Effects of the inclusion of treated jack beans (Canavalia ensiformis) and the amino acid canavanine in chick diets

Abstract

Three experiments were conducted in Merida, Mexico, between 1987 and1990 in which jack beans, treated in various ways, were included in chick diets at the rate of 300 g/kg diet. The diets were balanced by appropriate supplementation to provide the same concentrations of energy, minerals, vitamins and principal essential amino acids as control diets based on maize or sorghum and soyabean meal. Boiling jack beans or soaking and shaking them and the combination of boiling with soaking and shaking were studied with a view to removing or inactivating toxic factors and enhancing the utilization of the beans as a livestock feed. A fourth experiment was conducted to evaluate the contribution of canavanine to the deleterious effect observed when broiler chicks are fed diets containing treated jack beans and to examine the effect of canavanine on the efficiency of protein retention of broiler chicks.Boiling for 1 or 2 h reduced the toxicity of jack beans, but chick growth rate was only half that of controls. The combination of boiling, followed by soaking and shaking, removed most of the jack beans' anti-nutritional factors, but some toxic effects were left in the beans, causing a depression of c. 10% in feed intake and growth rate. Growth, feed intake and protein utilization of chicks were not affected when canavanine was added to a sorghum-soyabean diet at a level (3-5 g/kg diet) which matched the canavanine present in a diet containing 300 g/kg boiled jack beans.It was concluded that boiling was a satisfactory procedure for the inactivation of the heat-labile lectins in jack beans and that soaking and shaking was an effective method of reducing canavanine and the haemolytic activity of the saponins in jack beans. However, canavanine was found not to be the main toxic or anti-nutritional factor present in jack beans.

Effects of raw and treated jack beans(Canavalia ensiformis) and of canavanine on the short-term feed intake of chicks and pigs

“…To obtain two different levels of residual canavanine in treated jack beans for Expt 2, a batch of raw beans was passed through a forage chopper, which broke individual seeds into three or four pieces, and then divided into two parts. One part was boiled in tap water at 100 °C (1 kg beans/3 kg water) for 15 h and the other part was boiled in the same way and then soaked and shaken in tap water (1 kg beans/3 kg water) for 7 h. Further details of the process are given by Belmar & Morris (1994). For Expt 4, a batch of chopped raw jack beans was soaked and shaken in tap water (1 kg beans/3 kg water) for 8 h after boiling in tap water (1 kg beans/3 kg water) at 100 °C for 2 h. Treated beans were dried in a forced-draught oven at 70 °C for 36 h. Raw and treated beans for all four experiments were finely ground in a hammer mill and incorporated into the experimental diets.…”

“…The method of extracting canavanine from raw jack beans is described by Belmar & Morris (1994). The material used contained c. 94% canavanine as estimated by ion exchange chromatography.…”

“…c " et ' ^n e re<^uct ' on m growth rate of animals fed on treated jack beans has generally been associated with It is clear from the literature reviewed by Belmar & a fall in feed intake, suggesting that low growth rate Morris (1994) that the use of raw jack beans may be a result of low feed consumption, but the (Canavalia ensiformis) as a feedstuff is limited because, reason for this feed intake depression in diets in common with many other legume seeds, they containing jack beans is not well understood (D'Mello contain a variety of toxic or anti -nutritional factors, et al 1985;D'Mello & Walker 1991;Ologhobo et al These factors vary in composition and include the 1993). lectin concanavalin-A, the unusual toxic amino acids It is well established that feed intake is one of the canavanine and canaline, alkaloids, polyphenolic main determinants affecting growth rate and therefore compounds, saponins, trypsin inhibitors and immuno-animal production (Forbes 1986).…”

“…little attention has been paid to the feed intake Several methods of reducing the toxic effects of jack depression of chicks fed diets containing treated jack beans have been reviewed by Belmar & Morris (1994). beans.…”

Evaluation of Multiple-Use Cover Crops under Rainfed during Two Seasons in Yucatan, Mexico

“…However in spite of such results the interdisciplinary and interinstitutional assessments of several cover crops in Mexico shown a low adoption of velvet bean due to excessive competition of it over maize crop, as well as its displacement by other crops and peoples low knowledge of its grain uses. As result of all the above, due to the foreseen opportunity to be used as livestock feeding there has been an increase on researching chemical composition and nutritional attributes of velvet bean and sword bean [9]- [12].…”