Leucaena as a Protein Source

 A. J. Oakes and May Ritz Oakes
 Research Agronomist, USDA (Retired)
 Christiansted, St. Croix, U.S.V.I.


 The ubiquitous weedy form of Leucaena leucocephala
(Lam.) de Wit is capable of producing 1,000-2,000 kg/ha/yr
of good quality protein. Its production capacity responds to
elevation, rainfall, and soil type in addition to imposed
management practices. The cultivars 'El Salvador' and 'Peru'
produce 1,000-4,000 kg/ha/yr under similar treatments. Leu-
caena protein is high in nutritional quality. Amino acids are
present in well-balanced proportions. Information from
tropical and subtropical regions is sparse as to location and ex-
tent it is used as human food. Leaves, flowers, fruiting pods
and seeds at various stages of maturity are consumed either


cooked or uncooked. Various plant parts are eaten separately
or as components in salads or soups. Highly proteinaceous
foods such as "botok," "toge," and "tempeh lamtoro" are
made from leucaena. Leucaena is of limited value as a food
source in widely scattered regions of the tropics and sub-
tropics. Despite the known detrimental effects of leucaena, its
consumption as food probably exceeds that which is recorded
in the literature. Leucaena is unsurpassed as a renewable
source of high quality protein for food and feed.
Keywords: Leucaena leucocephala (Lam.) de Wit; Protein pro-
duction; Protein quality; Food; Feed.


 Leucaena provides a renewable and sustaining source of protein
for both mankind and his livestock. Multifarious uses are made of
leucaena which include a source of energy, food, feed, fuel, and
biomass. This paper addresses some aspects concerning the pro-
tein production potential of leucaena and its use as a protein
source both for human food and livestock feed. First, in view of
the nature and purpose of this meeting the production of protein
by leucaena and its use as food will be considered. At the same
time we must not neglect its use in livestock feed. Most of the leu-
caena literature concerns the production and utilization of the
crop as a source of feed and protein for livestock.


Protein Production
 Leucaena leucocephala (Lam.) de Wit is the best known and
most widespread in distribution of the ten leucaena species
recognized by Brewbaker (1978). The so-called ubiquitous,
weedy form of L. leucocephala known as the "Hawaiian ecotype"
has been evaluated and utilized as a forage crop more extensively
than other leucaena species or other lines ofL. leucocephala large-
ly because of its widespread distribution and availability. Other
lines of L. leucocephala and leucaena species have entered forage
evaluation trials in recent decades, however. The Hawaiian
ecotype has come to be known as the line by which all others are
compared in yield trials.
 Highly variable protein yields of L. leucocephala are reported
from different locations throughout the tropics and subtropics.
The Hawaiian ecotype, for example, produced only 454 kg/ha/yr
in Australia (Hutton and Bonner, 1960). Yields of 3,136 and
3,584 kg/ha/yr are also reported for this same ecotype when
grown in Australia (Anon., 1969; Hills, 1963). The cultivar 'Peru'
produced 2,464 and 3,603 kg/ha/yr in Queensland, Australia
(Hutton and Bonner, 1960) whereas the cultivar 'El Salvador' pro-
duced 1,915 kg/ha/yr (Hutton and Bonner, 1960). The yield of
an Australian line, C.P.I. 18228, was 1,479 kg/ha/yr (Hutton
and Bonner, 1960). The Hawaiian line ranged from 932 to 4,264
kg/ha/yr in a 58-inch rainfall belt in Colombia (Herrara, 1967).
 When the Hawaiian line was grown at different elevations in
Hawaii, the yields ranged from 550 to 3,233 kg/ha/yr (Gueverra
et al., 1975; Takahashi and Ripperton, 1949; Takahashi et al.,
1943). When the Hawaiian line and the cultivar 'El Salvador'
were grown at 110 m elevation in Hawaii, protein yields were 550


232


and 460 kg/ha/yr respectively (Gueverra et al., 1975). Takahashi
and Ripperton (1949) reported three-year yields of the Hawaiian

ecotype to be 3,233 kg/ha/yr when grown at a lower elevation.
Brewbaker et al., (1972) evaluated the yield potential of 104 leu-
caena lines, including the Hawaiian ecotype as the control, in
Hawaii. Yields of most lines in these trials exceeded those of the
Hawaiian type. Average yield of the top three lines (K8, K29,
K67) was 4,838 kg/ha/yr or about threefold that of K63, the
Hawaiian ecotype control. Yields of 2,352 to 3,080 kg/ha/yr are
reported from other Hawaiian trials involving the Hawaiian
ecotype (Takahashi et al., 1943).
 The Hawaiian ecotype produced 1,904 kg/ha/yr when grown
in a 60-inch rainfall belt in Mauritius, and 3,024 kg/ha/yr in In-
dia (Savur, 1953).
 Mendoza et al., (1976) report protein yields of 3,346 to 3,733
kg/ha/yr for the cultivar 'Peru' from the Philippines.
 A two-year mean yield of 2,511 kg/ha/yr of the Hawaiian line
is reported from Taiwan (Luh et al., 1961). Slick and Harris
(1971) obtained 672 kg/ha/yr from the Hawaiian line grown in
south Texas.
 Here in the Virgin Islands, the socalled weedy form produced
1,671 kg/ha/yr in one field trial (Oakes and Skov, 1962) and a
five-year average of 2,005 kg/ha/yr in a second trial (Oakes and
Skov, 1967). These trials were conducted on Fredensborg clay,
capable of producing 89,000-90,000 kg/ha/yr of sugarcane. The
trials were unfertilized and conducted in a 40-inch rainfall belt.
Experimental plantings of eight lines ofL. leucocephala produced
1,477 to 2,856 kg/ha/yr. The cultivars 'El Salvador' and 'Peru',
which produced 2,589 and 2,119 kg/ha/yr respectively, were
among the four lines which were superior in yield. All yields
reported from the Virgin Islands are from cutting trials.
 In summary, the lowest reported protein yields of the
Hawaiian ecotype of L. leucocephala are those from Queensland,
Australia and Texas, which are 454 and 672 kg/ha/yr respective-
ly. The highest is that of 4,838 kg/ha/yr of top-yielding lines in
Hawaii. Other yields from Australia, Colombia, Hawaii, India,
Mauritius, Philippines and the Virgin Islands are intermediate
between these extremes. All available yield data indicate that the
ubiquitous weedy form ofL. leucocephala is capable of producing
1,000-2,000 kg/ha/yr of good quality protein. The cultivar 'Peru'
is capable of producing 1,000-4,000 kg/ha/yr, as is the cultivar
'El Salvador.'

 PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY-VOL. XX