Chapter-IV Studies on the use of Limnocharis flava as feed...
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--------------------------------------------------------------------------------------------------------------------------------------- Chapter-IV Studies on the use of Limnocharis flava as feed to livestock
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Chapter-IV
Studies on the use of Limnocharis flava as feed to livestock
4.1. INTRODUCTION
The menace of aquatic weeds is reaching alarming problems in many parts of the world,
but it is particularly severe in tropical countries, where abundant sunlight and favorable
water temperature, increasing number of dams, barrage and irrigation channels foster
aquatic plant growth. The problems caused by aquatic macrophytes include: water loss
by evapo-transpiration, clogging of irrigation pumps and hydroelectric schemes,
obstruction of water flow, causing difficulties to fishing activities resulting in reduction
of fish yields, interference with navigation, public health problems and competing for
the nutrients leading to retardation of growth of cultivated aquatic crops. The water
bodies are often left unproductive with impeded light penetration and depletion of
dissolved oxygen. Regrettably, there is hardly any simple or cost-effective way to
control the infestation of these aquatic macrophytes in an environment friendly manner.
It has been found that chemical or biological control of weeds poses several problems
not only to the plants, human beings but also to the livestock. At this particular juncture,
a viable option to control the spread of weeds is weed utilization. The long term control
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of weeds requires initial clearance accompanied by periodic removal of regrown weeds
and proper utilization of the harvested weeds. The high productivity of such weeds can
be made as an asset, or else the weeds become a major nuisance to the environment
(Abbasi and Nipaney, 1986; Abbasi and Ramasamy, 1999b). There is also the paradox
of food shortages to livestock coexisting with large expanses of aquatic vegetation in
many developing countries, where the utilization of these plants as feed to livestock
would convert a weed problem into a valuable crop (Boyd, 1974). In one sense, they
provide a highly productive crop that requires no tillage, seed or fertilization (Ruskin
and Shipley, 1976). According to Little (1968), what is needed is, “radical change of
thinking since once a plant is called a weed it becomes accepted as being useless”.
The magnitude and complexity of exotic weeds, combined with the costs for their
control, necessitate the use of integrated weed management. Even though there are
several integrated weed management technologies, another option of control of exotic
weeds is to identify a suitable method of utilization so that the weed population can be
controlled. However, a perusal of the available literature shows that some of the aquatic
weeds are highly nutritive and therefore, one alternative solution to check the massive
population of these weeds might be their utilization through incorporation as
components of feedstuff for cattle and pigs. In fact, significant effort has been directed
toward evaluating the nutritive value of different non-conventional feed resources,
including terrestrial and aquatic macrophytes, to formulate nutritionally balanced and
cost-effective diets for cattle and pigs.
Kuttanad is highly complex, dynamic and unique rice growing agro-climatic tract of
Kerala lying 0.6 to 2.5m below MSL. This area contains an abundance of aquatic weeds
like Eichhornia, Pistia, Monochoria, Alteranthera, Nymphoides, Trapa, Limnocharis
etc. that grow throughout the year. Cattle rearing is one of the important occupations of
this region, and therefore the use of some of these weeds as nutrient sources for cattle
feed formulation will not only replace the rather expensive, conventional commercial
feeds - partially if not fully, but might restrict the alarming growth of these weeds that
are affecting the ecosystem. However, before advocating the utilization of these aquatic
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weeds as supplements of animal feeds, it is necessary to explore the nutritional quality
and chemical composition of these weeds.
An attempt has been made in this study to explore the possibility of the utilization of
an exotic aquatic weed, Limnocharis flava as unconventional feed resource to the
livestock. L. flava is a noxious weed in rice fields, so much so that paddy cultivation in
some of the fields in Ceylon had to be entirely abandoned. The probable cause of its
occurrence in Kerala is because of import of rice from South Asian countries like
Myanmar, Thailand and Srilanka. National Academy of Sciences, Washington (1976)
reported in Sumatra and other places, the plant is used as a fodder for cattle and pigs.
The use of L. flava as a livestock feed will help in enhancing the available feed resource
and control its spread. A detailed search on the literature has revealed that several
studies have been carried out on the nutritional and mineral characteristics of aquatic
macrophytes (Harper and Daniel, 1935; Bailey, 1965; Boyd, 1968; 1968a; 1969; 1972)
but no study has been reported so far on Limnocharis. Keeping this in view, the present
study was carried out to investigate the chemical composition and nutritional
characteristics of L. flava.
