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Bambara groundnut (Vigna subterranea) seeds


Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 

Bambara bean, bambara groundnut, congo goober, ground bean, hog-peanut, Congo groundnut, earth pea, njugo bean, Congo earth pea, kaffir pea, Madagascar groundnut, stone groundnut [English]; pois bambara, pois de terre, voandzou [French]; bambarra, guandsú, guisante de tierra, maní de bambarra [Spanish], jinguba de cagambe [Portuguese]; gongongu, gorosgoros, biriji daɓɓi, biriji damuɗi, ngalaa-wu/ji, ngalgalaa-wu/ji [Fulfulde]; Bambara-Erdnuss [German]; Kacang bogor [Indonesian]; mnjugu-mawe [Swahili]; لوبياء مطمورة [Arabic]; バンバラマメ [Japanese]


Glycine subterranea L., Voandzeia subterranea (L.) Thouars ex DC. (USDA, 2009)


The bambara groundnut (Vigna subterranea (L.) Verdc.) is an annual, creeping legume with glabrous, trifoliate leaves. It has a deep taproot surrounded by lateral profuse roots bearing N-fixing nodules. Flowers are presented as papilionaceous racemes. Once fertilized, the flower is drawn below the soil through a tunnel. Fruits are 2 or 3-seeded pods, 1.5 to 3 cm long, wrinkled and at first indehiscent. Seeds are round, smooth and very hard when dry (Ecoport, 2009). Average yields are 300-800 kg/ha, but can range from 100 kg/ha up to 4 t/ha.

Vigna subterranea grows well where groundnut does not (Brink et al., 2006). It is cultivated primarily for its seeds, which are used as human food. In Africa, it is the third most commonly eaten legume after groundnut and cowpea (Omoikhoje, 2008). The seeds are used in many types of foods, some of which are an important part of human diets. Mature, dry seeds are boiled and eaten as a pulse. Seeds can be milled to make flour. Ripe seeds are very hard and must be cooked for longer than those of other legumes. Cream-coloured seeds are often preferred to red and black seeds, because they are less bitter and take less time to cook. Large seeds are preferred to smaller ones, especially for use as a snack. Smaller seeds are ground into flour for use in various recipes.

The processing of Vigna subterranea results in by-products (shells of offals) that can be fed to animals. Seeds can also be fed to animals if surplus to human requirements. The leafy shoots are used as fodder (Brink et al., 2006).


Vigna subterranea originates from West Africa (Nigeria, Cameroon, Central African Republic and Chad) and is cultivated in drier tropical Africa. In Southern Africa, Zimbabwe is the centre of production. It can also be found in tropical parts of America, Asia and Australia but the present degree of cultivation outside Africa is basically negligible.

Vigna subterranea is adapted to hot, dry, marginal soils, from sea level to an altitude of 2000 m. It continues to grow in harsh conditions better than most crops (sorghum, maize and peanuts). Optimal conditions for growth are 30-35°C day-temperature for germination, average day temperatures ranging from 20 to 28°C under full sun, average annual rainfall of 600-750 mm (optimum yields are obtained when rainfall is higher), good P and K soil content and light sandy loams with a pH of 5.0-6.5. Vigna subterranea can grow in more humid conditions (annual rainfall > 2000 mm), and in every type of soil provided it is well drained and not too calcareous. It is tolerant to drought, to pests and diseases, particularly in hot conditions. In many traditional cropping systems it is intercropped with other root and tuber crops (Brink et al., 2006).

Environmental impact 

Like other legume plants, Vigna subterranea is a good soil fertilizer and a good rotation crop. It does not require any additional fertilizer. It is generally intercropped with cereals (maize, sorghum, and pearl millet), other pulses (cowpea, groundnut), root and tuber crops, or vegetables.

Nutritional aspects
Nutritional attributes 

Because of their relatively high protein content, Vigna subterranea seeds are a potentially valuable protein source for all classes of livestock. However, it has been recommended to use the shells and other by-products to feed animals and to use the seeds as food so that people can benefit from their protein and energy during the dry season. The essential amino acid profile of the seeds is comparable to that of soybean (Omoikhoje, 2008; Fetuga et al., 1975).

