Download diet and strain affect growth etc.WITH TABLES

ABSTRACT
Little is known about what diets and strains are optimal for production of hybrid bluegill.
The objective of this study was to determine if there were differences in the efficiency of
nitrogen (N) and lysine (lys) retention in two strains, Georgia Giant (GG) and
commercial hybrid bluegill (CHBG), of bluegill fed five different commercially
available diets. Diets 1,2,3,4, and 5 were formulated to contain the following crude
protein (CP) /fat contents; 32/3, 38/8, 40/10, 42/16, and 45/20, respectively. Diets and
fish, that had their gastrointestinal contents removed, were analyzed for N by Kjeldahl,
and for lys by HPLC after acid hydrolysis and phenylisothiocyanate derivitization. Fish
were randomly allotted to 20 tanks with 2 tanks per diet within strain. At twelve weeks,
GG had higher feed intake (P< 0.001) and weight gain (P<0.001) than HBG. However,
there was not a significant strain effect on feed efficiency or efficiency of N or lys
retention. Consumption of diets 2,4 or 5 resulted in better feed efficiency (P<0.05) than
diet 3 which was not different than diet 1. These data demonstrate that strain and diet
have important impacts on bluegill production and that the most nutrient dense diets
don't necessarily lead to enhanced performance relative to diets of lower CP and fat.
Diet and Strain Affect Growth, Feed Efficiency, and Retention
of Nitrogen and Lysine in Hybrid Bluegill
1
2
1
1
Beth Stinefelt , Jonathan Eya , Ken Semmens , and Kenneth P. Blemings
1
Division of Animal and Veterinary Science, West Virginia University, Morgantown, WV 26506
2
Department of Biology, West Virginia State College, Institute, WV 25112
CONCLUSIONS
RESULTS AND DISCUSSION
INTRODUCTION
Aquaculture has been recognized, in West Virginia, as a potential area of economic development due
to the large quantity of fresh water (D'Souza et al, 2003). This creates ideal conditions for either a fee
fishing operation or food fish production. Fee-fishing operations that stock bluegill provide
opportunity to easily catch fish since bluegill are especially vulnerable to anglers. Nutrient
requirements of hybrid bluegill for achievement of optimal growth are not well known. A diet
deficient in nutrients will prevent optimal performance, as will a diet with excess nutrients. Excess
nutrients in the diet also translates into increased organic wastes. How to rear hybrid bluegill in a way
that is economically feasible and minimizes environmental impact is of growing interest.
Significant differences were detected in measures of growth and performance between the two strains after 12 weeks (Table 2). At week 0 GG's and CHBG were of similar weights. After 12 weeks, GG's gained about
four times more weight than the CHBG. Contrary to the abstract, further statistical analysis revealed that GG's were more feed efficient than CHBG. No significant differences in survivability were detected.
After 12 weeks a significant effect of diet was detected (Table 3). Although all dietary treatment groups consumed similar amounts of feed, differences in growth were detected. GG's and CHBG consuming the diet
formulated to 42% protein gained more weight (P < 0.05) than fish treated with the other four diets. Fish consuming diets from 32%-40% protein and 45% protein gained a similar amount of weight. Since food
consumption was similar for all dietary treatments, fish consuming the 42% crude protein diet also exhibited the best feed conversion (P < 0.05).
A closer examination of differences between individual diet and strain combinations reveals an interaction on feed efficiency (P < 0.05, Figure 1) and a trend towards an interaction on weight gain (P < 0.09, Figure 2). The
interaction appears to be largely driven by the very poor feed efficiency of the CHBG consuming the 40% crude protein diet.
Table 4 shows nitrogen and amino acid retentions for the five dietary treatments. Standard error values for several of the amino acids and nitrogen values are high due to outlying data points and negative numbers. The
amino acids serine, histidine, arginine, tyrosine, isoleucine, leucine, and phenylalanine have low standard errors and reveal significant differences among treatments. Of these amino acids, all but phenylalanine have the
numerically best feed efficiency for the 42% crude protein diet. The effect of strain on the efficiencies of protein and amino acid retention did not reveal any consistent differences (data not shown). The high variability in
fish growth within a tank results in large standard errors and makes it difficult to determine small but significant differences between values. Statistical analysis would be more effective with an experimental unit repeated
more than twice. Additionally, pit-tagging would allow a more precise estimate of changes in composition than the approach used here where a single fish was used to estimate average composition.
F GG's had an overall growth rate four times faster than CHBG.
F GG's were more efficient feed consumers than CHBG.
F The diet formulated to 42% crude protein and 16% fat produced the optimal growth
among both strains of bluegill in aquaria conditions.
REFERENCES
F Association of Official Analytical Chemists, 15th Edition. 1990. Fat (Crude) or Ether
Extract in Animal Feed. (920.39) Official Methods of Analysis.
