Dissertations / Theses on the topic 'Rabbit'

There is a need to develop a range different VLP for use as nanoscale templates and vaccines. The aim of this research was to develop RHDV VLP as a versatile vaccine delivery system easily modified for use against a wide range of different diseases. Production of Rabbit haemorrhagic disease virus (RHDV) capsid protein in a baculovirus system led to the self-assembly of Virus-like Particles (VLP) that could be purified to greater than 99% purity using simple methods. The capsid gene, vp60, can be manipulated genetically to incorporate immunogenic peptide sequences or a functional DNA-binding site. Fusion of these small epitopes to VP60 was well tolerated, forming VLP and greatly enhanced the presentation of peptide to, and activation of CD4+ T helper cell hybridoma. To avoid constraints imposed on chimeric VLP and dramatically increase the versatility of RHDV VLP, rapid conjugation of antigen was carried out, employing the hetero-bifunctional chemical linker, sulpho-SMCC. Incorporation of sulfhydral groups by design or treatment with SATA allowed for great versatility, in turn enabling many diverse peptides and proteins to be conjugated to VLP. RHDV VLP and consequently the conjugated GFP antigen were efficiently taken up by DC with more than 85% of DC positive for GFP by flow cytometry. This was also visualised by confocal microscopy and electron microscopy of both gold- labelled VLP and conjugated antigen. RHDV VLP conjugate was shown to induce the significant up regulation of the activation markers CD40, CD80, CD86 and MHC class II on the surface of dendritic cells (DC). As well, DC pulsed with RHDV VLP/OVA effectively presented OVA to both CD4+ and CD8+ T cells transgenic for respective peptide-specific T cell receptors, eliciting a greater proliferative response in both T cell subsets than antigen delivered alone. The surface accessibility of peptides on VLP was demonstrated, while administration of VLP/Ovalbumin (OVA) conjugate in mice was shown to evoke very high titre antibody responses specific for conjugated antigen. VLP/OVA conjugates were also shown to induce IFN-γ production and OVA-specific cytotoxic killing in vivo, of up to 80% of fluorescently labelled, adoptively transferred target cells. No distinguishable cytotoxicity was detected in unimmunised control mice. This assay was also used to demonstrate the necessity for antigen to be conjugated to VLP, as antigen mixed with VLP induced only sub-optimal killing. To investigate the anti-tumour effects, mice vaccinated with VLP conjugated to OVA protein, CD4+ or CD8+ T cell OVA epitopes were inoculated with B16- OVA tumour cells and monitored for tumour growth. Untreated control mice had to be sacrificed by day 19, while mice immunised with either VLP/OVA or VLP conjugated with both CD4+ and CD8+ OVA epitopes, showed a significant delay in tumour growth (P = 0.0002), with one mouse remaining free of palpable tumour until day 92. These results show that RHDV VLP can be easily produced and purified and demonstrate the versatility of this RHDV capsid. Rapid conjugation techniques allowed the modification of VLP with both peptide and protein rendered these antigens highly immunogenic, stimulating both humoral and cell-mediated immunity targeted against conjugated antigens of choice. The versatility and immune stimulating properties of RHDV VLP provides a molecular tool with almost limitless applications within the fields of nanotechnology and immunology.

A small number of framed prints can be seen on approach to the exhibition. They are black and white — the predominant colours of the entire exhibition. Viewers will walk into a dimly lit room and see a frail, house-shaped structure made out of Perspex plates. The plates have images scratched into them, some with the residue of ink. Inside the house is an old iron rabbit trap as well as lighting which casts imprecise shadows into the surroundings. Around the walls are a series of charcoal drawings on paper. Most of the images are of a single object or figure. Circling around the room and weaving in and out of the viewers will be Pam on an old pushbike.

Dissertação (Mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão.
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Thesis (Ph. D.)--University of Nevada, Reno, 2007.
"May, 2007." Includes bibliographical references. Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2007]. 1 microfilm reel ; 35 mm.

The experiments described in this thesis were designed to assess changes in pasture dynamics (biomass and species composition of pasture) of grazing land on the Southern Tablelands of ACT and NSW, after 16 combinations of rabbit control treatments had been applied. The rabbit control performed by CSIRO Division of Wildlife and Ecology consisted of all combinations of presence-absence of Poisoning (using sodium monofluoroacetate, 1080: POIS), Ripping (ripping warrens using a tractor fitted with ripping tynes: RIP), Fumigation (pressure fumigation using chloropicrin: FUM) and repeated follow-up fumigation (using phostoxin pellets one, six and eighteen months after completion of the initial treatment: ANN). The pasture was assessed before treatments were applied, and every six months after rabbit control treatments. Treatment combinations were assigned randomly in a 24 factorial design on a total of 32 sites. There was a significant increase of pasture biomass at the RIP+ANN treatment at post-treatment sample 5. The analysis of covariance did not detect any other significant increase or decrease of pasture biomass for any rabbit control treatment, at any posttreatment sample. A significant increase of grass species occurred for the treatments of POIS+RIP+FUM, POIS and RIP+ANN for the post-treatment samples of 1, 3 and 5 respectively. There was a significant increase of thistles at the rabbit control treatments of POIS+RIP+FUM+ANN (post-treatment sample 1), RIP, ANN, RIP+FUM, RIP+FUM+ANN and POIS+RIP+FUM+ANN (post-treatment sample 3) and RIP and FUM+ANN (post-treatment sample 5). A significant increase of weeds occurred at FUM (post-treatment sample 3) and at FUM+ANN (post-treatment sample 5). No significant changes in the amount of herbs or legumes was apparent for any rabbit control treatment or post-treatment sample. There were no significant decreases for any species group. Except for the significant results for post-treatment sample 1, all significant increases of biomass for any species group occurred during spring (post-treatment sample 3 and 5) which suggests a growth phase during spring then subsequent dieback (particularly for thistles and weeds), as any change was not detected in the following autumn sample. No strong trend is evident for any particular rabbit control treatments, or any combination of treatments. Analysis of covariance revealed that the rabbit control treatment of RIP+ANN showed significant increases in both total biomass of pasture and grass biomass during post-treatment sample 5. This treatment reduced the number of active entrances the most. Significant positive correlations were found between pasture biomass (total) with grass, herb, legume, thistle and weed species groups. Significant negative correlations between grass biomass and the number of active entrances were found when the rabbit control had been highly effective in reducing the number of active entrances. When rabbit control had not been very successful, there was a significant positive but low correlation with the number of active entrances. There was no significant relationship between the number of active entrances with the weight of rabbit dung pellets. It is reasoned that they are different measures of rabbit abundance. More rabbit dung pellets were found closer to the warren than further away from the warren, but there was no correlation between rabbit dung and pasture biomass. Rainfall was above average for most of the experiment, biomass increased accordingly, and rabbit control was highly successful. The resulting changes in the pasture were difficult to detect, although some increases in species composition groups occurred. It is reasoned that the changes observed are partly attributable to seasonal conditions, and to high rainfall. Grazing by domestic animals, sheep and cattle, had been found to be consistent throughout the experiment.

