 |
|
Figure 1. Intakes of crude protein from dietary ingredients according to level of water spinach in the diet |
| Livestock Research for Rural Development 19 (12) 2007 | Guide for preparation of papers | LRRD News | Citation of this paper |
Twenty four crossbred castrated male pigs with initial body weight from 13.7 to 15.1 kg were allocated to 6 diets containing water spinach at levels of 0, 5, 10, 15, 20 and 25% in DM, replacing fresh leaves of water hyacinth at levels of 37, 32, 27, 22, 27 and 12% in DM. The other components of the diet (DM basis) were fish meal (4-5%), soybean meal (4-5%), rice bran (26-27%) and cassava root meal (26-27%). The experiment period was 120 days.
The replacement of 37% fresh leaves of water hyacinth by 12% water hyacinth leaves and 25% fresh water spinach (from 37 to12% of DM) with fresh water spinach (from 0 to 25% in DM) led to: (i) a 50% increase in DM intake; (ii) tripling of the rate of weight gain (from 78 to 215 g/day); and (iii) improved DM feed conversion (from 9.2 to 4.4).
It is concluded that there are no apparent benefits from including water hyacinth leaves in diets of growing pigs.
Key words: Growth rate, pigs, water hyacinth, water spinach
Water hyacinth (Echhornia crassipes) floats on water surfaces throughout SE Asia and is considered to be a common weed because of its capacity to grow and reproduce on nutrient-rich water bodies (Le Thi Men et al 2002). Water hyacinth has been investigated since the 1979’s for the treatment of municipal water waste (Boyd 1970). The young, light-green leaves and stems are rich in crude protein (18% on a DM basis) and have been fed to pigs in the Mekong Delta (Le Thi Men 2006).
Water spinach (Ipomoea aquatica) is widely cultivated in Cambodia for human food and for feeding to pigs. Previous studies by Chhay Ty and Preston (2005) at CelAgrid showed that mixing water spinach with fresh cassava leaves (65:35 fresh basis) resulted in pig growth rates on a basal diet of broken rice, which were higher than the average recorded for diets in which water spinach or cassava leaves were fed as the sole supplement. In a subsequent trial (Chhay Ty and Preston 2006) there were linear increases in pig growth rate when fresh water spinach replaced cassava leaves at levels of 10, 20 and 30%.
The hypothesis that was tested in this
study was that water spinach would have beneficial effects on growth rate of
pigs when it replaced water hyacinth as the main source of supplementary protein
in diets based on rice bran and cassava root meal.
The experiment was carried out from 23 October 2006 to 21 February 2007 at the Center for Livestock and Agriculture Development (CelAgrid), located in Phras Teat village, Rolous Commune, Kandal stung district, Kandal province about 25km from Phnom Penh City, Cambodia.
Twenty four crossbred castrated male pigs with initial body weight from 13.7 to 15.1 kg were allocated to 4 blocks according to live weight, and within blocks to 6 diets containing water spinach at levels of 0, 5, 10, 15, 20 and 25% in DM. Comparable levels of water hyacinth were: 37, 32, 27, 22, 27 and 12% in DM (Table 1). There were 4 replicates of each treatment.
|
Table 1. Proportions of ingredients in the diets and estimated content of DM and crude protein (based on analysis of individual ingredients shown in Table 2). |
||||||
|
|
WS0 |
WS5 |
WS10 |
WS15 |
WS20 |
WS25 |
|
Composition of diets, % DM basis |
||||||
|
Water spinach |
0 |
5 |
10 |
15 |
20 |
25 |
|
Water hyacinth |
37 |
32 |
27 |
22 |
17 |
12 |
|
Fish meal |
5 |
4 |
4 |
4 |
4 |
3.5 |
|
Soybean |
5 |
5 |
4 |
4 |
4 |
3.5 |
|
Cassava root meal |
26 |
26 |
27 |
27 |
27 |
28 |
|
Rice bran |
26 |
27 |
27 |
27 |
27 |
27 |
|
Salt |
1 |
1 |
1 |
1 |
1 |
1 |
|
Total |
100 |
100 |
100 |
100 |
100 |
100 |
|
Analysis, % |
|
|
|
|
|
|
|
Dry matter |
59.1 |
58.9 |
58.6 |
58.4 |
58.3 |
58.0 |
|
Crude protein in DM, % |
15.0 |
15.2 |
15.3 |
15.8 |
16.4 |
16.5 |
The pigs were housed in individual pens with concrete floor and provided with feeders and drinking nipples. The pigs were vaccinated against common diseases in Cambodia (Swine fever and salmonellosis) and were de-wormed with Ivermectin prior to being adapted to the feeds and the housing for 10 days before starting the experiment.
