School of Agriculture, Food and Ecosystem Sciences - Theses
Permanent URI for this collection
Search Results
1 - 1 of 1
-
ItemAnti-nutritional factors in legume seeds( 1990)The aim of this study was to assess the presence of lectins and trypsin inhibitors in the seeds of selected species of legume namely: lab lab purpureus L. (lablab) Vigna unguiculata [L.] Walp. (cowpea) and Phaseolus vulgaris (navybean) and to examine the degradation of these anti-nutritional factors in the rumen of sheep. This study also attempted to investigate whether laboratory measures of haemagglutinating activity or trypsin inhibitor activity of the legume seeds could be related to in vivo measurements i.e. animal growth and d-xylose absorption. Seeds of the selected legume species were tested with erythrocytes from three animal species (sheep, goat and cattle) to determine their haemagglutinating activity . Enterocytes were also used in the in vitro measurements of lectin content of the legume seeds. The results indicated that the legume seeds contain various levels of haemagglutinating activity and trypsin inhibitor activity, with navybean exhibiting the highest amount, followed by Lablab batch A, Lablab batch B, cowpea and lupin, the lowest. No significant difference was observed in the haemagglutination reactions when red blood cells from three animal species (sheep, goat and cattle) were used in the test. There was a high correlation (r=0.994) obtained between the haemagglutination activity of erythrocytes and enterocytes. A feeding trial was conducted over a 4-week experimental period . Twenty-five Merino wethers were housed indoors in metabolism crates and were divided into five treatment groups. All sheep were offered daily a mixture of equal parts of oaten chaff and barley straw ad libitum and of the five supplements at 1% of LW. The supplements were lupins, lablab batch A, lablab batch B, cowpea and navybean. The amounts of legume seed supplements given were on an air dry basis. (The five diets offered were; T1= 1% LW Lupin + roughage ; T2= 1% LW Lablab batch A + roughage ; T3= 1% LW Lablab t batch B + roughage ; T4= 1% LW cowpea + roughage ; and T5= 1% LW navybean + roughage. The roughage, which consisted of a mixture of equal parts of oaten chaff and barley straw, was offered ad libitum. The amounts of legume seed supplements given were on an air dry basis.) Samples of legume seeds placed in nylon bags were incubated in the rumen of the sheep at different periods (3, 6, 12, 24 ,48 hour) and examined for haemagglutination and trypsin inhibitor activity. A diminishing trend in activity was observed for all the legume seeds as the incubation time progressed. Minimal activity was still detected at 12 hour post incubation and virtually no activity was measured at 24 and 48 hour periods. The reduction in activity could probably be due to washing of the seeds in the rumen, hence, no apparent symptoms of toxicity were demonstrated by the sheep in contrast to a previously reported study of Ismartoyo (1989) Results of d-xylose test , feed intake and growth of sheep showed no significant difference among the treatment diets including other related experiments which involved supplementation of similar legume seeds. There was no clear relationship observed between the in vitro and in vivo measurements obtained in this experiment. Therefore, the anti-nutritional role of legume seeds on the sheep appeared to be of lesser significance compared to the monogastrics. This has been substantiated by the diminishing levels of toxic activity as determined in this experiment and absence of toxic symptoms in the sheep fed with legume of seeds at 1% of LW.