Mushrooms are widespread in nature and they remained the earliest form of fungi known to mankind. In Nigeria, many people in both urban and rural areas are familiar with mushroom growing around them some of which they exploit for food and medicine. This practice although reported all-over the country is more pronounced amongst the Yoruba speaking people.
Concomitant varieties of mushrooms i.e. lichenized, mycorrhizal, parasitic and saprotrophic that abound in Nigeria have continued to gain recognition and elicit different interests and questions as potentially resourceful tool in economic modulation pari passu prevailing reliance on leafy plants. It is saddening to see that people from all works of life associate mushrooms with negative events in Nigeria and most African countries.
This image, in addition to the slow development of mushroom cultivation practices is changing due to reports elsewhere in the world that illuminate the potentials of mushroom and mushroom products and their uses in different spheres of human welfare. This is apart from their hitherto pivotal roles in sustaining eco-energy balance in nature.
In Africa, mushroom resource exploration and exploitation is fraught with
- lack of infrastructure and technical supports from national and international agencies
- scarcity of mushroom scientists
- poor political and legislative support
- poor knowledge of mushroom biodiversity due to dearth of mushroom taxonomists
- bad press reports
- Widespread misconceptions about mushrooms.
- Lack of awareness of the importance of mushroom as sources of healthy nutrients and pharmacological compounds.
- Low consumption/marketing, due to its higher price in comparison with the wild type.
- Limited availability of quality spawns.
- Lack of interest by the government.
- Lack of the state of the art for identification and assessing the medicinal and other properties of mushroom.
- Short shelf life of mushrooms due to the warm tropical climate.
- Poor attitude of policy makers towards mushroom technology.
These problems among others are old and currently an underrepresentation of Nigerian mushroom’s diversity, composition and uses. African nations are seldom listed among the largest producers and exporters of edible mushrooms and mushroom products.
Mushrooms have become a multi-billion dollar industry and the demand is increasing sharply due to modern consumers seeking health-added benefits to their food. Worldwide production of cultivated mushrooms is estimated at 5 million tons. The leading countries are China, the US, the Netherlands and France. In Africa, mushroom farming for either the local or external markets is in most countries at its infancy. It is only South Africa, Zimbabwe and Kenya that have been reported to produce mushrooms at commercial scale.
A good number of mushrooms have been reported to be consumed by different tribal groups in Nigeria. People depending on their tribe slightly differ in the array of mushrooms consumed and reasons for their consumption. The Yoruba tribes however recorded the highest number of edible and medicinal mushrooms compared to the Hausa tribes. The reason for this trend is not fully understood but it is believed to be connected to the relatively few accounts of edible, medicinal and cultivable mushrooms in existing literature.
Factors may have contributed to the scarcity of mushroom information on the Hausas includes but limited to:
- The arid nature of the North occasioned by desert encroachment
- scarcity of mushroom biologists and mushroom interest
- availability of alternative sources of protein
Many culturally varied mycophagists are ignorant of the nutritional values of edible mushrooms but consume them based on their organoleptic property such as aroma, taste, flavour, and texture . Other reasons reported for mycophagy in Nigeria are subsumed in their local names e.g. Volvariella volvacea (Bull.) Singer is referred to by the Yoruba people as “ogiri agbe” meaning farmer’s spice while Lentinus sp is called “Ero atakata” by the Igbo speaking people, a name derived from its tough texture.