The present study was undertaken to investigate the nutritional potential and trace
metal content of L. flava - an invasive aquatic weed from northeast America, in order to
ascertain its suitability of using it as cattle feed. Keeping this in view, the present study
was designed to investigate the chemical composition and nutritional characteristics of
the plant L. flava as an unconventional feed resource to the livestock with the following
specific objectives.
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4.1.1. Objectives of the study
1. To explore the possibility of utilizing the exotic weed Limnocharis flava as an
unconventional feed to livestock.
2. To investigate the chemical composition and nutritional characteristics of the
plant L. flava.
3. To evaluate and compare the chemical composition, nutritive value and trace
element profiles of L. flava during its different growth stages such as pre-
flowering, flowering and post flowering.
4.2. REVIEW OF LITERATURE
Weed menace is one of the persistent environmental problems faced globally.
Utilization of aquatic weeds for human or animal consumption has received relatively
little interest, but the vast areas of water bodies infested with weeds in many tropical or
warm temperate regions must be considered as a potential source of food to the local
community and cattle population. Shortages of food and large expanses of aquatic
weeds often exist in the same locality and the utilization of these plants as food would
convert the weed problem into a valuable crop. The use of aquatic plants as feed for
livestock in technologically advanced nations will require the product to be competitive
in quality and cost with conventional feeds. Pilot studies in the United States
demonstrated that feeds of high quality can be made from several species of aquatic
plants. However, the cost of harvesting and processing the plants by mechanical
techniques prohibited the commercial exploitation.
4.2.1. Nutrient composition of aquatic macrophytes
Aquatic macrophytes have high water content in general, which is usually a major
deterrent to their harvest and utilization. According to Boyd (1968a) the water content
of 12 submerged species varied from 84.2 to 94.8%, and 19 emergent species from 76.1
to 89.7%. The water content of floating macrophytes varied from 89.3 to 96.1% (Little
and Henson, 1967). Higher crude protein values have been reported for duckweed as
high as 42.6% and the blue green alga Spirulina, 60 to 70% (Ruskin, 1975). There are
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considerable intraspecific variations in crude protein content due to both seasonality and
environment. Boyd (1969) determined the crude protein content of water hyacinth,
water lettuce, and Hydrilla from a wide variety of environmental conditions, and there
were only slight differences in the mean crude protein of these three species. The crude
protein content of Typha latifolia from different sites varied from 4.0 to 11.9% (Boyd,
1970a) that of water hyacinth grown on a stabilization pond was 14.8% compared to
11.3% samples from a lake (Bagnall et al., 1974b). There is evidence that the crude
protein content increases as the nutrient content of the water in which the plant grown
increases. According to Wolverton and McDonald (1979a), the crude protein content of
water hyacinth leaves grown on waste water lagoons averaged 32.9% dry weight, which
is comparable to the protein content of soybean and cotton seed meal. Although the total
protein content of aquatic macrophytes differs greatly, the amino acid composition of
many species is relatively constant, nutritionally balanced and similar to many forage
crops (Boyd, 1969, 1970; Taylor and James, 1966).
The concentrations of inorganic elements in most species of aquatic macrophytes fall
within the range or values for crop plants (Boyd, 1974). However, there may be
considerable interspecific differences in certain minerals (Boyd, 1970a; Linn, 1975a)
and also considerable intraspecific differences in plants harvested at different seasons
and from different localities. The low palatability of aquatic macrophytes to livestock
has been attributed to high mineral content.
4.2.2. Aquatic macrophytes as livestock fodder
Several species of aquatic macrophytes are used as livestock fodder (Table 4.1).
However, due to their high moisture content, animals cannot usually consume enough
fresh plant matter to maintain their body weight. Aquatic macrophytes must be at least
partially dehydrated to serve as fodder, but with many species there is also a palatability
problem, which restricts the amount of material consumed. The production of dry feed
from aquatic macrophytes is not economically feasible because the cost of harvesting,
transporting and processing plant matter with such high moisture content is too high
relative to the quality of the feed produced. The utilization of aquatic macrophytes as
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fodder is probably feasible only on a small scale using simple methods of dehydration,
Small amounts of aquatic macrophytes may be used in livestock diets on a regular basis,
but large amounts should only be used in times of conventional fodder shortages.
