near the ocean?
Trace concentrations of a volatile sulphur compound, Dimethylsulfide (DMS), were
discovered in the Earth's atmosphere about three decades ago.
The gas was also found to occur in ocean surface waters.
Some phytoplankton synthesize the molecule dimethylsulfoniopropionate (DMSP)
DMS is released by algal cells following death and ‘sloppy feeding’ by
zooplankton.
DMS a naturally produced biogenic gas essential for the Earth's biogeochemical
cycles.
Assumptions: (To be confirmed by taste tests and future studies)
DMSP is not produced by animals and may accumulate following feeding
DMSP is proportionately converted to DMS (Hill et al. 1995)
DMS causes the taste change (Hill et al. 1995, 2000, 2004)
DMSP loss is through excretion (e.g. planktonic copepods (Hill et al. 1993) or mucus loss (corals,
giant clams - Hill et al. 1995, 2004).
No DMS in live abalone (Hill et al. 1995)
Post mortem DMS content is due to:
DMS production from DMSP resulting from heat treatment during canning
Bacterial activity: DMSP lyase
Abalone do not have DMSP-lyase (true for other invertebrates - Hill et al. 2004)
Assumptions: (To be confirmed by taste tests and future studies)
DMSP is not produced by animals and may accumulate following feeding
DMSP is proportionately converted to DMS (Hill et al. 1995)
DMS causes the taste change (Hill et al. 1995, 2000, 2004)
DMSP loss is through excretion (e.g. planktonic copepods (Hill et al. 1993) or mucus loss (corals,
giant clams - Hill et al. 1995, 2004).
No DMS in live abalone (Hill et al. 1995)
Post mortem DMS content is due to:
DMS production from DMSP resulting from heat treatment during canning
Bacterial activity: DMSP lyase
Abalone do not have DMSP-lyase (true for other invertebrates - Hill et al. 2004)
DMSP and DMS in herbivoresDMSP and DMS in herbivoresDMSP and DMS in herbivoresDMSP and DMS in herbivores
The FutureThe Future
DMSP physiology
Important taste consequences in seafoods (Peavy and Riley 1993, 1994)
which limit cultivation e.g. Giant clams.
Values in cod and other finfish in the range 0.2 – 1 umol.g-1 are
considered commercially problematic, BUT very low concentrations of
DMS are part of the “valued flavor” of some clams and oysters
(Ackman & Hingley, 1968; Iida & Toukuaga, 1986; Brooke et al. 1968;
Hill et al. 2000)
Abalone physiology
Partitioning of DMSP – have tissue evolved properties that specifically
act to exclude DMSP
Can affect enzyme function (Karsten et al. 1996) therefore have
specialized enzymes formed to function in a high DMSP environment (Hill
et al. 2004).
Does it play role in ameliorating tissue oxygen stress (Sundra et al.
2002).
DMSP physiology
Important taste consequences in seafoods (Peavy and Riley 1993, 1994)
which limit cultivation e.g. Giant clams.
Values in cod and other finfish in the range 0.2 – 1 umol.g-1 are
considered commercially problematic, BUT very low concentrations of
DMS are part of the “valued flavor” of some clams and oysters
(Ackman & Hingley, 1968; Iida & Toukuaga, 1986; Brooke et al. 1968;
Hill et al. 2000)
Abalone physiology
Partitioning of DMSP – have tissue evolved properties that specifically
act to exclude DMSP
Can affect enzyme function (Karsten et al. 1996) therefore have
specialized enzymes formed to function in a high DMSP environment (Hill
et al. 2004).
Does it play role in ameliorating tissue oxygen stress (Sundra et al.
2002).