Studies on the nutritional values of edible and medicinal mushrooms ranked them with dairy, plant and animal food in vitamins, protein and mineral contents. This has however failed to neither improve mycophagy culture in urban cities in Nigeria nor promote the commercial productions of mushrooms. The most popular edible mushroom in Nigeria is the sclerotium-forming Pleurotus tuberregium (Fr.) Singer which is eaten as food and/or used as food supplement . The mushroom is used as a good substitute for meat protein in several suburban Nigerian soups by locals. Its popularity as food in many rural villages especially in the south zone of the country is ascribed to its substrate propensity, rapid growth, fruit-body longevity, incidences and distribution pattern. Other edible mushrooms consumed in Nigeria include Agaricus spp., Auricularia auricular Judae (Bull.) Quél., Collybia butyracea (Bull.) P. Kumm., Coprinus atramentarius (Bull.) Fr., Coprinus picaceus (Bull.) Gray, Lactarius trivialis Fr., Lentinus squarrosulus Mont., Pleurotus pulmonarius(Fr.) Quél., Pleurotus ostreatus Jacq., Macrolepiota sp., Psathyrella atroumbonata Pegler, Schizophyllum commune Fr., Termitomyces clypeatus Heim., Termitomyces globules Heim & Gooss, Termitomyces mammiformis Heim., Termitomyces microcarpus (Berk. & Br.) Heim, Termitomyces robustus (Beeli.) Heim, Tricholoma sp., Volvariella volvacea (Bull.) Singer and Volvariella esculenta (Mass.) Singer. Amanita mushrooms which were labeled poisonous in many parts of the world have been reported in Nigeria by Zoberi (1973) and elsewhere in Africa (Morris, 1990) to have species that are consumed as food. In the same vein, Chlorophyllum molybditis also featured amongst edible mushrooms analyzed for their nutrient contents in Nigerian and considered safe for consumption . The edibility of Amanita and Chlorophyllum species earlier reported as poisonous elsewhere in the world by Nigerians is not totally understood but it is believed that the controversy may stem from any one or combination of factors relating to environment, genetic and physiological differences which were determinants of tolerance level to toxins amongst racially, geographically and traditional varied people.
- The method of preparation of these mushrooms,
- insufficient expert taxonomist
- poor identification method coupled with the use of mono-graphic/ taxonomic books on western mushroom names for naming indigenous African macro-fungi may also have been responsible for this contention .
Regular and professional myco-systematic molecular-based approach coupled with frequent revised documentations of mushroom-forming fungi may resolve further the confusions associated with edible and poisonous mushrooms.
In Nigeria, a great quantity and variety of edible and medicinal mushrooms are sourced from the wild due to undeveloped mushroom farming culture. This practice of mushroom scouting/hunting existed for decades spanning generations and mostly embarked upon by children and women.
About twenty-five edible mushroom species of good repute whose knowledge were handed down generational lines through oral communication have been identified in Nigeria. Edible mushrooms collected from various farmlands, forests and plantations can be sold or cooked fresh, after treatment with warm salt water, with the addition of essential ingredients like pulped pepper, tomatoes, onions, salt and oil or smoked and/or sun-dried for later use.
The reliance on naturally growing edible mushrooms has greatly undermined the development of mushroom cultivation to a commercial scale despite available substrate materials in some African nations. Some of the substrate materials of diverse origin tested in the artificial cultivation of mushrooms in Nigeria are outlined in the table below.
|Rice straw/husk||Rice farms||Pleurotus ostreatus Jacq.,
P. tuberregium (Fr.)
volvacea (Bull.) Singer.
|Wheat straw/bran||Wheat farms||Lentinus squarrosulus (Mont.), P. tuberregium (Fr.)Singer.|
|Corn straw, bracts and cobs||Corn farms, roasted and boiled corn retailers, palp (locally called ogi or akamu) maker.||P. tuberregium (Fr.) Singer, Psathyrella atroumbonata Pegler.|
|Cassava peelings||Cassava mills/suburbs||P. pulmonarius (Fr.) Quél.|
peelings and pseudo-stems
|Farms, roasted plantain retailers||P. tuberregium (Fr.) Singer|
|Cocoa pod||Farms, local cocoa processing industries||P. ostreatus Jacq.|
|Coconut fruit fibre||Farms, industries||Lentinus subnudus Berk, P. tuberregium (Fr.) Singer, V. volvacea (Bull.) Singer.|
|Cotton wastes||Textile mills||P. pulmonarius (Fr.) Quél|
|Sawdust||Saw mills||Psathrella atroumbonata Pegler, P. tuberregium (Fr.) Singer.|
|Oil palm fruit fibre
|Oil palm mills||P. pulmonarius (Fr.) Quél, Psathrella atroumbonata Pegler.|
|Waste papers||Paper mills, printing factory, surrounding.||P. tuberregium (Fr.) Singer.|
Some substrates used for cultivation of edible and medicinal mushrooms in Nigeria.
