Effects of Different Protein Levels in Practical Diets on Growth and Survival of Australian Red Claw Crayfish Grown in Ponds Thompson, K.R., Muzinic, L.A., Webster, C.D., Aquaculture Research Center, Kentucky State University, Frankfort, KY 40601
Red claw is a large freshwater crayfish found in the river systems of northern Australia
RED CLAW
AUSTRALIAN RED CLAW (Cherax quadricarinatus) Males have distinct RED patch Females have NO RED patch MALE FEMALE
Considerable interest is currently being shown in the commercial culture of red claw both in Australia and elsewhere. Transplantations includes: USA, Mexico, Caribbean Islands, Ecuador, China, Southern Africa (Swaziland, Zambia), Italy, and Israel.
Farmers in Kentucky are looking to reduce their dependence upon tobacco Tobacco income, which exceeded $900 million in sales during 1999 and 2000, dropped to $600 million in 2002 Aquaculture Being viewed as a possible alternative to supplement farm income in KY
In Kentucky... Pond production of red claw is small-scale. Roughly, 5.5 acres (55,000 juveniles) will be dedicated to red claw this year. Currently, KY farmers use expensive high-quality commercial shrimp diets to ensure adequate nutrition No commercial red claw diet available since little production
ATTRIBUTES Potential large size (>1 lb); prices of $8-15/lb Exhibits fast growth rates (4-5 per lb in 4 months for males) Farmers can market them as home-grown freshwater lobsters Easy to grow Production technologies are straightforward no larval stages
High Meat Yield: AUSTRALIAN RED CLAW About 30% of the total body weight of red claw is edible tail meat;15-20% for our native crayfish... Excellent flavor
Presently, little information exists on the dietary protein requirements when grown in ponds... Since diet costs represent 30-70% of a farmers cost of operation Since protein is one of the most expensive ingredients in a prepared aquaculture diet Important to determine the minimal protein level for red claw in an effort to reduce diet costs for farmers and the industry
OBJECTIVE The purpose of this study was to determine the minimum dietary protein percentage for pond-cultured red claw, in an effort to reduce production costs and potentially increase profits.
MATERIALS AND METHODS
Description and stocking of ponds: Juvenile red claw obtained from supplier in Australia Stocked into 9 (0.02-ha) ponds on June 1, 2002 3 replicate ponds randomly assigned per diet
Description and stocking of ponds: Stocking rate of 500 red claw per pond (10,000/acre) Mean stocking weight of (4.6 g)
Red Claw were fed one of 3 practical diets containing different percentages of protein:
Formulation of practical diets fed to red claw crayfish. Ingredient 1 (22%) 2 (32%) 3 (42%) Menhaden FM (67%) SBM (50%) BGY (35%) Wheat flour (14%) Menhaden oil Corn oil Vitamin mix Mineral mix Wheat gluten (41%) Other 6.9 11.0 5.0 59.15 5.0 2.0 3.0 1.0 5.0 1.95 10.0 34.0 5.0 33.55 4.5 2.0 3.0 1.0 5.0 1.95 13.2 56.0 5.0 8.85 4.0 2.0 3.0 1.0 5.0 1.95
Experimental diets and feeding rates: Fed 5-mm sinking pellets (commercial feed mill)
Experimental diets and feeding rates: Fed twice daily (0800 h and 1530 h) for 117 days Fed a percentage of body weight based upon a feeding schedule devised by Dr. Carl Webster Feeding rates adjusted every 2 weeks Diets analyzed for proximate and AA composition
Water quality management: Water temperature and DO checked twice daily (0900 h and 1530 h) ph checked daily (1530 h) TAN, nitrite, & alkalinity taken 3 times/wk (1300 h)
Harvest: Ponds were manually harvested Sept 23-28, 2002 Total weight and number of red claw (by sex) from each pond were recorded at harvest
Harvest: Proximate composition measured on tail muscle 10 males and 10 females from each pond
