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The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs
Thesis (MScAgric)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613752713543680 |
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| access_status_str | Open Access |
| author | Nowers, Petrus Johannes |
| author2 | Van Zyl, Johan Hendrik Combrink |
| author_browse | Nowers, Petrus Johannes Van Zyl, Johan Hendrik Combrink |
| author_facet | Van Zyl, Johan Hendrik Combrink Nowers, Petrus Johannes |
| author_sort | Nowers, Petrus Johannes |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScAgric)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127132 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:41:07.950Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127132 The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs Nowers, Petrus Johannes Van Zyl, Johan Hendrik Combrink Cruywagen, C. W. Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science. Lambs -- Feeding and feeds Dohne Merino sheep -- Breeding Exogenous fibrolytic enzymes Ruminants -- Nutrition Digestive enzymes Proteins in animal nutrition Feedlot lambs Feedlots Lamb (Meat) -- Quality UCTD Thesis (MScAgric)--Stellenbosch University, 2023. ENGLISH ABSTRACT: The demand for animal protein and animal products are constantly increasing because of the rapid growth of the human population. The need for high-quality animal protein threatens global food security, therefore it is necessary to develop and adopt strategies to improve intensive, sustainable farming. Ruminants have the ability to digest fibrous forage materials and convert it into consumable products for human use. However, fibre material is only partially digested by ruminants. Several strategies to improve efficiency of fibre utilisation by ruminants exist. Exogenous fibrolytic enzymes (EFEs) are one of the methods to improve fibre digestibility and animal performance in ruminant production systems. VistaPre-T® (AB Vista, USA), a commercial exogenous fibrolytic enzyme cocktail, was used in a study to evaluate the potential improvement of fibre digestibility and consequently improvement in animal performance. The first study was conducted to evaluate the in vitro improvement of neutral detergent fibre (NDF) digestibility by treating three roughage substrates, lucerne hay, wheat straw and maize stover, with rice bran (control) and the EFE cocktail. The enzyme preparation was added to the treatment substrates at a recommended rate, equivalent to 165 g/t dry matter (DM). The samples were incubated at 39º for 0,12, 24 and 48h in jars containing rumen fluid and a buffer solution to simulate rumen conditions. It was concluded that the application of the specific combination of cellulase and xylanase did not improve in vitro NDF digestibility. The second study comprised of an in vivo study that was conducted at the University of Stellenbosch Welgevallen experimental farm to evaluate the effect of the commercial EFE cocktail on production and profitability parameters in feedlot lambs. In this study 48 Dohne Merino, castrated, lambs were fed under feedlot conditions in a 3 x 2 factorial layout with three forage substrates (lucerne hay, wheat straw and maize stover) either treated with EFE or not (control). The diets were formulated to be iso-caloric and iso-nitrogenous. The diets contained a commercial high protein concentrate (HPC) and maize meal. Lambs were fed for 6 weeks until a live weight of 42 kg was achieved whereafter they were slaughtered. No significant differences in production parameters including body weight, feed conversion ratio (FCR), average daily gain (ADG) and total dry matter intake (DMI) between the treated and control diets were observed. Carcass and profitability parameters, cold carcass weight (CCW), dressing %, gross income, feed cost nor margin above specified cost did not differ between treatments. It was concluded that the addition of an exogenous fibrolytic enzyme cocktail did not alter animal performance or profitability, which could be ascribed to the relatively low fibre inclusion in the diet. AFRIKAANSE OPSOMMING: Die vraag na dierlike proteïen en -produkte neem voortdurend toe as gevolg van die vinnige groei van die menslike bevolking. Die behoefte aan hoëgehalte diereproteïen bedreig wêreldwye voedselsekuriteit, daarom is dit nodig om strategieë te ontwikkel om intensiewe, volhoubare boerdery te verbeter. Herkouers het die vermoë om ruvoer te verteer en verder om te skakel in bruikbare produkte vir menslike gebruik. Ruvoer word egter slegs gedeeltelik deur herkouers benut. Verskeie tegnieke bestaan om die verteerbaarheid van vessel te verbeter. Eksogene fibrolitiese ensieme (EFE) is een van hierdie metodes om veselverteerbaarheid en diereprestasie in herkouerproduksiestelsels te verbeter. VistaPre-T® (AB Vista, VSA), 'n kommersiële eksogene fibrolitiese ensiem-mengsel, is in 'n studie gebruik om die potensiële verbetering in veselverteerbaarheid van ruvoer en gevolglik verbetering in diereprestasie te evalueer. Die eerste studie om die in vitro verbetering van neutrale bestande vesel (NBV) verteerbaarheid te evalueer deur drie ruvoersubstate, lusern hooi, koring strooi en mielie reste, met skoon rys semels (kontrole) en/of met die EFE-produk te behandel is uitgevoer. Die ensiem is by die ruvoer substrate teen 'n dosis gelykstaande aan 165 g/t om die effek op in vitro NBV-verdwyning te evalueer gevoeg. Die monsters is by 39º vir 0,12,24 en 48h in flesse wat rumenvloeistof en 'n bufferoplossing bevat het om rumentoestande te simuleer, geïnkubeer. Daar is tot die gevolgtrekking gekom dat die behandeling met ‘n spesifieke kombinasie van sellulase en xilanase nie in vitro NBV verteerbaarheid van enige van die ruvoersubstrate verbeter het nie. Die tweede studie was 'n in vivo evaluasie by die Universiteit van Stellenbosch, Welgevallen proefplaas om die effek van die kommersiële ensiem-mengsel op produksie- en winsgewendheidsparameters van voerkraallammers te evalueer. In hierdie studie is 48 Dohne Merino hammels onder voerkraaltoestande in 'n 3 x 2-faktoriale uitleg gevoer met drie ruvoer substrate (lusern hooi, koring strooi en mielie reste) wat of behandel met die EFE was of nie (kontrole). Lammers is vir 6 weke gevoer totdat 'n lewende massa van 42 kg behaal is waarna die diere geslag is. Geen betekenisvolle verskille in produksieparameters, soos liggaamsmassa, voeromsettings vermoë, gemiddelde daaglikse toename (GDT) en totale droeë material inname (DMI) tussen die behandelde en kontrole diete is waargeneem nie. Karkas- en winsgewendheidparameters, koue karkas massa, uitslag %, bruto inkomste, voerkoste en marge bo gespesifiseerde koste het ook nie beduidend tussen behandelings verskil nie. Daar is dus tot die gevolgtrekking gekom dat die byvoeging van die eksogene fibrolitiese ensiem kombinasie nie diereprestasie of winsgewendheid verander het nie en kon aan die relatief lae vesel insluiting in die dieet toegeskryf word. Masters 2023-03-06T13:13:06Z 2023-05-18T07:05:51Z 2023-03-06T13:13:06Z 2023-05-18T07:05:51Z 2023-03 Thesis http://hdl.handle.net/10019.1/127132 en_ZA Stellenbosch University xiii, 74 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Lambs -- Feeding and feeds Dohne Merino sheep -- Breeding Exogenous fibrolytic enzymes Ruminants -- Nutrition Digestive enzymes Proteins in animal nutrition Feedlot lambs Feedlots Lamb (Meat) -- Quality UCTD Nowers, Petrus Johannes The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title | The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title_full | The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title_fullStr | The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title_full_unstemmed | The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title_short | The effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| title_sort | effect of exogenous fibrolytic enzymes on fibre digestibility in feedlot lambs |
| topic | Lambs -- Feeding and feeds Dohne Merino sheep -- Breeding Exogenous fibrolytic enzymes Ruminants -- Nutrition Digestive enzymes Proteins in animal nutrition Feedlot lambs Feedlots Lamb (Meat) -- Quality UCTD |
| url | http://hdl.handle.net/10019.1/127132 |
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