Table 4.1 Common plants used as fodder to livestock
Name of Species Animals fed Country References Spirulina platensis Poultry India Seshadri, 1979 Azolla pinnata Pigs and ducks Vietnam, Thailand
and China Moore,1969;Cook et a1., 1974; Hauck, 1978
Salvinia Pigs and ducks Indo-China Moore, 1969 Pistia stratiotes Pig, cattle, and
duck food Malaysia,
Singapore and China
Varshney and Singh, 1976 Hauck, 1978
Typha sp and Nymphaea stellata
Pig and duck India Varshney and Singh,1976
Hydrilla Pig and duck - Varshney and Singh, 1976
Alternanthera philoxeroides
Cattle China Alford,1952 Hauck, 1978
Sagittaria sp Pigs - Cook et al., 1974 Coix aquatica, Paspalidium geminatum, Panicum geminatum, Leersia hexandra
Cattle India Subramanyan,1962
Ipomoea aquatica Pigs and cattle - Ruskin and Shipley, 1976
Eichhornia Cattle Bangladesh, India Sahai and Sinha, l970, Hora, 1951
4.2.3. Fresh and dehydrated material as fodder
Aquatic macrophytes compare favorably on a dry weight basis with conventional
forages (Boyd, 1974), but to use them efficiently as animal fodder, they should be
partially dehydrated, since typically aquatic weeds contain only about 5 to 15% dry
matter compared to 10 to 30% of terrestrial forages (Ruskin and Shipley, 1976).
Because of the high moisture content, animals cannot consume enough to maintain their
body weight. Attempts have been made to feed fresh water hyacinth to animals, since
cattle and buffalo have been observed to eat it. Animals in India fed only with fresh
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water hyacinth and straw showed a steady weight loss, indicating that the diet was not
even sufficient for maintenance of body weight. When the diet was supplemented with
linseed cab which is rich in minerals then, there was a slight weight gain. Chatterjee and
Hye (1938) concluded from their study that a moderate use of fresh water hyacinth as
fodder is possible provided it is fed in combination with other feeds.
4.3. MATERIALS AND METHODS
4.3.1. Experimental methods
Limnocharis flava seedlings (average height 5-10 cm in size) were collected from five
different sites, around 100 km radius of Kottayam district, Kerala. In order to examine
whether there exists any variation in the chemical composition of natural stand the
samples were collected from different locations of Kuttanad wetland ecosystem (Table
4.2). These seedlings were grown in separate pots labeled clearly with the name of the
location.
Table 4.2 Details of the locations from where the samples were collected.
Sl.
no
Sample
Location
Longitude Latitude Soil
type
Topogra
phy
Locality
1 Pennukara 76o36’28.99’’ 9o18’4.09’’ Clayey Slopping Ala
2 Thazhakara 76o33’49.87’’ 9o15’5.44’’ Lateritic Plain Thazhakara
3 Vellor 76o27’16.01’’ 9o49’16.9’’ Clayey Slopping Vellor
4 Chenganur 76o36’5.11’’ 9o18’56.4’’ Clayey Plain Chenganur
5 Nattakom 76o30’35.3’’ 9o32’35.4’’ Lateritic Plain Nattakom
The seedlings were grown in pots (35 cm height and 30 cm diameter) filled with the soil
brought from their respective sites (Plate X and XI). Sufficient replicates (5 seedlings
from each location) were raised. The holes of the pots were sealed and the plants were
watered every day. The pot culture study was conducted in a green house in the
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Environment Sciences Department. The plants were harvested from the pots at different
stages of their growth ie. at pre- flowering, flowering and post flowering period.