Potential constraints 

Like most legume seeds, Vigna subterranea seeds contain antinutritional factors such as trypsin inhibitors, phytates and tannins, including condensed tannins in the seed coat. Tannin content is correlated with coat colour, the cream-coloured seeds containing less tannin than brown or black seeds. Tannins can be deleterious to livestock performance though they have beneficial nutritional properties in some cases (by-pass protein in ruminants, anthelmintic effect).

Vigna subterranea seeds are reported to have higher antitryptic activity than soybean and the level of activity depends on the variety (landrace) (Tibe et al., 2007). Heat treatments such as boiling or roasting are usually effective in destroying trypsin inhibitors.

Phytates are found in high proportions in Vigna subterranea seeds and are known to reduce cation availability (Ca particularly) (Nwanna et al., 2005).

Cooking and other forms of processing (e.g. soaking, milling, hulling, germination, fermentation) reduce the concentration of antinutritional factors. However, processing does not always increase the feeding value (Nwanna et al., 2005; Oloyede et al., 2007).


Vigna subterranea seeds can be included in ruminant diets as an alternative cheap source of protein, energy and minerals (Belewu et al., 2008).


Feeding broilers and adult cockerels with raw Vigna subterranea seeds gave lower feed intake, live weight gain and feed conversion ratio compared to soybean meal, as those parameters are negatively correlated with trypsin inhibitors (Akanji et al., 2007; Oloyede et al., 2007). Boiling or roasting was effective in removing those antinutritional factors and it was possible to include treated seeds up to 30% in broiler diets (Bello et al., 2005). Still, heat-processed seeds compared unfavourably with soybean meal (lower protein quality and lower metabolizable energy) (Oloyede et al., 2007; Nji et al., 2003). They gave lower results than meat meal in starter diets but had greater effect than meat meal during the finishing stage (Teguia et al., 2005). Vigna subterranea seeds had a higher feeding value than groundnut cake and was more economically beneficial (Nwanna et al., 2005).


In Nigeria, the possibility of including toasted bambara groundnut seeds in growing rabbit feeds was tested by incorporating graded levels up to 35% in complete diets. A non significant positive influence of the graded level of bambara groundnut seed meal was observed on the rabbit daily weight gain, feed efficiency, dressing percentage and meat-to-bone ratio. The best results were obtained with the 25% level. Rabbits carcass cut-up parts as well as internal organs (liver, heart, kidneys and lungs) were not influenced by the dietary levels of bambara groundnut meal (Joseph et al., 2000).

The necessity of toasting the seeds before utilisation in rabbit feeding was not demonstrated, and may be questionable because the antitrypsin factor, the main limiting factor present in many legume seeds such as soybean seeds, was proved to be thermo-resistant in bambara groundnut seeds (Benjakul et al., 2000). In addition, good growth performances were obtained with rabbits fed on raw (non-toasted) bambara groundnut wastes (Ani, 2007).


Nile tilapia (Oreochromis niloticus)

Nile tilapia can be fed with Vigna subterranea seeds in combination with protein sources containing higher levels of limiting amino acids (Ogunji et al., 2003).

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 86.8 3.4 83.0 89.7 3  
Crude protein % DM 19.8 3.1 16.7 23.4 4  
Crude fibre % DM 10.8 5.6 3.4 17.0 4  
NDF % DM 24.2       1  
ADF % DM 16.0   14.0 18.0 2  
Lignin % DM 3.2       1  
Ether extract % DM 5.6 0.9 4.6 6.4 3  
Ash % DM 4.4   3.8 5.1 2  
Starch (polarimetry) % DM 41.2       1  
Gross energy MJ/kg DM 19.4         *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 1.4       1  
Phosphorus g/kg DM 2.6       1  
Potassium g/kg DM 14.6       1  
Magnesium g/kg DM 1.9       1  
Amino acids Unit Avg SD Min Max Nb  
Alanine % protein 4.4       1  
Arginine % protein 6.8       1  
Aspartic acid % protein 11.0       1  
Cystine % protein 1.5       1  
Glutamic acid % protein 16.9       1  
Glycine % protein 3.7       1  
Histidine % protein 3.1       1  
Isoleucine % protein 4.1       1  
Leucine % protein 7.6       1  
Lysine % protein 6.7       1  
Methionine % protein 1.3       1  
Phenylalanine % protein 5.5       1  
Serine % protein 4.7       1  
Threonine % protein 3.5       1  
Tryptophan % protein 1.2       1  
Tyrosine % protein 3.4       1  
Valine % protein 4.9       1  
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins, condensed (eq. catechin) g/kg DM 0.0       1  
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, Ruminant % 90.6         *
Energy digestibility, ruminants % 89.0         *
DE ruminants MJ/kg DM 17.2         *
ME ruminants MJ/kg DM 14.0         *
Pig nutritive values Unit Avg SD Min Max Nb  
Energy digestibility, growing pig % 73.1         *
DE growing pig MJ/kg DM 14.2         *
NE growing pig MJ/kg DM 9.9         *

The asterisk * indicates that the average value was obtained by an equation.


