Water hyacinth (Eichhornia crassipes): an invasive weed or a potential feed for goats?

Bui Phan Thu Hang, Vo Lam, Truong Thi Bich Phuong and T R Preston*

Angiang University, Faculty of Agriculture and Natural Resources, Vietnam,
bpthang@agu.edu.vn
* TOSOLY, AA48 Socorro, Santander, Colombia

Abstract

Water hyacinth (Eichhornia crassipes) infestation of water surfaces is usually thought to be a problem. On the other hand, its capacity to remove nutrients from polluted water is an asset. Developing ways to use economically the foliage of water hyacinth is therefore an important goal for researchers. The present study aimed to investigate if supplementation with other foliages would improve the utilization of water hyacinth by growing goats. Two experiments were conducted in the Angiang University Research Farm.  The digestibility study was a 4*4 Latin-square design with Sesbania sesban at levels of 1 or 2% of LW (DM basis) in basal diets of water hyacinth leaves or leaves + stems. The growth study was a Complete Randomized Design with the water hyacinth leaves ad libitum supplemented with either Sesbania sesban, water spinach, natural grass or sweet potato vines (all at 1% of LW on DM basis).

Feed intake and N retention were higher when water hyacinth leaves were the basal diet rather than leaves + stems. Growth rates were higher when Sesbania sesban, water spinach or sweet potato vines, rather than grass,  were used to supplement the water hyacinth leaves. 

Key words: digestibility, growth, N retention, nutrient intake, Sesbania sesban, sweet potato vines, water spinach

Introduction

Goat production in the Mekong delta of Vietnam is limited by lack of green feeds during certain times of the year, e.g. in the dry and flood seasons. However, during the course of flooding aquatic plants are abundant and offer potential as feed for goats.

Water hyacinth (Eichhornia crassipes) is the most abundant water plant in the Mekong delta. According to Penfound and Earle (1948) (cited by Joyce 1990) from ten water hyacinth plants as many as 655,000 plants covering 0.4 hectares are produced in eight months. This high rate of proliferation has led to it being treated as an invasive species. On the positive side, several authors have commented on the potential nutritive value of the leaves of water hyacinth (eg: Easley and Shirley 1974; Nguyen Nhut Xuan Dung 1996) citing values of crude protein (CP) of up to 20% and of 50% NDF/kg DM of leaves. According to Son and Trung (2002), farmers in the delta often feed the leaves to pigs, cattle and buffaloes.  Tran Van Triet and Nguyen Van Thu (2009) reported that water hyacinth stem and leaves can replace from 40 to 60% of the Para grass in diets for rabbits. Other observed uses of water hyacinth are for water purification, and as a green manure for the land. Recently, water hyacinth stems have been popularly used to make handicraft products for export.

Sesbania sesban (L.) Merr. is a leguminous short lived tree which may grow to 8 m tall. It grows in a wide range of soils, and is especially tolerant of acid sulphate soil. It appears to grow best where periodic water logging or flooding is followed by a progressively drier season (Nguyen Thi Hong Nhan et al 2009). Kustantinah et al (2005) reported that the leaves of S. sesban contained 27% CP in DM and that it was a valuable supplement for weaned local goats in Indonesia promoting improved feed intake and weight gain. Water spinach (Ipomoea aquatica) increased the feed intake, DM digestibility and N retention in goats when fed at a level of 26% of basal diet of cassava foliage (Pathoummalangsy Khamparn 2005). Higher levels of 40% of water spinach lowered the N retention apparently because of a diuretic effect increasing N losses in the urine.

The hypothesis underlying the present study was that both Sesbania and Water spinach would improve the performance of growing goats fed basal diets of water hyacinth leaves or combined leaves and stems.

Materials and methods

Experiment 1: Effect of feeding different proportions of Water hyacinth and Sesbania sesban foliage in the diet on intake, digestibility and N retention of growing goats

The animals used in the experiment were 4 male weaned crossbred goats (Bachthao male x local female) with an initial weight of 11 kg, and aged from 3 to 4 months. They were housed in metabolism cages, de-wormed with Ivemectin, vaccinated (foot-and-mouth disease) and gradually introduced to the experimental feeds over a period of 15 days.  

The goats were randomly assigned to four treatments in a 4 x 4 Latin square design, with four 21-day periods, comprising 14 days of adaptation, followed by 7-day periods of collection of feces and urine. The treatments were:  

• WHLS1: Water hyacinth leaves ad libitum + 1% of LW on DM basis of Sesbania foliage 

• WHLS2: Water hyacinth leaves ad libitum + 2% of LW on DM basis of Sesbania foliage 

• WHFS1: Water hyacinth foliage (leaves + stems) ad libitum + 1% of LW on DM basis of Sesbania

• WHFS2: Water hyacinth foliage (leaves+stems) ad libitum + 2% of LW on DM basis of Sesbania

Water hyacinth was collected every day from ponds, canals and rivers around Angiang University Research  Farm. Branches of  Sesbania sesban were harvested from trees growing locally. The Sesbania branches were hung in bunches above the feed trough. Water hyacinth leaves or combined leaves + stems were fed in plastic troughs for the goats to choose freely. Amounts offered were decided weekly based on individual live weights of the goats. The feeds were provided two times per day (08:00 h and 14:00 h); the goats had free access to water and a mineral lick. The composition of the feed ingredients is presented in Table 1.

Experiment 2: Growth of crossbred goats fed a basal diet of Water hyacinth leaves and supplements of water spinach, Sesbania, Sweet potato vines (Ipomoea batatas) or local grasses

The animals used in the experiment were 16 weaned crossbred goats (Bachthao male x local female) with an initial weight of 10 kg, and aged from 3 to 4 months. They were housed in individual cages, de-wormed with Ivomectin, vaccinated (foot-and-mouth disease) and gradually introduced to the experimental feeds over a 15 day period.  