In the past decades, a series of small peptides, Protein Transduction Domain (PTD), were discovered to be able to facilitate the delivery of small proteins into living cells. With the specific feature, researchers have successfully delivered some functional proteins into living cells. To fully explore and understand the functions and structures of intracellular proteins, more powerful tools are under demand. Recently, an increasing number of rabbit monoclonal antibodies (RabMAbs) have been approved to able to recognize subtle distinctions between the changes of intracellular proteins status. They could be good tools for researchers with the ability to traverse through cell membrane into living cells. In this dissertation, a novel delivery technology for RabMAbs was established. Transcriptional activator of transcription (TAT) peptide was utilized as a delivery carrier for RabMAbs. It was demonstrated that RabMAbs could be delivered into living cells by conjugating with TAT peptide. Different cell lines, including adherent and suspension cells, were tested for the delivery of RabMAbs. The delivery process was studied in terms of incubation concentration and time, and an optimal delivery condition was established. To investigate the biological function of delivered RabMAbs inside cytoplasm, three RabMAbs against actin, procaspase-3 and NF-κB respectively were studied. Their binding activities after delivery were verified via sandwich-ELISA data. The immunofluorescent staining of the delivered RabMAb against actin showed it specifically bound to the actin filament in its native morphology. The quantitative analysis of the delivered RabMAb against procaspase-3 showed that approximately 60% of delivered antibody bound to the antigen proteins. The delivered RabMAb against NF-KB apparently blocked the nuclear translocation of NF-KB introduced by TNF-a. The success of delivering the three rabbit monoclonal antibodies with binding or inhibiting functions demonstrated the feasibility of delivering various RabMAbs into living cells by TAT peptide for studying the biological functions of intracellular proteins. Furthermore, to overcome the efficiency and cost issues of the RabMAb delivery system, a universal delivery platform for RabMAbs was developed. This platform uses goat-anti-rabbit polyclonal antibody conjugated with TAT peptide as delivery vehicle. It was confirmed that the goat-anti-rabbit polyclonal antibody modified with TAT peptide was able to capture RabMAbs and deliver RabMAbs into living cells by the conjugated TAT peptide. The results provide a promising delivery platform for all RabMAbs.

The European rabbit lives in defined social groups of between two and about twenty individuals. There are distinct social hierarchies within each group. Rabbits are known to scent-mark their environment with secretions from several glands, and the secretion of the submandibular cutaneous gland is strongly correlated with social status. Dominant, male rabbits have a higher secretory activity of the gland, and show much more scent-marking behaviour than do any other individuals within the social group. This study was principally conducted at Hope Farm, Cattai National Park in New South Wales, Australia.The proteinaceous components of the secretion varied between individuals, but the protein profile of an individual did not change over time.It was found that dominant rabbits chin mark preferentially at the entrances to warrens, and at the boundaries of their territory.The work in this study provides new insights into the way that rabbit semiochemical messages work. The difference between the secretion of a subordinate and a dominant rabbit appears to be due to the presence or absence of one compound, 2-phenoxy ethanol. This compound, with known fixative properties, supports the idea that the only difference between dominant and subordinate secretions is whether or not they persist in the environment after marking. Such a mechanism for asserting dominance may be much more common in mammals than is apparent from the published literature
Doctor of Philosophy (PhD)

Thesis (Ph.D.) -- University of Western Sydney, Hawkesbury, 2000.
A thesis presented to the University of Western Sydney, Hawkesbury, in partial fulfilment of the requirements for the degree of Doctor of Philosophy, December, 2000. Includes bibliographical references.

This thesis relates to the work of building a mathematical model of the impact of Rabbit Calicivirus Disease (RCD) on the European Rabbit, Oryctolagus cuniculus, in Australia. After introducing the general biology of rabbits and the immunology of RCD, we build a time-dependent single site model. We construct a single-site population dynamic model with age structure, seasonal birth rate, density dependent regulation of the population size and climatic variability for various regions of Australia. After investigating suitable parameter ranges, we incorporate the disease dynamics through an indirect transmission model based on two different hypotheses which we call the Strong Juvenile hypothesis and the Weak Juvenile hypothesis. These differ in their assumption about Juvenile immunity to the disease. The ecological impact of both hypotheses is tested for both the single site and multiple site (spatial) models. The disease impact is investigated by varying the disease virulence, i.e. a parameter measuring the "strength" of the virus. Subsequently, a multiple site (spatial) model for the Riverina region is built by using the single-site model as building block. Data from Lake Urana is used to parameterize a seasonal emigration rate from each site. Density dependent immigration is added together with a hazard coefficient which rabbits face when leaving one site and trying to become established in another. Acceptance in a new site is regulated by the population density at the entry site. Several spatial configurations of sites are tested and the spatial dynamics of the disease is investigated. Finally, we construct a model to investigate the long term evolution of the disease virus. We postulate the existence of several strains of the disease and trade-offs between disease characteristics. We allow for mutation of the virus and run the model for two contrasting geographical regions of Australia. We compare the results for the different regions and the different hypotheses regarding Juvenile immunity (the Strong Juvenile hypothesis and the Weak Juvenile hypothesis). It is shown, unexpectedly, that intermediate levels of disease virulence are not selected.

