| dc.description.abstract | The biodiversity of plants in Botswana offers great opportunities for the development of ailing ruminant livestock farming. The qualitative and quantitative inadequacy of rangeland is the biggest challenge to livestock production in Botswana. Poor and rather irregular distribution of precipitation worsens the situation. However, pastures in these ecosystems harbour underutilized legumes that are endowed with essential nutrients. One of the potential protein sources that could improve ruminant nutrition is Morama bean cake (Tylosema esculentum). The nuts are often eaten raw or roasted by people who live where the plants are found, often in dry areas of the Kalahari Desert. To assess their potential in ruminant feeding, Morama beans were prepared using three distinct methods: roasted Morama bean cake (RMBC), whole Morama bean cake (WMBC), and decorticated Morama bean cake (MBCD). As feed formulations for ruminants typically include hulled sunflower seed cake (WSSC), a sunflower-based control diet was similarly prepared using hulled sunflower seed cake. The first study (comprising the first and second experiments) compared the differences between the nutritional attributes of the different Morama and sunflower seed cakes, as well as the in vitro DM and CP and in situ DM and CP rumen degradation properties. Therefore, the study objectives were achieved through laboratory methods (wet chemistry or close-up analysis and in vitro studies) and animal experiments (in situ). The techniques determined the nutritional values and potential rumen breakdown of the forage. xiii The in vitro and in situ results for Morama and sunflower seed cakes correlated in many ways, but the in vitro method appeared to significantly underestimate degradation rates compared to the in situ method. In this case, in vitro findings suggested that the crude proteins for WMBC and RMBC were less degradable in rumen fluid than MBCD and WSSC (P < 0.05). The CP disappearance values of WSSC and MBCD had reached 90% and 97.2%, respectively, within 24 hours of incubation. RMBC generally exhibited higher values for the a and b fractions, indicating a higher potential for CP degradation in the rumen. These findings underscore the importance of selecting appropriate feed treatments to optimize CP degradation and effective degradability in ruminants, ultimately enhancing nutrient utilization and animal performance. The second study objective was to compare the protein absorption capacity of roasted Morama bean cake and sunflower seed cake on a basal diet of rice straw at three different inclusion rates (0%, 10%, 20%, and 30%). The effects of Morama bean cake or sunflower seed cake on DM, CP, EE, ADF, ADL, cellulose, and non-fiber carbohydrates were significantly different after mixing with rice straw (P < 0.05). The amount of RMBC or WSSC added to rice straw increased its protein content and improved nutrient digestibility, ammonia concentration, and total volatile fatty acid formation (P < 0.0001). The inclusion of 30% roasted Morama bean cake (RMBC) in the diet resulted in a reduction of various degradability metrics. Specifically, it decreased in vitro dry matter degradability (ivADMdeg) by 12.2%, in vitro true dry matter degradability (ivTDMdeg) by 5.4%, and in vitro organic matter degradability (ivOMdeg) by 4.6%. Therefore, it was concluded that RMBC would benefit ruminants at different incorporation rates, except for 30%, where the possible increased xiv levels of condensed tannins, polyunsaturated fatty acids, phytic acid, glucosinolates, and saponins in the oilseed cake could affect rumen microbial activity and overall feed degradability. The studies underscore the potential of optimally processed Morama bean cake to enhance nutrient utilization and animal performance in ruminants. They also highlight the necessity of selecting the appropriate processing method and inclusion rate to maximize benefits while avoiding negative impacts from anti-nutritional constituents. | en_US |
