Pigs require large amounts
of energy and protein for fast growth and efficient feed utilization (NRC
1998). In most tropical countries grains for animal feed are scarce and cannot
be spared for feeding to pigs or the prices are prohibitive. However, the
tropical areas of the world can provide many high-energy yielding crops for
feeding pigs with evident advantage over conventional crops from temperate
countries (Gohl 1981; Perez 1997). These crops include sugar cane, oil palm,
water spinach and rice products. Nevertheless, protein is the most expensive
ingredient of pig diets, perhaps due to the fact that protein source
availability is not so evident. In this connection, very successful reports
have been made related to studies conducted with tropical, locally available
protein sources for pigs.
Amongst potential tropical
sources of protein, water spinach has not been extensively studied in pig
nutrition. In
There are two common types
of water spinach: one that grows on land and one that grows in water. The two
types bear different flowers and leaves. Land-grown water spinach has long,
narrow leaves with pointed ends and bears white flowers. The succulent foliage
and stem tips are light green in colour. To obtain
seeds, harvesting of the plants is stopped to allow developing flowers to
mature, from which seed bearing pods form. Two main cultivar groups can be
distinguished: var. aquatica and var. reptans. The
first is an aquatic plant or paddy vegetable in the Southern part of
It was known as a tropical
aquatic plant found in marshy or wet sandy areas, or floating on the water. At
every node it produces a member of adventitious roots, and along the edges of
low lands the roots exert much binding effect on soil. This characteristic has
given it the name “bind-weed”. It has 3 main cultivars: Red Green, Light Green
and Red Stem, in which Red Green is the most common type in the tropics (Tiwari and Chandra 1985). Water spinach is a member of the
family Convolvulaceae, and it is commonly used
as a green vegetable in
Tropical vegetables can be
grown in a range of soil types from sandy soils to heavy textured clay loams,
but friable well-drained soils high in organic matter are preferred. The ideal
pH range is 5.5 to 7.0 (NRE 2000). The best pH ranges for vegetable crops are
from pH 6.0 to 7.0. Many garden soils are low in organic matter because they
contain less than 5% organic matter. Soils that contain more than 20-28% clay
(clay loams) and are low in organic matter tend to be hard when dry and sticky
when wet. Soils high in organic matter are mellow (plant roots can penetrate
easily) and absorb water more readily than soils low in organic matter (Panas and Lindgren 1996).
Water spinach is a very popular
vegetable and grows prolifically throughout
Marshy lands, waterlogged soils
of ponds, tanks and ditches including those of the
According to Nguyen Nhuy Xuan Dung (1996), in
Practically all parts of
the young plant tissue of water spinach are edible although the shoot tips and
younger leaves are preferred. Coarse stems and leaves are often used for animal
feeding and water spinach can be fed to animals or eaten raw.
It has been claimed that water
spinach can contain up to 29% crude protein in the DM and has a lower fibre
content than alfalfa leaves (27.3 %) as referred by Thacker (1990). The trace
mineral content of fresh water spinach (mg/kg) was: Zn 5.03, Mn 22.2, Cu 1.37 and Fe 75.3 (NIAH 1995).
The feeding value of water
spinach for pigs has been studied in
The utilization of fibre in
animal monogastric species such as pigs is very important, due to the fact that
digestion of fibre may highly influence performance traits of economic
importance (Siers 1975; Frank et al 1983). In this
connection, structural carbohydrates or fibre utilization in growing pigs
largely depend on the level of fibre fed, source of fibre, stage of forage
maturity, and levels of other nutrients in the diet (Farrell and Johnson 1973;
Close 1993). Feeding diets with a high fiber content
will increase the time needed to consume the daily allowances (Morz et al 1986). The addition of fiber might also be
involved in inducing satiety through increasing gut distension.
According to Fernandez and
Jorgensen (1986), Dierick et al (1989), Bach Knudsen
and Jorgensen (2001), 94-99% of all carbohydrates are digested by the time they
reach the terminal ileum in pigs. However, digestion of hemicellulose and
cellulose up to the terminal ileum is very limited (Keys and DeBarthe 1974), and the amount of carbohydrates and other
nutrients transferred from the small intestine into the large intestine is
highly dependent on diet composition. Digestibility of lignin by the large
intestinal microbes is very limited, and lignin is not degraded in noticeable
amounts (Fernandez and Jorgensen 1986; Dierick et al
1989).
