Anti-Nutrients in Plants
Parsley, parsnip, celery
Onions, shallots, leeks, chives, scallions, and garlic.
Cooking and phase II liver detox.
Bad breath, and bad body odor, indigestion, acid reflux, diarrhea, stomach pain, gas, anemia, reduced blood clotting of open wounds., allergic reactions, accidental abortions in humans. Disturbs a baby's ability to breast feed.
Grains, legumes, nuts skin, stevia leaves.
Partially by cooking, sprouting.
Dysbiosis (candidiasis). Deleterious histological changes to the pancreas.
Amylase inhibitors: Amylase inhibitors are also known as starch blockers because they contain substances that prevent dietary starches from being absorbed by the body. Starches are complex carbohydrates that cannot be absorbed unless they are first broken down by the digestive enzyme amylase and other secondary enzymes (Marshall and Lauda, 1975; Choudhury et al., 1996). Pigeon pea have been reported to contain amylase inhibitors. These inhibitors have been found to be active over a pH range of 4.5-9.5 and are heat labile. Amylase inhibitors inhibit bovine pancreatic amylase but fail to inhibit bacterial, fungal and endogenous amylase. Pigeon pea amylase inhibitors are synthesized during late seed development and also degraded during late germination (Giri and Kachole, 1998).
Honey, basil, jasmine tea
Apple, carrot, celery, cherry, eggplant, endive, grapes, lettuce, pear, plum, potato, absinthe, anise, basil, caraway, dill, marjoram, rosemary, sage, savory, tarragon, thyme, coffee (roasted beans)
Green potatoes, egg plant, peppers, tomatoes, goji berries.
Liver and kidneys.
Calcinosis, muscle pain and tightness, morning stiffness, poor healing, arthritis, insomnia gall bladder problems.
Cooking and phase II liver detox and kidneys.
Abnormal blood cell counts, spleen enlargement, Lupus (if big amount of juice sprouts is taken).
L-(+)-(S)-Canavanine is a non-proteinogenic amino acid found in certain leguminous plants. It is structurally related to the proteinogenic α-amino acid L-arginine, the sole difference being the replacement of a methylene bridge (-CH
The toxicity of canavanine may be enhanced under conditions of protein starvation, and canavanine toxicity, resulting from consumption of Hedysarum alpinum seeds with a concentration of 1.2% canavanine weight/weight, has been implicated in the death of a malnourished Christopher McCandless. (McCandless was the subject of Jon Krakauer's book (and subsequent movie) Into the Wild).
Chemical structure of canavanine compared to arginine
Some specialized herbivores tolerate L-canavanine either because they metabolize it efficiently (cf. L-canaline) or avoid its incorporation into their own nascent proteins. An example of this ability can be found in the larvae of the tobacco budworm Heliothis virescens, which can tolerate massive amounts of dietary canavanine. These larvae fastidiously avoid incorporation of L-canavanine into their nascent proteins (presumably by virtue of highly discriminatory Arginine—tRNA ligase, the enzyme responsible for the first step in the incorporation of arginine into proteins). In contrast, larvae of the tobacco hornworm Manduca sexta can only tolerate tiny amounts (1.0 microgram per kilogram of fresh body weight) of dietary canavanine because their arginine-tRNA ligase has little, if any, discriminatory capacity. No one has examined experimentally the arginine-tRNA synthetase of these organisms. But comparative studies of the incorporation of radiolabeled L-arginine and L-canavanine have shown that in Manduca sexta, the ratio of incorporation is about 3 to 1.
Dioclea megacarpa seeds contain high levels of canavanine. The beetle Caryedes brasiliensis is able to tolerate this however as it has the most highly discriminatory arginine-tRNA ligase known. In this insect, the level of radiolabeled L-canavanine incorporated into newly synthesized proteins is barely measurable. Moreover, this beetle uses canavanine as a nitrogen source to synthesize its other amino acids to allow it to develop.
NZB/W F1, NZB, and DBA/2 mice fed L-canavanine develop a syndrome similar to systemic lupus erythematosus, while BALB/c mice fed a steady diet of protein containing 1% canavanine showed no change in lifespan.
Alfalfa seeds and sprouts contain L-canavanine. The L-canavanine in alfalfa has been linked to lupus-like symptoms in primates, including humans, and other auto-immune diseases. Often stopping consumption reverses the problem.
