Thesis (MPhil)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: The primary objective of today's pig producer is to maximize profit received per unit of pig space provided in a given facility. There are certain management strategies that a farmer can implement to ensure this. The goals of such strategies include maximizing performance and implementing proper pig flow schedules and to make sure current facilities are performing at maximum capacities or are better utilized. Labour in South Africa is still relatively inexpensive, but time is money. Feeding and cleaning small pens are time consuming and expensive to maintain (more feeders and water nipples, gates, walls and heating). Proper management of facility space is vital to remain competitive in today's pig industry. The amount of floor and feeder space provided within an animal's environment could vastly influence pig performance and profitability. Crowding pigs has a negative effect on Average Daily Gain (ADG) and overall performance. Conversely, facility cost per pig increases as additional space is provided, therefore, in the interest of pen efficiency, the space that allows for maximum individual performance may not be optimal for maximizing profit. Factors such as cleaning and cleaning time also have an effect on profitability. Another concerning factor associated with maximizing performance and maintaining the pig flow of a facility is that of Body Weight (BW) variation. Having uniform pigs at 70 day, post-weaning has been a major goal to ensure maximum performance in finishers. Numerous contradictions regarding the growth of piglets post-weaning (especially the effect of group size and floor space allowance) still exist in literature. Also, in South Africa, the majority of pig producers still believe that individual litters or small groups of pigs in the growers perform better and are the most economical production method. Therefore, this trial was performed to investigate the raising of large groups (200-450 pigs/group) compared to small groups (10-20 pigs/group) on their performance until 70 days when they were moved to growers. Over a period of two years, data was collected on a commercial 1200 sow unit in the Western Cape, South Africa. Crossbred pigs (n=14657; Landrace x Large White; both gilts and barrows) weaned at 19 to 24 days with average weaning weight of 5.11 kg were randomly divided into different group sizes. Groups of 10, 20, 200 and 450 were grouped together and were all given the same feed ration. The groups were housed in different buildings naturally ventilated with no artificial heating and with solid flooring. Pelleted diets were formulated (Startrite followed after two weeks with Expresweaner) by Meadows Feed Mills (Paarl, Western Cape) for weaned piglets and fed to all the piglets. The animals received the diets and water ad lib. All the piglets were weighed before being placed into the different pens (initial weight). After 69 - 72 days the piglets were weighed again (final weight). The pigs were weighed as a group and not individually. The data was statistically analysed by determining averages and standard deviations for each house. The results of this trial clearly indicate that raising piglets in larger groups does not negatively affect the performance of the piglet in terms of ADG and mortality. In larger groups, the less time (labour time) spent cleaning and the fewer feeders needed, also results in lower production costs. In today's economical environment, the producer that can lower his production cost while maintaining production standards has a significant advantage. Therefore, it is believed that by grouping pigs in larger groups, labor time (in terms of cleaning) can be reduced, and will lower production cost without reducing production standards. / AFRIKAANSE OPSOMMING: Die hoofdoel van vandag se varkprodusente is om maksimum wins per eenheid vark spasie te maak. Daar is sekere produksietegnieke wat 'n produsent kan volg om dit te verseker. Die doel van die tegnieke is om te verseker dat maksimale produksienorme en doeltreffende vark vloei gehandhaaf word asook dat huidige fassiliteite optimum benut word. Arbeid is nog relatief goedkoop in Suid-Afrika (SA), maar tyd is geld. Die voeding en skoonmaak van klein hokke is tydrowend en duur om te onderhou (meer voerbakke, waternippels, hekke, mure en verhitting). Om koste-effektief te boer, moet goeie bestuur van oppervlakte toegepas word. Die hoeveelheid oppervlakte en voerspasie beskikbaar, het 'n groot invloed op die produksievermoë en winsgewendheid van die varkies. Om te veel varkies per area aan te hou, het 'n negatiewe effek op die Gemiddelde Daaglikse Toename (GOT) en algehele prestasie. Soos die vloerspasie per varkie vergroot, neem die produksiekoste ook toe en is die area wat benodig word om varkies maksimaal te laat produseer, nie altyd die winsgewenste nie. Skoonmaak en skoonmaaktyd het ook 'n invloed op winsgewendheid. Die ideaal is om uniforme varkies op 70 dae te produseer. 