4.3.2. Analytical methods
The plants were harvested at different growth stages were brought to the laboratory and
washed liberally with water to remove attached coarse sediment. They were then
washed with 50g/L of EDTA (Ethylene Diamine Tetra Acetic acid) solution followed
by deionised water to remove mud particles adsorbed on the plant surface (Abbasi et al.,
1988). After draining off the water, the plants were spread on a filter paper and air dried
for 30 minutes. After air drying, the plants excluding the root portion were chopped
manually using a knife to pieces and dried in an oven to constant weight at 70oC to
determine the dry matter (DM) content. The samples were ground well and passed
through a 1mm screen and stored for later analyses. The samples were analyzed for ash
content, acid soluble ash, crude protein, crude fibre, nitrogen free extract (NFE), ether
extract (EE), phosphorous, potassium and calcium following standard procedures
described in AOAC, 1990. Flame photometer (Systronics make, Model-128) was used
for sodium and potassium estimation. The trace elements like iron, copper, manganese,
zinc, cadmium, lead, chromium and nickel were determined using Varian AA Spectra
20 Atomic Absorption Spectrophotometer at the appropriate wavelengths. The gross
energy of the plant was calculated using the formula 0.0226 CP + 0.0407 EE +
0.0192CF + 0.0177NFE (MJ kg-1 DM), Where CP, EE, CF and NFE are crude protein,
ether extract, crude fiber and nitrogen free extract respectively (Fergus, 2003).
4.3.3. Statistical Analysis
Variability of the chemical composition, nutritive value of forage harvested at three
stages of growth were analyzed by one way analysis of variance (ANOVA) (Gomez and
Gomez, 1984) to test effects of growth stages.
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4.4. RESULTS AND DISCUSSION
The study was done to evaluate the nutritional characteristics of L. flava and also to
determine the changes in the chemical composition, nutritive value and trace element
profiles of the plant during its different growth stages. The results of proximate analysis
of L. flava at its three morphological stages of growth are given in Table 4.3. The
moisture content, ash content, acid soluble ash content and the gross energy values
increased slightly during flowering stage, while crude protein, nitrogen free extract
(NFE), dry matter (DM) and ether extract (EE) decreased. The ash content was
significantly higher at the post flowering stage than the other two stages (P<0.05).
The mean values of selected inorganic nutrients (dry wt basis) in L. flava at its three
stages of growth are presented in Table 4.4. There are only slight differences in mean
calcium and phosphorous values at the three stages of growth. The potassium and
sodium concentrations at the pre- flowering and flowering stages differ significantly
while there is no significant difference in calcium and phosphorous concentrations at the
three stages of growth (P<0.05). The inorganic nutrient composition of L. flava at the
three morphological stages of growth are given in Figures 4.1 and 4.2. The trace metal
composition of L. flava on its life stages are presented in Table 4.5. It is observed that
except nickel and cadmium an increase in the concentration of all trace metals studied
was recorded at the different growth stages. The increase was found to be significant
with all metals except nickel and cadmium (P<0.05).
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Table 4.3 Chemical Composition and Nutritive value (%) of Limnocharis flava at
three stages of growth.
Analyses Pre-flowering
Flowering
Post-flowering
Moisture content 87.0 0.01a 90.0 0.01a 92.0 0.01a
Dry matter 13.0 0.02a 10.0 0.01a 8.0 0.01a
Ash content 7.80 0.54a 9.20 1.05a 9.68 0.36b
Acid Soluble ash 0.60 0.07a 0.80 0.05a 0.90 0.07a
Crude protein 13.90 0.4a 14.20 0.51a 11.44 0.76a
Crude fibre 5.30 0.58a 7.60 0.51a 7.94 0.5a
Nitrogen free extract 65.40 0.79a 72.84 0.44a 69.4 0.49a
Ether Extract 6.70 0.48a 7.53 0.44a 6.88 0.52a
Gross energy
(MJ kg-1 DM)
3.01 4.83 4.479
All values are mean of 5 samples S.D. Within a row, the values with different letters differ significantly (P<0.05)
Table 4.4 Selected inorganic nutrient composition (%) in Limnocharis flava at three stages of growth.