Association of SLE and alfalfa was first reported in a volunteer who developed lupus-like autoimmunity while ingesting alfalfa seed for a hypercholesterolemia study. This was corroborated with studies in monkeys fed with alfalfa sprout that developed SLE. Re-challenge with l-canavanine relapsed the disease. Arginine homologue l-canavanine, present in alfalfa, was suspected as a cause. l-canavanine can be charged by arginyl tRNA synthetase to replace l-arginine during protein synthesis. Aberrant canavanyl proteins have disrupted structure and functions. Induction or exacerbation of SLE by alfalfa tablets reported in a few cases remains controversial. Epidemiological studies on the relationship between alfalfa and SLE are sparse. In mice, NZB/W F1, NZB, and DBA/2 mice fed with l-canavanine show exacerbation/triggering of the SLE, however, BALB/c studies were negative.
L-canavanine incorporation may be more efficient in the presence of inflammation or other conditions that can cause arginine deficiency. The l-canavanine induced apoptotic cells can be phagocytosed and a source of autoantigens processed by endosomal proteases. Endogenous canavanyl proteins are ubiquitinated and processed via proteasome. Incorporation of l-canavanine into proteasome or endosome can also cause disruption of antigen processing. Alfalfa/l-canavanine-induced lupus will be an interesting model of autoimmunity induced by the modification of self-proteins at the translational level.
Coffee (roasted beans)
Corn and plants of the Solanaceae family.
Partially by cooking.
Chlorogenic acid (caffeic acid)
Apricot, cherry, peach, plum, coffee (roasted beans)
Chlorogenic acid: Sunflower meal contains high levels of chlorogenic acid, a tannin like compound that inhibits activity of digestive enzymes including trypsin, chymotrypsin, amylase and lipase (Cheeke and Shull, 1985). Because chlorogenic acid is uncondensed and non-hydrolyzable, its content of 1% or more of a total of 3-3.5% phenolic compounds in sunflower meal is not reported in tannin assays. Chlorogenic acid is also a precursor of ortho-quinones that occur through the action of the plant enzyme polyphenol oxidase. These compounds then react with the polymerize lysine during processing or in the gut. Although the toxic effects of chlorogenic acid can be counteracted by dietary supplementation with methyl donors such as choline and methionine. Chlorogenic acid is reported to be readily removed from sunflower seeds using aqueous extraction methods (Dominguez et al., 1993)
Beans, manioc, and many fruit pits (such as apricot kernels and apple seeds).
Cooking and phase II liver detox.
Cerebral damage and lethargy.
Cyanogenic glycosides: Some legumes like linseed, lima bean, kidney bean and the red gram contain cyanogenic glycosides from which Hydrogen Cyanide (HCN) may be released by hydrolysis. Some cultivars Phaseolus lunatus (lima bean) contain a cyanogenic glycoside called phaseolutanin from which HCN liberated due to enzyme action, especially when tissues are broken down by grinding or chewing or under damp conditions (Purseglove, 1991). Hydrolysis occurs rapidly when the ground meal is cooked in water and most the liberated HCN is lost by volatilization. HCN is very toxic at low concentration to animals. HCN can cause dysfunction of the central nervous system, respiratory failure and cardiac arrest (D’Mello, 2000).
Orange juice, mango, black pepper
Gluten-containing cereals are a main food staple present in the daily human diet, including wheat, barley, and rye.
Gluten intake is associated with the development of celiac disease (CD) and related disorders such as diabetes mellitus type I, depression, and schizophrenia. However, until now, there is no consent about the possible deleterious effects of gluten intake because of often failing symptoms even in persons with proven CD. Asymptomatic CD (ACD) is present in the majority of affected patients and is characterized by the absence of classical gluten-intolerance signs, such as diarrhea, bloating, and abdominal pain. Nevertheless, these individuals very often develop diseases that can be related with gluten intake. Gluten can be degraded into several morphine-like substances, named gluten exorphins. These compounds have proven opioid effects and could mask the deleterious effects of gluten protein on gastrointestinal lining and function. Here we describe a putative mechanism, explaining how gluten could mask its own toxicity by exorphins that are produced through gluten protein digestion. The precise pathway leading to the development of ACD still needs to be discovered. However, the putative mechanism presented in this review could explain this intruding phenomenon. The incomplete breakdown of the gluten protein, resulting in the presence of gliadin peptides with opioid effects, makes it plausible to suggest that the opioid effects of gluten exorphins could be responsible for the absence of classical gastrointestinal symptoms of individuals suffering from gluten-intake-associated diseases. Moreover, the partial digestion of gluten, leading to DPP IV inhibition, could also account for the presence of extra-intestinal symptoms and disorders in ACD and the occurrence of intestinal and extra-intestinal symptoms and disorders in CD and NCGS patients. If so, then individuals suffering from any of these conditions should be recognized in time and engage in a gluten-free lifestyle to prevent gluten-induced symptoms and disorders.
