| 1. |
- Handlin, Linda
(författare)
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Human-Human and Human-Animal Interaction : Some Common Physiological and Psychological Effects
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present thesis was to investigate hormonal and physiological effects in mothers during a breastfeeding session and in dogs and their owners in response to short-term interaction. In study one, sixty-six mothers receiving either exogenous oxytocin infusion and/or epidural analgesia (EDA) during labor or intramuscular oxytocin injection post partum were studied. Oxytocin, prolactin, adrenocorticotrophic hormone (ACTH) and cortisol levels, as well as blood pressure were measured during a breastfeeding session two days after birth. In response to breastfeeding two days after birth, the mothers displayed a pulsatile release of oxytocin and increasing prolactin levels. In addition, the activity in the HPA-axis was reduced and maternal blood pressure decreased. The results also show that EDA administration in combination with oxytocin during labor resulted insignificantly lower oxytocin levels and higher cortisol levels, as well as higher bloodpressure in response to breastfeeding two days after birth, compared to EDA administration alone. In addition, oxytocin infusions dose-dependently lowered the mothers’ endogenous oxytocin levels two days after birth. In study two, ten female dog owners and their male Labrador dogs participated, together with ten controls. Their levels of oxytocin, cortisol and insulin, as well as their heart rate, were measured. The connection between the quality of the dogowner relationship and hormone levels was also explored. Short-term interaction between dogs and their owners resulted in oxytocin release in both species and their cortisol levels and heart rate were also affected. Oxytocin levels and positive attitudes regarding the dog-owner relationship were positively correlated. In conclusion, both human-human and human-animal interactions induce oxytocin release and promote oxytocin mediated effects, such as decreasing cortisol levels and blood pressure. In addition, social interaction and oxytocin levels arepositively related.
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| 2. |
- Söderquist, Pär
(författare)
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Large-scale releases of native species : the mallard as a predictive model system
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human alteration of natural systems, and its consequences are of great concern and the impact on global ecosystems is one of the biggest threats that biodiversity stands before. Translocations of invasive species, as well as intraspecific contingents with non-native genotypes, whether they are deliberate or unintentional, are one such alteration and its consequences are continuously being assessed. The mallard (Anas platyrhynchos) is the most numerous and widespread duck in the world and a flagship in wetland conservation. It is also an important game species which is heavily restocked for hunting purposes, especially in Europe where over three million ducklings are released every year. Because of its hunted status, its abundance, and the number of released individuals, it can serve as a model species to study effects of releases, both for conservation and restocking for hunting, on wild populations. In this thesis the status of the mallard was assessed in the Nordic countries and the effects of releases on the wild populations were studied by mining historical ringing data, comparing morphology of present-day wild, farmed, and historical mallards, and analyzing phylogeography of wild and farmed mallards in Europe. The status of the mallard population in the Nordic countries are generally good, however, a joint effort of European countries is needed to monitor and manage the population. A significant difference between wild and farmed mallards concerning longevity, migration, bill morphology and genetic structure was also found, together with signs of cryptic introgression of farmed genotypes in the wild population with potential fitness reduction as a result. The effect is however limited by that only a fraction of released farmed mallards reach the breeding season due to low survival. A natural captive environment is crucial to keep individuals wild-like with high survival rates after release. However, with an introgression of potentially maladapted farmed genotypes leading to a reduction in fitness, a low survival of released mallards would favor the wild population. A legislative change regarding obligation to report numbers, provenance, and release sites of farmed mallard should be considered, together with practical solutions of ringing and genetic monitoring of released mallards.
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| 3. |
- Montelius, Malin
(författare)
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Chlorine Cycling in Terrestrial Environments
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 (36Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl–) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl– and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl– and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl– and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36Cl.
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| 4. |
- Felleki, Majbritt
(författare)
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Genetic Heteroscedasticity for Domestic Animal Traits
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Animal traits differ not only in mean, but also in variation around the mean. For instance, one sire’s daughter group may be very homogeneous, while another sire’s daughters are much more heterogeneous in performance. The difference in residual variance can partially be explained by genetic differences. Models for such genetic heterogeneity of environmental variance include genetic effects for the mean and residual variance, and a correlation between the genetic effects for the mean and residual variance to measure how the residual variance might vary with the mean.The aim of this thesis was to develop a method based on double hierarchical generalized linear models for estimating genetic heteroscedasticity, and to apply it on four traits in two domestic animal species; teat count and litter size in pigs, and milk production and somatic cell count in dairy cows.The method developed is fast and has been implemented in software that is widely used in animal breeding, which makes it convenient to use. It is based on an approximation of double hierarchical generalized linear models by normal distributions. When having repeated observations on individuals or genetic groups, the estimates were found to be unbiased.For the traits studied, the estimated heritability values for the mean and the residual variance, and the genetic coefficients of variation, were found in the usual ranges reported. The genetic correlation between mean and residual variance was estimated for the pig traits only, and was found to be favorable for litter size, but unfavorable for teat count.
