| Workshop-seminar, 23-25 May, 2005, MEKARN-CTU |
| Contents |
An experiment was carried out at the CanTho university pig farm from October to December 2004 with 24 castrated crossbred growing pigs with an average initial live weight of 60 kg and final live weight of 98 kg. The experiment included 4 dietary treatments with the Tra catfish residue meal replacing 0 % (0CF), 33 % (33CF), 66 % (66CF) and 100 % (100CF) of the fish meal. Six blocks, corresponding to 6 litters (4 pigs per litter) were allocated into 24 individual pens.
The nutritive values and feed allowances were
the same in all dietary treatments, except for the ether extract
(EE) content. Mean daily gains were not significantly different
among treatments, and were 681g, 691g, 730g and 736g for 0CF, 33CF, 66CF and
100CF diets, respectively. Feed conversion ratios were similar among diets. The
back fat thickness was 15.3, 16.0, 15.7 and 16.2 mm, for 0CF, 33CF, 66CF and
100CF, respectively, and were not significantly different between diets. The
feed cost per kg weight gain and feed benefits were better in
the 100CF and 66CF diets than in 33CF and 0CF diets. Thus the
economic benefit was higher for the 100CF (25 %), and 66CF (19 %)
diets in comparison with the 33CF and 0CF diets.
The cities of An Giang, Dong Thap and Cantho
are situated beside the border
with Cambodia and along the Hau river, where catfish cultivation
using the floating cage is dominant. Cantho province is not only
the geographic but also the political and economic center of the
Mekong delta. Intensive farming systems, including paddy rice,
fruits, animals and fish, are well developed in the province (Nguyen Van Sanh
et al 1998), and the two types of catfish cultivation, both in
ponds and in floating cages, are prevalent. Large factories produce
aqua-cultural products for export such as Pangasius filet.
The abundant residues and the whole small fish are processed to
give raw catfish meal, containing crude protein level of 53 % and EE
of 37 % in dry matter (Le Thi Men et al 2005). This source of
protein and energy supplement can be applied in
animal feeding, especially in pig production in the Mekong
Delta
The hypothesis of this study was that Tra catfish meal can replace protein of fish meal
in a diet for fattening pigs without affecting the pig growth performance and
with economic benefit to
producers.
The trial was conducted in the experimental farm of CanTho university. The experimental animals were 24 growing castrate male pigs of crossbred Large White with average initial live weight of 60 ± 5 kg. The trial consisted of 1 pig per pen, with 4 dietary treatments and 6 blocks (6 litters with 4 pigs per litter). The control diet (0CF) was based on broken rice, rice bran and fish meal. The 33CF treatment dwas based on the same ingredients but the Tra catfish residue meal replaced 33 % of the fish meal. The 66CF diet had 66 % of the fish meal replaced by the catfish meal, and the 100CF diet had all the fish meal replaced by the catfish meal. The daily allowance was restricted to 3.5 % of body weight. Samples of feeds and mixed feeds were taken for analysis of chemical composition. All animals were given free access to drinking water, and were weighed at the start and end of the trial. Details of the experiment was given in Tables 1 and 2
|
Table 1. Analyzed chemical compositions of the feedstuffs used in the experiment , as % DM basis (except for DM which is on "as fed" basis) |
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|
|
DM, % |
CP |
EE |
CF |
Ash |
ME, kcal/kg |
|
Broken rice |
88.5±0.49 |
7.04±0.16 |
0.28±0.06 |
1.45±0.41 |
0.47±0.03 |
3,452 |
|
Rice bran |
87.6±0.39 |
12.1±0.17 |
13.1±0.85 |
4.60±0.38 |
7.25±1.14 |
2,914 |
|
Tra catfish meal |
90.2±0.08 |
60.5±1.26 |
30.3±0.39 |
|
4.08±0.11 |
3,731 |
|
Fish meal |
89.9±0.40 |
59.5±1.26 |
16.7±2.46 |
|
34.0±0.62 |
3,644 |
Samples of each feedstuff were taken, and the content of DM, CP,
CF, EE were analyzed according to AOAC (2000). ME was estimated
(NIAH 1995). All pigs were weighed at the initial, and final time points of the
trial. Feed refusal in every pen was recorded every day. Backfat thickness at two opposite points of the 10-12th
ribs' mid-line of the all pigs was estimated using an ultrasonic
machine (RENCO Co., Ltd, Minneapolis, USA) at the final time point.
Data were analyzed by ANOVA using the General Linear Model of
Minitab Statistical Software version 13. Sources of variation were
treatments and blocks. The Tukey Test for paired comparisons was
used to separate means when the differences were significant at the
5% level.
