Download Overview of Largemouth Bass, Micropterus salmoides, Culture

Effect of Feed Pellet Characteristics
on Growth and Feed Efficiencies of
the Largemouth Bass
James H. Tidwell and Shawn D. Coyle
Kentucky State University
Aquaculture Research Center
Frankfort, K.Y. USA
Largemouth Bass Production
>500,000 kg/year in the U.S.
$8.50-12.00/kg Live Weight
Foodfish
Sold live to oriental markets in
Toronto, Chicago…
Sportfish
Uses: Rehabilitative stocking, Managed
trophy fisheries, "Put and Take" fisheries
Reducing Feed Cost
The largemouth is a strict predator.
Often fed salmonid diets based more on availability
than nutritional suitability.
► >35%
► Diets
► KSU
of production cost is feed cost
contain high levels of fish meal (>35%)
series of studies to develop species specific,
cost effective diets.
Study 1 Fish Meal Replacement
Poultry meal w/ no
fish meal
Average weight (g)
60
55
a
a
50
a
b
45
40
c
35
30
Control
Poultry w/out FM
BM/CGM w/out FM
Poultry & 7.5% FM
BM/CGM & 7.5% FM
Successfully replaced 100% of fish meal with poultry by-product meal
Study 2 –Alternatives to Fish Oil
These data indicate vegetable based oils can replace
fish oil in diets with no reduction in growth.
Average weight (g)
100
a
95
a
90
85
a
a
a
a
80
75
70
65
60
Fish oil
Corn oil
Sunflower oil
Linseed oil
DHA
ARA
Study 3 Impact of Carbohydrates
Most carnivorous species don’t require
CHO, and some cannot tolerate high
levels, liver necrosis.
Harvest Weights
100
400
380
360
340
320
300
280
260
240
220
200
Survival %
95
90
85
80
75
13% CHO
13% CHO
19% CHO
25% CHO
19% CHO
25% CHO
Study 4
Pond Verification
► Evaluate
low fish meal and least cost formulation
diets for under practical pond conditions
► Commercial
diet ~40% fish meal.
 Experimental diets reduced fish meal levels
(45, 24, & 8% = least cost)
► Maintained
CHO at or under 20%. Produced
experimental diets that were slow sink.
Growth
$450/ton
550
Average Weight (g)
500
450
$700/ton
400
350
300
Control
45% FM
250
23.5% FM
8% FM
200
May
June
July
August
Sample-Harvest
September
October
Harvest
Feed Cost / KG Gain
$1.10
a
Cost (US $ / kg)
$1.05
$1.00
Reduced feed costs > 30%
$0.95
With better growth
b
$0.90
$0.85
c
$0.80
$0.75
c
$0.70
$0.65
$0.60
Control
45% FM
23.5% FM
8% FM
Study 5 Impact of Pellet Characteristics.
1) Evaluate “Least Cost Formulation” under new
grain price structure (ethanol)
2) Evaluate the impact of pellet characteristics:
a) Floating vs. Sinking (reduced CHO)
b) Using a larger pellet for largemouth
Four diets- Testing Float vs. Sink & Size
► Diet
1 Commercial (CTL), 52% protein, 15% lipid
as a 1/4” floating pellet.
► Experimental
diets were all formulated
“Least Cost” (LC) > 45% protein , > 10% fish
meal, > 15% lipid, < 20% CHO.
► Diet
2 LC 6.4 mm floating pellet,
► Diet 3 LC 6.4 mm sinking pellet,
► Diet
4 LC 15.2 mm floating pellet.
Diet
Ingredient
Control
Float
Sink
Menhaden Fish Meal
-
10
10
Soybean Meal
-
16
18.6
Feather Meal
-
10
10
Poultry By- P Meal
-
16
15
DDG
-
0
10
Corn
-
10.6
7.8
Menhaden Fish Oil
-
9.9
9.0
Wheat Flour
-
8.0
3.0
Poultry Blood meal
7.5
7.4
Rice Bran Hi Fat
6.5
8.0
Mineral Mix
-
0.75
0.75
Vitamin Mix
-
0.25
0.25
DL-Methionine
-
0.7
0.7
Relative Feed Cost
1
0.78
0.83
Diet Analysis
Treatment
% Moisture
% Protein
% Fat
% Fiber
% Ash
NFE
Control
6.6
50.4
19.4
2.6
8.9
12.4
6 mm
Float
8.8
44.1
14.6
2.8
7.8
20.3
6 mm
Sink
9.1
43.6
18.4
2.6
7.4
18.9
15 mm
Float
8.8
44.3
14.7
2.8
7.7
21.8
Materials & Methods
► Twelve
0.04 ha. ponds were stocked with
juvenile LMB (185 g) at 9,880/ha
► Each
pond was randomly assigned to one of
four treatments with three replications/treatment
► Experimental
diets were
manufactured By Burris
Aquaculture, LA.
► All
treatments were fed slowly
to apparent satiation 1x/day
► The
study lasted from May
► to October ponds sampled
monthly.
► DO,
temp. and pH
monitored 2x/day
► Water
quality monitored
2x/week
► Treatments
were
statistically compared
using ANOVA (P<0.05)
Survival
%
a
a
a
a
Harvest Weights
Grams
650
600
a
550
a
b
b
500
450
400
350
300
Control
LC Float
LC Large
Sink
Flesh Proximate Analysis
Treatment
% Moisture
% Protein
% Fat
Control
6 mm Float
71.3+1.1
19.8+0.3
8.9+1.2
Least Cost
6 mm Float
71.8+0.7
19.3+0.2
8.1+1.0
Least Cost
6 mm Sink
70.2+0.6
19.6+0.2
9.3+0.5
71.0+0.5
19.4+0.2
9.1+0.4
Least Cost
15 mm Float
NSD = No significant differences
Feed Cost Per Unit Gain ($/kg)
$
a
bc
b
c
Conclusions
► The
shift to a Least Cost formulation resulted in
decreased growth for fish fed floating pellets.
► However,
when used as a sinking pellet, growth was
the same as the commercial control floating pellet.
► Feeding
a least cost formulation as a sinking pellet
produced a 20% decrease in feed cost per unit gain.
► However,
the use of sinking pellets requires slow
feeding, close monitoring and may not be suitable for
large scale production.
Questions