In vitro evaluation of nutritional content and anthelmintic values of Kigelia africana fruit to domesticated ruminants
Food security is at risk due to the ever growing world population. More effort should be put on improving agricultural production since farming provides the primary source of food for humans. Livestock farming; be it commercial or small scale, plays a major role in supplementing the protein component of human food especially with the expensive nature of plant proteins. In northern KwaZulu-Natal, both large (cow) and small (goat and sheep) ruminant farming plays a vital role in the rural communities as they do not only provide proteins, but are used for traditional ceremonies, bride price, prestige and clothing. These ruminants require adequate and constant nutrient availability to meet their best production standards but forage availability and quality declines, especially in winter, which results in poor animal performance. Besides forage limitation, water scarcity is also a major problem in this area with the recent drought that hit in 2015. Therefore, alternative indigenous forages with feed potential and high moisture should be investigated, as water from feed can assist in improving animal production in this area. Kigelia africana plant has been reported to produce fruits (sausage fruit) that are suspected to have high moisture, be rich in secondary compounds and persist throughout the dry season but are not used by animals as feed. Rather, it has been used by humans as flavour, to ferment traditional beers, treat worms and even as an aphrodisiac. Hence, the aim of the study was to explore Kigelia africana fruit (sausage fruit) as a potential feed supplement and its anthelmintic value in domesticated ruminants. Five feed portions were made from the sausage fruits; 1. Exocarp (Ex), 2. Endocarp (En), 3. Endocarp plus seeds (En+SS), 4. Seeds (SS) and 5. Whole fruit (Wf). The nutritional value of feed portions was determined by measuring their chemical composition and the force required to break-open the fruit (shear force). For chemical composition, dry matter (DM), moisture content (MC), crude protein (CP), condensed tannins (CT), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), cellulose and hemi-cellulose were measured. Fibre components were analysed using the ANKOM filter bag method while proteins were analysed using the Kjeldhal method. Acid butanol Assay and the Warner-Blatzer shear device were used to analyse condensed tannins. Shear force was measured using the Warner Blatzer shearing device where maximum force required the feed (F Max), distance covered vi by the blade at breakage (dL at break), and force during break (F at break) were measured. For in vitro digestibility the Daisy incubator from ANKOM Technology was used with inocula from rumen fluid and 1 g sample, incubated at 38ºC in an anaerobic chamber for 72h. Apparent (APD) and True degradability (TD) and microbial yields (MY) were measured. For anthelmintic activity, the Helminth motility test was conducted with extracts of phenolic compounds from Ex, En, En+SS and SS at five levels (control 0g, 5g, 10g, 15g and 20g) using Baerman’s technique and L3 larva survival was counted at 10x magnification. The results revealed that En+SS (21%) had the lowest (p<0.05) DM, followed by En, Wf, Ex and SS (49.65%). This implies that En+SS (79%) showed the highest (p<0.05) MC, followed by En, Wf, Ex and SS (50.3%). In terms of fibre composition, SS and Ex had the highest cellulose content (32% and 42% respectively). Ex had the highest (P˂0.05) NDF, ADF and ADL (70.67%, 59.18% and 17.69% respectively) compared to other feed portions. The highest protein content was observed in SS (12.55%), followed by Wf (3.9%) and En+SS (3.8%) while the lowest was seen in Ex (2.9%). There were higher contents of lignin and cellulose on the Ex than on the En, which was associated with plant mechanisms to protect themselves against herbivory. Ex required the highest FMax (1060.1N) to break the feed while En had the lowest shear force of 540N, which were all lower than the maximum force that can be generated by most ruminant’s jaws. For digestibility studies, En and En+S had the highest (p<0.05) TD of 554.46 g/kg and 539.32 g/kg respectively while Wf, Ex and En were not statistically different but Wf was relatively higher than both. For its anthelmintic potential, it was found that Kigelia africana fruit treatments had an overall of 96% larva mortality percentage when compared to the control. There were no significant differences between L3 larva survival and mortality at different treatment levels of all Kigelia africana extracts but for the control. The result from the chemical composition of the different feed portions and whole fruit, shows that Kigelia africana has feed potential as its constituents are comparable to most types of hay especially with a crude protein of above 8%. Its high moisture content could be of potential benefit especially in winter where water sources are scarce. The force required to break the Ex was a major limitation to gain access to En and SS that were relatively easier to break. Hence the removal of the hard exocarp can reduce Kigelia africana fruit’s shearing force and make it accessible for chewing. Both APD and TD showed vii digestible values higher than most hays, hence, it has feed potential for ruminants. Strong anthelmintic properties were also demonstrated in all extracts with high mortality of larva. Further in vivo experimentation is required to establish the anthelminthic activity prior to rural farmer’s application.
Anthelmintic values, Agricultural production, Farming
Networked Digital Library of Theses and Dissertations