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Ruminal and intestinal digestibility of rumen protected lysine and its effect on production responses in Merino rams

dc.contributor.advisorVan Zyl, J. H. C.en_ZA
dc.contributor.advisorCruywagen, C. W.en_ZA
dc.contributor.advisorCloete, J. J. E.en_ZA
dc.contributor.authorUys, Janienen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.en_ZA
dc.date.accessioned2020-02-18T10:23:59Z
dc.date.accessioned2020-04-28T12:09:34Z
dc.date.available2020-02-18T10:23:59Z
dc.date.available2020-04-28T12:09:34Z
dc.date.issued2020-03
dc.identifier.urihttp://hdl.handle.net/10019.1/107924
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2020.en_ZA
dc.description.abstractENGLISH ABSTRACT: Wool is a large export commodity in South Africa where the price is determined by supply and demand. The average clean wool price per kilogram for the 2017/2018 wool clip season was R183.84 (top lines). This represents a price increase of approximately R30.00/kg (16.3%) in just one clip season. Therefore, improving the production of wool or optimizing the cost of the production of wool is of importance to the economic contribution of this farming sector. A major objective in any animal production system is to increase the efficiency of converting nutrients into animal products. Some research suggested that the fibre growth of sheep may be limited by protein content that could be inadequate in the diet. These studies also reported that additional protein supplementation can influence wool yield. However, it was also reported that dietary protein supplementation had a negative influence by increasing fibre diameter. Another study reported that when ruminal degradation of high quality protein is reduced, substantial increases in the growth rate of wool is possible. Microbial protein (MP) alone is likely to meet the maintenance requirements of an animal but it is often insufficient to meet the demand for optimal production. Currently, various attempts have been made to develop and produce amino acids (AA) that escape degradation in the rumen. Due of the large quantities of AA that are degraded in the rumen, there is a lack of information on the availability of AA in the lower digestive tract of ruminants. This has prompted researchers to develop concepts to protect proteins from ruminal degradation, increase the supply of proteins for production and reduce nitrogen losses as urea via urine. Such methods include structural manipulation to produce AA analogues and AA coated with resistant materials. The capsule can thus resist degradation of AA in the neutral pH-environment of the rumen, but the AA would be made available for enzymatic digestion at the lower pH of the small intestine. Little research has been done, not only on the use of synthetic AA in ruminants, but more so on wool producing sheep. The purpose of the current study was thus to determine whether or not rumen-protected lysine could improve the wool production of Merino sheep. More so wool growth, thus fibre length, fibre diameter, staple strength, fibre curvature and clean fleece weight, by supplementing the diet with high or low levels of bypass lysine or rumen degradable lysine. The objectives of the study were to investigate the effect of different levels and type of dietary lysine on the production parameters of Merino rams. A secondary objective was thus to determine the difference in rumen degradability and intestinal digestion of rumen degradable lysine and bypass lysine. The final objective was to determine the absorption of this dietary lysine in the lower digestive tract when considering different inclusion levels of degradable and bypass lysine. In the first trial, 40 Merino rams were supplemented with a diet that contained either high or low levels of bypass lysine and rumen degraded lysine. Merino rams with an average weight of 37kg and 1.5 years old, were fed for three months and during this period the feed intake were recorded daily to calculate the average daily intake (ADI) and the sheep were weighed weekly to calculate average daily gain (ADG). Blood samples were taken at the beginning of the trial and once during the trial to determine lysine absorption into the blood plasma. At the end of the trial, all the rams were sheared to determine wool production parameters throughout the trial. This study showed that supplementation of the bypass AA significantly (P ≤ 0.05) increased the dry matter intake (DMI) of the rams. None of the measured wool parameters showed any differences between treatments. The blood plasma lysine levels were only significantly higher (P ≤ 0.05) for the diets high in lysine but were not affected by degradability type. It was concluded that the use of rumen protected lysine as a supplementation in Merino rams showed little response to production parameters. The second part of this study was to determine the apparent ruminal and intestinal digestibility values of a commercial lysine product by means of a three-step in vitro procedure, commonly referred to as the Ross Assay. The trial was done as a randomized block design with two types of commercial lysine products (rumen degradable and rumen protected) and six replications, where three cows were used as rumen fluid donors in two separate runs. The modified Ross Assay used in the trial was divided into two phases. This first phase represented the ruminal degradation phase and the second phase represented intestinal digestion. No significant differences in ruminal degradation or intestinal digestibility were observed between the two products. It was thus concluded that the encapsulation of the bypass lysine product did not decrease in vitro rumen degradation and neither did it increase the availability of lysine for absorption in the lower digestive tract.