Repair of bone defects is a major challenge in orthopaedic surgery. Current bone graft treatments, including autografts, allografts and xenografts, have many limitations making it necessary to develop a biomaterial to be a bone graft substitute. One such biomaterial is bioactive resorbable silica-calcium phosphate nanocomposite (SCPC). SCPC was processed using a 3D rapid prototyping technique and sintered at different temperatures to create porous scaffolds. SEM analyses and mercury intrusion porosimetry showed SCPC to be highly porous with micro- and nanopores. BET analysis indicated that SCPC had high surface area. Mechanical testing demonstrated that SCPC had a compressive strength similar to trabecular bone. Analysis of different thermal treatment temperatures indicated as the temperature was increased, the porosity decreased and the mechanical strength increased. When loaded with rhBMP-2 (SCPC-rhBMP-2), SCPC provided a sustained release profile of rhBMP-2 for 14 days. This was shown to be a greater release than hydroxyapatite (HA)-rhBMP-2. After immersion in SBF, ICP analyses showed the calcium concentration of SBF dropped drastically after one day of immersion. In conjunction, FTIR showed the formation of a hydroxyapatite layer on the SCPC surface and was confirmed by SEM. SCPC thermally treated at 850 ??C demonstrated the greatest dissolution/precipitation reactions when immersed in SBF. Processing the SCPC-rhBMP-2 hybrid using a rapid prototyping technique allowed for an exact replica of the rabbit ulna to be fabricated. This was implanted into a 10 mm segmental defect in the rabbit ulna. CT scans during the healing of the defect showed intimate union between SCPC-rhBMP-2 and the bone and about 65% healing of the defect after 4 weeks. Rabbits were euthanized after 12 and 16 weeks. Digital images show almost complete healing of the defect after 16 weeks. Torsional testing of the ulna after 12 weeks demonstrated restoration of maximum torque and angle at failure. Histological evaluation after 12 weeks showed the regenerated bone has all the morphological characteristics of mature bone. Through in-vitro and in-vivo testing, it can be recommended that the porous bioactive SCPC can serve as a successful delivery system for biological growth factors and serve as an alternative to autologous bone grafting.

The atrioventricular node (AVN) of the heart is responsible for the important conduction delay between atrial systole and ventricular systole. The anatomical architecture and functional properties of the AVN are complex. Ionic currents have been characterised in the AVN at both the whole tissue level and single cell level. However, little is known about the molecular basis of these ionic currents. There were two aims of this research: 1) to generate an accurate three-dimensional reconstruction of the rabbit AVN conduction axis and 2) to use real time PCR and in situ hybridisation to measure levels of mRNA for specific ion channels and membrane proteins in the rabbit AVN and surrounding atrial and ventricular tissue. Neurofilament-M (NF-M) immunolabelling revealed a tract of cells extending from the posterior nodal extension through the compact node to the common bundle. The PNE appeared to correspond to the slow pathway. Loosely packed atrial muscle comprised the anterior region of the AVN conduction axis closest to the enclosed part of the AVN and most likely represents the fast pathway. Lower nodal cells extended from the common bundle to the lower extremities of the compact node and PNE. Significant differences in the mRNA levels between the PNE and atrial muscle for the pacemaker channel HCN4, INa channels Navl. 1 and Na, 1.5, the Ica,L channel Cav1.3, the I to channel ß-subunit KChIP2 and Cx43 were found HCNI, Nav 1.1, Cav1.3 and NF-M mRNA were significantly higher in the PNE, compact node and common bundle compared to the atrium and ventricle. Kir 2.1 mRNA was significantly higher in the ventricular muscle compared to the PNE and atrial muscle. Atrial natriuretic peptide (ANP) mRNA, was significantly higher in the atrial muscle compared to other tissues. For mRNAs for the Ito channels, Kv 4.2 and Kv 4.3, the delayed rectifier K+ channels, Kv 1.5, ERG, K, LQTI and minK, the inward rectifier K+ channels, Kir 2.2, Kir6.2 and ß-subunit SUR2A, and the Ca2+ handling proteins, RYR2, RYR3, NCXI and SERCA2a, there were no significant differences between tissues. In situ hybridisation staining revealed further complexity of the AVN conduction axis tissue. A region of loosely packed atrial tissue immediately adjacent to the nodal tissue was KChIP2 negative and Nav1.5 negative, and the lower nodal cells were both Cav 1.2 and Cav 1.3 positive. This study has described a complex architecture of the AVN and added further complexity by providing a detailed account of ion channel expression throughout this tissue.