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| 5. |
- Abubaker, Jamal
(författare)
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Effects of fertilisation with biogas residues on crop yield, soil microbiology and greenhouse gas emissions : recycling of plant nutrients from bioenergy production
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The amount of residues generated by biogas production has increased dramatically due to worldwide interest in using renewable energy. Biogas residues (BRs) originate from anaerobic degradation of different types of rural and urban organic wastes and have been proposed as organic fertilisers because of their high content of ammonium and other valuable macro- and micro-nutrients. However, application of BRs to agricultural soils may be accompanied by environmental risks, since they may contain heavy metals and organic pollutants. Therefore the effects of BRs on crop production and on the soil ecosystem and environment urgently need to be investigated before their wider use. This thesis evaluated and compared different types of BRs against cattle slurry, pig slurry, compost and mineral fertiliser with respect to their (1) ability to provide plants with necessary nutrients, (2) impact on the soil microbial ecosystem and (3) effects on emissions of the greenhouse gas nitrous oxide (N₂O). The results from short-term laboratory experiments and a long-term field trial showed that BRs increased crop yield to the same extent or more than conventional mineral fertiliser and compost, but less than pig slurry. BRs generated from source-separated organic household waste had a tendency to give higher crop yield and soil microbial activities than other BRs. BRs had no general negative effect on soil respiration, but substrate-induced respiration decreased significantly in organic soil on addition of BRs. Although all BRs initially inhibited potential ammonium oxidation and potential denitrification activity, no long-term negative effects were detected. BRs stimulated ammonium assimilation, which can temporarily decrease nitrogen availability to the plant. Furthermore, the bacterial community structure in the sandy soil was altered by BRs and cattle slurry, but no significant change was seen in the community structure of clay and organic soil. Application of BRs and animal slurry increased N₂O emissions, but the total losses and flux patterns were affected by fertiliser type and soil type. In conclusion, the fertiliser value of BRs should be regarded as high and they apparently have no long-term adverse effects on soil microbial functions and structures. Thus the problematic amounts of residues associated with expansion of biogas production could be turned to advantage, as these residues seem to be safe and competitive fertilisers.
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| 6. |
- Ahmadi Afzadi, Masoud
(författare)
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Genetic variation in resistance to fungal storage diseases in apple : inoculation-based screening, transcriptomics and biochemistry
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Apple is one of the economically and culturally most important fruit crops and has many health-related benefits. Apple production is, however, sensitive to several fungal diseases including blue mold, caused by Penicillium expansum. Problems are more pronounced in organic production or in countries where postharvest application of fungicides is prohibited. To limit or overcome this problem, many studies have been focused on investigations of the mechanism of resistance/tolerance. No major gene(s) have as yet been identified, but quantitatively inherited traits, some of which are related to fruit texture and content of chemical compounds, have been shown to affect the ability of cultivars to withstand storage diseases. In the present thesis, inter-cultivar variation in terms of resistance to fungal storage diseases was investigated at two locations, i.e. Balsgård in Sweden and Njøs in Norway. The association of harvest date, fruit firmness and softening with lesion decay was investigated on large sets of cultivars. The contribution of four fruit texture-related genes (Md-ACO1, Md-ACS1, Md-Exp7 and Md-PG1) in explaining the fruit texture characteristics was examined. Fruit content of chemical compounds with a potential impact on disease resistance was also investigated, and finally the regulation of apple genes upon fungal infection was studied in order to identify candidate genes responsible for disease resistance. Inoculation-based screening indicated large variation across the investigated cultivars in terms of blue mold and bitter rot susceptibility. Harvest date and softening rate of fruits during storage had a large impact on resistance to fungal diseases, thus cultivars with moderate to firm fruits that soften comparatively little during storage could withstand the fungal infection comparatively well. Softening rate is, in its turn, closely associated with harvest date whereas four fruit texture-related genes had lower predictive power than expected. Quantifying the chemical compounds in the fruit samples revealed that some of these compounds, especially flavonols and procyanidin B2, could contribute to resistance against blue mold, whereas contents of malic acids or total titratable acidity had considerably less impact. Differential expression of FLS, LDOX, and CHS genes involved in biosynthesis of flavonoids and PGIP, TT10, WAK1 and CTL1 genes related to cell wall structure indicate the importance of fruit characteristics and biochemical compounds in the resistance mechanism.
