Comparison of fishmeal-free and fishmeal-based diets fed to walleye Sander vitreus in replicate RAS

John Davidson 1, Frederic Barrows 2, Brandon Gottsacker 3,6, Robert

Summerfelt 4, Christopher Good 1, Greg Fischer 5, Steven Summerfelt 1,6

1 The Conservation Fund’s Freshwater Institute2 USDA Agricultural Research Service

3 North Country Clear Waters LLC4 Iowa State University

5 Univ. Wisconsin-Stevens Point Northern Aquaculture Demonstration Facility6 Currently with Superior Fresh

Photo courtesy: Petuna Seafoods, Australiahttp://www.petuna.com.au/sustainability/

Image Courtesy Wisconsin Department of Natural Resources

http://dnr.wi.gov/topic/fishing/images/species/walleye.png

Important Trends

➢ Walleye as a commercial food-fish • Potential as niche-market aquaculture species

• Success with pike perch (zander) in Europe

Image Courtesy Wisconsin Department of Natural Resources

http://dnr.wi.gov/topic/fishing/images/species/walleye.png

➢ RAS becoming a viable fish production technology

➢ Declining use of marine ingredients in aquafeeds

Sources: Figure from – Marine Harvest, 2016. Salmon Farming Industry Handbook 2016. Data for plot sourced from: Ytrestøyl T., Aas T.S., Åsgård T. (2014) Resource utilisation of Norwegian salmon farming in 2012 and 2013. Nofima report 36/2014 pp. 35, NOFIMA, FAO (2012) World Fisheries and Aquaculture, UN (2010), FAO (2014) World Fisheries and Aquaculture, Holtermann

➢ Alternate ingredient diets fed in recirculation aquaculture systems must be compatible with….

Fish Performance • Growth rate• Health• Feed conversion• Survival

Water Quality • Minimize nutrient excretion• Optimize solids stability

Effluent Quality • Minimize effluent waste loads• Meet stringent discharge standards

Product quality attributes• Fillet yield• Fillet composition • Nutritional benefits

Diet Compatibility

https://c1.staticflickr.com/8/7175/6834472591_6a965d2d1d_b.jpg

Protein & Lipid Composition (g/kg)

Experimental Diets

Ingredient FM Diet FMF Diet

Fishmeal 29.42 -

Poultry Meal 18.82 31.20

Soybean Meal 18.32 -

Soy Protein Concentrate - 17.92

Corn Protein Concentrate - 7.80

Blood Meal 1.00 -

Fish Oil 12.65 5.00

Poultry Oil - 8.50

➢ Each diet formulated with protein/fat ratio of 42/18

➢ 6 Replicate RAS (9.5 m3) used

• 9-month study

• 99.9% recycle (flow basis)

• Hydraulic retention time – 135 days

➢ 90 walleye ( ̴ 45 g) stocked per RAS

• 85 g to begin study

• 3 RAS fed fishmeal-based diet

• 3 RAS fed fishmeal-free diet

Drawing Courtesy Freshwater Institute Engineering Services

Experimental Design

➢ Feed delivered via automated feeders

• 24 feedings, around-the-clock

• 3.4 - 3.7 kg feed/ m3 makeup water

➢ 24-h photoperiod

• Dim underwater LED lighting

• Fish culturists used headlamps

WQ Metric FM Diet FMF Diet

Dissolved Oxygen (mg/L) 8.51 ± 0.04 8.50 ± 0.02

Temperature (oC) 23.9 ± 0.02 23.9 ± 0.01

Alkalinity (mg/L) 205 ± 4 191 ± 3

Carbon Dioxide (mg/L) 14 ± 1 15 ± 1

pH 7.66 ± 0.01 7.65 ± 0.02

Total Suspended Solids (mg/L) 0.73 ± 0.09 0.75 ± 0.06

Biochemical Oxygen Demand (mg/L) 0.42 ± 0.01 0.44 ± 0.02

Oxidative Reduction Potential (mV) 289 ± 7 280 ± 6

Heterotrophic Bacteria (counts/mL) 959 ± 196 675 ± 94

Nitrite Nitrogen 0.007 ± 0.001 0.007 ± 0.001

Nitrate Nitrogen 39 ± 2 37 ± 1

Water Quality

➢ Water quality concentrations similar (P > 0.05) between diets

(mg/L) FM Diet FMF Diet

Color (Pt-Co units) 20.8 ± 1.4 17.3 ± 0.4

Ultraviolet Transmittance (%) 77.9 ± 0.1 81.4 ± 0.3

Total Ammonia Nitrogen 0.083 ± 0.002 0.072 ± 0.002

Total Nitrogen 39.4 ± 1.0 36.5 ± 0.5

Dissolved Copper 0.045 ± 0.009 0.033 ± 0.003

Total Phosphorous 1.73 ± 0.09 0.83 ± 0.02

Water Quality

➢ Mean water quality concentrations significantly different (P < 0.05)

between diets

Total phosphorous (culture water)• Fishmeal - 1.73 ± 0.09 mg/L

• Fishmeal-free - 0.83 ± 0.03 mg/L

Phosphorous

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 50 100 150 200 250

Tota

l Ph

osp

ho

rou

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g/L)

Day of Study

FM Diet FMF Diet

Dissolved phosphorous (culture water)• Fishmeal - 1.95 ± 0.12 mg/L

• Fishmeal-free - 0.85 ± 0.06 mg/L

Waste Production

➢ Backwashed biosolids collected 3 times during study.

• Combined waste flow radial flow settler and drum filter backwash

➢ Total phosphorous waste discharge greater (P< 0.05) for FM diet

Kg waste/ kg feed FM Diet FMF Diet

Total Suspended Solids 0.293 ± 0.028 0.247 ± 0.038

Total Phosphorous * 0.0107 ± 0.0027 0.0049 ± 0.00006

Total Nitrogen 0.031 ± 0.0010 0.030 ± 0.009

Biochemical Oxygen

Demand0.149 ± 0.025 0.116 ± 0.032

Mean weight

FM Diet - 571 ± 26 g

FMF Diet - 589 ± 15 g

Condition factor

FM Diet - 1.05 ± 0.02

FMF Diet - 1.03 ± 0.02

Feed Conversion Ratio

FM Diet - 1.32 ± 0.02

FMF Diet - 1.27 ± 0.03

Survival

FM Diet - 99.6 ± 0.4 %

FMF Diet - 98.5 ± 0.4 %

Thermal Growth Coefficient

FM Diet - 0.82 ± 0.01

FMF Diet - 0.83 ± 0.02

Walleye Performance

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100

200

300

400

500

600

700

-50 0 50 100 150 200 250

We

igh

t (g

ram

s)

Day of Study

FM Diet FMF Diet

Product Quality Attributes

➢ No significant differences in fillet yield; fillet or whole body composition

➢ FMF diet resulted in greater (P< 0.05) ratio of omega 6: 3 fatty acids and greater

gonadsomatic index

FM Diet FMF Diet

Skin, Scales On Fillet

Yield (%)47.1 ± 0.6 48.8 ± 0.7

Fillet Moisture (%) 74.1 ± 0.2 73.9 ± 0.4

Fillet Protein (%) 21.1 ± 0.3 21.4 ± 0.2

Fillet Fat (%) 2.2 ± 0.2 2.5 ± 0.3

Fillet Ash (%) 3.5 ± 0.1 3.4 ± 0.1

Omega 6: Omega 3 0.38 ± 0.02 0.66 ± 0.02 *

Gonadosomatic Index

(%)0.35 ± 0.09 0.89 ± 0.14 *

➢ First study to report comparable walleye growth and performance when feeding a fishmeal-free diet and while culturing walleye in RAS

➢ FMF diet produced half the total phosphorous in RAS and effluents

➢ Limiting phosphorous discharge increases feasibility of meeting stringent effluent requirements and possibly reduces capital investment for waste treatment technology

➢ This research provides information to industry about the potential for walleye production in RAS.

➢ More to learn…..

• Density limits ?

• Water quality thresholds ?

• Economical market/harvest size ?

• Broodstock/ consistent egg supply ?

• Economies of scale ?

https://www.doyouevenpaleo.net/grilled-walleye-mango-salsa/

Conclusions

➢ This research was supported by North Country Clear Waters, LLC (Arcadia, WI, USA) and by the Agricultural Research Service of the United States Department of Agriculture, under Agreement No. 59-1930-5-510.

➢ Opinions, conclusions, and recommendations are of the authors and do not necessarily reflect the view of the USDA.

➢ All experimental protocols were in compliance with Animal Welfare Act (9CFR) and have been approved by the Freshwater Institute Animal Care and Use Committee.

➢ Special thanks to Karen Schroyer, Susan Glenn, and Brianna Taylor for water quality analyses; to Clayton Raines and Heather Dailey for fish husbandry assistance; and to Dr. Brett Kenney and Susan Slider at West Virginia University for fillet quality analyses.

Acknowledgements