F Association of Official Analytical Chemists, 15th Edition. 1990. Protein (Crude) in
Animal Feed: Automated Kjeldahl Method. (976.05) Official Methods of Analysis.
OBJECTIVES
MATERIALS AND METHODS
Experimental conditions
CHBG and GG were purchased from Logan Hollow Fish Farm (Murphysboro, IL) and Ken's Fish
Farm and Hatchery (Alpaha, GA), respectively. All fish were reared at the West Virginia State
College Aquaculture wet laboratory. Fish were randomly assigned to 20 aquaria at 30 fish per 152 L
glass aquarium. Aquaria were supplied with a continual flow of 23 26 C dechlorinated city water at
the rate of 1 1.5 liters per minute. A 12 hour light: 12 hour dark photoperiod was maintained in a 68 C
room. Two replicate tanks were assigned to each strain by diet combination. Fish were fed to
satiation twice daily for twelve weeks. Daily feed consumption was recorded. At 0, 4, 8, and 12
weeks fish were counted, collectively weighed and a representative fish from each tank was chill
killed to enable a comparative slaughter approach to measure efficiencies of nutrient retention.
Before weighing, fish were anaesthetized with 3-aminobenzoic acid ethyl ester.
Five experimental diets were generously supplied by Melick Aquafeed (Chip, PA) and were
formulated to the compositions in Table I.
Sample Analysis
Fish samples were transported on ice to West Virginia University where the gastrointestinal contents
of each fish were removed and flushed with phosphate buffered saline. Fish were frozen in liquid
nitrogen, homogenized in a blender to a fine powder, and stored frozen for further analysis.
Amino Acid Analysis. Amino acid analysis was performed on the homogenized fish or feed
samples by reverse-phase high-performance liquid chromatography after precolumn
derivitization by phenyl isothiocyanate by a method adapted from Fierabracci et al (1991).
Preparation of 0.5 gram duplicate samples included delipidation in 2:1 chloroform: methanol
solution overnight followed by an incubation for 3 hours in a 1:1 methanol: water mixture.
Samples were then hydrolyzed in 6N HCl for 24 hours at 110 C. Five mL subsamples were
filtered and an internal standard (methionine sulfone) was added. HPLC was performed using a
Waters 1525 Binary HPLC pump, Waters 2487 Dual Absorbance Detector, and a Waters 717 plus
Autosampler. Data was processed and analyzed using Waters Breeze software.
Nitrogen Content. Total protein and nitrogen content of fish and feed were analyzed by the
Kjeldahl procedure in duplicate samples. (AOAC)
Fat Content. Fat content of fish and feed samples was determined using the ether extract
procedure. (AOAC)
Statistical Analysis. Data were analyzed by analysis of variance with PC-SAS General Linear
Models procedure for significant differences among treatment means. In the event of a
significant F value the LSD procedure was used for means comparisons.
Diet
Crude Protein
Fat
Aspartate
Glutamate
Serine
Glycine
Histidine
Arginine
Threonine
Alanine
Proline
Tyrosine
Valine
Isoleucine
Leucine
Phenylalanine
Lysine
1
36.2c (32)
2.6d (3)
2.43
4.48 a
1.66
1.93
0.69
2.22
1.23
1.8 ab
2.31 ab
0.92 ab
1.39
1.46
3.02 a
1.39
0.97
2
34.8c (38)
10.4c (8)
2.40
3.82 b
2.01
2.05
0.62
2.32
1.28
1.39 b
2.40 ab
0.78 b
1.42
1.09
2.30 b
1.23
0.78
3
b
38.4 (40)
12.4b (10)
2.40
4.09ab
1.56
1.56
0.66
2.39
1.33
1.49 ab
1.97 b
0.82 ab
1.39
1.10
2.35 b
1.21
0.99
4
44.5a (42)
17.7a (16)
2.96
4.47 a
1.98
2.51
0.76
2.82
1.56
1.97 ab
2.45 ab
0.98 a
1.37
1.26
2.85 a
1.27
1.05
5
45.6a (45)
13.7b (20)
2.91
4.53 a
2.22
2.94
0.78
2.77
1.61
2.10 a
2.85 a
0.79 ab
1.79
1.32
3.11 a
1.51
1.16
Pooled SEM
0.43
0.42
0.22
0.16
0.23
0.39
0.05
0.22
0.15
0.19
0.24
0.05
0.20
0.10
0.14
0.09
0.11
Table 4. Main Effect of Diet on Nitrogen and Amino Acid Efficiency.
Values are nitrogen or amino acid fed per nitrogen or amino acid gained after 12 weeks on dietary treatments.
Different superscripts indicate significant differences (P < 0.05, n = 2).
