Pattern of Lathyrus sativus (grass pea) consumption and beta-N-oxalyl-α-β-diaminoproprionic acid (β-ODAP) content of food samples in the lathyrism endemic region of northwest ethiopia

Physicochemical Properties and Effect of Processing Methods on Mineral Composition and Antinutritional Factors of Improved Chickpea (Cicer arietinum L.) Varieties Grown in Ethiopia

Chickpea (Cicer arietinum L.) is an important pulse crop grown and consumed all over the world because it is a good source of carbohydrates and protein. However, presence of antinutritional components restricts its use by interfering with digestion of macronutrients during consumption. Therefore, the objective of this study was to evaluate physicochemical properties and effect of processing methods on antinutritional factors and mineral composition of improved chickpea varieties (Natoli of Desi and Arerti of Kabuli) grown in Ethiopia. The experiment was factorial with complete randomized design. The result indicated that physicochemical properties such as seed mass, seed density, hydration capacity, swelling capacity, unhydrated seeds, and cooking time of Arerti and Natoli chickpeas had 260.69 and 280.65 g/1000 seeds, 3.48 and 3.61g/ml, 1.07 and 1.03 g/g, 2.12 and 1.94ml/g, 1.64 and 14.75%, and 21.00 and 246.33 min, respectively. After processing, Zn, Fe, and Ca contents of improved chickpea varieties had 4.48 to 5.85mg/kg, 8.52 to 10.17mg/kg, and 536.56 to 1035mg/kg, respectively. The antinutritional factors, tannin and phytic acid, in the raw chickpeas were reduced to 25 to 82.25% and 5.89 to 57.35%, respectively. The results of the current study showed that Arerti of Kabuli variety showed low antinutritional factors and better physicochemical properties, specifically low cooking time, than Natoli of Desi variety. All processing methods were effective in reduction of antinutritional factors; however, boiling was found to be the best for reduction of antinutritional factors.

Neurolathyrism: two Ethiopian case reports and review of the literature

Neurolathyrism is a toxic myelopathy caused by ingestion of the Lathyrus sativus grasspea. An irreversible acute to subacute spastic paraparesis or quadriparesis ensues. Despite public education, new cases of this preventable disease still occur. Two Ethiopian cases of neurolathyrism are reported to illustrate the disease, followed by a literature review. Two teenage male farmers from the same village developed irreversible spastic myelopathy following L. sativus ingestion. There was no sensory, sphincter or bulbar dysfunction. Likely causative factors identified were increased consumption of L. sativus prior to and following disease onset, heavy physical exertion and male gender, similar to those reported in the literature. Neurolathyrism is an entirely preventable neurotoxic myelopathy with permanent disability accrued. Treatment is symptomatic. Because of personal disability and subsequent socioeconomic effects, this disease warrants further public health measures to prevent occurrence. Education, avoidance of the grasspea and measures to reduce toxin burden are possible methods.

Studies on neurolathyrism in Ethiopia: dietary habits, perception of risks and prevention

This study describes the correlation of traditional perceptions and dietary habits with the incidence of neurolathyrism to propose preventive measures. Therefore, 118 households of South Wollo and North Gondar (Amhara Regional State, Ethiopia), of which one third had at least one neurolathyrism affected member, were interviewed. Most of the affected families in this study had one neurolathyrism victim, being predominantly male and of younger age. The incidence among youngsters (boys and girls) was significantly correlated with the consumption of green unripe seeds (eshet), confirming this as a risk factor for developing neurolathyrism. The consumption of other popular grass pea preparations was not age related. Neurolathyrism patients did not attempt any medication as most people knew that neurolathyrism is incurable, but the consumption of grass pea was abandoned after developing the disease. The minority 'Woito' tribe was virtually unaffected. They were the only people reporting to consume fish which is rich in amino acids such as methionine and using metallic kitchen utensils in addition to clay pots. This observation points to the correlation between low neurolathyrism incidence and a better balanced diet as well as metallic kitchen utensils, suggesting a new approach for neurolathyrism prevention.

