2024-03-29T15:49:24Z
http://opus.uni-hohenheim.de/oai2/oai2.php
oai:opus.uni-hohenheim.de:2
2000-03-22T00:00:00Z
ddc:630
pub-type:8
has-source-swb:false
The exocrine pancreatic secretion in pigs and its hormonal regulation as influenced by carbohydrates and fats given per os or infused intraduodenallyStefanJakob630SchweinBauchspeicheldrüseSekretionendokrine RegulationFettCholecystokininPeptid YYNicht-Stärke-Polysaccharidepigpancreassecretionendocrine regulationfatIn the present study the influence of carbohydrates in the form of potato fibre (NSP) and of different fats on the exocrine pancreatic secretion and on the regulative hormonal mechanisms was investigated. When feeding a diet supplemented with 2 potato fibre all measured parameters, e.g. volume of pancreatic secretion, protein output and total trypsin, lipase and alpha-amylase activities increased in pancreatic juice. Simultaneously there was a trend towards a decrease in plasma concentration of CCK. After the intraduodenal infusion of medium chain triglycerol (mct: glyceroltricaprylat), long chain triglycerol (lct: glyceroltristearat) or vegetable oils (olive oil or coconut oil) in all treatments a prandial peak was found as a direct reaction on feed intake for volume of secretion, total protein and colipase contents as well as the total activities of trypsin and lipase. After application of mct the secretion course occured in two phases. In phase 1 a parallel prandial increase in volume of secretion, total protein and colipse content as well as total activities of trypsin and lipase was found. For the same parameters in the second phase 60 min postprandially much lower values were observed compared to the preprandial values. The courses of the curves differed for total lipase activities. The diurnal course of plasma levels of CKK and PYY was not influenced. After coconut oil treatment the course of volume secretion was characterized by 2 phases. After a prandial peak in phase 1 the values decreased by 100 below the preprandial starting values. After the application of olive oil the specific lipase activity was elevated five times. In case of coconut oil there was only a prandial increase by 2.5. It is suggested that the exocrine pancreas responds differently in its secretion to different fat sources. Adaptation is probably regulated through a feedback-mechanism whereas CCK and PYY are of minor importance. Probably other hormones as e.g. secretin have a regulativeKommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät AgrarwissenschaftenGarbenstr. 15, 70593 StuttgartRainerMosenthin20002000Thesis.Doctoralurn:nbn:de:bsz:100-opus-29application/pdfenghttp://opus.uni-hohenheim.de/doku/lic_ubh.phpthesis.doctoralKommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät Agrarwissenschaften1aus: Praesentationsformathttp://opus.uni-hohenheim.de/volltexte/2000/2
oai:opus.uni-hohenheim.de:5
2000-07-31T00:00:00Z
ddc:630
pub-type:8
has-source-swb:false
Effect of mulch application in combination with NPK fertilizer in cowpea (Vigna unguiculata (L.) Walp.; Leg.) on two key pests, M. vitrata F. (Lepidoptera: Pyralidae) and M. sjostedti Trybom (Thysanoptera: Thripidae), and their respective parasitoidsNikolausZenz630MulchAugenbohneStickstoffdüngerNützlingWirtsfindungHülsenbohrerBlütenthripsParasitierungnatürliche Gegenspieleralternative Wirtspflanzenpod borerflower thripscowpeaparasitoidshost plantAfrican farmers use mulch to preserve soils from physical and nutritional degradation. No clear evidence exists whether mulch may also be used successfully to control pests. This study aimed to assess the effect of mulch in combination with NPK fertilizer on two key pests of cowpea (Vigna unguiculata (L.) Walp.; Leguminosae), the legume pod borer Maruca vitrata F. (Lepidoptera: Pyralidae) and the flower thrips Megalurothrips sjostedti Trybom (Thysanoptera: Thripidae), inclusive of their parasitoids. Trials were carried out in three regions of Benin, West Africa, from 1995 to 1997. This study focused on plant physiology, soil properties, climate as well as habitat structure, all of which were assumed to have a strong influence on pest abundance. Data on plant development represented by number of nodes, flowers, and pods were collected periodically. Flowers were sampled in parallel to monitor the abundance of both pests. Eggs and living larvae of M. vitrata and larvae of M. sjostedti were collected periodically and reared for studies on parasitism. Mortalities due to three braconid parasitoids were assessed belonging to the order of hymenoptera, Dolichogenidea sp., Phanerotoma leucobasis Kriechbaumer, and Braunsia kriegeri Enderlein, which represented the dominant species on larvae of M. vitrata. Ceranisus menes Walker (Hymenoptera: Eulophidae) was the only parasitoid found on M. sjostedti. Pods were harvested and assessed for damage of M. vitrata. Pod number, weight per pod, relative pod and grain damage were investigated and estimates were made of the yield losses. Yield of cowpea was measured and related to preceding pest abundance. Pods were counted, weighed, and husked, and grains were weighed. Flowers were collected from potential wild host species of both pests in the vicinity of cowpea fields. Insect counts from flowers in the adjacent cowpea fields served as comparison. Kommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät AgrarwissenschaftenGarbenstr. 15, 70593 StuttgartClausZebitzProf. Dr.19991999Thesis.Doctoralurn:nbn:de:bsz:100-opus-52application/pdfenghttp://opus.uni-hohenheim.de/doku/lic_ubh.phpthesis.doctoralKommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät Agrarwissenschaften1aus: Praesentationsformathttp://opus.uni-hohenheim.de/volltexte/2000/5
oai:opus.uni-hohenheim.de:7
2000-11-24T00:00:00Z
ddc:630
pub-type:8
has-source-swb:false
Untersuchungen zur Abundanz der Reblaus (Dactylosphaera vitifolii Shimer) und zur Nodositätenbildung in Abhängigkeit von UmweltfaktorenInvestigation to abundance of Phylloxera (Dactylosphaera vitifolii Shimer) and to the formation of nodosities in relation to environmental conditionsAndreasKopf630ReblausWeinrebeStickstoff Bodentyp PfalzIn vitroAbundanzPhylloxeraVitisNitrogenSoilIn vitroThe aim of the examinations was to investigate the abundance of Phylloxera (Dactylosphaera vitifolii Shimer), the occurrence of different biotypes of Phylloxera,
the reaction of rootstocks to the infestation by Phylloxera and the influence of abiotic environmental conditions on the interaction between insect and plant.