Harvest: Processing traits were measured from 20 males and 20 females from each pond which included (wetweight basis): Total weight Claw weight Tail weight (shell on) Tail muscle weight (shell off) Cephalothorax weight
RESULTS
Water Quality (No significant differences (P>0.05) All ponds averaged 7.51 mg/l (am) & 9.38 mg/l (pm) for dissolved oxygen Temperature (am) averaged 25 C Temperature (pm) averaged 27 C ph averaged 8.7 Significant differences (P<0.05) were found below: Parameter 1 (22%) 2 (32%) 3 (42%) TAN (mg/l) 0.32 b 0.38 b 0.55 a Nitrite (mg/l) 0.01 b 0.02 b 0.05 a Alkalinity (mg/l) 110 a 102 b 103 b
RESULTS 80 70 a a a 60 50 40 Diet 1 Diet 2 Diet 3 Final weight (g)
RESULTS 1650 1550 1450 1350 a a a 1250 1150 Diet 1 Diet 2 Diet 3 Weight gain (%)
RESULTS 2.5 a a a 1.5 0.5 Diet 1 Diet 2 Diet 3 SGR (%/day)
RESULTS 7 6 5 4 3 2 1 a b b Diet 1 Diet 2 Diet 3 FCR
RESULTS 70 60 50 40 30 a a b 20 Diet 1 Diet 2 Diet 3 Survival (%)
RESULTS 950 850 750 a a 650 550 450 b Diet 1 Diet 2 Diet 3 Yield (kg/ha)
Percentage of Males & Females at Harvest No significant differences in the % of males and females harvested among the three diets 48.5% 51.5%
Average Final Weight of Males and Females at Harvest No significant differences in the final mean of males and females fed any treatment (diet) 88.0 g 64.2 g Not comparing between sexes
Males TAIL MUSCLE ANALYSIS (Wet-weight basis) 1.52% 17.21% 79.01% a a 0.15% a a Protein Lipid Moisture Ash
TAIL MUSCLE ANALYSIS (Wet-weight basis) Females 18.08% 78.05% 1.64% * b a 0.21% a a Protein Lipid Moisture Ash *Diet 2 (P<0.05)
DISCUSSION Results indicate that red claw stocked at the rate (2.5 m 2 ) and size (4.6 g) in this study, can be fed 22% protein in ponds without adverse effects on growth, survival, and on water quality
DISCUSSION Natural foods consumed may have supplemented the diet of red claw; however, no measurement of pond organic matter was made in this study
Average final weights (75 g) were similar to, or higher than, other reports... Author Species Final weight (g) Brummett & C. quadricarinatus 56.1 (i.w. 2.0g; Alon (1994) 25,000/ha; 170 days) Webster et al. C. quadricarinatus 53.5 (i.w. 8.1g; (In Press) 24,000/ha; 70 days) Salame & C. quadricarinatus 30.0 (i.w. 2g; Rouse (2000) 4/m 2 ; 90 days) Rouse & Kahn C. quadricarinatus 76.0 (i.w. 7g; 20,000/ha; 135 days)
Mean survival rates (55%) were similar to, or higher than, other reports... Author Species Survival (%) Brummett & C. quadricarinatus 36 Alon (1994) Webster et al. C. quadricarinatus 43 (In Press) Salame & C. quadricarinatus 49.5 Rouse (2000)
Total yield (821 kg/ha) were similar to, or higher than, other reports... Author Species Yield (kg/ha) Salame & C. quadricarinatus 594 Rouse (2000) Tidwell et al. (1993) M. rosenbergii 833 Rouse et al. (1998) C. quadricarinatus 352
DISCUSSION Increased levels of TAN and nitrite in ponds fed 42% protein, especially in September, may have reduced survival
Changes in TAN in Ponds (by month) 1.2 1 0.8 Diet 1 Diet 2 Diet 3 0.6 0.4 0.2 0 June July August September
Changes in Nitrite in Ponds (by month) 0.16 0.14 0.12 0.1 Diet 1 Diet 2 Diet 3 0.08 0.06 0.04 0.02 0 June July August September
DISCUSSION All ponds were fed the same feeding rate daily, thus diet allowance was not a factor; but more protein nitrogen was fed to red claw fed Diet 3
DISCUSSION Data from the present study indicate that male red claw were larger than females when comparing body analysis This is in agreement with other reports Stocking all-male populations may allow producers to grow larger individuals since it appears that males grow larger and more rapidly than females
CONCLUSION It appears that red claw grown in single-season, temperate-climate ponds can be fed a diet containing 22% protein
CONCLUSION Use of a diet containing 22% protein (as fed) may allow producers to reduce diet costs and thereby, potentially increase profits
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