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| 7. |
- Alam, Mehboob
(författare)
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Microbial status of irrigation water for vegetables as affected by cultural practices : agronomic aspects
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Human pathogens present in irrigation water can be transmitted to plants. Consumption of fruits and vegetables irrigated with pathogen-contaminated water can cause illness in humans. Leafy vegetables that are consumed fresh are particularly prone to cause such illnesses. Understanding the microbiota of irrigation water and its decontamination and introducing some preventative pre-harvest cultural practices can help procure hygienically safe horticultural produce. Variations were found in water indicator organisms, including heterotrophic plate counts, total coliforms, thermotolerant coliforms, Escherichia coli and faecal enterococci, at five different sampling sites in an irrigation water distribution system (IWDS) on a commercial vegetable-growing farm. 454-pyrosequencing data showed that the IWDS bacterial community was dominated by Bacteriodetes and Proteobacteria, with classes within these phyla, including Flavobacteriia, Sphingobacteriia, α-, β- and γ-Proteobacteria, being found at all five sampling sites. The genera Arcicella, Flavobacterium, Limnohabitans, Sejongia, Fluviicola, Escherichia, Clostridium and Legionella were present at various sites. Indicator organisms and the pathogen Salmonella in the IWDS were significantly reduced by photocatalytic treatment in most cases. Pre-harvest cultural practices to reduce pathogen load, including cessation of irrigation with contaminated water three days before harvest and decreasing the water regime of the growing medium for leafy vegetables, were assessed. The results showed that an attenuated gfp-tagged E. coli O157:H7 decreased with increasing time to harvest after cessation of irrigation, but were present in the plant phyllosphere three days after cessation, irrespective of dose applied. Similarly, both attenuated gfp-tagged E. coli O157:H7 and an attenuated strain of L. monocytogenes persisted in vegetables grown at a reduced water regime in the growing medium. Total microbiota and Enterobacteriaceae remained unchanged on plants after cessation of irrigation with contaminated water and on plants grown on different water regimes. Use of contaminated irrigation water for leafy vegetable production should thus be avoided. Photocatalytic treatment can be used to decontaminate irrigation water.
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| 8. |
- Ali, Liaqat
(författare)
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Pre-harvest factors affecting quality and shelf-life in raspberries and blackberries (Rubus spp. L.)
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fruit including berries have been demonstrated to exhibit a broad spectrum of benefits including protection against cardiovascular, neurological, and lung diseases, as well as having antioxidant, antimicrobial, anti-inflammatory, anti- diabetic and anti-aging properties. These protective effects are reported to be due to their high content of bioactive compounds, such as vitamin C, vitamin E, phenolic acids, ellagitannins, flavonoids and carotenoids. This thesis investigated the effect of pre- and postharvest factors on the concentrations of bioactive compounds in raspberries and blackberries. The factors studied included genetic variability, organic and synthetic fertilizers, seasonal variation (harvest-to-harvest and annual variation) in greenhouse, high tunnel and open field production, and post-harvest storage. Concentrations of bioactive compounds (anthocyanins, vitamin C, ellagic acid, carotenoids) in the berries, or in the leaves, were quantitatively analysed by high-performance liquid chromatography, and total phenolics were analysed by a spectrophotometric method. Generative parameters (yield, fruit size) investigated for the cultivar difference and organic nitrogen, responded differently to the nitrogen level within cultivars and varied significantly in primocane raspberries. Taste compounds, such as total acidity and different sugars, varied during the season and with nutrient regimes. Time of harvest also affected the ellagic acid content, which was high in early season, and the vitamin C content, which was high in late season in primocane raspberries. Significant changes were also found between different years. Vitamin C decreased significantly with high synthetic N and with low K application, but the application of high N with high K showed positive influence in the level of nutrients and bioactive compounds in blackberries except for ellagic acid. Increased level of organic fertilization (12-17 g N/plant) in primocane raspberries caused only minor changes in the analysed compounds. The post-harvest performance of raspberries regarding the levels of bioactive compounds was less dynamic than in blackberries. In addition, raspberries harvested in late season showed comparatively less changes in sugar content during storage as compared to early harvest, indicating less enzymatic activity in the late season.
