Moringa oleifera

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General information

Moringa oleifera Lam. or 'horse-radish' tree (so-called because of the taste of a condiment prepared from the roots) or 'drumstick' tree (arising from the shape of the pods), or ‘never-die-tree’ is a multipurpose tree that thrives in both tropical and sub-tropical conditions. It is native to the sub-Himalayan regions of north-west India. This tree is now indigenous to many countries in Africa, Arabia, South East Asia, the Pacific and Caribbean Islands and South America, producing flowers and fruits continuously. Originally considered a tree of hot, semi-arid regions with annual rainfall 250 - 1500 mm, it has also been found to be well adapted to hot, humid, wet conditions with annual rainfall in excess of 3000 mm. Moringa can grow in a variety of soil conditions, from well drained sandy or loamy soils (which the plants prefer) to heavier clay soils. The tree is reported to be tolerant of light frosts and can be established in slightly alkaline soils up to pH 9. Currently, the young leaves and pods are used as vegetables, the oil extracted from kernels for culinary and industrial purposes, the water extract of the kernels as a water purifying agent, the seed cake as fertiliser, and various parts of the tree in traditional medicine (Foidl et al., 2001).

The tree is fast growing and high yielding (an estimated 3.0 t seed / ha compared to average yields of sunflower and groundnut of 2.0 and 0.5 t / ha respectively). It can also be planted for forage production under intensive farming conditions. Initial trials in Nicaragua have shown a high biomass production of up to 120 tons dry matter / ha / yr, in eight cuttings after planting 1 million seeds / ha (Makkar and Becker, 1999a). The plant starts bearing pods 6 - 8 months after planting but regular bearing commences after the second year. The tree bears for 30 - 40 years. The drought tolerant nature of the tree makes it particularly suited to those marginal areas where the costs associated with the cultivation and harvesting of other commercial crops are high.

Nutrient composition

The seed kernel contains, on average, 40 per cent by weight of oil, the fatty acid composition of which is similar to that of olive oil and could be used for both culinary and industrial purposes. The seed oil contains 9.3 per cent palmitic, 7.4 per cent stearic, 8.6 per cent behenic, and 65.7 per cent oleic acids among the fatty acids. Myristic and lignoceric acids have also been reported.

In addition to high macronutrient content (Table 3), moringa leaves and pods are also rich in vitamins and minerals. Leaves (100g) contain 440 mg Ca, 70 mg P, 7 mg Fe, 110 mg Cu, 5.1 mg I, 11,300 IU pro-vitamin A, 120 mg vitamin B, 0.8 mg nicotinic acid, 220 mg ascorbic acid, and 7.4 mg tocopherol per 100 g. Per 100 g, the pod is reported to contain 30 mg Ca, 110 mg P, 5.3 mg Fe, 184 IU pro-vitamin A, 0.2 mg niacin, and 120 mg ascorbic acid, 310 mg Cu, 1.8 mg I.

The high true protein content of leaves (23 per cent in DM, Makkar and Becker, 1997c), the high proportion of this protein potentially available in the intestine (Makkar and Becker, 1997c), the presence of adequate levels of essential amino acids (higher than the levels present in the FAO reference protein), and low levels of antinutrients indicate their high nutritional quality. The high pepsin soluble nitrogen (82 - 91 per cent) and the low acid detergent insoluble protein (1 - 2 per cent) values for the meal suggest that most of the protein in the meal is available to most animals (Makkar and Becker, 1997c). The meal is deficient in lysine, leucine, phenylalanine + tyrosine and threonine when compared to the standard FAO protein but the contents of sulphur-containing amino acids in these samples are much higher (see Table 10).

Antinutrients

Moringa leaves are free from antinutrients except for saponins and phenols (Table 4). The concentration of phenol is much below the toxic threshold levels for animals (Makkar and Becker, 1997c) and saponins were inactive as far as haemolytic properties are concerned. In addition to the antinutrients listed in Table 4, alkaloids are also present in kernel meals (root-bark have been found to have two alkaloids, moringine and moringinine; moringinine is known to stimulate cardiac activity, raise blood-pressure, act on sympathetic nerve-endings as well as smooth muscles all over the body, and depress the sympathetic motor fibres of vessels in large doses only.

Glucosinolates, lectins and alkaloids which form the major antinutrient substances in Moringa seed meal could be easily removed by water extraction (Makkar and Becker, 1999a). However, this method has the disadvantage of also removing some soluble nutrients. Solid state fermentation of the seed meal using Rhizopus oligosporus sp. could be considered as this mould has been found to degrade glucosinolates in defatted rapeseed meal (Bau et al., 1994).

Fish feeding trials

There are no studies so far which report utilisation of Moringa leaves or seed meal as fish feed ingredients. Preliminary results from a trial in our lab, where Moringa leaf meal was used in Tilapia nilotica feeds, indicate growth-reducing effects at high levels of inclusion of raw leaf meal. Moringa plant parts have the potential to be a supplier of macro and micronutrients in a fish feed derived from a mixture of plant products.