Diet
Nitrogen
Aspartate
Glutamate
Serine
Glycine
Histidine
Arginine
Threonine
Alanine
Proline
Tyrosine
Valine
Isoleucine
Leucine
Phenylalanine
Lysine
1
-5.95 b
5.53 a
58.24
4.64 a
4.84
1.86 ab
2.73 b
4.36
4.74 ab
2.75
2.13 a
8.34
3.02 a
2.80 a
1.03 b
4.78 a
2
-1.84 a
2.02 a
-6.04
5.82 a
-1.17
1.65 b
3.52 ab
-0.46
1.04 ab
9.21
1.57 ab
5.14
2.62 ab
2.35 ab
1.10 b
2.94 a
3
-2.81 a
-9.09 b
-0.92
5.39 a
2.05
2.11 a
4.53 a
47.51
-6.28 b
0.51
1.67 ab
2.87
2.89 ab
2.44 ab
0.86 b
-1.36 b
4
4.25a
3.36 a
60.33
3.26 b
5.16
1.46 b
2.25 b
2.62
2.46 ab
4.46
1.21 b
-0.60
1.72 b
1.82 b
1.83 a
1.98 a
Hybrid Bluegill
Table 2. Main Effect of Strain on Growth Performance.
Values are average performance after 12 weeks of dietary treatment (* P < 0.001 vs GG, n=2).
Initial Wt (g)
Wt Gain (g)
Percent Wt Gain
Feed Intake (g)
Feed per Gain
% Survivability
Georgia Giant
33.1
25.8
78.3
33.1
1.32
90.0
Hybrid Bluegill
34.3
6.4*
18.4*
12.2*
2.36*
79.7
Pooled SEM
0.46
0.80
2.25
0.92
0.12
4.0
1
12.1 b
21.1
2.15b
90.3
2
15.8 b
24.3
1.69 b
78.3
3
14.9 b
21.3
2.57 b
81.8
4
22.2 a
24.3
1.17 a
79.0
5
15.4 b
22.2
1.60 b
95.8
5
Pooled SEM
2.99
3.16
39.9
0.80
3.94
0.14
0.49
33.9
3.55
4.96
0.17
10.46
0.38
0.26
0.22
1.51
4
Georgia Giant
b
3
bc
cd
cd
cd
cd
d
1
0
38
40
42
45
Formulated Dietary Protein
Pooled SEM
1.27
1.46
0.19
7.0
Figure 2. Interaction Between Diet and Bluegill Strain on Weight Gain.
Interaction between each diet by strain combination after 12 weeks of dietary treatment. Error bars
represent pooled SEM. Different superscripts represent significant differences (P < 0.05, n=2).
Hybrid Bluegill
Georgia Giant
40
a
30
b
b
bc
c
20
d
10
e
de
de
e
0
32
38
40
42
Formulated Dietary Protein (%)
F Fierabracci, Masiello, Novelli, and Bergamini. 1991. Application of animo acid
analysis by high-performance liquid chromatography with phenyl isothiocyanate
dervitization to the rapid determination of free amino acids in biological samples.
Journal of Chromatography, 570:285-291.
ACKNOWLEDGEMENTS
F Thanks to Melick Aquafeeds for their generous donation of all experimental diets.
cd
cd
2
F D'Souza R, D. Miller, K. Semmens, and D. Smith. 2003. Mine water aquaculture as
an economic development strategy: linking coal mining, fish farming, water
conservation and recreation. Aquaculture America conference, Louisville, KY,
February 18-21, Book of Abstracts, p 80.
F Grant support comes from WV Ag. For. Expt. Sta. H413 (KPB), USDA-CSREES
2001-34386-11238 (KPB & KJS), WVU Fac. Senate (KPB), WVU Res. Corp.
(KPB) and USDA NRI 2002-35208-11580 (KPB).
a
32
Table 3. Main Effect of Diet on Growth Performance.
Values are averages after 12 weeks of dietary treatment. Different superscripts within indicate significant
differences (P < 0.05, n = 2).
Diet
Weight Gain (g)
Feed Intake (g)
Feed per Gain
% Survivability
5
2.64 a
4.36 a
10.09
4.28 a
-4.29
1.95 a
2.92 b
4.18
10.19 a
3.54
1.37 b
25.84
2.43 ab
2.78 a
1.05 b
3.08 a
Figure 1. Interaction Between Diet and Bluegill Strain on Feed per Gain.
Interactions between each diet by strain combination after 12 weeks of dietary treatment. Error bars represent
pooled standard error of the means. Different superscripts represent significant differences (P < 0.05, n = 2).
Feed per Gain
F Examine responses of the two strains to five commercially available diets to determine which
diet would be optimal and to test for diet by strain interactions.
Table 1. Protein, Fat, and Amino Acid Composition of Diets.
Values are grams crude protein, fat, or amino acid per 100 grams of feed. Numbers are averages of replicate
samples. Values in parenthesis are formulated crude protein and fat composition. Different superscripts
within a row indicate significant differences between diets (P < 0.05).
Weight Gain (g)
F Investigate measures of growth and protein metabolism in two strains of hybrid bluegill, a
commercial hybrid bluegill strain (CHBG) and a strain known as Georgia Giants (GG).
45