Rice bran was purchased from the rice mill near CelAgrid. Cassava root meal, fish meal and soybeans were purchased from shops in Phnom Penh city. Fresh water hyacinth leaves were harvested every day from ponds in CelAgrid or in the immediate vicinity. Water spinach was purchased from traders who harvested it from lagoons receiving waste water from Phnom Penh city.
The water hyacinth leaves were separated from the stems and chopped into small pieces prior to being mixed with the water spinach in proportions depending on the treatments. The amounts of the feeds offered were adjusted to be close to ad libitum but with minimal residues. The mixed dry meal components of the diets were offered three times daily (8.00, 12.00 and 17.00h). After the dry meals were consumed the mixed forages were offered in amounts equivalent to the intended proportion in the diet (37% of the diet DM; Table 1).
The pigs were weighed every 10 days during the 120 days of the experiment. Feeds offered and residues were recorded daily. Representative samples of feeds offered and residues were taken daily to estimate DM content, the dried samples being bulked on a weekly basis for analysis of N. The DM content was determined using the microwave method of Undersander et al (1993). N was analyzed following procedures of AOAC (1990).
Data for weight gain, DM feed intake,
and crude protein intake and feed conversion rate were analyzed using the
general linear model (GLM) option of the ANOVA software of Minitab (2000). The
sources of variation were blocks, treatments and error. Relationships among
variables were estimated by regression analysis using the same Minitab software.
The crude protein content of the water spinach was 50% higher than in the leaves of water hyacinth (Table 2).
|
Table 2. Chemical characteristics of the ingredients of the diets |
||
|
|
% DM |
N*6.25, % in DM |
|
Water spinach |
10.1 |
30.1 |
|
Water hyacinth leaves |
13.8 |
19.9 |
|
Fish meal |
88.0 |
34 |
|
Soybean meal |
90.0 |
46 |
|
Cassava root meal |
84.3 |
3 |
|
Rice bran |
88.9 |
11 |
|
Salt |
- |
- |
Daily DM intake (Table 3; Figure 2) increased as the proportion of water spinach in the diet increased, but there were no differences when feed intake was expressed as a proportion of live weight.
