Utilization preparation of Senegalia mellifera to produce animal fodder
| dc.contributor.advisor | Tyhoda, Luvuyo | en_ZA |
| dc.contributor.advisor | Gorgens, Johann F. | en_ZA |
| dc.contributor.author | Neethling, Alwyn | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of AgriSciences. Dept. of Forest and Wood Science. | en_ZA |
| dc.date.accessioned | 2023-03-07T07:43:38Z | en_ZA |
| dc.date.accessioned | 2023-05-18T07:09:13Z | en_ZA |
| dc.date.available | 2023-03-07T07:43:38Z | en_ZA |
| dc.date.available | 2023-05-18T07:09:13Z | en_ZA |
| dc.date.issued | 2023-03 | en_ZA |
| dc.description | Thesis (MScFor)--Stellenbosch University, 2023. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: Senegalia mellifera, a tree species associated with significant bush encroachment, has been noted to cause great harm to the environment, the agricultural sector and inevitably the greater economy in Namibia. This is due to Namibia having one of the most severe cases of bush encroachment caused by Senegalia mellifera, which occupies about 70% of all arable land. The severe loss in arable land causes a reduction in available grazing for livestock. Furthermore, clearing these encroached areas could increase available grazing areas for livestock. In addition, due to droughts occurring in Namibia, farmers struggle to keep livestock alive and tend to reduce the number of livestock on their farms. As these droughts intensify, animal feed prices increase, making it unaffordable. Thus, by de-bushing encroached areas and making use of Senegalia mellifera to produce animal fodder, one could aid farms in keeping livestock alive during droughts, while addressing a significant ecological, environmental and biodiversity threat. Furthermore, in the event of animal feed being produced from Senegalia mellifera, farmers tend to only use the small, nutritious branches. By making use of these branches, the farms produce a form of feed that requires additives and they do not solve the problem of bush encroachment caused by Senegalia mellifera. Thus, by harvesting and utilising the complete tree for animal-fodder, one could establish whether the nutritional characteristics are influenced when proportions of stem material are added, and how various pre-treatment methods could overall affect the material digestibility. The objectives of the study were to: (1) evaluate the chemical composition and nutritional characteristics of a mixture of Senegalia mellifera wood that consisted of twigs leaves and mature stems; (2) comparatively study the use of different pre-treatment methods, namely steam explosion (160-220°C, 2-10 min), alkaline catalysed steam explosion (160-220°C, 2-10 min, 1-7 wt.% NaOH) and aqueous ammonia soaking (60-120°C, 1-6 hours, 5-15 wt.% NH3) to increase the material digestibility and available metabolizable energy of Senegalia mellifera. The chemical compositional analysis of Senegalia mellifera raw material indicated a high concentration of lignin (32.06 ± 0.054 %DM) and low levels of cellulose (27.19 ± 0.094 %DM). Nutritional analysis indicated a low level of crude protein (CP) (4.9 ± 1 %DM) in the animal feed mixture. Finally, the feed also had a low digestibility (EDOM) (50.02 g/kg DM) and available metabolizable energy (0.46 MJ/kg DM MEEDOM & 1.32 MJ/kg DM NviroTek), which can be attributed to a high degree of lignification and cellulose crystallinity. After the raw material had been pre-treated, a significant improvement (p < 0.05) on material digestibility and available metabolizable energy was observed in all samples. The effectiveness of the individual treatments in terms of material digestibility was as follows: The most effective method was alkaline catalysed steam explosion, followed by the auto catalytic steam explosion, and the least effective method was aqueous ammonia soaking. Alkaline catalysed steam explosion had the most significant influence on material digestibility by improving it 11-fold to 580.30 g/kg DM (58 %DM) and increasing the available metabolizable energy by just over 15 times to a maximum of 7.19 MJ/kg DM in the most severe conditions (220°C, 10 min, 7 wt.% NaOH). Auto catalytic steam explosion also increased the material digestibility 5-fold to 254.7 g/kg DM (25.47 %DM), while increasing the available metabolic energy (7.8-fold) to 3.59 MJ/kg DM in treatment condition (220°C, 2 min). Finally, the use of aqueous ammonia soaking was the least effective method as it only increased the digestibility twice and the metabolizable energy was increased almost 4-fold to 138.1 g/kg DM (13.81%DM) and 1.79 MJ/kg DM in the most severe treatment conditions (120°C, 6 hours, 15 wt.