Despite the fact that about 20% of the world’s population was reported to be starving, African nations are still lacking amongst the mushroom exporting nations of the world. Tapping into the benefits of commercial mushroom production in Nigeria will reduce the country’s unemployment rate, increase her food security and revenue base while bridging her rural-urban migration gap. The number of cultivable edible mushrooms worldwide amounts to over a hundred with an annual production of over 4.5 million tons and still increasing.
The provision of safe sustainable access to edible and medicinal mushrooms in Nigeria can be achieved in a number of ways which may include
(i) promoting opportunities for co-operation between all stakeholders- such as the mushroom farmers, researchers/mycologists, politicians and other mushroom prospectors (marketer, NGOs and government agencies on agriculture, youths and women etc.) in the country;
(ii) through the creation of public enlightenment initiatives – via talk shows on the positive potentials of mushrooms and mushroom products in radio and television programs, monthly newsletter, seminars and workshops. This will remove the negative publicity associated with mushrooms, increase market sources of edible mushrooms, limit the dangers associated with mushroom hunting from the wild and improve awareness on both the nutrient quality and benefits of mushroom consumption;
(iii) by developing a model that allows for spawn availability to farmers and steady flow and/or exchange of proprietary culture (mother cultures and pure-lines).
(iv) Cross fertilization of cultivation technologies between developing and industrial nations,
(v) Creation of recognized indigenous mushroom growers association.
(vi) The establishment of sustainable regional mushroom germplasm banks and research centers to maintain mushroom genetic stability.
(vii) Quality control of mushroom culture collections and spawn.
(viii) Preservation of cultures of extant and extinct myco-resources can also enhance the overall uses of mushrooms in the country.
One cannot but add that the elevation of mushrooms to a cash-crop status in Nigeria requires improved
- political will and
- solid infrastructural setting (steady electricity, flowing water, buildings etc.)
These will have unprecedented impact on the development of the country’s mushroom industries in providing food, drugs and chemicals. It will equally offer opportunity for conservation strategies and preservation of mushrooms that will add value to medicine, pharmacy, industries and agriculture.
Despite the high level of progress made through the Global Network on Mushroom Research and Development under the aegis of F.A.O and the advancement of mushroom cultivation industries in many developed nations, growing mushrooms in homes or even on a commercial scale is still uncommon in Nigeria.
Researchers are therefore challenged to:
- reduce dependence on naturally occurring mushrooms,
- eliminate the incidences of mushroom poisoning and
- expand the nation’s edible and medicinal mushroom base.
Many indigenous edible mushrooms heritage and knowledge may have escaped recognition and documentation and/or completely lost over the years. Although, few works of researchers offer a long-term study on the ethnomycological, taxonomic and myco-diversity profile of indigenous mushroom resources on a national scale will form the inertia for mushroom prospecting initiatives and successful exploitation in developmental economic issues in Nigeria.
Traditionally, mushrooms are used for nutritional, medicinal and economic benefits in Nigeria. It isacknowledged that the uses of mushroom genetic resources are not only of high interest in agronomy, agriculture, human food and animal feed but also for the discovery, production and development of molecules or components with high added value in industries such as chemical and pharmaceutical industries.
A model that shows the interaction between maximal utilization of mushroom resources that yields economic benefits and their exploration is attempted in Fig. 1. This emphasized the relative significance of field study and effective documentations as the bedrock for efficient mushroom exploitation. The nutrients and toxicological profile of edible wild mushrooms in Nigeria have been studied.
There is however dearth of information on the anti-oxidant property of edible and medicinal mushrooms indigenous to Nigeria. The level of mushroom nutriceuticals on a global scale confirmed that mushrooms are good health food and reports abound in Nigeria on their use for the treatment of malnutrition in infants, diabetes, obesity or hyperlipidemea, sterility, anemia, mumps, fever and protein deficiency.