Mineral content
Pre-flowering
Flowering
Post-flowering
Calcium 4.80.04a 5.620.44a 5.760.42a
Phosphorous 0.660.03a 0.760.04a 0.790.05a
Potassium 0.480.05a 1.200.36b 1.290.46b
Sodium 0.020.01a 0.030.004b 0.0480.004b
All values are in percentage (%) All values are mean of 5 samples S.D. Within a row, the values with different letters differ significantly (P<0.05)
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Table 4.5 Trace metal composition of Limnocharis flava at three stages of growth
Trace metals Pre-flowering
Flowering
Post-flowering
Iron 19010.025a 19800.013a 22300.011b
Copper 20.00002a 230.00002a 250.00008b
Manganese 710.00001a 760.00003a 800.00004b
Zinc 0.20.00002a 0.40.00001a 0.70.00001b
Lead 0.0090.0007a 0.0120.0013a 0.00170.0017b
Chromium 0.070.0003a 0.080.0001a 0.080.0004a
Nickel ND ND ND
Cadmium ND ND ND
All values are in g/kg. All values are mean of 5 samples S.D. Within a row, the values with different letters differ significantly (P<0.05) ND-Non Detectable
In the present study, the chemical composition, the nutritive value and the trace element
profiles of the weed, L. flava at three morphological stages of growth was analyzed and
determined. The crude protein, ash content, ether extract, crude fiber and nitrogen free
extract contents on its flowering stage resemble that of other common aquatic plants
(Table 4.6). Boyd (1969) states that protein content declines rapidly with maturity. So
harvesting the plant for fodder should be done during a growth stage at which the plant
possesses maximum protein content. The analytical result of this study agrees with
Boyd’s observation. Accordingly, the highest value of crude protein, crude fiber,
nitrogen free extract and ether extract were obtained at the flowering stage. Therefore,
the harvesting of the plant for feed at the flowering stage is the most recommended.
A similar study on the chemical composition, nutritive value, fatty acid and amino acid
contents of Galega officianalis during its growth stages reveals that the moisture
content and crude fibre increased during maturation, while the crude protein, dry matter,
gross energy, NFE and EE found decreased with increasing stages of growth (Peiretti
and Gai, 2006).
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Boyd (1969) found that the crude protein levels in Pistia stratiotes and Hydrilla
verticillata was 0.78% and 1.37% respectively. The crude protein concentration of
L. flava was appreciably higher than that of most other common aquatic weeds of
Kerala (Table 4.6). The crude fibre content of L. flava was comparable to the studies by
Alfrod, 1952 and Linn, 1975a on Alternanthera philoxeroides and Chara vulgaris.
Studies conducted by Kalitha et al. (2007) with common aquatic plants like, Salvinia
cucullata, Trapa natans , Lemna minor and Ipomoea reptans have shown that the CP
content ranged from 11 to 32.2%. Similar comparison with Eichhornia show a protein
content varying from 7.4 to 42.6%. The mean crude protein level of L. flava was as high
as values reported for many high quality forages. Comparing the chemical composition
of L. flava with other common tropical feed stuffs, it has been observed that the plant
has rather similar or high values than the other common feeds for most of the
parameters studied (Table 4.7).
The calcium, phosphorous and potassium content during its mature stage was 5.76%,
0.79% and 1.29% respectively (Table 4.4) are equal to or above the nutritional
requirement for finishing cattle (National Academy of Sciences, 1976). Comparing the
mineral requirements of lactating dairy cattle (Table 4.8) with that of the mineral
content of L. flava, the calcium, phosphorous and potassium concentrations are found to
be higher than values prescribed for lactating cattle (National Academy of Sciences,
1976).
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Table 4.6 Results of Proximate Analysis of some common aquatic weeds.
Plant CP
%
Ash
%
EE
%
CF
%
NFE
%
References
Eichhornia crassipes 5.70 0.62 0.40 2.90 64.20 Muktar, 1967
Alternanthera
philoxeroides
6.40 12.0 0.80 7.50 60.80 Alfrod, 1952
Pistia stratiotes 0.78 2.00 0.30 --- --- Boyd, 1969
Hydrilla verticillata 1.37 3.20 0.27 --- --- Boyd, 1969
Lemna minor 17.86 1.61 2.19 11.82 66.52 Linn, 1975
Ceratophyllum
demersum
17.00 2.18 1.51 15.2 64.11 Linn , 1975
Chara vulgaris 7.92 5.62 0.12 7.65 77.56 Linn 1975a
Typha angustifolia 6.92 0.93 0.98 27.32 53.46 Linn , 1975a
Potamageton
pectinatus
14.05 3.22 0.09 15.64 67.00 Little and Henson, 1967
Limnocharis flava 14.20 9.20
7.53 7.60 72.84 Present study
CP-Crude protein; EE-Ether Extract; CF-Crude Fiber; NFE-Nitrogen Free Extract
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Table 4.7 Chemical Composition (% of dry matter) in some common tropical feeds.