All natural and unprocessed plants and mushrooms
Diverticular disease, constipation, haemorrhoids, bloating, anal bleeding, abdominal pain, leaky gut syndrome, inflammatory bowel diseases, a host of other autoimmune diseases, bowel cancer, depletes vitamins and minerals from the body
Barley, buckwheat, durum wheat, bulgur, wheat bran, wheat germ, triticale, quinoa, millet, spelt and teff.
Incidentally, antibodies to gliadin are capable of binding to nervous system tissue and may contribute to immune-mediate neurological impairment, such as cerebellar ataxia and gluten encephalopathy. Gliadin, particular the omega fraction, is also responsible for allergic responses, including Bakers� asthma and the odd wheat-dependent, exercise-induced analyphylaxis (WDEIA).)
All wheat, rye and barley plants.
Digestive problems, leaky gut syndrome or autoimmune disease, allergic reactions, and cognitive problems.
Soy, peanuts and cruciferous vegetables.
Goitrogenic substances, which cause enlargement of the thyroid gland, have been found in legumes such as soybean and groundnut. They have been reported to inhibit the synthesis and secretion of the thyroid hormones. Since thyroid hormones play an important part in the control of body metabolism their deficiency results in reduced growth and reproductive performance (Olomu, 1995). Goitrogenic effect have been effectively counteracted by iodine supplementation rather heat treatment (Liener, 1975).
cotton seed (Gossypium spp)
Gossypol is a naturally occurring polyphenolic compound present in the pigment glands of cotton seed (Gossypium spp). The average gossypol content varying from 0.4-2.4% within glanded cotton seeds to less than 0.01% free gossypol within some low-gossypol cotton seed meals (Liener, 1980; Robinson and Brent, 1989; Castaldo, 1995). Reduced lysine availability has been reported with cotton seed protein due to the ability of heatgossypol to bind with the reactive epsilon amino group of lysine during heat processing (Wilson et al., 1981; Robinson, 1991; Church, 1991). The general symptoms of gossypol toxicity are depressed appetite, loss of weight, laboured breathing and cardiac irregularity. Death is usually associated with reduced oxygen carrying capacity of the blood, haemolytic effects on erythrocytes and circulatory failure. Dietary gossypol also causes olive-green discolouration of yolks in eggs (Church, 1991; Olomu, 1995; McDonald et al., 1995).
Grains, pseudo-grains, seeds, nuts, legumes, nightshade vegetables, diary, eggs.
Cooking with seaweeds and mucilaginous vegetables (okra). Partially by soaking, boiling in water, fermenting, sprouting.Wheat, soy, peanuts and dried beans are the most resistant to neutralization.
Leaky gut, neurodegenerative disease, inflammatory diseases, infectious and autoimmune diseases, blood clotting.
Neochlorogenic acid (caffeic acid)
Apple, apricot, broccoli, brussels sprouts, cabbage, cherry, kale, peach, pear, plum, coffee (roasted beans)
Other animals: alpha-galactosidase. Sprouting, fermentation. Bacteria in the colon.
Grains bran, nuts, soy, spinach, rhubarb, swisschard, chocolate, black tea, some fruits and vegetables. Metabolite of fungus and dysbiotic flora. Metabolism of the amino acids glycine and serine, vitamin C and sugar.
Partially by cooking.
Binding with calcium: Calcium and magnesium deficiency, kidney stones, disturb digestive enzymes. Hyperoxaluria may play a significant role in autism, COPD/asthma, thyroid disease, fibromyalgia, interstitial cystitis, vulvodynia, depression, arthritis. Researchers believed that "Oxalate hyperabsorptionmay be the main reason for stone formation in more than half of the idiopathic calcium oxalate stone formers".