Mushrooms can also be used in improving the digestibility in ruminant animals. Recently, Ganoderma species have been successfully tested in poultry farming for the improvement of egg-laying and disease resistant capacity of birds in Nigeria.
Although the locals and other folk medicine practitioners demonstrated deep knowledge of the medicinal use of mushrooms, they are however ignorant of the active principle(s) responsible for the remedy observed. This inherited knowledge has been a source of wealth and reference for practitioners.
Prolific discoveries of value added products e.g. ergot, cordycepin, cyclosporine, griseoflvin and other antitumour, antiviral, immuno-modulator, hormonal and antimicrobial products used in medicine and/or pharmacopeias elsewhere in the world are however challenging.
Furthermore, the 2009, 2nd African Conference on Edible and Medicinal Mushrooms revealed that Beta-glucan based dietary supplements of mushroom origin are effective for the treatment of Buruli ulcer caused by Mycobacterium ulcerans in Ghana while Ganoderma lucidum Tested in separate study for the treatment of Eimeria tenella infected broiler chickens in Nigeria. Documentations of their uses in the treatment of both human and animal ailments and/or on the production of drugs (molecules) in Nigeria are scanty.
Many of the heresy and mythological records implicated indigenous Nigerian mushrooms in the preparation of different charms (talismans or voodoo) by traditional worshippers (personal communication). They are also symbolically used and given out to adversaries as form of warnings by the Igbo speaking people of Nigeria while the Yorubas used selected mushrooms with psychoactive and hallucinogenic effects for idol worshipping and spiritualism.
The presence of Schizophyllum or Daldinia species on dead decaying woods posit quality-burning trait or tinder by fire-wood gatherers in Nigeria. A few elders of the Edo/Delta region confirmed that Ganoderma species when brewed is good for improving libido and vitality in adults.
The 2nd African Conference on Edible and Medicinal Mushrooms in Ghana, March 24-28, 2009, also revealed that Cordyceps and Ganoderma were being tried for treatment of alcoholism in Asia. A recent study on the ethnomycological uses of macrofungi in Edo State, South-South of Nigeri observed that Pycnoporus cinnabarinus (Fr.) was used as hair-dye and lipstick by the maidens of Okomu.
The potentials inherent in diverse mushroom around the globe are therefore infinite even amongst Nigerian’s mushroom. Nigeria by virtue of its vantage tropical location is one of the world’s potential hotspots for various forms of biological resources including mushroom. This position is also derived from the diversity of vegetation i.e. savannah, rainforests, riparian forests and mangroves that characterized Nigeria. Currently, the exploitation of indigenous Nigerian mycoresources is still overshadowed by the preponderance of green plants.
Vigorous researches on these easily-overlooked forest members might evolve an accidental source of drugs that would resolve the world’s cancer, AIDS and leukemia problems. The poor knowledge and documentation of mushroom uses in healthcare delivery coupled with the lack of up-to-date, inventory on mushroom taxa in Nigeria impairs government efforts at developing complimentary (folk) medicine practices to the level witnessed in China and other Asian countries.
One of the strongest technical points recently advancing mushroom production in Nigerian besides improving food options is the conversion of ordinarily valueless or toxic wastes of diverse origin to value added products via a permaculture system. Nigeria by virtue of her population size generate several tons of agricultural, industrial, municipal and domestic wastes that overwhelms the nation’s waste disposal machinery and are potentially degradable by mushrooms. These wastes are tried as substrates or solid-waste substrate supplements and/or ingredients for compost in mushroom cultivation.
Mushroom are gaining global popularity in both liquid fermentation of industrial effluents and many lignocellulosic wastes such as waste papers, banana and plantain leaves, and/or peelings, sawdust of different tree origin, oil palm fruit fibres, bunches and cakes. There are huge potential socio-economic benefits associated with the effective and efficient bioconversion of agro-industrial wastes to valued edible mushrooms.
