Download Cherax quadricarinatus

Redclaw (Cherax quadricarinatus)
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Cherax
 Endemic to Australia
 3 Cherax species : Excellent candidates for commercial aquaculture
Redclaw (C. quadricarinatus)
Yabby (C. destructor)
Marron (C. tenuimanus)
Figure 1. Natural distribution of redclaw, yabby and marron (Wingfield, 2008)
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Cherax
Redclaw
Yabby
Marron
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Crayfish aquaculture
 Freshwater crayfish are an ideal
aquacultural commodity
●
Have excellent flavour and lobster-like
appearance - high market value
●
No larval stages - no need for expensive
sophisticated hatcheries
●
Omnivorous, opportunistic feeders - can
be fed with inexpensive feeds
●
More sustainable than prawn culture - no
need for higher stocking densities /
expensive coastal sites
 Female redclaws bearing eggs
and juveniles
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Feed / Feeding
 The largest operating cost (> 50%) of most fish and crustacean farming
 Fish meal (FM) and fish oil
 Expensive
 Future availability ? (climate change / overexploitation)
 Research priority
 Reduction of dependency on FM and fish oil inputs
 Identification of alternative high-protein and low-cost feed ingredients
 Feed optimization
 Require specific nutrient requirement identification
 Understanding of digestive enzyme activities of target species
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Cellulose digestion/Endogenous cellulase
 ECE discovered in commercially cultured decapod crustaceans including
freshwater crayfish
 ECE enables freshwater crayfish to breakdown complex polysaccharides (e.g.
cellulose) and utilise plant-derived ingredients
Cellulose
Cellobiose / cello-oligomers
Glucose
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Crayfish growth studies
 Previous growth and digestibility studies
 Protein and lipid digestibility widely assessed
 Less information on carbohydrates (types/amounts)
 Effect / potential of soluble cellulose not investigated
 C. destructor & C. tenuimanus less evaluated
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Objectives
 Objectives
To investigate the effect of soluble dietary
cellulose on growth performance and digestive
enzyme activities in 3 Cherax species
 Growth performance: Feeding trial
 Enzyme activities: Enzyme assay
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Methods
(I) Feeding trial
Table 1. Composition of experimental diets
(gkg-1)
Ingredient
RD
TD
581
581
-
200
Diets:
Fish meal
Reference diet (RD)
Corn starch
200
-
Fuller’s earth
79
79
Gluten
40
40
Gelatine
50
50
Vitamin/mineral pre-mix
25
25
Fish oil
25
25
Proximate composition
%
%
Dry matter
92.6
92.6
Crude protein
32.9
32.8
Ash
5.0
4.9
Gross energy
17.3
15.8
Test diet (TD)
n= 34
Feeding: 3% per day, twice
Carboxymethyl cellulose
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Methods
(I) Feeding trial
 Culture: 12 wk independent trials
Table 2. Culture conditions maintained through out the experimental period
Species
Temp. / oC Cond./µscm-1
pH
DO / ppm
Redclaw
26.0±0.01
517±4.0
7.9±0.01
7.42±0.05
Marron
20.4±0.03
499±1.0
7.9±0.01
8.67±0.02
Yabby
26.2±0.02
536±5.0
7.9±0.01
7.60±0.02
 Outcome: 𝑆𝑆𝑆𝑆𝑆𝑆 = 100 𝑋𝑋 𝑙𝑙𝑙𝑙 (𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓𝑓 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤ℎ𝑡𝑡/𝑔𝑔) – 𝑙𝑙𝑙𝑙 (𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖𝑖 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏 𝑤𝑤𝑤𝑤𝑤𝑤𝑤𝑤ℎ𝑡𝑡/𝑔𝑔)
𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆𝑆 𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟 =
𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷𝐷 𝑜𝑜𝑜𝑜 𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒𝑒 (𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑)
𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 𝑜𝑜𝑜𝑜 𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎 𝑎𝑎𝑎𝑎 𝑒𝑒𝑒𝑒𝑒𝑒
𝑋𝑋100
𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛𝑛 𝑜𝑜𝑜𝑜 𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎𝑎 𝑎𝑎𝑎𝑎 𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏𝑏
 Analysis : Two-way ANOVA
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Methods
 Specifications:
 36 tanks / 27 L each
 Recirculating /purifying
system
 Automatic control of pH,
temp., CD at a set value
 Constant water exchange
rate at a desired value
 Aquaculture facility – QUT Pilot Plant Precinct,
Banyo, QLD
 Individual tank unit with cages
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Methods
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Methods
(II) Enzyme assay
 Enzymes assayed from the Hepatopancreas
 Protease
 Amylase
 Cellulase

Specific enzyme activity (enzyme units (U)
per milligram of protein) was calculated
 Methods
 As described by Pavasovic et al. (2004)
 Analysis: Independent “t” test
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Results
(I) Feeding trial
Table 3. SGR and Survival rate (%)
Species
Redclaw
Marron
Yabby
Diet
SGR
RD
TD
RD
TD
RD
TD
0.193±0.019a
0.093±0.019b
0.146±0.019a
0.107±0.017a
0.105±0.018a
0.086±0.017a
Survival rate (%)
Female Male
Total
100.0a
88.2a
94.1a
94.1a
64.7a
79.4a
100.0a
94.1a
97.1a
88.2a
94.1a
91.2a
82.4a
100.0a 91.2a
100.0a
64.7b
82.4a
[Significance level = p<0.05]
 Redclaw: SGR of (RD) significantly higher than (TD)
 Lower survival rates observed in TD than in RD
 Overall, females showed higher survival rates
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Results
(II) Enzyme assay
Table 3. Specific enzyme activity levels (±SEM) in the hepatopancreas.
Species
Redclaw
Marron
Yabby
Diet
Average specific enzyme activity (U/mg of protein)
Protease
Amylase
Cellulase
AZO-Casein
AZCL-HEAZO-CMCellulose
Cellulose
(X 10-3)
RD
2.469±0.18a
3.731±0.31a 3.408±0.20a 9.690±0.62a
TD
1.718±0.23b
2.257±0.30b 2.985±0.33a 7.338±1.12a
RD
0.622±0.07a
0.168±0.02a 2.492±0.24a 5.535±0.54a
TD
0.315±0.04b
0.079±0.01b 1.540±0.16b 2.203±0.27b
RD
1.409±0.11a
2.753±0.21a 1.151±0.08a 4.372±0.38a
TD
0.930±0.13b
2.025±0.24b 0.861±0.09b 2.435±0.29b
[Significance level = p<0.05]
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Conclusion/Future studies
 All three species responded in same direction for experimental diets
 They appear to utilize starch more efficiently than soluble dietary
cellulose
 Inclusion of 20% soluble cellulose did not appear to have a significant
negative effect on individual growth rate in yabby and marron
 However, digestibility of soluble cellulose is needed to investigate
 Further testing (lower levels) needed to evaluate potential of soluble
cellulose to be used as a feed ingredient in commercial formulated
diets
 Results provide useful information towards formulating low cost
crayfish diets for commercial aquaculture
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Acknowledgment
 Supervisory team
 Ridley Agri products, Australia
 Crayfish suppliers
 Cherax Park, QLD
 Aquatic Resource Management Pty Ltd, WA
 Burns Yabby Farm / Reedy Creek Crays, NSW
 Technical staff at QUT
 Family & Friends
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