Genetic improvement of grass pea for low neurotoxin (β-ODAP) content

Grass pea is a promising crop for adaptation under climate change because of its tolerance to drought, water-logging and salinity, and being almost free from insect-pests and diseases. In spite of such virtues, global area under its cultivation has decreased because of ban on its cultivation in many countries. The ban is imposed due to its association with neurolathyrism, a non-reversible neurological disorder in humans and animals due to presence of neurotoxin, β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in its seedlings and seeds. The traditional varieties of grass pea contain 0.5-2.5% β-ODAP. Exploitable genetic variability for β-ODAP has been observed for development of low ODAP varieties, which along with improved agronomic and detoxification practices can help reduce the risk of lathyrism. Collaborative efforts between ICARDA and NARS have resulted in development of improved varieties such as Wasie in Ethiopia, Ratan, Prateek and Mahateora in India, and BARI Khesari-1 and BARI Khesari-2 in Bangladesh with <0.10% β-ODAP. Soil application of 15-20 kg ha(-1) zinc sulphate, early planting, and soaking seeds in water have shown significant effects on β-ODAP. Because of the often cross-pollination nature, the current breeding procedures being followed in grass pea requires paradigm shift in its approach for a possible genetic breakthrough.

Lathyrus sativus (grass pea) and its neurotoxin ODAP

Lathyrus sativus (grass pea) is a high-yielding, drought-resistant legume consumed as a food in Northern India and neighboring countries as well as in Ethiopia. Its development into an important food legume, however, has been hindered by the presence of the neurotoxin - beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (beta-ODAP) in seeds which, if consumed in large quantities for prolonged periods, can cause irreversible paralysis. Recently, some low-toxin lines have been developed that may prove safe for both animal and human foods. Cultivation of L. sativus should thus be considered in suitable regions because the demand for legume animal feed protein products is expected to increase. This paper addresses advances in understanding L. sativus from the perspective of its taxonomy, genetics, ecology, chemistry, nutrition, medicine, biology and for animal nutrition.

Improvement of nutritive value of grass pea (Lathyrus sativus) seed meal in the formulated diets for rohu, Labeo rohita (Hamilton) fingerlings after fermentation with a fish gut bacterium

Eight isonitrogenous (35% crude protein approximately) and isocaloric (4.0 kcalg(-1) approximately) diets were formulated incorporating raw and fermented grass pea (Lathyrus sativus) seed meal at 10%, 20%, 30% and 40% levels by weight into a fish meal based diet and fed to rohu, Labeo rohita, fingerlings for 80 days and fish performance was studied. A particular bacterial strain (Bacillus sp.) isolated from the intestine of adult common carp (Cyprinus carpio) reared in the wild having significant amylolytic, cellulolytic, lipolytic and proteolytic activities were used for fermentation of seed meal for 15 days at 37 degrees C. Fermentation of grass pea seed meal was effective in significantly reducing the crude fibre content and anti-nutritional factors, such as tannins, phytic acid and the neurotoxin, beta-ODAP and enhancing the available free amino acids and fatty acids. In terms of growth response, feed conversion ratio and protein efficiency ratio, 30% fermented grass pea seed meal incorporated diet resulted in significantly (P < 0.05) better performance of rohu fingerlings. In general, growth and feed utilization efficiencies of fish fed diets containing fermented seed meal were superior to those fed diets containing raw seed meal. The apparent protein digestibility (APD) values decreased with increasing levels of raw seed meal in the diets. The APD for raw seed meal was lower at all levels of inclusion in comparison to those for the fermented seed meals. The highest deposition of carcass protein was recorded in fish fed the diet containing 40% fermented seed meal. The results indicated that fermented grass pea seed meal can be incorporated in carp diets up to 30% level compared to 10% level of raw seed meal.

