Innovations and Georgia

Aquaculture

Gary Burtle

Animal & Dairy Science

The University of Georgia

Aquaculture Industry

• Channel catfish

culture dominates

– 50,000 acres in SE US

• Tilapia gaining

popularity in US

• Georgia has sport fish

hatcheries that equal

other aquaculture in

value

Aquaculture Programs at UGA-Tifton

• Aquaculture Species Nutrition

• Cyanobacteria

• Fish Disease Control

• Catfish and Bluegill Spawning

• Disease & Fish Pond Diagnostics

• Aquaculture Development

• Teaching

Feed Ingredients of Local Origin

Used in Aquaculture Diets

Ingredient

Protein

digestibility

Protein %

Brewers grains

75* 23.1

Peanut meal

93.8 49.0

Cottonseed meal

77.7 41.7

Meat and bone

meal

82.6 50.9

Poultry byproduct 85* 59.7

*Estimated

Brewers Grains

• A protein source

• Some digestible energy

• Fiber is about like Wheat Middlings

• May substitute at 20 to 30% of catfish diet

• Used as a substrate for Hermetia illucens

bioconversion to protein source

Peanut Meal

• Once was used extensively in catfish feed, 25 to

40% of catfish diet

• CAUTION: Aflatoxins present, but catfish have a

tolerance to aflatoxin (up to 500 microgram/kg)

• Catfish get some Aflatoxin from Corn already

• Peanut crushing plants control sales to the feed

industry

Protein from Black Soldier Fly

Hermetia illucens

Adult

Pre-

Pupae

Mass Culture on Byproduct

Channel Catfish

Fingerling channel catfish (4 aquaria per diet) were fed diets consisting of

five rates of Hermetia prepupae substituted for menhaden fish meal in a

base diet containing 8% fish meal. Replacement rates were 0, 25, 50, 75,

and 100% for diets 1-5, respectively, plus a commercial diet (diet 6) was

included as a positive control (Table 3).

Fish weight gain and feed/gain were similar for diets 1 and 2, while both

were superior (P<0.05) to all other diets for feed/gain, including the

commercial fingerling feed.

Dried Hermetia prepupae meal can be use to replace at least 25% of the

fish meal in diets for channel catfish fingerlings.

Up to 75% replacement compares to commercial catfish diet.

Feed Efficiency and Weight Gains of Channel Catfish Fingerlings Fed Black Soldier Fly

Prepupal Supplemented Diets, and Comparison with a Commercial Diet Control.

Diet 1 2 3 4 5 6 (Control)

Replacement rate (%) 0 25 50 75 100 NA

Feed/Gain 1.87a 1.96a 2.29b 2.31b 2.55c 2.2b

Gain/Fish (g) 17.96a 17.27a 14.94b 15.94a 13.68c 15.90b

a, b, c Means with different superscripts are different, P<0.05.

Drying Rendering

High

Protein

Meal

Oil

Other Potential Uses

Other

Potential

Products Chopping

Either or All

Other

Ingredients

Feed for Fish

or Other Animals

Collected Prepupae

(Last Larval Stage)

Feed

Preparation

or or

or

Can be fed directly to some animals,

but likely will be processed.

Utilization of Collected Prepupae

Grinding or

Catfish Only - Cyanobacteria

Numbers (x 1,000,000/L)

0

10

20

30

40

50

60

70

80

90

100

Jan Mar Apr May Jun Jul Aug

Pond 13

Pond 15

Pond 21

Cyanobacteria blooms above 35,000,000/L start in April.

Shad Results - Cyanobacteria

Numbers (x 1,000,000/L)

0

5

10

15

20

25

30

35

Jan Mar Apr May Jun Jul Aug

Pond 14

Pond 17

Pond 22

Threadfin shad at 1,440/ha delayed and reduced cyanobacteria blooms.