'n Variasie in gewig is rede tot kommer, aangesien dit die produksie in die groeiafdeling beïnvloed. Verskeie teenstrydighede aangaande die groei van varkies naspeen (veral die effek van goepgrootte en vloerspasie) bestaan steeds in die literatuur. In SA is die meeste produsente ook nog onder die indruk dat klein groepe varkies beter presteer as groot groepe en die mees ekonomiese metode is om te boer. Daarom is 'n proef geloods om vas te stel hoe die produksie verskil tussen klein groepe (10 - 20 varkies per groep) teenoor groot groepe (200 - 450 varkies per groep) tot 70 dae ouderdom wanneer hulle na die groeiafdeling skuif. Oor 'n periode van twee jaar is data gekollekteer op In kommersiële 1200 sog-eenheid in die Wes-Kaap, Suid-Afrika. Kruisgeteelde varke (n=14657; Landras x Groot Wit; beide beertjies en soggies) is gespeen tussen 19 en 24 dae, met 'n gemiddelde speen gewig van 5.11 kg en ewekansig verdeel in verskillende groepgroottes. Groepe van 10, 20, 200, en 450 varkies was saamgegroepeer en het almal dieselfde dieet ontvang. Die groepe is in verskillende geboue gehuisves en al die geboue het soliede vloere gehad en was natuurlik geventileerd met geen kunsmatige verhitting nie. 'n Verpilde dieet is deur Meadows Voermeule (Paarl, Wes-Kaap) geformuleer (Startrite vir twee weke en dan Expresweaner vir die res van die proef). Die varke het die dieet en water ad lib ontvang. AI die varkies is geweeg voordat hulle in die verskillende hokke geplaas is (aanvangsmassa). Na 69 - 72 dae is die varkies weer geweeg (eindmassa). Die varkies is as 'n goep en nie individueel geweeg nie. Die data is statisties verwerk deur gemiddeldes en standaard-afwykings vir elke huis te bepaal. Die resultate van hierdie proef het duidelik aangetoon dat die grootmaak van varkies in groter goepe nie die produksie van die varkies (i.t.v. GOT of mortaliteit) nadelig beïnvloed het nie. In groter goepe is minder tyd nodig om die hokke skoon te maak en is minder voerders nodig. Dit lei tot 'n verlaging in produksiekoste. Deesdae het die produsent wat sy produksie koste kan verlaag, sonder om produksiestandaarde in the boet, 'n aansienslike voorsprong. Die gevolgtrekking word dus gemaak dat deur varkies in groter groepe aan te hou, arbeid (in terme van skoonmaak) verminder kan word en dus kan produksiekoste verminder sonder dat produksie self afneem.

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L'objectiu de la present tesis fou estudiar si la incorporació d'ingredients fibrosos a la dieta de garrins recent deslletats, era una bona estratègia per minimitzar els desordres intestinals que normalment ocorren durant l'etapa post¬deslletament, i d'aquesta manera facilitar l'adaptació digestiva dels animals en les següents etapes de creixement. Per aconseguir aquest objectiu, es dissenyaren quatre proves (capítols 4 a 7) experimentals.En la Prova 1 (Molist et al., 2009a), primer de tot volíem confirmar uns resultats preliminars obtinguts en una prova anterior on s'havia observat un major creixement dels animals quan una font de fibra insoluble (segó de blat, WB) fou introduïda en una dieta de garrins post-deslletament. Al mateix temps, també volíem analitzar si aquest tipus de fibra insoluble era adequada per aquest període de creixement dels animals, o si per contra, era més interessant incorporar un tipus de fibra soluble (com la polpa de remolatxa, SBP). L'objectiu de l'estudi era explorar l'efecte d'incloure dos tipus diferents de fonts de fibra (WB, insoluble i SBP, soluble) sobre el creixement, les característiques físico-químiques de la digesta i l'activitat metabòlica i la composició de la microbiota intestinal. Els resultats mostraren que la fermentació intestinal fou baixa durant la primera setmana post-deslletament. L'addició de WB o WB i SBP en la dieta incrementaren la fermentació intestinal i la concentració d'àcid butíric en la digesta cecal juntament amb una reducció de la població d'enterobactèries en les femtes. La conclusió de l'estudi fou que el consum d'un tipus de fibra insoluble durant els primers dies després del deslletament (ja sigui WB o WB-SBP) modifica les característiques físico-químiques de la digesta i afecta la colonització microbiana a l'intestí gros. També especularem que els efectes observats amb la inclusió de WB podrien està relacionats amb: 1.- canvis en les característiques físico-químiques de la digesta, tals com una majora capacitat de retenció d'aigua (WRC) i una major fermentació de la digesta intestinal, 2.- un efecte físic relacionat amb la mida de partícula gran o 3.- una reducció del temps de trànsit de la digesta intestinal. En la Prova 2 (Molist et al., 2009b), es volia confirmar la reducció de la població d'enterobactèries promoguda pel WB, i la seva capacitat per reduir els desordres digestius front a una infecció experimental amb E. coli K88. A més a més, es volia clarificar si aquest efecte observat amb la introducció de WB en la dieta estava relacionat amb la seva mida de partícula. Els resultats obtinguts confirmaren que la inclusió de WB reduïa la població de E. coli en la digesta ileal, i encara més interessant, també reduïa l'adhesió del E. coli K88 a la mucosa ileal. Al mateix temps, el WB amb mida de partícula grollera reduí la diversitat de la microbiota intestinal en comparació amb el WB molturat. La tercera prova (Prova 3, Molist et al., 2010a) fou dissenyada per esbrinar si els efectes positius del WB sobre la microbiota intestinal es devien a un efecte del WB sobre el trànsit intestinal dels animals. La hipòtesi del treball fou que la incorporació de WB en la dieta podia estimular el trànsit intestinal i reduir la paràlisis de la digesta intestinal dels garrins, causada per l'anorèxia que pateixen els animals en el període post-deslletament. En aquest experiment, el WB fou comparat amb un fàrmac que s'utilitza en medicina humana per tractar la diarrea que al mateix temps redueix el trànsit intestinal (loperamida). Els resultats de nou mostraren els efectes del WB sobre les característiques físico-químiques de la digesta (increment de la WRC) i la promoció de la fermentació intestinal (incrementant la concentració d'àcid butíric i disminuint la concentració dels isoàcids en la digesta intestinal). De forma inesperada, la loperamida incrementà el consum d'aliment i el creixement dels animals. Suggerírem que aquest efecte estava relacionat amb l'efecte analgèsic i l'activitat opioide d'aquest fàrmac en el tracte intestinal. No poguérem confirmar si el WB reduí el temps de trànsit intestinal o el possible rol que juga la modificació del temps de trànsit intestinal sobre els canvis de la microbiota intestinal. En l'última prova (Prova 4, Molist et al., 2010b) la intenció era confirmar tots els resultats previs (reducció de la població d'enterobactèries i increment de la concentració d'àcid butíric) en un comparació entre la incorporació de WB amb la inclusió d'òxid de zinc (ZnO) en la dieta. El ZnO és un ingredient àmpliament utilitzat en les dietes post-deslletament pel seu efecte antimicrobià similar al que s'obtenia amb la incorporació d'antibiòtics promotors de creixement (AGP) en el pinso, i per tant oposat a l'efecte promogut per la incorporació de fibra en la dieta. A més a més, considerant els resultats observats sobre la reducció de l'adhesió del E. coli K88 a la mucosa ileal promogut per l'addició de WB, es volia clarificar si el WB també podia exercir un efecte físic i blocar l'adhesió del E. coli K88 a la mucosa. Els resultats foren una mica sorprenents perquè s'observà una interacció negativa entre el WB i el ZnO sobre la microbiota intestinal. Aquesta interacció negativa s'associà a la presència de fitats en la dieta. Aquests resultats posaren de relleu la recomanació d'incorporar enzims (fitases) en les dietes després del deslletament amb l'objectiu d'incrementar la biodisponibilitat del zinc de la dieta. També detectarem una alta habilitat de la fracció soluble extreta del WB d'unir-se al E. coli K88 in-vitro. Aquest resultat ens permet suggerir que part dels efectes positius sobre la microbiota intestinal observats amb la incorporació de WB en la dieta eren deguts entre altres factors, a la seva capacitat de blocar l'adhesió de E. coli patògens a la mucosa intestinal. Els resultats exposats en la present tesis, avalen l'estratègia d'incloure un nivell moderat de fibra (>60 g FND/kg per porcs entre 6 - 12 kg) en les dietes post-deslletament. Els resultats obtinguts mostren els efectes positius derivats de la inclusió d'una font de fibra insoluble, com WB, en la modificació de l'ambient intestinal i la instauració d'una microbiota saludable. Aquests efectes beneficiosos observats amb l'addicció de WB s'associaren a modificacions en les característiques físico-químiques de la digesta (increment de la WRC de la digesta) i amb la seva habilitat per blocar l'adhesió del E. coli a la mucosa ileal. Tot i així, el contingut en fitats d'aquest ingredient pot reduir la biodisponibilitat i l'eficàcia del ZnO en la dieta, fins i tot quan es subministra a dosis terapèutiques. És per aquest motiu que proposem considerar l'addició de fitases en dietes post-deslletament a base de cereals per: 1.- incrementar la biodisponibilitat de Zn, 2.- mantenir els efectes beneficiosos relacionat amb la inclusió de ZnO o WB en la dieta, o 3.- reduir la dosis de ZnO en la dieta. / The objective of this thesis was to study whether the incorporation of fibrous ingredients in the diet of piglets would minimize the intestinal disorders that usually occur during the early period after weaning and facilitate the adaptation of the digestive system of the animals in the subsequent growing periods. To achieve this goal, four trials (chapters 4 to 7) were designed. In Trial 1 (Molist et al., 2009a), we first wanted to confirm some preliminary positive results associated with a higher growth rate of the animals obtained when an insoluble fibre source (wheat bran, WB) was introduced in post-weaning diets. At the same time, we wanted to assess whether this type of fibre source was appropiate for this period, or whether it would be more advantageous to incorporate a soluble fibre source (such as the sugar beet pulp, SBP). The study aimed to explore the effects of including two fibre sources (WB, insoluble and SBP, soluble) on the performance, the physicochemical properties of digesta and the metabolic activity and composition of the intestinal microbiota. Results showed that intestinal fermentation was low during the first week after weaning. The addition of WB or WB plus SBP in the diet increased intestinal fermentation and the concentration of butyric acid in the caecum digesta, and reduced the enterobacteria population in faeces. It was concluded that consumption of an insoluble fibre source during the first days after weaning (either WB or WB-SBP) modifies the physicochemical properties of digesta and affects the microbial colonization in the hindgut. We also speculated that the effects observed with the inclusion of WB could be associated with: 1.- changes in the physicochemical properties of digesta, such as the higher water retention capacity (WRC) and fermentation promoted in digesta, 2.- a physical effect related to its larger particle size or 3.- a reduction in the transit time of digesta. In Trial 2 (Molist et al., 2009b), we wanted to confirm the referred reduction of the enterobacteria population promoted by WB, and its likely ability to reduce digestive disturbances after an experimental infection with E. coli K88. In addition, we wanted to clarify whether this effect of WB was related to its particle size. The results confirmed that WB inclusion reduced the E. coli population in the ileum digesta and, more interesting, also reduced the E. coli K88 attachment to the ileum mucosa. Coarse particle size reduced the microbial diversity compared to finely milled WB. The third trial (Trial 3, Molist et al., 2010a) was designed to elucidate whether the positive effects of WB on the intestinal microbiota could be due to an effect of WB on the intestinal transit of the animals. Our hypothesis was that incorporation of WB in the diet could stimulate the intestinal transit and so reduce the intestinal stasis of digesta in the piglets provoked by post-weaning anorexia. In this experiment, WB was compared with a drug used in human medicine to treat diarrhoea that slows the intestinal transit (loperamide). The results again showed the effects of WB on the physicochemical properties of digesta (increasing WRC) and the enhancement of gut fermentation (increasing butyric acid and lowering isoacid concentration associated to gut fermentation). Unexpectedly, loperamide increased the feed intake and animal growth. We suggested that this effect could be associated to its analgesic effect on and opioid activity in the intestinal tract. We were not able to confirm if WB reduced the intestinal transit time or the likely role of the modification of the intestinal transit time in the changes in intestinal microbiota. The last trial (Trial 4, Molist et al., 2010b) intended to confirm all the previous results (the reduction of enterobacteria population and increasing the butyrate concentration) in a comparison between the incorporation of WB with the inclusion of zinc oxide (ZnO) in the diet. ZnO is a widely used ingredient in post-weaning diets producing antimicrobial effects resembling those of the antibiotic growth promoters (AGP) and therefore opposed to the inclusion of fibre in the diet. In addition, and considering the previous observed effects on the E. coli K88 adhesion to the ileum mucosa, we wanted to clarify whether WB could have a physical role on the blockage of the adhesion of E. coli K88 to the mucosa. The results were quite surprising because a negative interaction between WB and ZnO was observed on the intestinal microbiota, which was associated to the presence of phytates in the diet. These results highlighted the recommendation of incorporating enzymes (phytases) in the post-weaning diets in order to increase the bioavailability of zinc. We also detected a high ability of soluble WB extract to bind E. coli K88 in-vitro, which suggests that part of the positive effects on the intestinal microbiota reported with the WB inclusion were due to its ability to block the adhesion of pathogenic E. coli to the intestinal mucosa. Results exposed in this thesis, support the strategy of including a moderate amount of fibre (>60 g NDF/kg for pigs between 6 - 12 kg) in the diets of early weaned pigs. Our results show the positive effects of including an insoluble source, such as WB on the modification of the intestinal environment and the instauration of a healthy microbiota. These beneficial effects of WB inclusion were associated to changes on the physicochemical properties of digesta (like an increasing WRC of the digesta) and with its ability to block E. coli attachment to the ileum mucosa. However, the presence of phytates in this ingredient may also reduce the availability and efficacy of ZnO in the diet, even when it is provided at therapeutic doses. We propose the consideration of the inclusion of phytase in the post-weaning cereal based diets in order to: 1.- increase Zn biovailability, 2.- maintain the beneficial effects related to ZnO or WB inclusion, or 3.- reduce the therapeutic doses of ZnO in the diet.

A piglet model of gastrointestinal inflammation (INF) and protein energy malnutrition (PEM) was developed to determine the mechanisms responsible for growth retardation and muscle wasting during inflammatory stress. Acute PEM decreased liver and plasma protein fractional synthesis rates (FSR), measured by stable isotope (2H3-leucine) incorporation. Conversely, both rates increased during PEM+INF at the expense of growth and muscle FSR. INF increased plasma protein synthesis by 77% in PEM without increasing its plasma concentration, demonstrating that the measurement of plasma protein concentration alone underestimates the metabolic impact of INF. INF during PEM results in a re-prioritization of amino acids from muscle protein synthesis and growth to hepatic synthesis of plasma proteins to support the acute phase response. This underscores the critical role of adequate protein-energy nutrition during inflammation in preventing muscle wasting and growth failure. This new piglet model can be applied to investigate nutritional and therapeutic interventions in inflammatory bowel disease.

A model was developed in growing piglets to study the use of urinary total sulfur excretion as an indicator of sulfur amino acid (SAA) catabolism and the nitrogen (N)/sulfur (S) balance ratio as an indicator of non-protein SAA storage. The recovery of administrated methionine as urinary total S over 48 hours was 106% in well-nourished piglets, but only 69% in protein malnourished piglets. The N/S balance ratio of protein malnourished piglets was lower than that of well-nourished piglets, and this ratio further decreased after methionine administration. We conclude that in a protein malnourished state, relatively more S than N is retained and a significant portion of the S derived from administrated methionine is retained in non-protein pools. These results demonstrate that urinary total S excretion can provide an accurate measure of SAA catabolism; and the N/S balance ratio can provide valuable information about non-protein SAA storage in growing piglets.

Thesis (Ph.D.). / Written for the School of Dietetics and Human Nutrition. Title from title page of PDF (viewed 2007/08/29). Includes bibliographical references.

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No description available.

Thesis (PhD)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: This study describes the use of a gastro-intestinal model to screen lactic acid bacteria isolated from the gastro-intestinal tract of post-weaned piglets (raised on six different diets) for probiotic properties. Intestinal bacteria were isolated from ,the stomach, duodenum, jejunum, caecum, ileum and colon. The highest cell numbers (6 x 107 cfulg) were isolated from the ileum. No significant differences in viable cell counts were recorded for piglets raised on the six diets. Isolates with the best overall probiotic properties were identified as members of Lactobacillus salivarius and Lactobacillus fermentum. The two strains selected for further studies were Lactobacillus plantarum 423 (originally isolated from sorghum beer) and Lactobacillus salivarius 241 (isolated from pig intestine). Enterococcus faecalis FAIR E 92 was originally isolated from pig intestine and was included in this study as a non-pathogenic challenge strain. L. plantarum 423 produces a bacteriocin plantaricin 423, active against E. faecalis FAIRE 92. L. plan/arum 423 and L. salivarius 241 were included in the gastro-intestinal model and their adhesion to the mucus of porcine ileum studied with fluorescent-in-si/u-hybridization (FISH). A decrease in viable cell numbers of L. plan/arum 423 was recorded in the duodenum, jejunum and ileum in the presence of bile and pancreatic juice. However, higher cell numbers were recorded in the caecum and anterior colon, which suggested that strain 423 recovered from these stress factors. Plantaricin 423 was detected for up to 28 hours in the duodenum, jejunum, ileum and middle colon. Lower cell numbers (one log unit) of L. salivarius 241 were recorded in the gastro-intestinal model over seven days, compared to strain 423. Piglets of one, 14 and 28-days-old were dosed with L. plan/arum 423 and L. salivarius 241, separately and in combination (1: 1). In a separate experiment, 14-day-old piglets were challenged twice with E. faecalis FAIRE 92, followed by dosage with strains 423 and 241. New-borne piglets dosed with L. plantarum 423 gained more weight (4 kg over 19 days) compared to piglets dosed with L. salivarius 241 (2.2 kg over 19 days), or a combination of the two strains (2 kg over 19 days). Piglets of 14 and 28-days-old, on the other hand, gained more weight when dosed with a combination of strains 423 and 241. The cell numbers of E. faecalis FAIR E 92 and other enterococci decreased drastically (two log units) when the piglets were dosed with the latter two strains. Overall, piglets of various ages reacted differently when administered L. plantarum 423 and L. salivarius 241, separately or in combination. Fluorescent-in-situ-hybridization (FISH) was used to study the in vivo adhesion of L. plantarum and L. salivarius to mucus in the stomach, duodenum, jejunum, ileum, caecum and colon. The highest number of L. plantarum cells was recorded in the ileum, whereas L. salivarius favoured adhesion to the duodenum. A decrease in cell numbers of E. faecalis in the ileum mucus was recorded when a combination of the probiotic strains 423 and 241 was administered. This study provided a reliable estimation of the presence and/or adhesion of L. plantarum and L. salivarius to various parts of the porcine gastro-intestinal tract, without the use of expensive cultivation techniques. Insight was gained into the co-evolution existing between probiotic bacteria and the porcine gastro-intestinal tract, emphasizing the use of gastro-intestinal models to study the dynamics of the gastro-intestinal tract. / AFRIKAANSE OPSOMMING: Hierdie studie beskryf die gebruik van 'n gastro-intestinale model, om melksuurbakterieë wat geïsoleer is uit die spysverteringskanaal (SVK) van reeds gespeende varkies (gevoed op ses verskillende diëte) vir probiotiese eienskappe te toets. Ingewandsbakterieë is uit die maag, duodenum, jejunum, caecum, ileum en kolon geïsoleer. Die hoogste aantal selle (6 x 107 kve/g) is geïsoleer uit die ileum. Geen betekenisvolle verskille in lewensvatbare seltellings, vir varkies gevoed op ses verskillende voere is aangeteken nie. Isolate met die beste algehele probiotiese eienskappe is as Lactobacillus salivarius en Lactobacillus fermentum geïdentifiseer. Vir verdere studie is twee isolate Lactobacillus plantarum (oorspronklik uit sorghum-bier geïsoleer) en Lactobacillus salivarius (uit die varkdermkanaal geïsoleer) geselekteer. Enterococcus faecalis FAIRE 92, oorspronklik uit die varkdermkanaal geïsoleer, is in hierdie studie as 'n nie-patogeniese indikator gebruik. L. plantarum 423 produseer 'n bakteriosien plantarisien 423 wat aktief is teen E. faecalis FAIR E92. L. plantarum 423 en L. sa/ivarius 241 is ingesluit in die gastro-intestinale model, en vashegting van die bakterieë aan die mukus van vark-ileum is met fluoresensie-in-si/uhibridisasie (FISH) bestudeer. 'n Afname in lewende selgetalle van L. plan/arum 423 in die duodenum, jejunum en ileum is aangetoon in reaksie tot die byvoeging van gal en pankreatiese sappe. Hoër selgetalle is nietemin aangeteken in die caecum en voorste gedeelte van die kolon, wat 'n aanduiding gee dat isolaat 423, ten spyte van hierdie stres-faktore, oorleef. Plantaricin 423 is vir 'n tydperk (28 uur) in die duodenum, jejunum, ileum en sentrale kolon gevind. Laer selgetalle (een logaritmiese eenheid) van L. salivarius 241 is in die gastro-intestinale modeloor 'n tydperk van sewe dae aangetoon, in vergelyking met isolaat 423. Een, 14 en 28 dag oud varkies is met L. plantarum 423 en L. salivarius 241 (afsonderlik en in kombinasie 1:1) twee keer gedaag met E. faecalis FAIR E 92, opgevolg met dosering van 423 en 241. Pasgebore varkies het die hoogste gewigstoename getoon (4 kg oor 19 dae) na dosering met L. plantarum 423 in vergelyking met varkies gedoseer met L. salivarius 241 (2.2 kg oor 19 dae) of 'n kombinasie van die twee isolate (2 kg oor 19 dae). Daarenteen het veertien- en 28 dag oud varkies beter gewigstoename getoon na dosering met 'n kombinasie van isolate 423 en 241. Die selgetalle van E. faecalis FAIRE 92 en ander enterococci het drasties afgeneem (twee logaritmiese eenhede) nadat die varkies met laasgenoemde twee isolate gedoseer is. Varkies van onderskeie ouderdom het verskillend gereageer na dosering met L. plantarum 423 en L. salivarius 241 afsonderlik of in kombinasie. Fluoresensie-in-situ-hibridisasie (FISH) is gebruik om die in vivo vashegting van L plantarum en L. salivarius tot die vark mukus in die maag, duodenum, jejunum, ileum, caecum en kolon te bestudeer. Die hoogste telling van L. plantarum selle is aangeteken in die ileum, terwyl L. salivarius aanhegting tot die duodenum verkies het. 'n Afname in seltellings van E. faecalis in die ileum mukus was aangeteken na toediening met 'n kombinasie van probiotiese isolate 423 en 241. Hierdie studie het 'n betroubare bepaling van die voorkoms en/ofvashegting van L. plantarum en L. sa/ivarius isolate in verskeie gedeeltes van die varkspysverteringskanaal voorsien, sonder die hulp van duur kwekings tegnieke. Probiotiese bakterieë is in 'n gastro-intestinale model, wat die natuurlike omgewing verteenwoordig, bestudeer. Insig oor die ko-evolusie tussen probiotiese bakterieë en die SVK van die vark is verkry. Die gebruik van 'n gastro-intestinale model om die dinamika van die SVK te bestudeer is met hierdie studie beklemtoon.

Thesis (MScAgric)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Starch is the main component of cereal grains and is usually the primary energy source for pigs and poultry. Feed manufacturing can adopt several measures, including physical treatments such as milling or pelleting and other techniques, such as enzyme treatment, to disrupt cell structure. Grinding and pelleting are the most common food processing methods used for pigs. However, pelleting of complete balanced feeds is no longer such an economical proposition due to rising energy and equipment costs; therefore this cost has to be outweighed by an increased production efficiency. It has been known for many years that grinding is an essential prerequisite for the satisfactory blending of the ingredients of a multi-component food. Feed cost represents the major item in the cost of animal production. Without doubt, research and production efforts will continue to refine feed processing techniques to reduce the cost of feed and to increase the value of feed for a target animal. The possibilities for improvements in feed are endless; however the cost of each innovation must be carefully weighed against demonstrated improvements in animal performance. Experiment 1: The effect of feed processing techniques on weanling pig growth-performance The effects of processing of the carbohydrate source and the feed on growth performance of commercial Landrace x Large White piglets (n=480) weaned at 28 ± 2 d were investigated. Two processing combinations of the carbohydrate source were used with 3 processing conditions of the diet in a 2 x 3 factorial design. The pigs were blocked by weight (7.196 ± 2.03 kg BW) and then allotted randomly to 1 of 6 dietary treatments. Ten pens of 8 piglets each were fed with each dietary treatment. The two main processing conditions of the carbohydrate source were raw or extruded maize and the 3 processing conditions of the diet was meal or pelleted or extruded. No carbohydrate processing x diet processing interactions were observed (P > 0.05) for ADG, ADFI or FeR. In this experiment, extrusion of the maize led to an significant decrease in FeR efficiency (P < 0.05) (1.57 vs. 1.42) when compared to a raw maize diet. Pelleting a diet had no significant effect (P > 0.05) on ADG but tended to decrease ADFI (P < 0.07) and significantly improve FeR efficiency (1.49 vs. 1.66) when compared to a meal diet. Extruding the whole diet did not have any significant (P > 0.05) effect on ADG but tended to decrease ADFI (P < 0.07) and gave an significant improvement in FeR when compared to a meal diet (1.34 vs. 1.66). This processing technique also gave a significant improvement (P < 0.01) in FeR when compared to a pelleted diet (1.34 vs. 1.49). Experiment 2: The effect of pig feed processing conditions on pig metabolism parameters The effects of processing of the carbohydrate source and the diet on certain metabolism and production parameters of commercial Landrace x Large White pigs (n=24) were investigated. Two processing combinations of the carbohydrate source were used with 3 processing combinations in a 2 x 3 factorial design. Six diets were formulated on an iso-nutrient basis (14.48 MJ/kg metabolizable energy (ME), 23.01 crude protein (CP), 1.092% lysine, 0.742% methionine and cystine and 0.271% tryptophan on a DM basis). The pigs were blocked by weight (26.02 ± 0.25 kg BW) and then allotted randomly to I of 6 dietary treatments. The carbohydrate source was raw or extruded maize and the diets was meal or pelleted or extruded. No carbohydrate processing x diet feed form interactions were observed (P > 0.05) for dry matter intake (DMI), dry matter digestible energy (DE), Nitrogen (N) or dry matter intake (DMI). In a metabolism and nitrogen (N) balance study, apparent N digestibility, digestible energy and metabolizable energy contents were found not to be significantly (P > 0.05) influenced by carbohydrate or diet processing. / AFRIKAANSE OPSOMMING: Stysel is die hoof komponent in grane en is gewoonlik die primêre verskaffer van energie vir varke en pluimvee. Voermeulens kan verskeie metodes implementeer, insluitend fisiese behandeling soos bv. maal, verpilling en ensiem behandelings, om sel struktuur te verander. Maal en verpilling is die mees algemene prosessering metodes wat vir varkvoer gebruik word. Maar, verpilling van totaal geballanseerde voere is nie meer so ekonomies geregverdig nie as gevolg van stygende energie en masjinerie koste. Daarom moet die koste van voervervaardiging oorbrug word deur 'n verhoogde produksiedoeltreffendheid. Dit is al lankal bekend dat maal 'n voorvereiste is vir effektiewe vermenging van grondstowwe van 'n multi-komponent voer. Voerkoste verteenwoordig die hoof item van die koste van intesiewe diereproduksie. Voedingskudiges sal sonder twyfel voortgaan om voerprosessering te verfyn om so die koste van die rantsoen te verlaag en om die waarde van die rantsoen te verhoog vir die dier. Die moontlikhede is veelvuldig, maar die koste van elke ontwikkeling moet opgeweeg word teen verhoogde diereproduksie. Eksperiment 1: Die effek van voerprosesserings-tegnieke op speenvark groei en produksie 'n Proef is uitgevoer om die prosesseringseffek van 'n koolhidraat bron en voer op die groei van Landras x Groot Wit speenvarke (n=480) wat gespeen is op 28 ± 2 d te bepaal. Twee prosesserings-kombinasies van die koolhidraat bron en drie prosesserings-kondisies van die dieet is in 'n 2 x 3 faktoriaal ontwerp uitgevoer. Die varkies is geblok volgens massa (oorspronklik 7.196 kg ± 2 kg) en toe ewekansig in I van 6 dieët behandelings ingedeel. Die proefdiëte is vir lO hokke varkies gevoer, elke hok het 8 varkies in gehad. Die twee hoof prosesserings-kondisies van die koolhidraat bron was rou of gaar mielies en die drie prosesserings-kondisies van die dieët was meelof gaar of geëkstrueer. Geen koolhidraat prosesserings x dieët prosesserings interaksie van die dieët was opgemerk (P > 0.05) vir gemiddelde daaglikse toename (GOT), gemiddelde daaglikse voer inname (GDVI) of voer omset doeltreffendheid (VOD) nie. In die eksperiment was die VOD van die geëkstrueerde mielie dieët, statisties betekenisvol laer (P < 0.05) (1.57 vs.1.42) as die rou mielie dieët. Verpilling van die dieët het geen statisties betekenisvolle effek (P > 0.05) op GDV! gehad nie, maar die VOD was statisties betekenisvol (P < 0.05) beter (1.49 vs. 1.66) wanneer dit met die meel dieët vergelyk word. Ekstrusie van die dieët het geen statisties betekenisvolle effek op GOT en GOVI gehad nie, maar die VOD was statisties betekenisvol (P < 0.05) beter wanneer dit met die meel (1.34 vs. 1.66) en verpilde dieët (1.34 vs 1.49) vergelyk word. Eksperiment 2: Die effek van voer prosessering op vark metabolisme parameters 'n Eksperiment is uitgevoer op Landras x Groot Wit bere (n=24) om die effek van prosessering van 'n koolhidraat bron en voer te bepaal. Twee prosesserings-kombinasies van die koolhidraat bron en drie prosesserings-kondisies van die dieët is in 'n 2 x 3 faktoriaal ontwerp uitgevoer. Ses diëte is geformuleer op 'n iso-nutriënt basis (14.48 MJ/kg metaboliseerbare energie (ME), 23.01 ru-proteïen (RP), 1.092% lisien, 0.742% metionien and sistien en 0.271 % tryptofaan op 'n droeë materiaal (DM) basis). Die varke is geblok volgens massa en ewekansig aan 1 van 6 diëte toegeken. Die koolhidraat bron was gaar of rou mielies en die diëte was meel, verpil of geëkstrueer. Geen koolhidraat-prosessering x dieet interaksie is opgemerk (P > 0.05) nie. In 'n metabolisme en stikstof (N) balans-studie is daar gevind dat DM verteerbaarheid, skynbare N verteerbaarheid, verteerbare energie (GE) en ME inhoud nie beduidend deur die behandelings beïnvloed word nie.