The utilization of fiber in
growing pig depends on the level of fiber fed, source of fiber, stage of forage
maturity, and level of other nutrients in the diet (Farrell and Johnston 1973).
Most fiber digestion occurs in the caecum and large
intestine of pigs and is a microbial fermentation process. Volatile fatty acids
from fiber fermentation serve as an energy source for pigs and can provide from
5% to 28% of the energy requirements of the growing pig (Friend et al 1963;
Farrell and Johnson 1973).
Pigs require about twenty amino
acids. Some of these, which cannot be synthesized by the animal or are
synthesized at an insufficient rate to meet its requirement, are called
essential amino acids. For optimum performance, a diet must provide adequate
amount of essential amino acids, energy and other indispensable nutrients.
Protein requirement may be stated in term of the “ideal protein” (McDonald et al 1995).
The pig’s requirement for total protein are usually determined in feeding trials
in which growth rate is the main criterion of adequacy, and are stated as the
concentration of protein in the diet. The pig has specific requirements for ten
essential amino acids, and the ratio of amino acids to lysine is particularly
important. NRC (1998) and NIAH (1995) recommend ratios of methionine + cysteine to lysine of 50%, and of threonine
to lysine of 60% (Tables 1 and 2).
In pig diets, protein
quality is often limited by a deficiency of one or two of the indispensable
amino acids. If total protein standards are accompanied with standards for
these amino acids they become more meaningful. The concepts of “limiting” amino
acids refer to the most deficient amino acids, and for the pigs it is likely to
be lysine (McDonald 1995). Protein requirements of growing pigs depend on many
factors, such as breed, age and growth rate.
Studies of production and carcass traits of some pig breeds which are raised in Cambodia, showed that the exotic breeds (Yorkshire or Landrace or their crosses) have a higher genetic potential in growth rate, as well as higher lean ratios than local breeds (Hainam, Kondol and Kampot) and F1 crossbreeds between local and exotic pigs. For that reason, protein requirement of F1 pigs as recommended by NIAH (1995) is lower than of exotic breeds recommended by NRC (1998).
|
Table 1. Requirements of protein and amino acid (% in DM) for growing pigs at different live weights (NRC 1998) |
|||
|
|
10 – 20 kg |
20 – 50 kg |
> 50 kg |
|
Crude protein |
18 |
15 |
13 |
|
Lysine |
0.95 |
0.75 |
0.60 |
|
Methionine+cystine |
0.48 |
0.41 |
0.32 |
|
Threonine |
0.56 |
0.48 |
0.40 |
|
Table 2. Requirements of protein and amino acids (% in diet DM) for growing F1 pigs (NIAH 1995) |
|||
|
|
15 – 30 kg |
30 – 50 kg |
> 50 kg |
|
Crude protein |
16 |
14.5 |
12 |
|
Lysine (%) |
0.90 |
0.70 |
0.60 |
|
Methionine + cystine |
0.45 |
0.35 |
0.30 |
Water spinach is traditionally
grown and used by farmers in
Making better use of locally
available feed resources such as water spinach may be an approach to the
problem of alleviation of the scarcity of locally available protein sources for
pig production in the tropics especially in
From the reports studied in this
literature review, it can be concluded that fiber content is an important
factor determining organic matter digestibility in different forages. In
addition, the availability of protein, and
specifically the amino acid profile is affected by forage fiber components,
resulting in differences in live weight gain and nitrogen retention.
The pig species can utilize to a certain
extent the dietary structural carbohydrates. However, the conversion of
tropical, fibrous sources of protein into valuable products such as meat, remains to be fully studied.
References
APH
2001 Annual
report of Animal production and Health in
Bui Huy Nhu
Phuc 2000 Tropical Forages for Growing pigs. Digestion and Nutritive value.
Doctoral thesis. Swedish University of Agricultural Sciences, Department of
Animal Utrition and Management,Uppsala.
Bruemmer, J.H.
and Roe, B. 1979 Protein extraction from water spinach (Ipomoea
aquatic). Proc. Fla Stat. Hortic. Soc. 92:140-143.
Bach Knudsen K E and Jorgensen H 2001 Intestinal degradation of dietary
carbohydrates from birth to maturity. In: Digestive Physiology of Pigs (J E
Lindberg and B O Ogle, editors). CABI Publishing.