Myocardial ischemia activates a phospholipase A2 that targets plasmalogen phospholipids and liberates 1-0-alkenyl-Iysoplasmenylcholine (LPLC) in preference to 1-0- acyl-Iysophosphatidylcholine (LPC). Although LPC is a pro arrhythmic ischemic metabolite, the effect of LPLC on cardiac electrophysiology is unknown. At the lowest doses investigated, LPLC induced spontaneous contractions in otherwise quiescent rabbit ventricular myocytes significantly faster than LPC. Spontaneous contractions developed with median times of 16.4 (n = 64), 27.4 (n = 36), and >60 min (n = 25) during exposure to 5, 2.5, and 1 JlM LPLC compared with 38.0 (n = 48) and >60 min (n = 29) for 5 and 2.5 JlM LPC, respectively. Median times for 10 JlM lysolipids were not different. To characterize the mechanism of spontaneous activity, membrane potential (Em) and whole-cell currents were measured. LPLC caused an abrupt and sustained depolarization of Em by z 50 m V and culminated in the loss of excitability (n = 7). Voltage-clamp analysis of steady-state currents revealed an inward current at the normal resting Em that reversed at - 18.5 ± 0.9 m V (n = 12). The reversal potential of this current was insensitive to Ca-channel blockade by Cd2+ (n = 3), or by lowering bath [Cl-]. However, a lO-fold reduction in bath [Na+] caused repolarization and reduced the inward current by 56.6 ± 3.6% at -83 m V (n = 4). In contrast, Na-channel blockade by tetrodotoxin (n = 4) or saxitoxin (n =3) failed to inhibit membrane depolarization or the current induced by LPLC. Two lanthanides were studied to determine if the LPLC current was mediated by stretch-activated channels (SACs). Gd3+ ( 100 IlM), a known SAC blocker, and La3+ (100 IlM), devoid of SAC blocking activity, inhibited the LPLC-induced current by 80.2 ± 8.3% (n = 7) and 80.7 ± 8.3 % (n = 6), respectively, at -83 mY. Exposure to hypertonic bathing medium and cell shrinkage failed to restore Em (n = 5) or inhibit the LPLC-induced current (n = 2), which confirmed that lanthanides were not acting through inhibition of SACs. Consistent with the effects on membrane current, pretreatment with 100 IlM Gd3+ or La3+ but not Cd2+, significantly delayed spontaneous activity in 5 IlM LPLC (median times: Gd3+, 55.4 min (n = 35); La3+, 53.0 min (n = 38); Cd2+, 17.4 min (n = 19)). Lanthanides increase phospholipid ordering and may oppose membrane perturbations induced by LPLC. LPLC may contribute to ventricular dysrhythmias during ischemia.

Lactational anoestrus and anovulation place limitations on the economic and biological efficiency of the three main domestic farm species ie cow, pig and sheep by reducing reproductive efficiency. The factors of Remating Interval, Nutrition and Suckling have been shown to influence fertility during lactation in these species. The objective of the present study was to examine the effects of these factors on fertility and identify the mechanisms by which they act, using the lactating domestic rabbit as an experimental model and so provide information which may help overcome the obstacles preventing concurrent pregnancy and lactation in the domestic farm species. Experiment 1 provided data on the fertility of primiparous crossbred lactating does in the immediate postpartum period. This information was used to decide on which day postpartum does should be remated in subsequent experiments. Sixty-four does each suckling 6 pups were mated on day 1 (N = 17), 2 (N = 17), 3 (N = 15) or 4 (N = 15) postpartum (where day 0 = the day of parturition) and killed on day 10 postcoitum (where day 0 = the day of mating) to assess fertility. Overall fertility levels were high during this period. There were no significant differences between does remated on day 1- 4 postpartum in their mating response (percentage of those does tested for mating, which mated) and, overall this was 97%, ovulation response (percentage of those does mating, which ovulated), overall 77%, implantation response (proportion of those does ovulating, which implanted ova), overall 83%, implantation rate, overall 8.7 or pre-implantation mortality (%), overall 24%. Ovulation rate was significantly increased in does mated on day 3 (13.3) and 4 (13.1) compared with those on day 1 (10.2) (P 0.05) and 2 (9.6) (P 0.01) postpartum. From these results day 1 postpartum remating was found to result in the highest level of absolute fertility (ie by multiplication of the estimated pregnancy rates (the percentage of does implanting ova of those mated) of' 82%, 60%, 60% and 53% with the implantation rate 7.9, 8.1, 9.4 and 9.6 of does mated on day 1 (N = 17) , 2 (N = 15), 3 (N = 15) and 4 (N = 15) postpartum respectively, giving a total of 111, 73, 85 and 77 pups on day 1, 2, 3 and 4 respectively) during this period postpartum and was therefore used in future experiments concerning the remating interval. In Experiment 2, the effects of the remating interval and nutrition on the fertility of lactating crossbred does was examined. Eighty-six does each suckling six pups were remated on either day 1 or 14 postpartum and offered diets with digestible energy (D.E.) contents of 8.5 or 15.4 M.J./ kg D.M. and digestible crude protein contents (D.C.P.) of 129 or 227 g/kg D.M. and which were otherwise nutritionally adequate for lactating does. The experiment was carried out over three consecutive lactations and does were killed at selected times in each lactation to assess fertility and body composition. Diet had no effect on any aspect of fertility, while in contrast the remating interval was shown to have a significant effect. Does remated on day 1 had a significantly greater ovulation response in the first (82% vs 63%, P 0.10) and second (100% vs 77%, P 0.05) lactation compared with those mated on day 14 postpartum. Pregnancy rate was also significantly greater in does remated on day 1 in the first (76% vs 51%, P 0.05) and the second (100% vs 67%, P 0.01) lactation compared with those mated on day 14 postpartum. There were no differences in pre or post-implantation mortality between does remated on day 1 and 14 postpartum and therefore pregnancy rate was determined by the initial ovulation response. Litter size at term was found to be related to the initial ovulation rate and both were greater in does remated on day 14 compared to day 1 postpartum. This reached significance for litter size at term in the first lactation (7.8: day 1 vs 10.1: day 14, P 0.01) and ovulation rate in the second lactation, which was 12.4 for does remated on day 1 and 17.8 for those remated on day 14 postpartum (P 0.01). There was no significant difference in the body composition of pregnant does on the various treatment combinations over the course of the experiment or in lactation performance between does which were pregnant and those which were not. Experiment 3 was undertaken to confirm the effects of the remating interval on fertility observed in does on Experiment 2 and also to record measures of doe lactation performance to assess if they could be related with the effects of this factor.

This thesis investigates aspects of the community ecology of rabbit parasites with particular emphasis upon the gut helminths, utilising a 23 (later extended to 26) year time series of rabbits and their parasites. A clearer understanding of parasite communities can lead to more effective biological control strategies. Rabbits are regarded as a serious pest species throughout Europe and the Antipodes and the use of the myxomatosis virus, as a biological control agent, has already been tried and failed. However, a clearer picture of the parasite community may offer future possibilities for control. Additionally, the rabbit is a good model for other grazing species, as it carries a similar gut helminth community. Drug resistance is an increasing problem in a wide range of parasites. A clearer appreciation of parasite communities could also aid in the search for effective and environmentally sound pathogen control strategies (e.g. via cross immunity or competition with benign species). Theoretical models have revealed the importance of aggregation to the stability of the host parasite relationship, to parasite evolution and to interspecific parasite interactions. A number of models have considered the effect of varying aggregation upon these dynamics with differing outcomes to those where aggregation was a fixed parameter. Here the stability of the distribution for each of the rabbit helminths was examined using Taylor's power law. The analyses revealed that aggregation was not a stable parameter but varied with month, year, host sex, host age, and host myxomatosis status. Evidence for the existence of interspecific parasite interactions in natural systems has been equivocal. Factors influencing parasite intensity were evaluated for the gut helminth. A network of potential interactions between the parasites was revealed. Only month was shown to be of greater influence on the community. Following, from the above analyses, a community model was constructed which incorporated both seasonal forcing and interspecific parasite interactions, with interaction mediated via host immunity. One unexpected emergent property was an interaction between the seasonality and the immune decay rate with slower immune decay resulting in a shift of the immune response out of phase with the species against which it was produced. The model was also used to assess the potential effects of two control strategies, an anticestodal and a single species vaccine. The vaccine had greater effects on the whole community than the anticestodal because of the immune- mediated interactions. The host is also an integral part of the community as the parasite dynamics are linked with that of their host. Therefore an assessment of the parasites' impact upon host condition and fecundity was also undertaken. This revealed a variety of positive and negative associations between the parasites and their host, with potential implications for future host control strategies. This study has shown that ignoring parasite-parasite or parasite-host interactions and interactions of both the host and the parasite with the external environment, could result in a poor description of the community dynamics. Such complexities need to be considered and incorporated into theory if future control strategies for either host or parasites are to be effective.

Myocardial stunning is best defined as the persistent, yet reversible, contractile dysfunction that occurs with brief myocardial ischemia / reperfusion (I/R) injury. In contrast, prolonged ischemia results in myocardial infarction that leads to cell death of necrosis of the tissue. The causes of stunning are not fully elucidated, however two major hypotheses currently exist; firstly changes to calcium handling resulting from lowered cellular pH by means of anaerobic respiration, and altered Nair/H)r antiporter kinetics, and secondly, the generation oxygen free radical (OFR) that may occur in a dramatic ‘surge’ at the onset of reperfusion. Treatment of ischemic myocardium with calcium channel blockers and / or OFR scavengers has been successfully shown to prevent stunning in various animal models. Whilst much is known about the physiological and biochemical changes that occur in stunned myocardium, very little is known about events at the molecular level. Since stunning occurs after only brief (15 minutes low-flow in the rabbit model) ischemia and subsequent reperfusion, we hypothesized that these molecular events are not predominated by large changes in protein expression and abundance, yet rather by subtle and / or transient changes to protein post-translational modifications (PTM). Such changes at the protein level are best analysed using the technologies encompassed under the term ‘proteomics’.

This master’s thesis contains design of laboratory stand for learning programming microcontrollers. Stand is equipped with two Rabbit modules, which are connected together over local area network. Exercises are focused on working with basic peripheries as digital inputs and outputs,PWM modulation, serial communication. Exercises are interested in evaluation of matrix keyboard and communication with alphanumeric display controller. With the ability to easy access the Internet some exercises are designed for work with this interface. To these exercises is made a preparation of external peripherals. Through these peripherals there can be can be controlled DC motors, step motor, binary outputs and inputs. Each lab exercise contains an introduction, task, instructions and the flowchart of realized exercise. Instructions are written so that it contains important steps to properly manage assignments. Individual exercises are designed to gradually increasing complexity of exercises.

Two populations of rabbits (Oryctolaqus cuniculus) were investigated to see whether polygynous, multi-male groups formed in the absence of large multi-entranced warrens. They did not. Rabbits neither gathered in space nor time. The small warrens were spread out evenly across homogeneous patches and the females were well spaced out. Monogamy, distinguished by a battery of tests, was prevalent, with the more dominant males as 'mate' rabbits. That the polygyny frequently mentioned in the literature was a result of male dominance and female defense was considered. The genetic structure of each population was investigated by taking blood from rabbits and having it analysed electrophoretically and for immunoglobulins. A method for assessing relatedness between groups of pairs of animals was implemented, then validated and developed with Monte Carlo simulations. With the seven polymorphic allele obtained, no non-zero relatedness was found but it was sometimes possible to exclude high relatedness. The bearing of sociality on vigilance during feeding was investigated. Although a rabbit's vigilance decreased as its 'mate' approached, the presence of other rabbits was correlated with increased vigilance. It was concluded that the need for social vigilance outweighed the benefit of 'many eyes' watching for predators. This conclusion was tested by experiment, using stuffed animals as stimuli. Rabbits increased their vigilance during grazing bouts both by increasing the length and frequency of scans. Scans could be short or long: the probability of ending a scan decreased sharply at a certain point; a form of positive feedback. The durations of short 'maintenance' scans were dependent on chewlength (the amount of food in the mouth). This fitted a timesharing definition as supported by experiment. Long scans in response to a visible threat did not involve chewing.

[ES] Cualquier mejora en el conocimiento de la nutrición y el manejo de los futuros conejos reproductores debe considerarse como prioritario en la producción cunícola. Sin embargo, los principales esfuerzos en investigación se han centrado en estos animales durante la fase de reproducción propiamente dicha. La hipótesis inicial de esta tesis fue que alcanzar un desarrollo temprano adecuado durante la gestación, lactancia, engorde y recría, con la ayuda de programas ajustados de alimentación en algunos de estos períodos, mejoraría el rendimiento reproductivo y la vida útil de los futuros conejos reproductores. Para evaluar esta hipótesis, se llevaron a cabo dos tipos de ensayos, tanto en conejos hembra de líneas maternas como en machos de líneas seleccionadas por velocidad de crecimiento y destinadas a la inseminación artificial. El primero de estos ensayos se centró en los diferentes patrones de crecimiento, desde el nacimiento hasta el final de la fase de recría, y su influencia en la carrera reproductiva y la vida útil del conejo. En el segundo tipo de pruebas, se evaluó el efecto del uso de diferentes dietas o programas de alimentación durante el período de recría en la productividad a corto y medio plazo. Los resultados muestran dos fases importantes en el desarrollo temprano, de acuerdo con sus efectos sobre el rendimiento reproductivo y la vida útil. Mostrar un mayor desarrollo corporal desde el nacimiento hasta los 63 días de vida parece tener una influencia positiva en el grado de madurez y la productividad al comienzo de su vida reproductiva, además de poder mejorar su supervivencia a corto plazo, pero con posibles efectos negativos en la esperanza de vida a largo plazo. Sin embargo, el desarrollo durante el período de recría (desde los 63 días de vida hasta el comienzo de la carrera reproductiva) parece tener un mayor impacto en la productividad y la esperanza de vida de nuestros futuros conejos reproductores. Las hembras más engrasadas en la primera inseminación tuvieron tamaños de camada más pequeños y un mayor riesgo de ser sacrificadas que las magras (P<0.05). Además, los machos que mostraron una mayor ganancia media diaria durante el período de recría tuvieron un número y porcentaje de eyaculados viables más bajos a lo largo de su vida productiva y mayor riesgo de muerte o sacrificio. Estos resultados podrían indicar que la clave para llevar a cabo un desarrollo adecuado durante el período de recría debería basarse tanto en conseguir que los conejos alcancen un grado de madurez apropiado, tanto fisiológica como reproductivamente, así como evitar un excesivo engrasamiento al inicio de su vida productiva. En los ensayos destinados a evaluar los programas de alimentación durante la recría, el uso de una restricción alimentaria en hembras, y especialmente el uso de dietas fibrosas (de 8.5 a 10 MJ ED/kg MS) permiten un desarrollo corporal gradual y adecuado a la edad de cubrición, con suficientes reservas corporales para afrontar el comienzo de la vida reproductiva y mejorando tanto su rendimiento reproductivo como su vida útil. El éxito de estos programas de alimentación de recría depende del momento y la duración de la aplicación de estos, mejorándose con la aplicación de un cambio a un pienso enriquecido energéticamente alrededor del primer apareamiento. En los machos, se observó que un programa de alimentación durante la recría adecuado debería adaptarse a la capacidad de ingesta de estos y a sus necesidades nutricionales en períodos concretos de la recría, consiguiendo así mejoras en algunos parámetros del semen al inicio de su vida reproductiva. En conclusión, tanto un desarrollo temprano adecuado desde la gestación hasta el comienzo de su vida reproductiva, como el uso de programas adecuados de alimentación durante la recría podrían mejorar significativamente el rendimiento reproductivo futuro, así como la esperanza de vida, tanto en conejos he
[CAT] Qualsevol millora en el coneixement tant de la nutrició com del maneig dels futurs conills de criança ha de considerar-se com a prioritari en la producció de conills. No obstant açò, els principals esforços en investigació s'han centrat en aquests animals durant la fase de reproducció pròpiament dita. La hipòtesi inicial d'aquesta tesi va ser que aconseguir un desenvolupament primerenc adequat durant la gestació, lactància, engreix i criança, amb l'ajuda de programes ajustats d'alimentació en alguns d'aquests períodes, milloraria el rendiment reproductiu i la vida útil dels futurs conills reproductors. Per a avaluar aquesta hipòtesi, es van dur a terme dos tipus d'assajos, tant en conills femella de línies maternes, com en mascles de línies seleccionades per a la velocitat de creixement i destinades a la inseminació artificial. El primer d'aquests assajos es va centrar en els diferents patrons de creixement, des del naixement fins al final de la fase de criança, i la seua influència en la carrera reproductiva i la vida útil del conill. En el segon tipus de proves, es va avaluar l'efecte de l'ús de diferents dietes o programes d'alimentació durant el període de criança, en la productivitat a curt i mig termini. Els resultats obtinguts semblen indicar que podríem diferenciar dues fases en el desenvolupament primerenc, d'acord amb els seus efectes sobre el rendiment reproductiu i la vida útil. Mostrar un major desenvolupament corporal des del naixement fins als 63 dies de vida sembla tenir una influència positiva en el grau de maduresa i la productivitat al començament de la seua vida reproductiva, a més de poder millorar la seua supervivència a curt termini, però amb possibles efectes negatius en l'esperança de vida a llarg termini. No obstant açò, el desenvolupament durant el període de sembla tenir un major impacte en la productivitat i l'esperança de vida dels nostres futurs conills reproductors. Les femelles més greixades en la primera inseminació van tenir grandàries de ventrada més xicotets (tant nascuts com deslletats) i un major risc de ser sacrificades que les magres (P<0.05). A més, els mascles que van mostrar un major guany mitjà diari durant el període de criança van tenir un nombre i percentatge d'ejaculats viables més baixos al llarg de la seua vida productiva i major risc de mort o sacrifici. Aquests resultats podrien indicar que la clau per a dur a terme un desenvolupament adequat durant el període de criança hauria de basar-se tant a aconseguir que els conills aconseguisquen un grau de maduresa apropiat, per a afrontar els futurs desafiaments productius, com evitar un excessiu greixatge a l'inici de la seua vida productiva. En els assajos destinats a avaluar els programes d'alimentació durant la criança, l'ús d'una restricció alimentària en femelles, i especialment l'ús de dietes fibroses (de 8.5 a 10 MJ ED/kg MS) permeten un desenvolupament corporal gradual i adequat a l'edat de cobriment, amb suficients reserves corporals per a afrontar el començament de la vida reproductiva i millorant tant el seu rendiment reproductiu com la seua vida útil. L'èxit d'aquests programes d'alimentació de criança depèn del moment i la durada de l'aplicació d'aquests, millorant-se amb l'aplicació d'un canvi a un pinso enriquit energèticament al voltant del primer cobriment. En els mascles, es va observar que un programa d'alimentació durant la criança adequat hauria d'adaptar-se a la capacitat d'ingesta d'aquests i a les seues necessitats nutricionals en períodes concrets de la criança, aconseguint així millores en alguns paràmetres del semen a l'inici de la seua vida reproductiva. En conclusió, tant un desenvolupament primerenc adequat des de la gestació fins al començament de la seua vida reproductiva, com l'ús de programes adequats d'alimentació durant la criança podrien millorar significativament el rendiment reproductiu futur, així com l'esperança
[EN] Any improvement on the knowledge of both nutrition and management of the future rabbit breeders should be considered as crucial. However, main research efforts have been focused on animals during reproduction phase. The initial hypothesis of this thesis was that achieving an adequate early development during young rabbits' gestation, lactation, fattening and rearing, with the help of fitted feeding programmes in some of these periods, would be improved reproductive performance and lifespan of the future breeding rabbits. To evaluate this hypothesis, two types of trials, both in rabbit females from maternal lines selected for litter size at weaning and males from paternal lines selected for growth rate and intended on artificial insemination, were carried out. The first of these trials were mainly focused on the different growth patterns, from birth to the end of the rearing age, and their influence on rabbit's reproductive career and lifespan. In a second type of trials, the effect of the use of different diets or feeding programs during the rearing period in the performance in the short- medium-term was evaluated. The results obtained from the evaluation of the different growth patterns trials seem to indicate that, we could differentiate two parts on the early development according to their effects on reproductive performance and lifespan. To show a greater body development from birth to 63 days of life seems to have a positive influence on the maturity degree and productivity at the beginning of their reproductive life, as well as being able to improve their survival in the short-term, but it could be even negative for long-term lifespan. However, the development during the rearing period (from 63 days of life to the beginning of reproduction career) seems to have a higher impact on the productivity and lifespan of our rabbit breeders. Fatter rabbit females at first insemination had smaller litter sizes (born and weaned) and a higher risk of being culled (+13% per positive change in mm of perirenal fat) than lean ones (P<0.05). Also, rabbit males that showed a greater average daily gain during rearing period had a lower number and percentage of profitable ejaculates through it productive life (-10.1 and -4.9% per each 10 g of daily gain increase, respectively; P<0.05) and higher risk of death or culling (+16.2% per each increase in one standard deviation unit on live weight; P<0.05). These results could indicate that the key to carrying out an adequate development during the rearing period should allow the rabbits to reach an appropriate degree of physiological and reproductive maturity to face the future productive challenges, avoiding an excessive fatness at the beginning of their productive life. The use of a feeding restriction in rabbit females, and especially the use of fibrous diets (from 8.5 to 10 MJ DE/ kg DM) lead a gradual and adequate body development at mating, with enough body reserves to face the beginning of reproduction life and improving their whole reproductive performance and lifespan. The success of these rearing feeding programs depends in the moment and duration of application of them and improved with the application of a nutritional flushing around first mating. In rabbit males, it was observed that an adequate rearing feeding program should adapt it to the male's intake capacity and their nutritional requirements rearing period, especially to their high DP needs at the beginning of rearing period or when their requirements were close to maintenance, to improve some semen parameters at the beginning of their reproduction life. In conclusion, both the adequate early development of future rabbit breeders, from their own gestation to the beginning of their reproductive life, and the use of appropriate rearing feeding programs could significantly improve their future reproductive performance, as well as their life expectancy, both in rabbit females and males.
Martínez Paredes, EM. (2019). Rearing programmes for breeding rabbits. Effect of early development and feeding on future reproductive performance of rabbit females and males [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/124969
TESIS