% NH3).One of the major concerns regarding proper rumen microbial function is the requirement of crude protein (CP). It was thus important to track this key nutritional factor throughout the pre-treatment process. Aqueous ammonia soaking was the most effective in preserving the crude protein content, followed by auto catalytic steam explosion, and the least effective method was alkaline catalysed steam explosion. Regarding the nutritional characteristics, it was observed that even though alkaline catalysed steam explosion improved material degradability and available energy, the already low level of CP was sacrificed, reducing it to 1.05 %DM, which is significantly lower (p < 0.05) when compared to the CP preservation by auto catalytic steam explosion and aqueous ammonia soaking. Finally, regarding crude protein, aqueous ammonia soaking increased the CP and the available nitrogen in fodder by 13.5-282.78 g/kg DM (1.35-28.28 %DM) due to the chemical binding of nitrogen to the prepared feed. This can be a possible reason for a false negative regarding the increase in crude protein noted during aqueous ammonia soaking. In conclusion, by comparing the in vitro enzymatic digestibility, the overall available metabolised energy and available crude protein of three different means of pre-treatment, this study showed that alkaline catalysed steam explosion provided the best overall increase in the digestibility of Senegalia mellifera and thus increased the available metabolic energy for ruminants, even though the crude protein fraction was sacrificed in the pre-treatment process. Regarding animal feed, it is plausible that the removal of a Senegalia mellifera as a whole bush consisting out of stem branches and leaves could be used as an animal feed after the optimal ACS pre-treatment. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: Senegalia mellifera, ’n boomspesie wat met aansienlike bosindringing geassosieer word, rig opmerklike groot skade aan die omgewing, die landbousektor en, onvermydelik, die groter ekonomie in Namibië. Dit is te wyte aan Namibië wat een van die ernstigste gevalle van bosindringing het wat deur Senegalia mellifera veroorsaak word, en dit beslaan ongeveer 70% van alle bewerkbare grond. Die erge verlies aan bewerkbare grond veroorsaak ’n afname in beskikbare weiding vir vee. Verder kan die skoonmaak van hierdie aangetaste gebiede die beskikbare weidingsgebiede vir vee vermeerder. Boonop, weens droogtes wat in Namibië voorkom, sukkel boere om vee aan die lewe te hou en is hulle geneig om die aantal vee op hul plase te verminder. Soos hierdie droogtes toeneem, styg die pryse van veevoer, wat dit onbekostigbaar maak. Dus kan ’n mens plase help om vee tydens droogtes aan die lewe te hou deur aangetaste gebiede te ontbos en Senegalia mellifera te gebruik om veevoer te produseer, terwyl ’n beduidende ekologiese, omgewings- en biodiversiteitsbedreiging aangespreek word. Verder, in die geval van veevoer wat van Senegalia mellifera geproduseer word, is boere geneig om slegs die klein, voedsame takke te gebruik. Deur van hierdie takke gebruik te maak, produseer die plase ’n vorm van voer wat bymiddels benodig en hulle los nie die probleem van bosindringing op wat deur Senegalia mellifera veroorsaak word nie. Dus, deur die hele boom vir veevoer te oes en te benut, kan daar vasgestel word of die byvoeging van proporsies stammateriaal die voedingseienskappe kan beïnvloed, en of verskeie oorbehandelingsmetodes in die geheel die materiaalverteerbaarheid kan beïnvloed. Die doelwitte van die studie was om: (1) die chemiese samestelling en voedingseienskappe van ’n mengsel van Senegalia mellifera-hout wat uit takkiesblare en volwasse stamme bestaan het, te evalueer; (2) die gebruik van verskillende voorbehandelingsmetodes vergelykend te bestudeer, naamlik stoomontploffing (160-220°C, 2-10 min), alkalies-gekataliseerde stoomontploffing (160- 220°C, 2-10 min, 1-7 wt.% NaOH) en waterige ammoniakweek (60-120°C, 1-6 ure, 5-15 wt.