The growth of mushroom production industries and the use of agro-industrial based substrate as the major raw material may provide a partial solution to the nation’s waste management problems and pollution challenges, poverty and rising youth unemployment. The potential use of spent substrates in crop farming as soil conditioner and/or mycorrhization practices have also been strongly emphasized. Mycorrhization by spore has been successfully adopted in Congo and South Africa in Pinus agroforestry with Pisolithus tinctorius. Documented account in forest and/or agroforest management in Nigeria is dearth despite high incidence of mycorrhiza mushrooms . To fully tap into the verse mycorrization potentials of mushrooms, it is significant to improve the nation’s knowledge of mushroom diversity and mushroom status of many indigenous Nigerian trees via further studies.
Spent substrates derived from a few small-scale mushroom cultivation farms across the country also have been poorly exploited as sources of single-cell protein, animal feeds, organic manure, soil amendments/conditioner and biofuel in Nigeria as observed in some developed nations of the world.
This is attributed to undeveloped mushroom production, accessible alternatives such as fertile lands, manure from animal dung and chemical fertilizer, annual national output of used composts and substrates coupled with a lack of technical knowledge on sustainable re-use of spent substrates in the country.
Human activities have been reported to impact negatively on arable lands contaminating them with pesticides, petroleum hydrocarbons, heavy metals and waste engine oil pollutants, and consequently causing arable land shortage and other environmental challenges. A survey of land use practice in Nigeria revealed that bush fallowing is more popular in addressing the problems of contaminated (polluted) and/or low-yield agricultural lands. This practice allows for the slow process of natural restoration or remediation. Other strategies reportedly used in recovering contaminated farmlands are capital and labour intensive and this include excavation followed by incineration and/or secured land-filling.
These methods currentlyundermine bioremediation posed varying degree of environmental problems to humans. Therefore, the replacement of bush-fallow system with bioremediation in rehabilitating polluted arable land is slowly being embraced as a faster, cheaper and more environment friendly method in Nigeria.
Mushrooms through the evolution of specialized feeding habit or saprotrophism along with other plant resources have been tested in this regards. P. tuberregium and P. pulmonarius were the most widely used mushrooms in bioremediation studies in the country.
. There is however no documentation on the use of indigenous Nigerian mushrooms biopulping and delignification process. Some resarchers has also implicated mushrooms in cassava processing. The ex situ application of mushrooms in tackling various oil-spill and heavy metal contamination challenges in Nigeria is uncommon due to failure of field trials of laboratory results,
The uses of mushroom in Nigerian agricultural practices is still undefined in the areas of pest and disease control despite reports that Cordiceps, Gibellula, Beauveria bassiana, Leptinortarsa decenliniata, Pseudogibellula are entomogenous . Some wood-decaying fungi occurring in Nigeria e.g. Pleurotus, Schizophyllum and Hohenbuehelaria are nematophagous – utilize the nutrient in nematodes to supplement the low level of accessible Nitrogen in their wood substrate.
Few achievements have been recorded using different species of Nigerian mushrooms as antagonist of other harmful pathogens of bot plants and animals. Data on mushrooms do not yet compare to those of plant genetic resources around the globe.
Although, Nigeria actively contributed to the global plan of action on the state of the world’s plant genetic resources, it is still ranked low amongst the few nations of Africa yet to place national ex situ collections under the auspices of the F.A.O and develop their own gene bank. The reason for this may be political or attributed to lack of technical knowledge and assistance in the areas of sampling, identifying and preserving mushrooms.
Indigenous Nigerian mushrooms are limited to food and folk medicinal uses as well as for income through their sales in village markets. This may have been the reason why conservatively speaking, only roughly less than 20% of the potentials inherent in Nigerian mushroom genetic resources have been tapped.
A well established and sustainable national mushroom culture/germplasm bank will
- Improve accessibility to strains that can add value to the growth of industries, economy, medicines, pharmacy, environment and agriculture .
- Encourage mushroom researches and explorations for human benefits.
Nigerian mycologists are therefore challenged to collaborate with mycological herbaria and international agencies such as the United Nation and Food and Agricultural Organization for educational, scientific and technical support in the areas of training mushroom scientists and improving food security. This is primordial to solving national problems associated with hunger, poverty, economic development, diseases and unemployment using mushroom-forming fungi as veritable tool.