|
Table 3. Mean values of feed intake of pigs fed different proportions of water spinach and fresh water hyacinth leaves as supplements to rice bran and cassava root meal |
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|
|
WS0 |
WS5 |
WS10 |
WS15 |
WS20 |
WS25 |
SEM |
Prob |
|
DM intake, g/day |
||||||||
|
Water spinach |
0 |
53 |
124 |
175 |
293 |
341 |
|
|
|
Water hyacinth |
215 |
167 |
144 |
130 |
93 |
54 |
|
|
|
Total foliage |
35.5 |
35.2 |
40.9 |
38.6 |
48.1 |
44.9 |
- |
- |
|
Fish meal |
36.3 |
36 |
41.8 |
39.5 |
49.1 |
46 |
|
|
|
Soybean |
36.3 |
36.0 |
41.8 |
39.5 |
49.1 |
45.9 |
|
|
|
Rice bran |
187 |
185 |
215 |
203 |
253 |
236 |
|
|
|
Cassava root meal |
179 |
177 |
206 |
194 |
242 |
226 |
|
|
|
Total DM |
652a |
654a |
771b |
780bc |
977de |
947e |
10.8 |
0.001 |
|
g DM/kg LW |
36.7ae |
36.2ac |
33.1b |
35.3ce |
38.1d |
35.3e |
0.23 |
0.001 |
|
Crude protein intake, g/day |
|
|
|
|
|
|||
|
Water spinach (WS) |
0 |
16 |
37.2 |
52.7 |
88.1 |
102 |
|
|
|
Water hyacinth |
44.3 |
34.5 |
29.6 |
26.6 |
18.9 |
10.8 |
|
|
|
Foliage |
44.3 |
50.5 |
66.8 |
79.3 |
107 |
113 |
|
|
|
Fish meal |
12.1 |
12.0 |
13.9 |
13.1 |
16.3 |
15.3 |
|
|
|
Soybean |
16.7 |
16.6 |
19.2 |
18.2 |
22.6 |
21.1 |
|
|
|
Rice bran |
20.5 |
20.3 |
23.6 |
22.3 |
27.8 |
25.9 |
|
|
|
Cassava root meal |
5.37 |
5.32 |
6.18 |
5.83 |
7.26 |
6.78 |
|
|
|
Total CP intake |
99.0a |
105a |
130b |
139bc |
181de |
182e |
2.13 |
0.001 |
|
CP, g/kg DM |
152 |
160 |
168 |
178 |
185 |
192 |
|
|
|
WS CP/total CP |
0 |
0.16 |
0.28 |
0.38 |
0.47 |
0.55 |
0.002 |
0.001 |
|
abcde: Means within main effects within rows without common letter are different at P<0.05 |
||||||||
Total intake of crude protein, and the proportion in the diet DM, increased as water spinach replaced water hyacinth in the diet (Table 3 and Figures 1 and 3). At the highest level of water spinach, the protein from this source provided slightly more than 50% of the total diet crude protein.
|
|
|
Figure 1. Intakes of crude protein from dietary ingredients according to level of water spinach in the diet |
|
|
|
|
Figure 2. Relationship between proportion of protein intake from water spinach and total dry matter intake |
Figure 3. Relationship between proportion of protein intake from water spinach and crude protein intake |
Growth rate and feed conversion
Growth rate was linearly and positively related to the proportion of dietary protein derived from water spinach (Table 4; Figures 4 and 5). The relationship between DM feed conversion and proportion of dietary protein derived from water spinach appeared to be curvilinear and negative (Figure 6).
|
Table 4. Mean values of live weight gain and feed conversion ratio of pigs fed different proportions of water spinach and fresh water hyacinth leaves as supplements yo rice bran and cassava root meal |
||||||||
|
|
WS0 |
WS5 |
WS10 |
WS15 |
WS20 |
WS25 |
SEM |
Prob |
|
Live weight, kg |
||||||||
|
Initial |
14.9 |
13.7 |
14.9 |
14.4 |
15.1 |
14.5 |
1.77 |
0.99 |
|
Final |
24.6 |
25.0 |
35.8 |
35.5 |
40.4 |
42.9 |
3.60 |
0.01 |
|
Daily gain, g |
78.1a |
85.6a |
165b |
176b |
207b |
215b |
16.3 |
0.001 |
|
DM feed conversion |
9.24 |
9.71 |
4.59 |
4.49 |
4.68 |
4.42 |
1.22 |
0.014 |
|
ab: Means within main effects within rows without common letter are different at P<0.05 |
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|
|
|
|
|
|
|
|
|
|
|
The results of this study confirm our earlier research findings (Chhay Ty and Preston 2005, 2006) on the benefits of using fresh water spinach as a major protein source in diets of growing pigs.
In contrast, there appears to be little
justification for including water hyacinth in pig diets which agrees with
related research done in the Mekong Delta. In these studies the levels of water
hyacinth in the diets were low (5% of diet DM [Le Thi Men et al 2002]; 6% in
diet DM [Luu Huu Manh et al
2002]; and 5% in the diet DM [Nguyen Ba Trung 2006]).
