School of Agriculture, Food and Ecosystem Sciences - Theses
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ItemRoasted legumes for lambs( 1997)Whole lupin (Lupinus angustifolius) and narbon bean (Vicia narbonensis) seeds were dry roasted at 100, 110, 120, 130, 140, 150 and 160C for 15, 30 and 45 minutes. The effect of roasting on in vitro solubility of crude protein (CP) and 'dry matter digestibility (IVDMD) were determined. From the solubility results, seeds roasted at 130C for 15, 30 and 45 minutes were chosen to study the effect of roasting on in situ ruminal disappearance of CP and dry matter (DM). From the in situ results seeds roasted at 130C for 45 minutes were chosen to be fed to crossbred wethers for nine weeks in a 2 (grain legumes) x 2 (raw vs roasted) experiment, in rations consisting of 70% concentrate (legume seed + barley) and 30% roughage (lucerne + oaten chaff). The effect of roasting on feed intake, growth, dry matter and nitrogen digestibility, nitrogen utilization, carcass weight and fat thickness were determined. For both legumes, CP solubility decreased with increasing temperature and time of roasting. The decrease was slightly lower in narbon than in lupin. CP solubility of lupin was decreased from 84.7% (raw) to 17.3% (160C, 45 min) and that of narbon from 68.0% (raw) to 18.3% (160C, 45 min). Dry roasting had no significant (P<0.05) effect on IVDMD measured over 72 hours. In situ DM and CP disappearance was estimated by incubating nylon bags in the rumen of sheep for 2, 6, 12 and 24 hours. Dry roasting significantly (R<0.05) reduced disappearance of CP from the bags with the reduction being slightly greater for lupin (a difference of 17.8% between the raw and 45 min sample after 24 hours of incubation) than narbon (a difference of 15.0% between the raw and 45 min sample after 24 hours of incubation) but had no significant effect on DM disappearance after 24 hours of incubation. Feed intake, growth, feed conversion ratio, dry matter digestibility, carcass weight and fat thickness were not affected (P>0.05) by roasting. Nitrogen retention, expressed as a percentage of nitrogen intake or as a percentage of nitrogen absorbed, was significantly (R<0.05) higher for lambs fed diets containing roasted narbon than for lambs fed diets containing raw narbon (as % of intake 20.3 is 12.3; as % of absorbed 25.6 vs 15.4), but was lower for lambs fed diets containing roasted lupin than those fed diets containing raw lupin (as % of intake 23.1 vs 30.9; as % of absorbed 27.3 vs 37.4). Dry roasting of lupin and narbon bean seeds decreased in vitro CP solubility and reduced ruminai disappearance of CP. Nitrogen utilization in lambs fed diets containing roasted narbon seeds was improved. Roasted lupin significantly (R<0.05) reduced nitrogen utilization in lambs. However, roasting these legumes had no significant (R>0.05) effect on growth.
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ItemCowpea and navy bean seeds as supplements for sheep( 1992)This study was conducted to determine the feeding value of cowpea and navy bean seeds as supplements for growing sheep fed equal amounts of oaten chaff and barley straw (basal diet) and the digestibility of the basal diet when cowpea and navy bean seeds were used. Thirty-six sheep were used both in period 1 and period 2 of the feeding trial (Experiment 1), randomly assigned to no supplement, 0.5, 1.0 and 2.0% LW of lupin, cowpea and navy bean, and 2.0% LW of lupin and navy bean plus antibiotics, and twenty-four sheep were used in the digestibility trial (Experiment 2) using 1.0% LW of lupin, cowpea and navy bean and no supplement. Results indicated that navy bean seeds and cowpea seeds when used as supplements should be limited by up to 0.5 and 1.0% LW respectively for sheep fed equal amounts of oaten chaff and barley straw.
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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.