Oxalates affects calcium and magnesium metabolism and react with proteins to form complexes which have an inhibitory effect in peptic digestion. Ruminants, however unlike monogastric animals can ingest considerable amounts of high-oxalate plants without adverse effects, due principally to microbial decomposition in the rumen (Oke, 1969). The hulls of sesame seeds contain oxalates and it is essential that meals should be completely decorticated in order to avoid toxicities (McDonald et al., 1995). Chemical analysis carried by Alabi et al. (2005) on locust bean seeds revealed that the testa of locust bean seeds had the highest concentration of oxalate (4.96 mg/100 g) followed by the pulp (3.40 mg/100 g) and the cotyledon (1.15 mg/100 g). Olomu (1995) reported that pigeon pea contains about 0.38% oxalic acid. Oxalic acid binds calcium and forms calcium oxalate which is insoluble. Calcium oxalate adversely affects the absorption and utilization of calcium in the animal body (Olomu, 1995).
Bran of grains and pseudo-grains, all kind of seeds, nuts, legumes, potatoes.
Birds and ruminant animals: phytase enzyme. Partially by soaking, cooking, fermenting, sprouting.
Binding with minerals of food in the gut: deficiency of iron, zinc, calcium and other minerals. Reduces the digestibility of starches, proteins, and fats.
Phytic acid occurs naturally throughout the plant kingdom and is present in considerable quantities within many of the major legumes and oilseeds. This includes soybean, rapeseed and cotton seed. Matyka et al. (1993) reported that about 62-73% and 46-73% of the total phosphorus within cereal grains and legume seeds being in form of organically bound phytin phosphorus, respectively. As phytic acid accumulates in storage sites in seeds, other minerals apparently chelates to it forming the complex salt phytate (Erdman, 1979). Studies by Martinez (1977) revealed that in oilseeds, which contain little or no endosperm, the phytates are distributed throughout the kernel found within subcellular inclusions called aleurone grains or protein bodies. Whole soybeans have been reported to contain 1-2% phytic acids (Weingartner, 1987; Osho, 1993). The major part of the phosphorus contained within phytic acid are largely unavailable to animals due to the absence of the enzyme phytase within the digestive tract of monogastric animals. Nwokolo and Bragg (1977) reported that in the chicken there is a significant inverse relationship between phytic acid and the availability of calcium, magnesium, phosphorus and zinc in feedstuffs such as rapeseed, palm kernel seed, cotton seed and soybean meals. Phytic acid acts as a strong chelator, forming protein and mineral-phytic acid complexes; the net result being reduced protein and mineral bioavailability (Erdman, 1979; Spinelli et al., 1983; Khare, 2000). Phytic acid is reported to chelate metal ions such as calcium, magnesium, zinc, copper, iron and molybdenum to form insoluble complexes that are not readily absorbed from gastrointestinal tract. Phytic acid also inhibits the action of gastrointestinal tyrosinase, trypsin, pepsin, lipase and “-amylase (Liener, 1980; Hendricks and Bailey, 1989; Khare, 2000). Erdman (1979) stated that the greatest effect of phytic acid on human nutrition is its reduction of zinc bioavailability.
The article gives an overview of phytic acid in food and of its significance for human nutrition. It summarises phytate sources in foods and discusses problems of phytic acid/phytate contents of food tables. Data on phytic acid intake are evaluated and daily phytic acid intake depending on food habits is assessed. Degradation of phytate during gastro-intestinal passage is summarised, the mechanism of phytate interacting with minerals and trace elements in the gastro-intestinal chyme described and the pathway of inositol phosphate hydrolysis in the gut presented. The present knowledge of phytate absorption is summarised and discussed. Effects of phytate on mineral and trace element bioavailability are reported and phytate degradation during processing and storage is described. Beneficial activities of dietary phytate such as its effects on calcification and kidney stone formation and on lowering blood glucose and lipids are reported. The antioxidative property of phytic acid and its potentional anticancerogenic activities are briefly surveyed. Development of the analysis of phytic acid and other inositol phosphates is described, problems of inositol phosphate determination and detection discussed and the need for standardisation of phytic acid analysis in foods argued.