Changes to Phytoplankton after Treatment 0.25 mg/L CuSO4 plus 9.3 mg/L Sodium Carbonate Peroxyhydrate

Time Microcystis Aphanocapsa Rhabdoderma Scenedesmus

Initial 1,544 33,977 6,037 1,895

24 hr. Post

Treat

210** 22,324 1,334** 2,257

48 hr. Post

Treat

929** 14,531** 772** 7,582

72 hr. Post

Treat

421** 12,987** 351** 7,722

Pond 18 – Moderate Cyanobacteria Bloom

** Significant decrease in Colony units per milliliter, average of 4 samples.

Changes to Phytoplankton after Treatment 0.25 mg/L CuSO4 plus 9.3 mg/L Sodium Carbonate Peroxyhydrate

Time Microcystis Aphanizomenon Rhabdoderma Scenedesmus

Initial 53,212 2,808 842 9,547

24 hr. Post Treat 54,194 1,544* ND 6,318

48 hr. Post Treat 35,942 421** 982 9,126

72 hr. Post Treat 45,541 421** 421* 9,574

Pond 22 – Dense Cyanobacteria Bloom

** Significant change in Colony units per milliliter, average of 4 samples.

Proliferative Gill Disease in Channel Catfish

• Caused by a protozoan (Myxozoan)

• Hosted by an aquatic worm (Dero digitata)

• Worm releases spore capsule into water

• Spores penetrate gill surface and cause an inflammatory response in tissues

The Fathead Minnow

• Less than 7.5 cm long

• Eats worms, algae, benthic organisms

• 4,400 per kg

• Stock at 11 kg/ha for

PGD control

- Reduce aquatic worm

host of triactinomyxid

Oligochaete numbers from commercial catfish ponds after stocking fathead

minnows at the rate of 11 kg/ha.

Sample Date Pond 1 Pond 2 Pond 3

Initial 1,200 520 14,160

Month 1 524 136 1,208

Month 2 116 52 2,004

Month 3 152 132 1,468

Declining oligochaete numbers are associated with decline of

Dero digitata, the host of the PGD parasite.

Effect of Minnow Stocking on Frequency of PGD Cases

• Cases with heavy fish losses dropped to zero in the first year after wide scale stocking

• Second year had reports of moderate losses to PGD in isolated cases, where minnows were lost

• Third year reports of few cases and PGD in ponds where minnows were lost

Aquaculture Extension and

Teaching Programs

Industry Impact

• Fish Farm Development – Earthen ponds and

recirculating water systems

• Processing plant development – Consultant for business

plan preparation and operations

• Feed mill development – Business plan

development

Processing Plant

80 acre fish farm

Diagnostics

• Distance Diagnostic System – Fish disease, pond weeds, toxic

algae, water quality problems

• Approximately 250 cases, 7,500 contacts per year

• Valued at $3,000,000 per year in money savings to producers, pond owners, and pond managers

Teaching at Tifton Campus

• Aquaculture – ADSC

3660

– Offered in the fall on

alternate years

• Issues in Animal

Agriculture – ADSC

4010

– Offered each spring

International Activities Ingredient (calculated

composition)

Catfish Diet 1

%

Catfish Diet 2

%

AMPRO 57 (meat meal) 61.19 0

Corn 7.35 5.0

Soybean Meal 48% CP 10.0 45.0

Wheat middlings 19.7 13.7

Poultry Fat 1.46 6.0!!

Fish meal, menhaden 0 30.0

Vitamin Premix** 0.2 0.2

Mold inhibitor 0.1 0.1

Calculated composition

Crude protein 44.0 44.0

Ash 19.45 9.02

Fat 10.0 10.0

Fiber 3.9 3.0

Dry matter 91.0 92.25

Calcium 3.9 1.7

Phosphorus 2.0 1.4

Lysine*** 2.4 2.9

Cys + Met*** 1.4 1.4

Digestible energy (estimated) 2,947 kcal/kg 3,577 kcal/kg

**Vitamin mix will provide Vitamin C as 0.025% of diet, Vitamin A as 4,400 IU/kg,

Vitamin D as 2,200 IU/kg and Vitamin K as 55 IU/kg diet. (125 mg Vitamin C, 4,400,000

IU Vitamin A, 2,200,000 IU vitamin D, and 55,000 IU Vitamin K per kilogram Vitamin

Premix with Wheat Middlings filler.)

***Lysine above 1.6% and Cystine + Methionine above 1.1% was considered adequate for

Clarius gariepinus by FAO United Nations. !!This fat should be sprayed on after pellets are dried and cooled.

Cooperation with African and

Latin American Catfish and

Tilapia interests.

-Training.

-Feed Formulations.

-Joint Venture Assistance.

Cameroonian at a

Georgia fish farm

University of Georgia

Aquaculture Unit - Tifton