Post on 22-Dec-2015
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Effects of soluble dietary cellulose on specific growth rate, survival and digestive enzyme activities in three
freshwater crayfish (Cherax) species
Redclaw (Cherax quadricarinatus)
Lalith Dammannagoda*Ana Pavasovicǂ
David Hurwood*Peter Mather*
*Science & Engineering FacultyǂHealth FacultyQueensland University of Tech.Brisbane, AUSTRALIA
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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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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
Feed / Feeding
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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
endo β-1,4-glucanses
cellobiohyrolases
Cellobiose / cello-oligomers
Glucose
β-glucosidases
cellobiohyrolases Cellulose
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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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(I) Feeding trial
Diets:
Reference diet (RD)
Test diet (TD)
n= 34
Feeding: 3% per day, twice
MethodsTable 1. Composition of experimental diets
Ingredient (gkg-1)
RD TD
Fish meal 581 581
Carboxymethyl cellulose
(CMC)
- 200
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
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(I) Feeding trial Culture: 12 wk independent trials
Table 2. Culture conditions maintained through out the experimental period
Outcome:
Analysis : Two-way ANOVA
Methods
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
𝑆𝑢𝑟𝑣𝑖𝑣𝑎𝑙 𝑟𝑎𝑡𝑒= 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑎𝑛𝑖𝑚𝑎𝑙𝑠 𝑎𝑡 𝑒𝑛𝑑𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑎𝑛𝑖𝑚𝑎𝑙𝑠 𝑎𝑡 𝑏𝑒𝑔𝑖𝑛𝑛𝑖𝑛𝑔𝑋100
𝑆𝐺𝑅= 100 𝑋 𝑙𝑛 (𝑓𝑖𝑛𝑎𝑙 𝑏𝑜𝑑𝑦 𝑤𝑒𝑖𝑔ℎ𝑡/𝑔) – 𝑙𝑛 (𝑖𝑛𝑖𝑡𝑖𝑎𝑙 𝑏𝑜𝑑𝑦 𝑤𝑒𝑖𝑔ℎ𝑡/𝑔)𝐷𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑒𝑥𝑝𝑒𝑟𝑖𝑚𝑒𝑛𝑡 (𝑑𝑎𝑦𝑠)
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Methods
Aquaculture facility – QUT Pilot Plant Precinct, Banyo, QLD
Individual tank unit with cages
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
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Methods
Methods
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(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
Redclaw: SGR of (RD) significantly higher than (TD)
Lower survival rates observed in TD than in RD
Overall, females showed higher survival rates
[Significance level = p<0.05]
Species Diet SGRSurvival rate (%)
Female Male Total
RedclawRD 0.193±0.019a 100.0a 88.2a 94.1a
TD 0.093±0.019b 94.1a 64.7a 79.4a
MarronRD 0.146±0.019a 100.0a 94.1a 97.1a
TD 0.107±0.017a 88.2a 94.1a 91.2a
YabbyRD 0.105±0.018a 82.4a 100.0a 91.2a
TD 0.086±0.017a 100.0a 64.7b 82.4a
Table 3. SGR and Survival rate (%)
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Results
Table 3. Specific enzyme activity levels (±SEM) in the hepatopancreas.
(II) Enzyme assay
[Significance level = p<0.05]
Species Diet
Average specific enzyme activity (U/mg of protein)Protease Amylase Cellulase
AZO-Casein AZCL-HE-
CelluloseAZO-CM-Cellulose(X 10-3)
RedclawRD 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
MarronRD 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
YabbyRD 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
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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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