Fermentation of seeds of Teff (Eragrostis teff), grass-pea (Lathyrus sativus), and their mixtures: aspects of nutrition and food safety

Fermentation of pure teff (Eragrostis teff), pure grass-pea (Lathyrus sativus), and their mixtures, 9:1 and 8:2 (teff/grass-pea) has been done at two temperatures (room temperature and 35 degrees C) in duplicate using the strains of Lactobacillus plantarum, for bacterial fermentation, and Aspergillus oryzae and Rhizopus oligosporus in succession for solid-state fungal fermentation as inocula. In addition, the natural or spontaneous and back-slopping methods of bacterial fermentation have been done on the above four substrate groups. The pH and essential amino acid profiles of the different fermentation processes were compared. The back-slopping in teff at a temperature of 35 degrees C gave the sharpest pH drop. All fermentations done at 35 degrees C showed a steeper slope in their pH versus time plot compared to their room temperature counterpart. Fungal fermentation gave an improved amino acid profile for the essential ones in all of the substrate groups, except in pure grass-pea. Fermented teff/grass-pea (8:2) in this fungal fermentation has been found to be quite comparable in essential amino acid profile to an ideal reference protein recommended for children of 2-5 years of age. None of the bacterial fermentations produced a net change in their essential amino acid profile in any of the substrate groups investigated. Solid state fungal fermentation on pure grass-pea using the fungal strains R. oligosporous and A. oryzae in succession has shown that the neurotoxin beta-N-oxalyl-alpha,beta-diaminopropionic acid (beta-ODAP) in grass-pea has been removed by 80% on average for the high-toxin variety and by up to 97% for the low-toxin variety as determined by an improved chromatographic method with bioelectrochemical detection coupled on-line with refractive index detection.

ABO blood groups, grass pea preparation, and neurolathyrism in Ethiopia

An exploratory study was conducted in the rural Estie district of Ethiopia in 1997 to identify the role of ABO blood group, rhesus factor, and type of grass pea (Lathyrus sativus) diet in the susceptibility to neurolathyrism. Five-hundred study subjects (250 cases and 250 controls) were examined and interviewed, and had their ABO and rhesus blood groups determined. The majority (86%) of the cases were males. Blood group O was the most common in the patients and controls followed by groups A, B, and AB. The vast majority of the study subjects were rhesus-positive. The gravy (Shiro) grass pea preparation was consumed by 91.6% of the study population, boiled (Nifiro) by 86%, and roasted (Kollo) by 56.4%. Almost half (48%) of the cases had consumed grass pea for > 4 months compared to 8% of controls (P < 0.001). There was a significant association between the risk for neurolathyrism and the consumption of boiled (adjusted odds ratio [AOR] = 98.4) and roasted (AOR = 55.62) forms of grass pea. There was no risk of paralysis associated with consumption of the gravy form of grass pea (AOR = 0.40, 95% confidence interval 0.1-2.0). Blood group O remained significantly associated with the disease after adjusting for age, type of grass pea preparation consumed, and duration of consumption (AOR = 2.90).

Neurolathyrism in Ethiopia: assessment and comparison of knowledge and attitude of health workers and rural inhabitants

A cross sectional community based study was done in the Amhara Regional State of Ethiopia in 1999-2000 to assess and compare knowledge and attitude towards neurolathyrism among health workers and the rural community. A sample of 217 health workers selected by probability proportional to size and randomly selected 589 heads of household from a rural district were interviewed using pre-tested questionnaires. Neurolathyrism was widely known among the health workers and the community. More than half of community respondents associated the disorder with walking or lying on the straw and the stalks of grass pea. In a multivariate analysis. poor neurolathyrism knowledge among the community was associated with illiteracy and with presence of a neurolathyrism patient at home. Among health workers, contact with vapour or steam of grass pea foods was the commonest cause cited. In a multivariate analysis nurses had the poorest knowledge among the health workers. Depending on the subject, health workers and community respondents had more or less knowledge than the other. The prevailing recurrent adverse climatic conditions might promote grass pea as a 'friendly' crop to the poor peasants in marginal areas who otherwise rely on it only during times of food shortages and could increase the incidence of neurolathyrism. The poor knowledge among health workers and the community and the general neglect of neurolathyrism requires urgent intervention. Appropriate strategies for the dissemination of information education, and communication (IEC) are needed.