Thesis (MA)--Stellenbosch University, 2004.
ENGLISH ABSTRACT: Meat processing industries in South Africa are faced with the challenge to produce a variety of white meats. This is due to the fact that consumers tend to consume less red meat and more chicken and pork that are perceived to be healthier due to the negative publicity surrounding red meat and health. The nutritional emphasis is on leaner carcasses and an increase in the consumption of polyunsaturated fatty acids while reducing the ratio of n-6:n-3 polyunsaturated fats in the diet. Another way in which this can be achieved is through introducing rabbit meat which has low fat, low cholesterol content and high protein content, while displaying a positive fatty acid profile. Carcass quality and meat quality in rabbits may to a large extent be affected by age of slaughter and type of breed. This study had a dual purpose. Firstly it aimed at quantifying the effects of breed and age on parameters pertaining to carcass quality and meat quality of commercial rabbits, namely California breed and hybrid (California x Dutch red). Secondly, to determine the differences between ethnic groups on their perceptions towards rabbit meat, thereby providing information on its marketing potential. To accomplish the first objective 50 rabbits from the two breeds were housed in individual cages, weighed on weekly basis and fed ad libitum. The rabbits were slaughtered at 9, 11, 13, 15 and 17 weeks of age (n=5 from each breed). For the second objective the perceptions of three ethnic groups on factors affecting consumers' choice of rabbit meat were determined through a structured questionnaire. The questionnaire was tested for validity beforehand. There was no significant difference between the two breeds regarding body weight, feed intake, carcass weight and drip loss. The California breed had a higher dressing percentage (53.7%) and meat yield (29.2%) compared to the hybrid (52.5% and 27.5% respectively). Age treatments showed a highly significant difference on all parameters investigated. Increasing the age proportionately increased the amount of fat, while the moisture content decreased. The California breed exhibited higher percentages of fat compared to the hybrid at all ages of treatment. California breed contained more phosphorus, magnesium and zinc as opposed to the hybrid, the only exception being copper, where the hybrid had higher concentrations. The total fatty acid (169.2 mg/100 g) of the California breed was higher than that of the hybrid (133.5 mg/100 g). As a result there were more saturated fatty acids (55.4 mg/100 g) and monounsaturated fatty acids (62.3 mg/100 g) in the California breed than in the hybrid (44.2 and 45.6 mg/100 g respectively). Both breeds had 67% unsaturated fatty acids. Although there was no significant difference between the P:S ratio of the two rabbit breeds, the values obtained were higher (+0.9) than the value of 0.7. This is an indication that the rabbit meat contains a P:S ratio that could be considered very desirable. The n-6:n-3 ratio for both breeds were high (11.6 for California and 12.7 for hybrid). The cholesterol and amino acid profile of the two breeds were not affected by the type of breed. The consumer survey indicated that 52% (n=158) of respondents had never eaten rabbit meat before due to reasons such as scarcity, lack of knowledge about the meat, associating rabbits with pets and cultural constraints. Nevertheless, 57% of these people were optimistic about eating rabbit meat. In addition, having eaten rabbit meat before seemed to contribute positively towards acceptance of rabbit meat. Generally, respondents preferred purchasing rabbit meat in portions as opposed to live or whole carcasses. Their decision to purchase rabbit meat was firstly driven by price, thereafter freshness, leanness and tenderness of meat. The respondents expect to buy rabbit meat at a price lower than that of chicken. Rabbit meat contained low sodium and high proportion polyunsaturated fatty acids-some of the most important food attributes required to maintain and improve health. However, most of the respondents in this study were not familiar with the positive attributes of rabbit meat and need to be taught the benefits of this product.
AFRIKAANSE OPSOMMING: In Suid Afrika is daar 'n uitdaging vir die vleisproduserende voedselindustrieë om 'n verskeidenheid witvleis te bemark. Dit word toegeskryf aan die feit dat verbruikers minder rooi vleis as hoender en vark eet wat as meer gesond beskou word weens die negatiewe publisiteit wat geassosieer word met rooivleis en gesondheid. Die voedingsfokus is op maerder karkasse, groter inname van polionversadigde vetsure, en 'n vermindering in die verhouding n-6:n-3 poli-onversadigde vetsure in die dieet. Een van die maniere waarop dit gedoen kan word, is die bekendstelling van konynvleis wat gekenmerk word deur lae vetinhoud, lae cholesterolinhoud en 'n hoë proteïninhoud, en 'n positiewe vetsuurprofiel. Karkas- en vleiskwaliteit van konyne word tot 'n groot mate geaffekteer deur ouderdom van slagting en die ras. Hierdie studie het 'n tweeledige doel. Eerstens mik dit na die kwantifisering van die effek van ras en ouderdom op die parameters wat met karkas- en vleiskwaliteit van die Kaliforniese ras en die kruisgeteëlde ras (Kaliforniese X Hollandse rooi) verband hou. Tweedens, om die verskille in etniese groepe vas te stel met betrekking tot hulle persepsies van die faktore wat hulle keuse van konynvleis beïnvloed, en op dié wyse inligting te verkry t.o.v die bemarkingspotensiaal daarvan. Om in die eerste doelwit te slaag is 50 konyne van die twee rasse in individuele hokke gehuisves, op 'n weeklikse basis geweeg en ad libitum gevoer. Die konyne was geslag op 9, 11, 13, 15 en 17 weke (n=5 vir elke ras). Vir die tweede doelwit, is die persepsies van drie etniese groepe oor die faktore wat die verbruikerskeuse van konynvleis kan bepaal, m.b.v. 'n gestruktureerde vraelys bepaal. Die vraelys is vooraf vir geldigheid evalueer. Daar was geen beduidende verskil tussen die twee rasse wat betref liggaamsmassa, voedselinname, karkasgewig en dripverlies nie. Die Kaliforniese ras het 'n hoër uitslag-persentasie (53.7%) en vleisopbrengs (29,2%) in vergelyking met die kruisgeteëlde ras (52.5% en 27.5% respektiewelik) gehad. Ouderdom het hoogsbeduidende verskille op al die parameters wat ondersoek was, getoon. Die toename in ouderdom was gepaardgaande met proporsionele toename in karkasvet en afname in vog. Die Kaliforniese ras het, by alle ouderdomsbehandelings, in vergelyking met die kruisgeteëlde ras, 'n hoër persentasie vet opgelewer. Die Kaliforniese ras het teenoor die kruisgeteëlde ras hoër fosfor, magnesium en sink bevat. Die uitsondering was koper waar die kruisgeteëlde ras 'n hoër waarde gehad het. Die totale vetsure vir die Kaliforniese ras (169.2 mg/100 g) was hoër as vir die kruisgeteëlde ras (133.5 mg/100 g). Om dié rede was daar in die Kaliforniese ras meer versadigde vetsure (55.4 mg/100 g) en monoonversadigde vetsure (62.3 mg/100 g) as vir die kruisgeteëlde ras (44.2 mg/100 g en 45.6 mg/100g onderskeidelik). Beide rasse het 67% onversadigde vetsure gehad. Hoewel daar geen beduidende verskille was in die polionversadigde:versadigde (P:V) verhouding nie, was die waardes hoër (+0.9) as die 0.7 wat aanbeveel word. Die n-6:n-3 verhouding vir beide rasse was hoog (11.6 vir die Kaliforniese ras en 12.7 vir die kruisgeteëlde ras). Die cholesterol- en die aminosuurprofiel was nie deur die ras beïnvloed nie. Die verbruikersnavorsing het getoon dat 52% (n=158) van die respondente om verskeie redes nog nie konynvleis geëet het nie, weens redes soos onverkrygbaarheid, gebrekkige kennis van die vleis, die assosiasie van konyne met troeteldiere en kulturele beperkinge. Desnieteenstaande is daar 57% van die respondente wat optimisties is oor die eet van konynvleis. Die eet van konynvleis by vorige geleenthede het bygedra tot die positiewe aanvaarding van konynvleis. Oor die algemeen het die respondente verkies om konynvleis in porsies te koop, in plaas van lewendig of heel karkasse. Die besluit om konynvleis te koop, is hoofsaaklik gedryf deur prys, daarna deur varsheid, maerheid en sagtheid van die vleis. Die respondente verwag dat die prys vir konynvleis laer sal wees as vir hoender. Konynvleis bevat lae natrium en 'n hoë verhouding poli-onversadigde vetsure - van die mees belangrike voedingeienskappe om gesondheid te handhaaf en te verbeter. Ongelukkig was meeste van die respondente in hierdie studie nie vertroud met die positiewe eienskappe van konynvleis nie, en moet hulle geleer word deur middel van omvattende bemarkingsaksies van die voordele van hierdie produk.