Chapter-IV Studies on the use of Limnocharis flava as feed to livestock

Transcription

1 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

2 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

3 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

4 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 preflowering, flowering and post flowering 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 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

5 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 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

6 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 Malaysia, duck food Singapore and Varshney and Singh, 1976 Hauck, 1978 China Typha sp and Pig and duck India Varshney and Nymphaea stellata Singh,1976 Hydrilla Pig and duck - Varshney and Singh, 1976 Alternanthera Cattle China Alford,1952 Hauck, philoxeroides 1978 Sagittaria sp Pigs - Cook et al., 1974 Coix aquatica, Cattle India Subramanyan,1962 Paspalidium geminatum, Panicum geminatum, Leersia hexandra Ipomoea aquatica Pigs and cattle - Ruskin and Shipley, 1976 Eichhornia Cattle Bangladesh, India Sahai and Sinha, l970, Hora, 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

7 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 MATERIALS AND METHODS 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. Sample Longitude Latitude Soil Topogra Locality no Location type phy 1 Pennukara 76 o o Clayey Slopping Ala 2 Thazhakara 76 o o Lateritic Plain Thazhakara 3 Vellor 76 o o Clayey Slopping Vellor 4 Chenganur 76 o o Clayey Plain Chenganur 5 Nattakom 76 o o 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

8 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 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 70 o C 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, 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 CP EE CF NFE (MJ kg- 1 DM), Where CP, EE, CF and NFE are crude protein, ether extract, crude fiber and nitrogen free extract respectively (Fergus, 2003) 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

9

10 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)

11 Table 4.3 Chemical Composition and Nutritive value (%) of Limnocharis flava at three stages of growth. Analyses Pre-flowering Flowering Post-flowering Moisture content a a a Dry matter a a a Ash content a a b Acid Soluble ash a a a Crude protein a a a Crude fibre a a a Nitrogen free extract a a a Ether Extract a a a Gross energy (MJ kg- 1 DM) 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 a a a Phosphorous a a a Potassium a b b Sodium a b b 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)

12 Table 4.5 Trace metal composition of Limnocharis flava at three stages of growth Trace metals Pre-flowering Flowering Post-flowering Iron a a b Copper a a b Manganese a a b Zinc a a b Lead a a b Chromium a a a 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)

13 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)

14 Table 4.6 Results of Proximate Analysis of some common aquatic weeds. Plant CP Ash EE CF NFE References % % % % % Eichhornia crassipes Muktar, 1967 Alternanthera Alfrod, 1952 philoxeroides Pistia stratiotes Boyd, 1969 Hydrilla verticillata Boyd, 1969 Lemna minor Linn, 1975 Ceratophyllum demersum Linn, 1975 Chara vulgaris Linn 1975a Typha angustifolia Linn, 1975a Potamageton pectinatus Little and Henson, 1967 Limnocharis flava Present study CP-Crude protein; EE-Ether Extract; CF-Crude Fiber; NFE-Nitrogen Free Extract

15 Table 4.7 Chemical Composition (% of dry matter) in some common tropical feeds. DM CP Ash Crude References (%) (%) (%) fibre (%) Chopped whole Sugarcane Van and Ledin,2001 Rice straw Keir et al.,1997 Flemingia macrophylla Van et al.,2005 Jackfruit foliages Van and Ledin,2001 Acacia mangium Van et al., 2005 Cassava hay Keir et al., Rubber seed cake Hao and Ledin,1999 Ground nut cake Hao and Ledin,1999 Limnocharis flava 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 % 5.76% Phosphorous % 0.79% Potassium % 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

16 Concentration (%) Ca preflow ering Ca flow ering Ca post flow ering Concentration (%) Na pre flow ering Na flow ering Na post flow ering 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

17 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. Concentration (%) P preflow ering P post flow ering K flow ering P flow ering K preflow ering K post flow ering 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

18 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