The experimental plan followed a Complete Randomized Design (CRD) with 4 treatments and 4 replications. The supplements offered at1% of LW (DM basis) to a basal diet of Water hyacinth leaves were:

• SS:  Sesbania

• WS: Water spinach

• NG: Natural grass

• SPV: Sweet potato vine

Collection of water hyacinth leaves and Sesbania sesban followed the same procedures as in Experiment 1.  Water spinach, natural grass and sweet potato vines were obtained from local farmers (Table 2).

The DM, CP and ash were determined according to AOAC (1990). The N content of feeds offered, refusals, fresh feces and urine was measured by the Kjeldahl method; ash was determined by incinerating samples at 600^oC (AOAC 1990). NDF and ADF were determined according to Van Soest and Robertson (1985), using sodium sulphate and amylase and expressed with residual ash.

All raw data of the experiment were computed and stored in worksheets of the Excel Software Release XP version and processed by analysis of variance using the General Linear Model (GLM) procedure of Minitab Software Release version 13.1 (Minitab 2000). Sources of variation were Treatments, Periods, Animals and Error in Experi,emt 1; and Treatments, Replicates and Error in Experiment 2. When the differences in treatment means were significant at the probability level of P<0.05 or 0.01, the means were compared using the Tukey’s pair-wise test in the Minitab software.

Results and discussion

Digestibility experiment

There was an increase in total intake of DM when water hyacinth leaves were fed rather than leaves + stems (Table 3; Figure 1). DM intake tended to be increased when Sesbania was fed at the higher level.

Figure 1:  Mean values for nitrogen retention in goats fed water hyacinth leaves or leaves + stems with two levels of Sesbania

The trends in apparent digestibility of DM were similar to those for DM intake, with increases due to the higher level of Sesbania when Water hyacinth leaves and stems were offered as opposed to leaves only (Table 4). 

Nitrogen retention was higher in the diets containing water hyacinth leaves as opposed to leaves + stems. The level of Sesbania sesban did not affect N retention on the basal diet of water hyacinth leaves but doubled the N retention on the basal diet of water hyacinth leaves and stems (Table 5; Figure 2).

Figure 2: Mean values for nitrogen retention in goats fed water hyacinth leaves or leaves + stems with two levels of Sesbania

Figure 3: Mean values for apparent dry matter digestibility in goats fed water hyacinth leaves or leaves + stems with two levels of Sesbania

Growth experiment

Total DM intake was higher for the diet with sweet potato vine than for the other diets (Table 6). The CP intake was lowest for the diet containing natural grass. The diets supplemented with Sesbania sesban, water spinach or sweet potato vine supported a higher daily weight gain as compared to the diet supplemented with natural grass (Figure 40.. 

Figure 4: Growth curves of goats fed leaves of Water hyacinth and supplements of Sesbania, Water spinach, natural grass or sweet potato vines

Conclusions

• Growing goats had higher nutrient intake and N retention when their diets were based on water hyacinth leaves rather than the whole aerial part (leaves plus stems).
  
  
• Growth rates were higher when Sesbania sesban, water spinach or sweet potato vine, rather than grass, were used to supplement the water hyacinth leaves.
  
  
• Water hyacinth leaves can be used as green forage for growing goats in small-holder farms.

References

AOAC 1990 Official Methods of Analysis, 15th edition. Association of the Official Analytical Chemists. Washington D.C.

Easley J F and Shirley R L 1974 Nutrient elements for livestock in aquatic plants. Hyacinth Control Journal, 12, 82-85.

Joyce J C 1990 Aquatic Weeds. The Ecology and Management of Nuisance Aquatic Vegetation. Oxford University Press.

Kustantinah Hartadi H, Yusiati L M, Utomo  R, Agus A, Suhartanto B, Holil F  and Dahono E 2005  Effect of supplementation of protein feeds to various roughages as a basal feed on the performance of Bligon goats in Indonesia. http://www.tropentag.de/2004/abstract/full/145.pdf

Minitab 2000 Minitab Reference Manual, Release 13.1 for Windows. Minitab Inc, USA.

Nguyen Nhut Xuan Dung 1996 Identification and evaluation of non-cultivated plants used for livestock feed in the Mekong delta of Vietnam. MSc. Thesis. Swedish University of Agricultural Sciences.

Pathoummalangsy Khamparn 2005 Effect of a supplement of fresh water spinach on feed intake and digestibility in goats fed a basal diet of cassava foliage. MEKARN Mini-projects, 2005-07  Article # 04. Retrieved, from http://www.mekarn.org/MSC2005-07/minpro/kham04.htm

Son V V and Trung N B 2002 Utilization of Water Hyacinth (Eichhornia crassipes) as a supplement in diet of fattening-finishing pigs. In: Workshop on development of new technologies and their practice for sustainable farming systems in the Mekong Delta of Vietnam. Cantho University, Vietnam, November 26^nd-28^th, 2002.

Tran Van Triet and Nguyen Van Thu 2009 Replacement of para grass (Brachiaria mutica)  by water hyacinth (Eichroria crassipes L): Effects on digestibility, feed intake and live weight gain in growing rabbits. BSc. Thesis. Cantho University, Vietnam.   

Van Soest P  J  and Robertson J B 1985  Analysis of forages and fibre foods. A Laboratory Manual for Animal Science 613. Department of Animal Science. Cornell University. Ithaca, New York.

Received 8 June 2011; Accepted 28 June 2011; Published 1 July 2011

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