To investigate this interaction galls on rootlets (nodosities) and leaf galls were examined. The abundance of Phylloxera and the issue of the holocyclical reproduction in the wine region palatinate were evaluated in a field monitoring.
In a special field trial the occurrence of different stages of Phylloxera and their damages on the rootstock were registered. With a dual aseptical in vitro system Phylloxera of different origins were examined on their aggressiveness to different varieties of rootstocks.
In pot trials the influence of the type of soil and the effect of N-fertilization on the development of nodosities were investigated.
The results of the examination show that Phylloxera can be found in nearly every part of the palatinate and that the improper cultivation of grafted rootstocks promotes the spreading of Phylloxera.
Through shoots of rootstocks ? as they can be found in vineyards run wild - a holocyclical development of Phylloxera is made possible under appropriate climatical circumstances.
Fitness, population dynamics of Phylloxera and the number of nodosities caused by the insects are correlating with their adaptation to a host rootstock. Pot studies have demonstrated that Phylloxera populations develop better in clay soil than sandy soil.
High densities of Phylloxera in combination with a lack of N-supply increase a growth depression on grafted roots. It could also be proved that N-fertilization reduces the Phylloxera populations and the development of nodosities up to 98 %.
Kommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät AgrarwissenschaftenGarbenstr. 15, 70593 StuttgartRolfBlaichProf. Dr.20002000Thesis.Doctoralurn:nbn:de:bsz:100-opus-76application/pdfgerhttp://opus.uni-hohenheim.de/doku/lic_ubh.phpthesis.doctoralKommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät Agrarwissenschaften1aus: Praesentationsformathttp://opus.uni-hohenheim.de/volltexte/2000/7
oai:opus.uni-hohenheim.de:8
2000-12-12T00:00:00Z
ddc:630
pub-type:8
has-source-swb:false
Ökosystem-Funktionen als Kriterium einer Operationalisierung ökologischer Aspekte von Nachhaltigkeit?Ecosystem-functioning as a criterion to translate ecological aspects of sustainability into practice?Susanne MariaDoppler630NachhaltigkeitÖkosystemTheoretische ÖkologieNaturschutzEthikecosystemtheoretical ecologynature protectionethicsIn recent times, against the background of system-theoretical principles, the description of ecosystems as complex, dynamic systems has been strongly promoted. Therefore the capacity of selforganization of ecosystems is strengthened to be integrated into environmental planning processes.
The aim of the following work is to point out the limitations and possibilities given by the scientifically-based criterion 'ecosystem-functioning' in the context of sustainability.
The investigations are based on a literature-supported analysis and a theoretical argument about the 'function of ecosystems' in relation to the concept of ecosystems.
The results of this argument were submitted (1) to a scientific and science-theoretical analysis and criticism as well as considered in the light of (2) environmental protection issues and ethically relevant aspects of the description and observation of the natural world.
The aim of this consideration was to establish to what extent the criterion 'ecosystem functioning' is suitable. The central question about limitations and possibilities of the application of the criterion is answered as follows:
The criterion 'ecosystem functioning', formulated via system-theoretical principles of dynamic systems does not meet the requirements of both the natural and ethical issues given by the paradigm of sustainability.
A possible alternative is to observe ecosystems and the criterion 'ecosystem-functioning' from a utilitarian position of anthroporelativism.
The implementation of this perspective in the world of nature through the criterion 'ecosystem functioning' makes it possible (1) to integrate ethical issues of sustainability and (2) to maintain natural values as well as cultural ones in the countryside for this and future generations.
Kommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät AgrarwissenschaftenGarbenstr. 15, 70593 StuttgartReinhard ; KauleBöckerProf. Dr.20002000Thesis.Doctoralurn:nbn:de:bsz:100-opus-83application/pdfgerhttp://opus.uni-hohenheim.de/doku/lic_ubh.phpthesis.doctoralKommunikations-, Informations- und Medienzentrum der Universität HohenheimHohenheimFakultät Agrarwissenschaften1aus: Praesentationsformathttp://opus.uni-hohenheim.de/volltexte/2000/8