The phytate content of several foods is presented. Published zinc values were used to calculate phytate:zinc molar ratios. These ratios can be used to estimate the relative risk of having an inadequate intake of zinc. They may be used in planning menus to select the combination of foods that will supply the most available zinc to the daily diet. On the basis of animal experiments to date, a daily phytate:zinc molar ratio of 10 or less is thought to be acceptable in providing adequate dietary zinc, and daily ratios consistently above 20 may jeopardize zinc status. Many factors other than the daily dietary phytate:zinc molar ratio influence zinc nutriture, but the ratio concept is a tool which may contribute to a more accurate assessment of zinc status.
Soybeans and soy products, tempeh, linseed (flax), sesame seeds, wheat berries, fenugreek (contains diosgenin, but also used to make Testofen, a compound taken by men to increase testosterone). oats, barley, beans, lentils ,yams, rice, alfalfa, mung beans, apples, carrots, pomegranates, wheat germ, rice bran, lupin, kudzu, coffee, licorice root, mint, ginseng, hops, bourbon whiskey, beer, fennel and anise, red clover (sometimes a constituent of green manure).
Accelerated aging process, androgen hormone imbalances, autoimmune disorders such as lupus, breast tenderness, cervical dysplasia, difficultly losing weight, early onset of menstruation, endocrine imbalances, low male sex hormones, fibrocystic breasts, fibromyalgia, gynecomastia (or man boobs), infertility in men and women, irregular menstrual periods, low sperm count, low sex drive/libido, endometriosis.
Phytoestrogen risks: hypothyroidism, infertility, infants
Riskiest of all are the high levels of phytoestrogens (plant estrogens) in soybeans. Although these are said to be ‘weak estrogens’ and are promoted as ‘safe and natural’ hormone replacement therapy, they are strong enough in numbers to cause significant endocrine disruption, leading most often to hypothyroidism, with its symptoms of weight gain, fatigue, brain fog and depression.
More than 70 years of human, animal and laboratory studies show that soybeans put the thyroid at risk.19 Although individuals deficient in iodine are especially prone to soy-induced thyroid damage, this can also occur even when iodine levels are replete.
Soy phytoestrogens also have a ‘contraceptive effect’. Fertility problems in cows, sheep, rabbits, cheetahs, guinea pigs, birds and mice have been regularly reported since the 1940s.20
In women, soy can impair the ovarian development of babies, alter menstrual cycles and cause hormonal changes indicative of infertility for adults.21 In men it lowers testosterone levels, the quantity and quality of sperm and the libido.22 Although scientists discovered only recently that soy lowers testosterone levels, tofu has traditionally been used in Buddhist monasteries to help the monks maintain their vows of celibacy. Thus couples desiring to become pregnant are wise to cut out soy.
Humans and animals appear to be the most vulnerable to the effects of soy estrogens pre-natally, during infancy and puberty, during pregnancy and lactation, and during the hormonal shifts of menopause.23 Of all these groups, infants on soy formula are at the highest risk because of their small size and developmental phase, and because formula is their main source of nutrient. Soy formula now represents about 25 percent of the bottle-fed market and has been linked to premature puberty in girls, delayed or arrested puberty in boys, thyroid damage and other disorders.24
Soy formula also contains 50 to 80 times the amount of manganese found in dairy formula or breast milk, toxic levels that can harm the infant’s developing brain, causing ADD/ADHD and other learning and behavioural disorders.25 Because ADD/ADHD has been linked to violent tendencies and crime, the California Public Safety Committee is considering making soy infant formula illegal except by prescription.
These and other known hazards of soy formula have led the Israeli Health Ministry, the Swiss Federal Health Service, the British Dietetic Association and others to warn parents and pediatricians that soy infant formula should never be used except as a last resort. Although children and teenagers are less vulnerable than infants, their young bodies are still developing and are highly vulnerable to endocrine system disruption by soy.
Alter transcription of LDL-receptor
Nutmeg, mace, black pepper
Berries and dried fruits, some vegetables, herbs and spices.
Same as medicines (aspirin): bleeding of the stomach and gastrointestinal tract, dyspepsia, skin reactions, liver toxicity, prolonged bleeding time, impaired kidney function, dizziness, mental confusion, allergic reactions.
Legumes, pseudo-grains, potatoes, red wine.
Different results in studies for soaking, cooking and fermentation. Cholesterol and bile.