Also in most cases the basal diets were purchased concentrates hence the
nutritional significance of the supplementary water hyacinth was difficult to
assess. In all these studies there were no apparent advantages from inclusion of
the water hyacinth in the diets.
In diets for young growing pigs, based
on rice bran and cassava root meal, the replacement of fresh leaves of water
hyacinth (from 37 to12% of DM) with fresh water spinach (from 0 to 25% in DM)
led to: (i) a 50% increase in DM intake; (ii) tripling of the rate of weight
gain (from 78 to 215 g/day); and (iii) improved DM feed conversion (from 9.2 to
4.4).
Acknowledgments
The authors would like to express their
gratitude to the MEKARN project financed by SIDA-SAREC and to the Center for
Livestock and Agriculture Development (CelAgrid), for providing resources for
conducting this experiment.
References
AOAC 1990 Official Methods of Analysis. Association of Official Analytical Chemists. 15th edition (K Helrick editor). Arlington pp 1230
Boyd C E 1970 Vascular aquatic plants for mineral nutrient removal from polluted water. Economic Botany 24: 95-103
Chhay Ty and Preston T R 2005 Effect of water spinach and fresh cassava leaves on growth performance of pigs fed a basal diet of broken rice. Livestock Research for Rural Development. Volume 17, Article No. 76 http://www.cipav.org.co/lrrd/lrrd17/7/chha17076.htm
Chhay Ty and Preston T R 2006 Effect of different ratios of water spinach and fresh cassava leaves on growth of pigs fed basal diets of broken rice or mixture of rice bran and cassava root meal. Livestock Research for Rural Development. Volume 18, Article No. 57. http://www.cipav.org.co/lrrd/lrrd18/4/chha18057.htm
Luu Huu Manh, Nguyen Nhut Xuan Dung, Seishi Yamasaki and Ryozo Takada 2002 Replacement of Concentrate by Water Hyacinth (Eichroria Crassipes): Effects on Digestibility, Feed Intake and Live Weight Gain in Pig Production. . Proceeding of the final workshop of JIRCAS Mekong Delta project,http://www.ctu.edu.vn/institutes/mdi/jircas/JIRCAS/research/workshop/Pro02/C21-%20Replacement.pdf
Le Thi Men 2006 Genetic and nutritional diversity of sweet potato (Ipomoea batatas), water spinach (Ipomoea aquatica) and water hyacinth (Echhornia crassipes) and their potential as pig feed in the Mekong Delta of Vietnam. Workshop-seminar "Forages for Pigs and Rabbits" MEKARN-CelAgrid, Phnom Penh, Cambodia, 22-24 August, 2006. Article #3 RetrievedJune 3, 2007, from http://www.mekarn.org/proprf/lemen.htm
Le Thi Men, Yamasaki S, Caldwell J S, Thuan T K, Yamada R, Khoa D V A and Takada R 2002 Effect of rice based balanced resources and the water hyacinth in diet on pig production in Tan Phu Thanh village, Cantho province. Proceeding of the final workshop of JIRCAS Mekong Delta project, 1http://www.ctu.edu.vn/institutes/mdi/jircas/JIRCAS/research/workshop/Pro02/C22-%20Evaluation.pdf
MINITAB 2000 Minitab Reference Manual release 13.31.
Nguyen Ba Trung 2006 Agricultural potential and utilization of water hyacinth (Eichhornia crassipes) as forage for fattening pigs in the Mekong delta of Vietnam. Workshop-seminar "Forages for Pigs and Rabbits" MEKARN-CelAgrid, Phnom Penh, Cambodia, 22-24 August, 2006. Article # 12. RetrievedJune 3, 2007, from http://www.mekarn.org/proprf/trung.htm
Undersander D, Mertens D R and Theix N 1993 Forage analysis procedures. National Forage Testing Association. Omaha pp 154
Received 2 June 2007; Accepted 23 August 2007; Published 12 December 2007