Liquid chromatographic determination of total and beta-N-oxalyl-L-alpha,beta-diaminopropionic acid in lathyrus sativus seeds using both refractive index and bioelectrochemical detection

A further improved chromatographic method for the simultaneous determination of the total amount of ODAP, selectively the amount of its neurotoxic form, beta-ODAP, and free L-glutamate in raw Lathyrus sativus (grass pea) seed samples is described using post-column refractive index in combination with bioelectrochemical detection. The biosensor is based on crosslinking horseradish peroxidase (HRP) and an Os-containing mediating polymer with poly(ethyleneglycol)(400) diglycidyl ether (PEGDGE), forming an inner hydrogel layer and then immobilising L-glutamate oxidase (GlOx) as an outer layer on top of a graphite electrode. Addition of polyethylenimine (PEI) to the hydrogel is believed to have sensitivity and stability enhancing effect on the biosensor. The double-layer approach in the biosensor construction avoided direct electrical wiring of GlOx and resulted in a higher sensitivity of 4.6 mA/M cm2 with respect to beta-ODAP and a wider linear range (1-250 microM) for both L-glutamate and beta-ODAP when compared with a single-layer approach where GlOx, HRP, and Os-polymer are crosslinked together. The limit of detection for the chromatographic-biosensor system was found to be 2 microM with respect to beta-ODAP and 0.7 microM with respect to L-glutamate. The refractive index detection on-line with the biosensor enabled full control of the chromatographic system for the determination of the total amount of ODAP, selectively the amount of beta-ODAP and L-glutamate. Ten grass pea samples have been collected from Lathyrism prone areas of Ethiopia to test the applicability of the presently developed analytical system for real sample analysis. The toxin levels of grass pea collections were determined in an aqueous extracts and ranged from 0.52 to 0.76%, dry mass basis. Comparison of results of an established spectrophotometric assay and that of the present system has shown an extraordinary degree of agreement as revealed by parallel "t" test (90% confidence limit). The present system has operational stability of more than 50 h. Analysis time per sample is 10 min after extraction for 90 min.

Analysis of neurotoxin 3-N-oxalyl-L-2,3-diaminopropionic acid and its alpha-isomer in Lathyrus sativus by high-performance liquid chromatography with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization

A method was developed for the quantitative determination of the neurotoxic nonprotein amino acid, 3-N-oxalyl-L-2,3-diaminopropionic acid (beta-ODAP), and its nontoxic alpha-isomer, 2-N-oxalyl-L-2, 3-diaminopropionic acid (alpha-ODAP), in the plant samples of Lathyrus sativus after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) by reversed-phase high-performance liquid chromatography (HPLC). Hippuric acid was used as an internal standard. A linear response was recorded in the concentration rang 0.32-32 nmol with r > 0.999. The RP HPLC detection limit for both isomers is 1.8 ng. According to different experimental needs, a ternary gradient system can be used to determine toxin and other nonprotein amino acids. The RP HPLC method and a colorimetric method were compared for measuring ODAP.

Food toxins, ampa receptors, and motor neuron diseases

Environmental chemicals involved in the etiology of human neurodegenerative disorders are challenging to identify. Described here is research designed to determine the etiology and molecular pathogenesis of nerve cell degeneration in two little known corticomotoneuronal diseases with established environmental triggers. Both conditions are toxic-nutritional disorders dominated by persistent spastic weakness of the legs and degeneration of corresponding corticospinal pathways. Lathyrism, a disease caused by dietary dependence on grass pea (Lathyrus sativus), is mediated by a stereospecific plant amino acid (beta-N-oxalylamino-L-alanine) that serves as a potent agonist at the (RS)-alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid (AMPA) subclass of neuronal glutamate receptors. A neurologically similar disorder, konzo ("tied legs"), is found among protein-poor African communities that rely for food on cyanogen-containing cassava roots. Thiocyanate, the principal metabolite of cyanide, is an attractive etiologic candidate for konzo because it selectively promotes the action of glutamate at AMPA receptors. Studies are urgently needed to assess the health effects of cassava and other cyanogenic plants, components of which are widely used as food.