AFZ, 2011; Belewu et al., 2008; CIRAD, 1991; Ologhobo, 1992

Last updated on 26/02/2013 15:13:38

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 91.8 3.3 85.7 97.7 12
Crude protein % DM 20.6 2.4 15.7 24.9 16
Crude fibre % DM 5.2 1.8 2.0 8.8 14
NDF % DM 7.8 1
ADF % DM 3.6 1
Lignin % DM 0.3 1
Ether extract % DM 6.3 1.2 3.2 7.5 15
Ash % DM 4.1 0.9 3.1 5.7 14
Starch (polarimetry) % DM 49.1 48.1 50.1 2
Gross energy MJ/kg DM 19.4 0.5 18.1 19.4 3 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 0.5 0.2 0.1 0.8 9
Phosphorus g/kg DM 3.5 2.0 2.0 8.4 9
Potassium g/kg DM 11.7 1.9 8.8 13.0 4
Magnesium g/kg DM 2.1 0.9 1.4 3.7 5
Manganese mg/kg DM 13 10 15 2
Zinc mg/kg DM 33 28 38 2
Copper mg/kg DM 14 12 16 2
Iron mg/kg DM 34 27 42 2
Amino acids Unit Avg SD Min Max Nb
Alanine % protein 4.2 0.5 3.6 4.5 3
Arginine % protein 6.2 2.0 4.2 8.1 3
Aspartic acid % protein 12.4 1
Cystine % protein 0.8 0.5 0.4 1.4 3
Glutamic acid % protein 14.0 3.4 11.1 17.7 3
Glycine % protein 3.7 3.7 3.8 2
Histidine % protein 3.9 0.3 3.7 4.2 3
Isoleucine % protein 3.3 0.6 2.8 4.0 3
Leucine % protein 7.2 0.5 6.6 7.6 3
Lysine % protein 6.2 1.6 4.3 7.7 4
Methionine % protein 0.8 0.6 0.4 1.4 3
Phenylalanine % protein 4.4 0.9 3.7 5.4 3
Proline % protein 3.7 1
Serine % protein 4.0 2.2 5.8 2
Threonine % protein 4.5 4.1 5.0 2
Tryptophan % protein 1.2 1
Tyrosine % protein 2.9 2.6 3.2 2
Valine % protein 3.8 0.8 3.0 4.6 3
Secondary metabolites Unit Avg SD Min Max Nb
Tannins (eq. tannic acid) g/kg DM 2.3 0.7 4.0 2
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 92.3 *
Energy digestibility, ruminants % 90.6 *
DE ruminants MJ/kg DM 17.6 *
ME ruminants MJ/kg DM 14.4 *
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 81.9 *
DE growing pig MJ/kg DM 15.9 *
NE growing pig MJ/kg DM 11.5 *
Poultry nutritive values Unit Avg SD Min Max Nb
AMEn broiler MJ/kg DM 10.5 8.5 12.5 2

The asterisk * indicates that the average value was obtained by an equation.


AFZ, 2011; Aganga et al., 2000; Akanji et al., 2007; CIRAD, 1991; Nwokolo, 1987; Ogunji et al., 2003; Oloyede et al., 2007; Oluyemi et al., 1976; Omoikhoje, 2008; Owusu-Domfeh et al., 1970; Yagoub et al., 2007; Yusuf et al., 2008

Last updated on 24/10/2012 00:43:14

Datasheet citation 

Heuzé V., Tran G., Lebas F., 2016. Bambara groundnut (Vigna subterranea) seeds. Feedipedia, a programme by INRAE, CIRAD, AFZ and FAO. https://feedipedia.org/node/530 Last updated on July 29, 2016, 10:07

English correction by Tim Smith (Animal Science consultant) and Hélène Thiollet (AFZ)