% NH3) om die materiaalverteerbaarheid en beskikbare metaboliseerbare energie van Senegalia mellifera te verhoog. Die chemiese samestellingsanalise van Senegalia mellifera-grondstof het ’n hoë konsentrasie lignien (32.06 ± 0.054 %DM) en lae vlakke van sellulose (27.19 ± 0.094 %DM) aangedui. Voedingsontleding het ’n lae vlak van ruproteïen (CP) (4.9 ± 1 %DM) in die veevoermengsel aangedui. Laastens het die voer ook ’n lae verteerbaarheid (EDOM) (50.02 g/kg DM) en beskikbare metaboliseerbare energie (0.46 MJ/kg DM MEEDOM & 1.32 MJ/kg DM NviroTek) gehad, wat aan ’n hoë mate van verharding en sellulose kristalliniteit toegeskryf kan word.Nadat die grondstof vooraf behandel is, is ’n beduidende verbetering (p < 0.05) op materiaalverteerbaarheid en beskikbare metaboliseerbare energie in alle behandelings waargeneem. Die doeltreffendheid van die individuele behandelings in terme van materiaalverteerbaarheid was soos volg: Die doeltreffendste metode was alkalies-gekataliseerde stoomontploffing, gevolg deur die outokatalitiese stoomontploffing, en die minste doeltreffende metode was waterige ammoniakweek. Alkalies-gekataliseerde stoomontploffing het die mees betekenisvolle invloed op materiaalverteerbaarheid gehad deur dit 11-voudig te verbeter tot 580.30 g/kg DM (58 %DM) en die beskikbare metaboliseerbare energie met net meer as 15 keer te verhoog tot ’n maksimum van 7.19 MJ/kg DM in die ernstigste toestande (220°C, 10 min, 7 wt.% NaOH). Outokatalitiese stoomontploffing het ook die materiaalverteerbaarheid 5-voudig verhoog tot 254.7 g/kg DM (25.47 %DM), terwyl die beskikbare metaboliese energie (7.8-voudig) tot 3.59 MJ/kg DM in behandelingstoestand (220°C, 2 min) verhoog is. Laastens was die gebruik van waterige ammoniakweek die minste doeltreffende metode aangesien dit die verteerbaarheid net twee maal verhoog het en die metaboliseerbare energie byna 4-voudig tot 138.1 g/kg DM (13.81 %DM) en 1.79 MJ/kg DM in die ernstigste behandelingstoestande (120°C, 6 ure, 15 wt.% NH3) verhoog is.Een van die groot kommernisse rakende behoorlike rumen mikrobiese funksie is die vereiste van ruproteïen (CP). Dit was dus belangrik om hierdie sleutelvoedingsfaktor regdeur die voorbehandelingsproses dop te hou. Waterige ammoniakweek was die doeltreffendste in die behoud van die ruproteïeninhoud, gevolg deur outokatalitiese stoomontploffing, en die minste doeltreffende metode was alkalies-gekataliseerde stoomontploffing. Wat die voedingseienskappe betref, is daar waargeneem dat alhoewel alkalies-gekataliseerde stoomontploffing materiaalafbreekbaarheid en beskikbare energie verbeter het, is die reeds lae vlak van CP opgeoffer en tot 1.05 %DM verlaag, wat aansienlik laer is (p < 0.05) in vergelyking met die CP-bewaring deur outokatalitiese stoomontploffing en waterige ammoniakweek. Laastens, met betrekking tot ruproteïen, het waterige ammoniakweek die CP en die beskikbare stikstof in voer met 13.5-282.78 g/kg DM (1.35-28.28 %DM) verhoog as gevolg van die chemiese binding van stikstof aan die voorbereide voer. Dit kan ’n moontlike rede vir ’n vals negatief wees met betrekking tot die toename in ruproteïen wat tydens waterige ammoniakweek opgemerk is. Ten slotte, deur die in vitro ensiematiese verteerbaarheid, die algehele beskikbare gemetaboliseerde energie en beskikbare ruproteïen van drie verskillende middels van voorbehandeling te vergelyk, het hierdie studie aangetoon dat alkalies-gekataliseerde stoomontploffing die beste algehele toename in die verteerbaarheid van Senegalia mellifera verskaf het en het dus die beskikbare metaboliese energie vir herkouers verhoog, al is die ruproteïenfraksie in die voorbehandelingsproses opgeoffer. Wat veevoer betref, is dit aanneemlik dat die verwydering van ’n Senegalia mellifera as ’n hele bos bestaande uit stamtakke en blare as veevoer na die optimale AKS-voorbehandeling gebruik kan word. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | xiv, 168 pages : illustrations (some color) | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/127196 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject.lcsh | Senegalia mellifera -- Classification | en_ZA |
| dc.subject.lcsh | Animal nutrition -- Namibia | en_ZA |
| dc.subject.lcsh | Feeds -- Namibia | en_ZA |
| dc.subject.lcsh | Agriculture -- Effect of environment on -- Namibia | en_ZA |
| dc.subject.lcsh | Droughts -- Namibia | en_ZA |
| dc.subject.lcsh | Alkaline catalysed steam explosion | en_ZA |
| dc.subject.lcsh | Energy metabolism | en_ZA |
| dc.subject.name | UCTD | en_ZA |
| dc.title | Utilization preparation of Senegalia mellifera to produce animal fodder | en_ZA |
| dc.type | Thesis | en_ZA |
Files
Original bundle
1 - 1 of 1
Loading...
- Name:
- neethling_utilization_2023.pdf
- Size:
- 3.78 MB
- Format:
- Adobe Portable Document Format
- Description: