What do the Experts Say about Replacing Fish in

Fish Food

History of Fish Diets

The original extruded fish diets were primarily soy

Based. Soy based diets extrude very well and fish

grew.

PROBLEMS:

Fish didn’t taste much like their wild counter parts

Water Quality

Feed Efficiency

BASIC NUTRITION

“Series of processes by which an organism takes in and assimilates food for maintenance, growth, production and reproduction”

NUTRIENT

“Chemical element or compound that is required in the diet of a given animal to permit normal functioning:

CLASSES OF NUTRIENTS:

Amino Acids Carbohydrates

Fatty Acids Vitamins Minerals

CARBOHYDRATES

Various combinations of carbon and water •NFE:

–Sugars

–Starches - amylose, glycogen

•Fiber:

–Structural - hemicellulose, cellulose, lignin

•Plants:

–Energy storage and structure

•Animals:

–Metabolic fuel - available energy

FAT

•Triglycerides - three fatty acids esterified to a glycerol

•Certain fatty acids are essential

•Other lipids

•Most concentrated form of energy storage

•Long-term energy storage in animals

Combination of C, H, and O

PROTEINS

Combination of C, H, O and N

•Made of many amino acids linked end to end

•Animals’ structure ad function:

Scales, skin

Hemoglobin, insulin, actin & myosin

•No protein requirement, per se

Most expensive component of diet Protein quality (not quantity)most important

Historically Fish Meal has been best – fish protein to grow fish 100s of scientific papers on the “replacement value” for a protein source – always compare to fish meal as the gold standard

Dietary Protein

DIGESTION

Small Intestine - Enzymatic Degradation

•Carbohydrates:

Amylases, Lactase, Sucrase

•Fats:

Bile Salts, Lipases

•Proteins:

Proteases, Trypsin, Chymotrypsin, Peptidases

DIGESTION

Consumed Absorbed*

Carbohydrates…………………………Simple Sugars

Fats…………………………………….Fatty acids, glycerol

Proteins………………………………..Amino acids

*Absorbed into blood or lymph

GI TRACT

Reflects an animal’s eating habits

•Complexity

•Length

Digestion and Absorption • What about fiber? Plants contain fiber. • FISH

•No foregut fermentation

•Little or no hindgut fermentation

•Mastication/grinding

–Carp - pharyngeal teeth

–Milkfish, gizzard shad - gizzard

–Grass Carp

Fish • Efficiency of converting food into meat or eggs

FCR (feed conversion ratio; units = g food per g gain

–Cattle = 6-8

–Hogs = 3

–Chickens = 2-3

–Fish = 1-1.5

These efficiencies are under optimal conditions, and will drop with underfeeding or

overfeeding!

– Land Animals »Sheep 35:1, Ruminants »Pigs 14:1, sacculation »Cats 4:1, simple

GI Tract

Terrestrial Animal

Stevens and Hume, 1996

GIZZARD SHAD

>5 x B.L.

Bluegill:

B.L. = 20 cm G.I.T. = 24 cm G.I.T.:BL = 1.2

Why are fish so efficient?

-Fish have reduced energy requirements - Cold blooded (poikilothermic) - energy not needed to maintain body T - Aquatic - not fighting gravity - able to excrete nitrogen more easily - Generally utilize readily available nutrients - e.g., unlike a cow that needs microbial digestion to use it’s food

Fish Diets

FISH vs. TERRESTRIAL ANIMALS

Carbohydrate Utilization •Little amylase activity = varies

–Warm vs. Cold water species

–Fresh vs. Salt water species

•Cooked vs. Raw starch

•Aquatic vs. Terrestrial Carbohydrate

Carnivorous & Omnivorous

• Carnivorous: Trout, Bass, Perch, Walleye, Bluegill – All Starting fish – Protein-based diets

• Omnivorous: Catfish, Carp, Koi, Tilapia

– Can utilize some carbohydrates

Effect of replacing dietary fish oil with Soy Oil in cobia

• SO can replace a substantial amount of FO in aqua feeds.

• Production performance is largely unaffected by partial replacement of FO with SO

• FA composition is significantly altered, even at low levels of FO substitution.

• Aggressive FO replacement may result in development of EFA deficiency, particularly in reduced-fish meal Formulations.

Fisheries and Illinois Aquaculture Center, Southern Illinois University Carbondale, Carbondale, IL; 2 Virginia Seafood Agricultural Research and Extension Center, Virginia Tech, Hampton, VA; 3 International Initiative for Sustainable and Biosecure Aquafarming, Norfolk, VA, USA; 4 Marine Fish Culture Laboratory, Institute of Oceanography, Federal University of Rio Grande, Rio Grande, RS, Brazil

Effects of replacing fish meal with SPI on growth

and nutrient utilization in Rainbow Trout

• Soy protein concentrate can replace 50% of the fish meal in high-lipid, extruded diets for rainbow trout without reducing performance..

• Replacing 75 or 100% of the fish meal with soy protein may reduce growth because of lower feed intake and low lipid digestibility.

M Mambrini, A J Roem, J P Carvèdi, J P Lallès and S J Kaushik

Insect-based fish feed for rainbow trout

Black soldier fly (Hermetia illucens) Sophie St-Hilaire1, Wendy Sealey2, Mark A. McGuire2Jeffery Tomberlin3, Craig Sheppard4, Larry Newton4, MirielleChahine2, Mario De HaroMarti 2, and Carolyn Ross 5

1Idaho State University2University of Idaho 3Texas A &M University 4University of Georgia5 Washington State University

Insect-based fish feed for rainbow trout

• Black soldier fly (Hermetia illucens) • Between 20 and 50% reduction in phosphorus

and nitrogen in remaining material • Pupae by-product is a suitable animal grade

foodstuff ~40% protein ~30% fat

Insect-based fish feed for rainbow

trout

25% fishmeal replacement

Change

Control diet

25% fishmeal replacement

50% fishmeal replacement

Weight gain (g)

Feed Conversion Ratio *

2054a

1815a,b

1559b

-25%

1.18a

1.22a

1.47b

-20%

Human Health and Nutrition

• American Heart Association recommends the consumption of oily fish at least twice a week1

• Omega-3 content of farmed fish depends on the FO levels in fish diets2

• Determines health benefits of seafood consumption • Example: consumption of salmon raised on the high-FO

diet reduced triglycerides and improved other health indicators of patients with coronary heart disease

• These effects were not significant in patients consuming salmon raised on low-FO diets2

1Lichtenstein et al. 2006, 2Seierstad et al. 2005

Reducing fish meal and fish oil inputs in feed

• Feed is the largest production cost for commercial

aquaculture thus improving feed efficiency in industrial systems is already a priority

• Research to develop substitutes for FM & FO is now focused on commodities such as oilseeds (especially soybeans), meat byproducts (such as blood meal and bone meal) and microbial protein

• complete replacement of fish meal and fish oil in aquaculture feeds faces severe barriers

• Primary goal - to replace FM and FO in fish diets

• 33 partners, 14 countries

• Four years of research and $21.6 MM

• Replacement of FM with a mixture of corn gluten, wheat gluten, soy concentrate, krill meal, and amino acids resulted in 17% weight reduction of fish

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

30% FM + 6.5% FO 12% FM + 16% FO 12% FM + 7% FO

Sal

mon

wei

ght (

kg)

a b

b

*Bars not sharing a common letter are significantly different (P < 0.05) Torstensen et al., 2008

Fish Meal Replacement: AquaMax

Questions