Leaky-gut, disturbs digestive enzymes.
Lectins (phytohaemagglutinins): Phytohaemagglutinins or lectins are glycoproteins widely distributed in legumes and some certain oil seeds (including soybean) which possess an affinity for specific sugar molecules and are characterized by their ability to combine with carbohydrate membrane receptors (Pusztai, 1989). Lectins have the capability to directly bind to the intestinal muscosa (Almeida et al., 1991; Santiago et al., 1993), interacting with the enterocytes and interfering with the absorption and transportation of nutrients (particularly carbohydrates) during digestion (Santiago et al., 1993) and causing epithelial lesions within the intestine (Oliveira et al., 1989). Although lectins are usually reported as being heat labile, their stability varies between plant species, many lectins being resistant to inactivation by dry heat and requiring the presence of moisture for more complete destruction (Ayyagari et al., 1989; Poel et al., 1990; Almeida et al., 1991).
Sesame seeds (heated oil)
Sinigrin (allyl isothiocyanate)
Cabbage, collard greens, cauliflower, brussels sprouts, mustard (brown), horseradish
Legumes, some fruits and vegetables, tea, chocolate, wine, coffee, vinegar.
Tannin-binding salivary proteins. Partially by soaking and cooking. About 90% by germination.
Zinc and iron deficiency, decrease in both growth rate and body weight gain, perturbation of mineral absorption, inhibition of digestive enzymes, accelerate blood clotting, produce liver necrosis.
Tannins are water soluble phenolic compounds with a molecular weight greater than 500 daltons. They have the ability to precipitate proteins from aqueous solution. There are two different groups tannins:- hydrolyzable tannins and condensed tannins. Condensed tannins are widely distributed leguminous forages and seeds. Cattle and sheep sensitive to condensed tannins, while goats are more resistant (Kumar, 1983; Kumar and Horigome, 1986; Kumar and Vaithiyanathan, 1990; D’Mello, 2000).Tannins may form a less digestive complex with dietary proteins and may bind and inhibit the endogenous protein, such as digestive enzymes (Kumar and Singh, 1984). Tannin-protein complexes involve both hydrogenruminants bonding and hydrophobic interactions. The precipitation of the protein-tannin complex depends upon pH, ionic strength and molecular size of tannins. Both the protein the precipitate increase with increase in molecular size of tannins (Kumar and Horigome, 1986). However, when the molecular weight exceeds 5,000 daltons, the tannins become insoluble and lose their protein precipitating capacity and degree of polymerization becomes imperative to assess the role of tannins in ruminant nutrition (Kumar, 1983; Lowry, 1990). Tannins have been found to interfere with digestion by displaying anti-trypsin and anti-amylase activity. Helsper et al. (1993) reported that condensed tannins were responsible for the testabloat bound trypsin inhibitor activity of faba beans. Tannins also have the ability to complex with vitamin B (Liener, 1980). Other adverse nutritional effects of tannins have been reported to include intestinal damage, interference with iron absorption and the possibility of tannins producing a carcinogenic effect (Butler, 1989).