Crude protein and crude fibre were similar for the four dietary treatments, but the EE was higher on the CF diets (Table 2)
|
Table 2. Ingredients, calculated chemical composition and feed costs of experimental diets for fattening pigs |
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|
|
Diets |
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|
|
0CF |
33CF |
66CF |
100CF |
|
|
Ingredient, % |
|
|
|
|
|
|
Broken rice |
52 |
52 |
52 |
52 |
|
|
Rice bran |
35 |
35 |
35 |
35 |
|
|
Tra fish meal |
0 |
4 |
8 |
12 |
|
|
Fish meal |
12 |
8 |
4 |
0 |
|
|
Premix |
1 |
1 |
1 |
1 |
|
|
Total |
100 |
100 |
100 |
100 |
|
|
Chemical composition |
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|
ME, MJ/kg |
12.0 |
12.2 |
12.3 |
12.5 |
|
|
CP, % |
14.8 |
14.8 |
14.9 |
14.9 |
|
|
EE, % |
6.6 |
7.2 |
7.7 |
8.2 |
|
|
CF, % |
2.4 |
2.4 |
2.4 |
2.4 |
|
|
Feed cost, VND/kg1) |
3,459 |
3,434 |
3,409 |
3,383 |
|
|
1) Prices per kg for broken rice: 3,000; rice bran: 2,500; Tra fish meal: 7,875; premix: 6,000 and fish meal: 8,500 VND |
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Mean daily weight gains, feed conversion rates and back-fat were not different among treatments (Table 3), probably because the polyunsaturated fatty acids in catfish oil were effectively utilized as an energy source by the pigs, as reported by Harmon (2000). As shown in results of Wood (1984), increasing the proportion of dietary energy derived from unsaturated fatty acids such as C18:2 would result in decreased back-fat thickness at the 10th rib in pigs.
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Table 3. Effect of experimental diets on growth performance of pigs |
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|
|
Diets |
SEM |
P |
|||
|
0CF |
33CF |
66CF |
100CF |
|||
|
Daily gain, g/d |
681 |
691 |
730 |
736 |
31.1 |
0.518 |
|
Feed intake, kg/d |
2.24 |
2.29 |
2.27 |
2.23 |
0.04 |
0.687 |
|
Feed conversion |
3.31 |
3.34 |
3.14 |
3.04 |
0.12 |
0.235 |
|
Back-fat thickness, mm |
15.2 |
16.0 |
15.6 |
16.2 |
0.472 |
0.553 |
The feed cost per kg weight gain was lowest in 100CF (Table 4). Sale price per kg live weight of the finished pigs was the same for all diets (17,500 VND/kg). As a result, the gross income per total weight gain was best in 100CFWS and 66CF.
|
|
Diets |
SEM |
P |
|||
|
0CF |
33CF |
66CF |
100CF |
|||
|
Gross income1), VND |
617,167 |
621,250 |
658,000 |
658,000 |
27,836 |
0.595 |
|
Feed cost/kg gain, VND |
11,467 |
11,483 |
10,683 |
10,268 |
396 |
0.119 |
|
Total feed expense, VND |
399,313 |
403,409 |
398,057 |
385,887 |
7,212 |
0.382 |
|
Feed benefit, VND |
217,854 |
217,841 |
259,943 |
272,113 |
23,797 |
0.279 |
|
% Relative |
100 |
100 |
119 |
125 |
|
|
|
1) Sale price per kg live weight of finishing pig was 17,500 VND for each diet |
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The Tra catfish residue meal can completely replace fish meal in pig diets based on high amount of broken rice as main ingredient.
Backfat thickness was not affected by the high level of catfish meal.
Catfish residue meal can be recommended for producers.
AOAC 2000 Official Methods of Analysis. American
Association of Analytical Chemists. Washington,
DC.,USA
Harmon B G 2000 Swine nutrition and management. Purdue University. USA .
Le Thi Men, Vo Cong Thanh, Y Hirata and S Yamasaki 2005 Evaluation of the genetic diversities and the nutritional values of the Tra (Pangasius hypothalamus) and the Basa (Pangasius bocourti) catfish cultivated in the Mekong Delta of Vietnam. Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 5: 671-677.
Nguyen Van Sanh, V T Xuan and T A Phong 1998 History and future of farming systems in the Mekong Delta. In Development of Farming Systems in the Mekong Delta of Vietnam. (Eds) Vo-Tong Xuan and Shigeo Matsui). Ho Chi Minh Publishing House. Ho Chi Minh City, Vietnam, pp.17-80.
Wood J D 1984
Fat deposit and the quality of fat tissue in meat animal. In Fats in
Animal Nutrition. (ed) Wiseman, J. Butterworths, London, England, 407-435.