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| 9. |
- Andersson, Helena
(författare)
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The role of subsoil properties for phosphorus leaching in agricultural soils
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) leaching from agricultural land is a large contributor to eutrophication of many surface waters and the Baltic Sea. Better knowledge of P sorption and release in the subsoil could enable the development of effective mitigation strategies for P leaching. This thesis examined the impact of soil properties on P leaching from four Swedish agricultural soils (two clays, two sands), using intact soil columns extracted with (length 1.05 m) and without (length 0.77 m) topsoil. The role of the subsoil as a source or sink for P leaching was also investigated, and placement of quicklime (CaO) on top of the subsoil as a mitigation strategy for P leaching was evaluated. Leaching of dissolved reactive P (DRP) from subsoil lysimeters was 94% of that from full-length lysimeters in one of the clay soils, and 70% in the other. The higher contribution of the former clay subsoil was probably due to high P content deeper in the soil. Leaching of DRP was low from full-length and subsoil lysimeters (0.12 and 0.08 kg ha-1 yr-1, respectively) in one of the sandy soils, despite high topsoil P content, due to high P sorption capacity and low degree of P saturation in the subsoil. However, leaching of DRP was very high from full-length and subsoil lysimeters (3.33 and 3.29 kg ha-1 yr-1, respectively) from the other sandy soil with moderate topsoil P content, due to high P content and low P sorption capacity in the subsoil. These results indicate that the subsoil can function as both a source and sink for P leaching. Phosphorus leaching increased with increasing P content and DPS in subsoil and decreasing P sorption capacity in topsoil and subsoil, indicating that these parameters could be used for P leaching risk assessments. However, on soils with preferential flow in the subsoil, P leaching may be high despite high subsoil P sorption capacity. Hence, both chemical and physical properties of topsoil and subsoil must be considered in implementation of appropriate, cost-effective mitigation strategies for P loss reductions. Application of lime on top of the subsoil significantly reduced leaching of particulate P (PP) in both clay subsoils by 49 and 51%, respectively, compared with unlimed controls. This suggests that subsoil liming might be an appropriate method to reduce P leaching from clay soils.
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| 10. |
- Calleja-Rodriguez, Ainhoa
(författare)
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Quantitative Genetics and Genomic Selection of Scots pine
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The final objective of tree improvement programs is to increase the frequency of favourable alleles in a population, for the traits of interest within the breeding programs. To achieve this, it is crucial to decompose the phenotypic variance accurately into its genetic and environmental components in order to obtain a precise estimation of genetic parameters and to increase genetic gains. The overall aim of this thesis was to increase the accuracy of genetic parameter estimation by incorporating new quantitative genetics models to the analysis of multiple traits in multiple trials of Scots pine, and to develop a genomic selection protocol to accelerate genetic gain. Factor analysis was incorporated to multivariate multi-environment analyses and it allowed to evaluate up to 19 traits simultaneously. As a result, precise patterns of genotype-by-environment interactions (G E) were observed for tree vitality and height; moreover, it was possible to detect the main driver of the G E: differences in temperature sum among sites. Traditional quantitative trait loci (QTL) analysis of phenotypic data was compared with the detection of QTL with estimated breeding values (EBV) for the first time in a three generation pedigree and, as outcome, it was noticed that if a QTL was associated to a EBV and to a phenotypic trait, the proportion of variance explained by the QTLEBV was higher than the QTL-phenotype. Additionally, several QTL were detected across several ages, which may make them suitable as candidates for early selection. Genomic selection (GS) could aid to reduce the breeding cycle by shortening the periods of progeny field testing, and consequently increasing genetic gains per year. Genomic predictions, including additive and non-additive effects through different prediction models were compared with traditional pedigree-based models; it was seen an overestimation of genetic parameters for pedigree-based models, even larger when nonadditive effects could not be discerned from additive and residual effects. Prediction accuracies and abilities of the genomic models were sufficient to achieve higher selection efficiencies and responses per year varying between 50-90% by shortening 50% the breeding cycle. For the selection of the top 50 individuals, higher gains were estimated if non-additive effects are incorporated to the models (7 – 117%).
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