Fruits, wheat, vegetables nuts etc
Allergies, stimulate immune system or disrupt physical barriers
Toxic Amino Acids
Toxic Amino Acids: A wide range of toxic non-protein amino acids occur in the foliage and seeds of plants. These toxic non-protein amino acids appear to play a major role in determining the nutritional value of a number of tropical legumes (D’Mello, 1982). It has been proposed that these amino acids act antagonistically towards certain nutritionally important amino acids (Liener, 1980). Fowden (1971) suggested that the metabolic pathways culminating in the synthesis of certain non-protein amino acids might reflect subtle alteration in the genome responsible for directing the formation of crucial amino acids. Bell (1971) reported that while non-protein amino acids function primarily as storage metabolites, they may also provide an adaptive advantage to the plants, for example to render the plant less susceptible to attack by various animals and lower plants. Some of these toxic amino acids includes; djenkolic acids, mimosine and canavanine. Mimosine, a toxic non-protein amino acid structurally similar to tyrosine, is contained in the legume Leucaena leucocephala (D’Mello and Acamovic 1989; D’Mello, 2000). Mimosine has been proven effective in defleecing sheep and goats (Jacquemet et al.,1990; Luo et al., 2000). Mimosine a pyridoxal antagonist, which inhibits DNA replication and protein synthesis; thus, it may elicit defleecing by arresting cell division in the follicle bulb (Reis, 1979). In monogastric animals, mimosine causes poor growth, alopecia and reproductive problems. Levels of Leucaena meal above 5-10% of the diet for swine, poultry and rabbits generally result in poor animal performance. The major symptoms of toxicity in ruminants are poor growth, loss of hair and wool, lameness, mouth andoesophageal lesions, depressed serum thyroxine level and goitre. Some of these symptoms may be due to mimosine and others to 3, 4-dihydroxypyridine, a metabolite of mimosine in the rumen (Jones and Hegarty, 1984). Djenkol beans (Pithecolobium lubatum) when ingested sometimes lead to kidney failure which is accompanied by the appearance of blood and white needle-like clusters in the urine. The clusters are sulphur-containing amino acids known as djenkolic acids which are present in the bean in the free state, to the extent of 1-4%. This toxic amino acid is structurally similar to cystine, but it is not degraded in the animal body. Due to its insolubility it crystallizes out in the kidney tubules and escapes through urine (Enwere, 1998). The toxic, non-protein amino acid, canavanine, occurs widely in unbound form in various legume plants of the sub-family Papillonoideae (Bell et al., 1978) and abundantly in jack bean (Canavalia ensiformis (L). DC), constituting up to 63 g/kg dry weight of the seed (Ho and Shen, 1966). Canavanine, a structural analogue of arginine, was first isolated from jackbean by Kitagawa and Tomiyama (1929). Canavanine is believed to exert its toxic influence by virtue of its structural similarity with the nutritionally indispensable amino acid, arginine. Canavanine may antagonize arginine and interfere with Ribonucleic Acid (RNA) metabolism (Rosenthal, 1982). Canavanine has been demonstrated to reduce feed intake of non-ruminants but this was observed only at the equivalent of about 300 g/kg dietary level of raw jackbean Tschiersch, 1962). Saponins: Saponins are a heterogeneous group of naturally occurring foam-producing triterpene or steroidal glycosides that occur in a wide range of plants, including pulses and oil seeds such as kidney bean, chickpea, soybean, groundnut, lupin and sunflower Liener, 1980; Price et al., 1987; Jenkins and Atwal, 1994). It has been reported that saponins can affect animal performance and metabolism in a number of ways as follows: erythrocyte haemolysis, reduction of blood and liver cholesterol, depression of growth rate, bloat (ruminants), inhibition of smooth muscle activity, enzyme inhibition and reduction in nutrient absorption Cheeke, 1971). Saponins have also been reported to alter cell wall permeability and therefore produce some toxic effects when ingested (Belmar et al., 1999). Saponins have been shown to bind to the cells of the small intestine thereby affecting the absorption of nutrients across the intestinal wall (Johnson et al., 1986). The effect of saponins on chicks have been reported to reduce growth, feed efficiency and interfere with the absorption of dietary lipids, cholesterol, bile acids and vitamins A and E (Jenkins and Atwal, 1994).
Grains and legumes.
Partially by cooking, sprouting.
Growth inhibition and pancreatitis.
Protease inhibitors: Protease inhibitors are widely distributed within the plant kingdom, including the seeds of most cultivated legumes. Protease inhibitors have the ability to inhibit the activity of proteolytic enzymes within the gastrointestinal tract of animals (Liener and Kakade, 1980). Trypsin inhibitor and chymotrypsin inhibitor are protease inhibitors occurring in raw legume seeds. Protease inhibitors are the most commonly encountered class of antinutritional factors of plant origin. These inhibitors have been reported to be partly responsible for the growth-retarding property of raw legumes. The retardation has been attributed to inhibition of protein digestion but there is evidence that pancreatic hyper- activity, resulting in increased production of trypsin and chymotrypsin with consequent loss of cystine and methionine is also involved (McDonald et al., 1995). Trypsin inhibitors have been implicated in reducing protein digestibility and in pancreatic hypertrophy (Liener, 1976). Trypsin inhibitors are polypeptides that form well characterized stable complexes with trypsin on a one-to-one molar ratio, obstructing the enzymatic action (Carlini and Udedibie, 1997). Protease inhibitors are inactivated by heat especially moist heat, because of even distribution of heat (Bressani and Sosa, 1990; Liener, 1995).