Legume digestibility

The nephrotoxic amino acid, lyskioalanine [18810-04-3] formed upon alkaline treatment of proteki, was reported ki 1964 (108). Its toxicity seems to be mitigated ki proteki ki that it is not released by normal digestion (109). Naturally occurring new amino acids, which can be classified as protekiaceous or non-protekiaceous, can, as ki the case of those from some legumes, show a remarkable toxicity (110). Eor the details of amino acid toxicity, see reference 6. Enzyme inhibition by amino acids and thek derivatives have been reviewed (111). 

Some of the best investigated anti-nutrients are the enzyme inhibitors present in legumes and other plants. The Bowman-Birk and the Kunitz inhibitors of trypsin and other proteases are among the best characterized. In contrast to the non-specific and widespread influences of tannins and lectins (Carmona, 1996), the Bowman-Birk, Kunitz and other such inhibitors target specific enzymes. Corresponding with this, proteases and other digestive enzymes vary in sensitivity to the different inhibitors. 

CARBONARO M, GRANT G, CAPPELLONi M, puszTAi A (2000) Perspectives into factors limiting in vivo digestion of legume proteins antinutritional compormds or storage proteins JAgric Food Chem. 48 742-9. 

THORNE M J, THOMPSON L u, JENKINS D J (1983) Factors affecting starch digestibility and the glycemic response with special reference to legumes. Am J Clin Nutr. 38 481-8. 

Wheat grain, legumes Colon cancer Contains digestion-resistant starch and other non-digestible carbohydrates which increase fermentation in colon and hence production of volatile fatty acids... 

The proximate analyses, mineral composition, digestibility coefficients and nutritive values of brassicas, by-products, grains, grasses, hays, legumes, oil cakes, root crops, seeds and silages are given in MAFF/ADAS (1971) Nutrient Allowances and Composition of Feedingstuffs for Ruminants (Advisory Paper No. 11). 

As such it is an ideal protein for complementation of legumes. Villegas et al. (73) pointed out that methionine supplementation using sesame protein has several advantages over supplementation with free methionine, including an even and more adequate release into the digestive tract. 

Some legumes and dry beans contain considerable quantities of oligosaccharides which cannot be adequately digested by man because we lack appropriate digestive enzymes. Cramps,... 

Buxton DR, Russell JR. 1988. Lignin constituents and cell wall digestibility of grass and legume stems. Crop Sci 28 553-558. 

Fay JP, Cheng KJ, Hanna MR, Howarth RE, Costerton JW. 1980. In vitro digestion of bloat-safe and bloat-causing legumes by rumen microorganisms Gas and foam production. J Dairy Sci 63 1273-1281. 

McAllister TA, Martinez T, Bae FID, Muir AD, Yanke LJ, Jones GA. 2005. Characterization of condensed tannins purified from legume forages Chromophore production, protein precipitation, and inhibitory effects on cellulose digestion. J Chem Ecol 31 2049-2068. 

Faba beans contain several ANFs such as tannins, protease inhibitors (vicin/ convicin) and lectins. Use of low-vicin/convicin cultivars may allow substantial levels of faba beans to be included in poultry diets (Danner, 2003). The levels of trypsin inhibitor and lectin activities are low compared with other legume seeds and do not pose problems in poultry diets when faba beans are incorporated into diets at the levels shown below. Of most concern for poultry is the tannin fraction, which has been shown to depress digestibility of the protein and AA (Ortiz et al., 1993). Tannins in whole faba beans are associated with the seedcoat (testa), and the tannin content is related to the colour of the seedcoat (and flowers). Tannins are lower in white than in the colour-seeded varieties. 

Nielsen, S.S., Deshpande, S.S., Hermodson, M.A., Scott, M.P. 1988. Comparative digestibility of legume storage proteins. J Agric Food Chem 36(5) 896-902. 

If formula diets are not used, then the type of protein used is important due to considerations of biological value and digestibility. Milk, animal proteins, egg, certain legumes, and soy products are appropriate, rich sources. If lactose intolerance is encountered, then milk should be replaced with soy-based feeds or an alternative. Fish and vegetable oils are good sources of fats as they provide generous amounts of essential fatty acids and long-chain unsaturated fatty acids. 

Some of the proteins are toxic in nature. Ricin present in castor bean is extremely toxic to higher animals in very small amounts. Enzyme irvhibitors such as trypsin inhibitor bind to digestive enzyme and prevent the availability of the protein. Lectin, a toxic protein present commonly in legumes, agglutinates red blood cells. A bacterial toxin causes cholera, which is a protein. Snake venom is protein in nature. 

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