DM
(%)
CP
(%)
Ash
(%)
Crude
fibre (%)
References
Chopped whole Sugarcane 23.7 2.5 2.3 41.1 Van and
Ledin,2001
Rice straw 89.4 3.88 4.9 ---- Keir et al.,1997
Flemingia macrophylla 28.5 18.3 5.4 52 Van et al.,2005
Jackfruit foliages 32.8 14.8 10.6 50.6 Van and
Ledin,2001
Acacia mangium 31.6 16.2
4.6 49.8 Van et al., 2005
Cassava hay 28.5 15.6 9.8 --- Keir et al., 1997.
Rubber seed cake 12.5 14.8 5.9 34.7 Hao and
Ledin,1999
Ground nut cake 88.1 3.02 1.3 26.2 Hao and
Ledin,1999
Limnocharis flava 10.0 14.20 9.20 7.60 Present study
DM-Dry Matter; CP-Crude Protein
Table 4 .8 Comparison of the mineral content of L .flava with the recommended mineral requirements for lactating cattle. Mineral
Constituent
Recommended
Mineral requirements
Present study
(L .flava)
Calcium 0.43-0.77% 5.76%
Phosphorous 0.28-0.49% 0.79%
Potassium 0.90-1.00% 1.29%
Sodium 0.18% 0.048%
Iron 50ppm 2.23ppm
Copper 0.10ppm 0.025ppm
Manganese 40ppm 0.08ppm
Zinc 40-60ppm 0.007ppm
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Ca post f low eringCa flow eringCa preflow ering
6.5
6.0
5.5
5.0
4.5
4.0
Na post f low eringNa flow eringNa pre f low ering
.05
.04
.03
.02
.01
0.00
3
Fig. 4.1 Change in calcium and sodium concentrations of Limnocharis flava harvested
at three stages of growth (1) Preflowering (2) Flowering (3) Post flowering. The mean is
Concentration (%)
Concentration (%)
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indicated by the horizontal line, the heavy vertical line represents one standard
deviation and the light vertical line indicates the range; Ca-Calcium, Na-Sodium.
K post flow eringK f low ering
K pref low eringP post flow ering
P f low eringP pref low ering
2.5
2.0
1.5
1.0
.5
0.0
Fig. 4.2 Change in potassium and phosphorous concentrations of Limnocharis flava
harvested at three stages of growth (1) Preflowering (2) Flowering (3) Post flowering.
The mean is indicated by the horizontal line, the heavy vertical line represents one
standard deviation and the light vertical line indicates the range; P-Phosphorous, K-
Potassium
Concentration (%)
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4.4.1 Conclusion
In this study, the possibility of utilizing Limnocharis flava as an unconventional feed to
livestock was examined. Based on the proximate and chemical analysis done, the plant
species appeared to be a potential food for domestic livestock. It produces mono
specific stands which cover large areas. Therefore, methods of utilization would lead to
a utilization based weed management strategy.
The moisture content, organic matter (OM), acid detergent fibre content increased
during maturation, while CP, DM and EE were found decreasing with increase in
growth stage. Only slight fluctuations in calcium, potassium, phosphorous and sodium
contents were noticed at the three stages of growth. The highest values for crude
protein, fibre content, NFE, EE and gross energy were observed at the flowering stage.
This plant posses several characteristics which makes it a nutritious feed suitable for
domestic livestock, particularly at the flowering stage of growth. Analysis of the
dehydrated samples indicate that the plant contain rather large amounts of crude protein,
crude fibre and ether extract and had satisfactory level of micro-minerals like iron,
copper, manganese and zinc. More over the concentrations of macro-minerals like
calcium, potassium and phosphorous is very high and rather higher than the
requirements for lactating cattle.
Even though the analytical results indicate L. flava as a promising plant for the
production of animal feed, further testing on palatability, digestibility, feed trials etc.
can only confirm the suitability of this plant for animal fodder. Besides, the ability of
this plant to accumulate heavy metals from the habitat as evidenced from Chapter -II of
this study cautions its utility as animal fodder. There are several reports that L. flava is
fed to cattle and pigs (Cook et al., 1974; Ruskin and Shipley, 1976), in this regard a
more detailed study on the heavy metal content of this plant is very essential. It is much
safer to collect the plants from unpolluted or less polluted fresh water bodies and use
them as animal fodder. The plants from contaminated sites need to be avoided in the
context of animal fodder.