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Wol is grootliks ‘n uitvoerkommoditeit in Suid-Afrika waar die prys deur vraag en aanbod bepaal word. Die gemiddelde skoonwolprys per kilogram vir die 2017/2018 wolskeerseisoen was R183.84 vir die toplyne. Hierdie prys verteenwoordig ‘n toename van ongeveer R30.00/kg (16.3%) in net een skeerseisoen. Die optimering van wolproduksie, sowel as die koste van wolproduksie, is van kardinale belang tot die ekonomiese bydrae van hierdie boerderyvertakking. Die hoofdoelwit in enige veeproduksiesisteem is om die doeltreffendheid van omskakeling van nutriënte na diereprodukte te verhoog. Navorsingsresultate dui aan dat die veselgroei van wolskape beperk kan word deur onvoldoende dieëtproteïeninname. Hierdie studies het ook aangedui dat addisionele dieetproteïen wolopbrengs verhoog, maar dat dit terselfdertyd die veseldeursnit benadeel deur dit te verdik. Verdere navorsing het aangedui dat ‘n verhoging in die groeitempo van wol moontlik is indien proteïendegradering in die rumen verlaag kan word. Mikrobiese proteïenproduksie alleen voldoen normaalweg aan die onderhoudsvereistes van die dier, maar dit is dikwels onvoldoende om aan hoogproduseerende diere se vereistes te voldoen. Daar word tans verskeie pogings aangewend om aminosure te vervaardig wat degradering in die rumen vryspring. As gevolg van die groot hoeveelheid aminosure wat deur mikrobes in die rumen verteer word, is daar ongelukkig nog nie veel kennis oor die beskikbaarheid van aminosure in die laer spysverteringskanaal van herkouers nie. Dit veroorsaak dat navorsers verskeie konsepte ontwikkel wat ten doel het om dieetproteïen te beskerm teen rumendegradering. Hierdie konsepte het ten doel om proteïen vir produksie te verhoog, asook om stikstofverliese in die vorm van ureum via uriene te verlaag. Hierdie metodes sluit in stukturele manipulasie van aminosuur-analoë, asook om aminosure te kapsuleer met weerstandige materiale. Hierdie kapsulerings poog om die afbraak van aminosure deur rumenmikrobe in die rumenomgewing te weerstaan, maar om dit dan weer by die laer pH van die dunderm beskikbaar te stel vir ensiematiese vertering. Weinig navorsing is tot dusver op die gebruik van sintetiese aminosure in herkouervoeding gedoen en nog minder in wolproduserende skape. Die doel van hierdie studie was dus om te bepaal of die voeding van rumenbeskermde lisienprodukte die wolproduksie van Merinoskape kan beïnvloed. Wolproduksie sluit vesesllengte, -deursnit, -kartel, staplesterkte, en skoon opbrengs in. Wolproduksieparamenters van Merinoramme is bepaal na die voeding van verskillende kombinasies van hoë- en lae vlakke van beide degradeerbare en nie-degradeerbare lisienprodukte. Die doelwit van hieridie studie was eerstens om die invloed van verskillende vlakke van dieetlisien op verskeie produksieparameters van Merinoramme te ondersoek. ‘n Tweede doelwit was om te bepaal of daar ‘n verskil tussen die produkte is in terme van rumendegradeerbaarheid en vertering in die laer spysverteringskanaal Die finale doelwit was om te bepaal of daar ‘n verskil in die absorpsie van lisien in die laer spysvereringskanaal van Merinoramme is indien verskillende insluitingsvlakke van rumendegradeerbare- en verbyvloeilisien gevoer word. In die eerste eksperiment is 40 Merinoramme se diëte met verkillende aanvullings van hoë- of lae vlakke van verbyvloeilisien en rumendegradeerbare lisien aangevul. Agtien maand oue Merinoramme met ‘n gemiddelde gewig van 37kg het die behandelings vir drie maande ontvang waartydens die daaglikse voerinnames bepaal is ten einde die gemiddelde daaglikse inname te bereken. Die skape is eenmaal per week geweeg om die gemiddelde daaglikse toename te bereken. Bloedmonsters is versamel om die plasmalisienvlakke voor en gedurende die proef te bepaal. Aan die einde van die proef is al die ramme geskeer om wolproduksieparameters na afloop van die proef te bepaal. Hierdie studie het aangedui dat dieetaanvulling van verbyvloeilisien die droëmateriaalinname van die ramme betekenisvol (P ≤ 0.05) verhoog het. Geen verskille in enige van die wolparameters is tussen behandelings waargeneem nie. Die plasmalisienvlakke was slegs betekenisvol hoër (P ≤ 0.05) vir die diëte hoog in lisien, maar is nie beïnvloed deur lisiendegradeerbaarheid nie. Die gebruik van rumenbeskermde lisien as ‘n aanvulling vir Merinoramme het produksieparameters weinig beïnvloed. Die tweede deel van hierdie studie het gepoog om die verdwyning van ‘n kommersiële lisienproduk in die rumen, sowel as die laer spysverteringskanaal, te bepaal deur middel van die Ross in vitro metode. Die proef is as ‘n ewekansige blokontwerp gedoen met twee tipes kommersiële lisienprodukte (rumen degradeerbare- en verbyvloeilisien) en ses herhalings waar drie koeie in twee verskillende sessies gebruik is. Die gemodifiseerde Ross-metode wat vir hierdie studie gebruik was, is in twee fases verdeel. Die eerste fase het ruminale degradering gesimuleer en die tweede fase het intestinale vertering gesimuleer. Die resultate van hierdie studie het geen betekenisvolle verskille tussen die degradeerbare en nie-degradeerbare lisienprodukte getoon nie. Die studie het verder aangedui dat daar geen verskille tussen die produkte was ten opsigte van die intestinale vertering nie. Die gevoltrekking is gemaak dat die kapsulering van die verbyvloei lisienproduk nie die rumendegradeerbaarheid daarvan kon verlaag nie en gevolglik ook nie intestinale lisienbeskikbaarheid in die laer SVK kon verhoog nie.af_ZA
dc.format.extentxii, iv, 59 leaves : illustrations (some color)
dc.language.isoenen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.subjectRumen fermentationen_ZA
dc.subjectWool -- Qualityen_ZA
dc.subjectMerino sheep -- Breedingen_ZA
dc.subjectProteins in animal nutritionen_ZA
dc.subjectUCTDen_ZA
dc.subjectRuminants -- Digestive organsen_ZA
dc.subjectInterstinal absorptionen_ZA
dc.subjectLysine in animal nutritionen_ZA
dc.titleRuminal and intestinal digestibility of rumen protected lysine and its effect on production responses in Merino ramsen_ZA
dc.typeThesisen_ZA
dc.description.versionMastersen_ZA
dc.rights.holderStellenbosch Universityen_ZA


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