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 Pavasovic ǂ David Hurwood* Peter Mather* *Science & Engineering Faculty ǂ Health Faculty Queensland University of Tech. 1
Effects of soluble dietary cellulose on specific growth rate, survival and digestive enzyme activities in three freshwater crayfish (Cherax) species. Lalith Dammannagoda * Ana Pavasovic ǂ David Hurwood * Peter Mather* *Science & Engineering Faculty ǂ Health Faculty - PowerPoint PPT Presentation
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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
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