Sweet lupins

Lupine seed, though used primarily in animal feeds (see Feeds AND FEED ADDITIVES), does have potential for use in human appHcations as a replacement for soy flour, and is reported to contain both trypsin inhibitors and hemagglutenins (17). The former are heat labile at 90°C for 8 minutes the latter seem much more stable to normal cooking temperatures. Various tropical root crops, including yam, cassava, and taro, are also known to contain both trypsin and chymotrypsin inhibitors, and certain varieties of sweet potatoes may also be impHcated (18). 

Garlic, sweet potato, wheat, barley, sunflower, bean (mung), sesame, lupine, strawberry, artichke (Jerusalem), bean (kidney), bean (lima), groundnut/peanut Moderately sensitive (1.0-2.0ppm)... 

All these data support the idea that QA may function as chemical defense compounds. We also tested whether this chemical defense is relevant for the survival of a lupin plant. Lupins offer a unique chance to explore this question experimentally plant breeders have selected "sweet" varieties, which have a very low alkaloid content. These varieties can be compared to semi-bitter or bitter ones. We have grown Lupinus albus strains that differ in their alkaloid content in our experimental garden and greenhouse and have monitored their susceptibility to attack by plant pests. As can be seen from Figure 2, "sweet" lupins are preferentially eaten by rabbits (Cuniculus europaeus) or are infested by aphids (Aphidae) or leaf miners (Agromyzidae). Literature data also support the assumption that alkaloid-rich lupins are much more resistant to plant pests than "sweet" varieties (30-32). We conclude therefore, that QA are indeed important for the fitness of a lupin plant and that they constitute a major part of its chemical defense system, in which... 

Lupin seeds provide a protein- and lipid-rich diet that is almost equivalent to Soya. In order to avoid the toxic alkaloids, sweet lupin varieties have been selected by plant breeding. But in view of our results it is doubtful whether it is wise to destroy a natural resistance factor. It is thus not surprising that sweet... 

The simple ohservahon that white seeds are sweeter that black seeds was used in the construction of a practical method of judging lupine seeds qualitatively. This method cannot he used with confidence, because, especially in white lupine, even very white seeds can have a high alkaloid content. On the other hand, plants from the same species are sweet . In some species, for example in the case of L. angustifolius or l. luteus, the tendency of white seeds to be sweet is more likely but not absolutely certain. 

Bellester, D. R., Brunser, M. T Saitua, M. T Egana, E. 0 Yanez, E. O. and Owen, D. F. 1984. Safety evaluation of sweet lupin Lupinus albus cv. Multolupa). II. Nine-month feeding and multigeneration study in rats. Journal of Chemistry and Toxicology, 22 45 8. 

Aniszewski, T., Drozdov, S. N., Kholoptseva, E. S., Kurets, V. K., Obshatko, L. A., Popov, E. G. and Talanov, A. V. 2001. Effects of light and temperature parameters on net photosynthetic carbondioxide fixation by whole plants of five lupin species Lupinus albus L., Lupinus angustifolius L., Lupinus luteus L., Lupinus mutabilis Sweet, and Lupinus polyphyllus Lindl.). Acta Agriculturae Scandinavica, 51 17-27. 

The widely planted and ornamental laburnum trees offer a particular risk, since all parts, including the pealike seeds, contain dangerously high amounts of alkaloids. So-called sweet lupins are selected strains with an acceptably low alkaloid content (typically about a quarter of the total alkaloids of bitter strains), which are grown as a high protein crop. 

Zduhczyk et ol. (1996) studied the nutritive value of low-alkaloid varieties of white lupin and found that the lysine contents were relatively low (4.70-5.25g/16g N), with methionine as the limiting AA. Roth-Maier and Paulicks (2004) studied the digestibility and energy contents of the seeds of sweet blue lupins (L. angustifolius) and found digestibility coefficients of 0.43-0.5 for organic matter, 0.36-0.43 for protein, 0.69-0.83 for fat, 0.46-0.58 for NFE and an ME concentration of 7.54-8.22 MJ. 

Moschini et al. (2005) conducted a study in which sweet white lupin seed was included in broiler diets at 50 and 100 g/kg as a replacement for soybean meal. Growth rate was improved with the lower level of lupin seed but was reduced with the higher level. 

Farrell, D.J., Perez-Malondano, R.A. and Mannion, P.F. (1999) Optimum inclusion of field peas, faba beans, chick peas and sweet lupins in poultry diets. II. Broiler experiments. British Poultry Science 40, 674-680. 

Rubio, L.A., Brenes, A. and Centeno, C. (2003) Effects of feeding growing broiler chickens with practical diets containing sweet lupin (Lupinus angustifolius) seed meal. British Poultry Science 44, 391-397. 

Table 4.1.17A. Lupinseed meal sweet white (IFN 5-27-717). The ground whole seed of the species Lupinus albus, Lupinus angustifolius or Lupinus luteus. It has to contain less than 0.3g total alkaloids/kg. The species of seed must be listed after the name Sweet lupin seeds, ground . (From CFIA, 2007.) ...

Selective advantage of lupins with alkaloids as compared to sweet lupins. 

Fig. 1.3 Importance of quinolizidine alkaloids for lupins against herbivores.ln this experiment, lupins with or without alkaloids were grown in the field. When rabbits got into the field, they preferentially consumed the sweet, alkaloid-free lupins. Also larvae of mining flies preferred sweet lupins.

The transport of toxic alkaloids in the phloem can be an advantage for plants against phloem-feeding insects, such as aphids [8], For example alkaloid-rich lupins are avoided by aphids, whereas sweet lupins with very low alkaloid contents are preferred by polyphagous aphids [8,22]. 

Lupines have relatively large seeds which contain up to 40-50% protein, up to 20% lipids, and 2-8% alkaloids. To use lupine seed for animal or human nutrition, Homo sapiens, for several thousand years, used to cook the seeds and leach out the alkaloids in running water. This habit has been reported for the Egyptians and Greeks in the Old World, and for the Indians and Incas of the New World. The resulting seeds taste sweet, in contrast to the alkaloid-rich ones which are very bitter. In Mediterranean countries people still process lupines in the old way, and sometimes the... 

Bitter (Alkaloid-Rich) versus Sweet (Low-Alkaloid) Lupines... 

Sheep n.i." n.i. Sweet lupines are preferred, bitter discriminated 458... 

The lupine example also tells us about the standard philosophy and problems of plant breeding. With our present knowledge on the ecological importance of QAs for the fitness of lupines, it seems doubtful whether the selection of sweet lupines was a wise decision. In order to grow them... 

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