Close W H 1993 Fibrous diets for pigs. In: Animal production in Developing Countries. (M
Gill, E Owen, G E Pollot and T L J Lawrence, editors)
British Society of Animal production Occasional Publication No 16 p 107-116
Dierick NA, Vervaeke I J, Demeyer DI and Decuypere J A 1989 An approach to the
energetic importance of fibre digetion in pits. I. Importance of
fermentation in the overall energy supply. Animal Feed Science and Technology
23:141-167
Fernandez J A and Jorgensen N 1986 Digestibility and absorption of nutrients as
affected by fiber content in the diet of the pig. Quantitative
aspects. Livestock Production Science 15:53-71
Friend D.W.
H.M. Cunningham and J.W.G. Nicholson 1963 In Swine nutrition. Eds.
Miller, E.R., Ullrey, D.E. and Lewis, A.J.
Butterworth- Heinemann. 1991, p 289.
Frank G R, Aherne F X and Jensen A H 1983 A study of relationships between performance and dietary component
digestibilities by swine fed different levels of dietary fiber. Journal of
Animal Science 57:645-654
Farrell D.J.
and K.A. Johnson 1973 In swine Nutrition. Eds. Miller, E.R., Ullrey,
D.E. and Lewis, A.J. Butterworth- Heinemann. 1991, p289.
Gohl B 1981 Tropical Feeds: Feed Information Summaries and Nutritive Values. FAO Animal Production and Health Series No 12.
Jain, S.K.,
Gujral, G.S. and Vasudevan, P. 1987 Potential utilization of
water spinach (Ipomoea aquatic). J. Scient. Ind. Res. 46:77-78.
Keys Jr J E and DeBarthe J V 1974 Cellulose and hemicellulose digestibility in the
stomach, small intestine and large intestine of swine.
Journal of Animal Science 39:53-57
Kean Sophea and
Preston T R 2001 Comparison of biodigester effluent and urea as
fertilizer for water spinach vegetable. Livestock Research for Rural
Development (13) 6: http://www.cipav.org.co/lrrd/lrrd13/6/Kean136.htm
Lich, L.B., and Tuyen, D.K., 2001 Livestock production development in the Northern
Provinces of Vietnan. Unpublished (www.vcn.vnn.vn).
Le Thi Men 1999 Evaluation of water spinach
(Ipomoea aquatica) fro Baxuyen and Large White
sows and fattening crossbred pigs. M.Sc. Thesis.
Swedish University of Agricultural Sciences, Department of Animal Utrition and
Management,Uppsala.
Morz Z.,
Partridge, I.G., Mitchell, G. & Keal, H.D. 1986 In forages for growing
pigs.
McDonald, P.,
Edwards, R.A., Greenhalgh, J.F.D and Morgan, C.A. 1995
Ninh Thi Len 2001 Evaluation of chicken
manure and cassava residue as feed for fattening F1 pigs under village
conditions in
NRC 1998 Nutrient requirements of swine.
NRE 1996 Water convolvulus or water spinach (Ipomoea
aquatica) Asian vegetables Newletter. Issue No. 9, October 1996
(English Edition)
NRE 2000 Asian vegetable. Agricultural notes, Notes
Series No AG0633 Farm Diversification Information Service.
Nguyen Nhut Xuan Dung 1996 Identification and
evaluation of indigenous plants for livestock and humans in the Mekong Delta
region in
National
Panas E J and Lingren D T 1996 A gardener’s guide for soil and nutrient management
in growing Vegetables, NebGuide, University of
Nebraska-Lincoln. http://www.island.wsu.edu/crops/watercon.htm
Peter,
R.E.,
Perez R 1997. Feeding pigs in the tropics. FAO Animal Production and
Health Paper No. 132.
Palada M C and Crossman S M A 1999 Evaluation of Tropical leaf
vegetables in the
Prak Kea, T R Preston and J
Ly 2003 Studies of the
influence of graded levels of palm oil on nutrient digestibility in young pigs
fed diets based on water spinach and broken rice. Master in Science Thesis.
Mekarn Program of the Swedish University of Agricultural Sciences
Rubatzky V 1991 Water convolvulus, Chinese Water Spinach, Swamp Cabbage,
Kang Kong.
http://www.island.wsu.edu/CROPS/watercon.htm
Siers D G 1975 Chromic oxide determined
coefficients and their relationship to rate of gain and feed efficiency in
individually fed
Tiwari, N.C and Chandra, V. 1985 Water spinach its varieties
and cultivation. National Botanical Research Institute. Indian
Horticulture.
Thacker P A 1990 Alfalfa meal. In: Nontraditional Feed
Sources for Use in Swine Production (P A Thacker and R
N Kirkwood, editors) Butterworths,