Chrysomya rufifacies and Cochliomyia macellaria are two medically and forensically important necrophagous flies that dominate ephemeral resources in the southern US. Since its introduction in 1981, Ch. rufifacies has become established throughout the New World due to its larvae being facultative predators. Through this research I examined the interaction between the native, primary colonizer C. macellaria and the invasive, secondary colonizer Ch. rufifacies and elucidated the olfactory mechanisms used to locate, colonize, and exploit ephemeral resources. This work used competition experiments, olfactometer experiments, and high-throughput sequencing to investigate the effects of priority colonization of ephemeral resources on both species, the olfactory mechanisms employed by gravid females to locate a resource, and the effects of egg-associated volatiles on those females. Results from competition experiments indicated that priority sequence significantly affected the fitness of both C. macellaria and Ch. rufifacies. Regulation of colonization time is not chiefly governed by resource age, as previously thought, but is affected by colonization of the resource by conspecific and heterospecific individuals. Colonizing adults may use cues from early colonizers to assess resource quality. These cues may be derived from the physiology of the eggs, the 31-39 species of bacteria I determined are present on the egg chorion, or some combination of both. Design of these experiments facilitated the development of techniques to surface-sterilize Calliphoridae eggs, analyze behavior of adults in a dual choice olfactometer, and associate adult response to conspecific and heterospecific eggs with environmental cues that ultimately affect larval fitness.

The main aim of this thesis was to study domestication effects on foraging behaviour in chickens and to investigate whether and how domestication and selection for high production have influenced adaptability in chickens. Two domestic strains of chickens (egg layers and meat type chickens) and their wild ancestor, the red jungle fowl (RJF) were compared in different test situations with respect to foraging behaviour and adaptability. The domestic strains showed a modified foraging strategy, where they were less inclined to explore and feed from a hidden food source, i.e. they showed less contrafreeloading (CFL, the behaviour of working for food even though identical food can be easily obtained) than RJF. The difference in CFL between RJF and the layers were not altered by food deprivation, which suggests that the lower CFL in the layers represents a genetically based difference in feeding strategy. In addition, CFL decreased with age in RJF and layers and social isolation decreased CFL in RJF. Furthermore, when foraging, RJF acquired information about the quality of different food sources, which was utilised after a change in environmental conditions. Contrary to this, layers gained less information during foraging and showed an impaired spatial learning ability compared to RJF, and in this respect, layers showed a lower degree of adaptability. Chronic stress impaired the learning capacity of both breeds but RJF seemed to be overall faster to learn to locate food in a spatial learning task. Furthermore, stressed RJF started to eat faster in the spatial learning test than non-stressed RJF, and contrary to this, stressed layers showed a more passive response by prolonging the time to start feeding compared to non-stressed layers. This indicates a more active response to stress in RJF than in layers. Similarly, when RJF and layers were exposed to food deprivation, RJF showed an active response by increasing their time spent on foraging behaviour. The general results in this thesis most likely reflect different adaptive strategies, where RJF appear to be better adapted to a stochastic environment, and the domestic strains to grow and produce egg in a more predictable environment. The findings are in accordance with the resource allocation theory, which suggests that animals selected for high production are expected to reallocate a high proportion of resources into production traits and hence fewer resources might be left to other biological processes, e.g. exploratory behaviour. Selection for high production seems to influence the ability of chickens to cope with a changing environment, which may have implications for the welfare of chickens in a production environment.

I studied carotenoids in the eggs of American coots (<i>Fulica americana</i>) from 3 study sites in Saskatchewan, Canada. I supplemented two diet types designed to reduce carotenoids in the diet of laying coots to investigate the relationship of carotenoids and the size of eggs and to examine the allocation of carotenoids into eggs.</p><p>In chapter 2, I examined influences of local environment, food quantity and food quality on egg size. Carotenoid content and stable nitrogen and carbon isotopes in yolk were measured and used to elucidate whether variation in type of food eaten contributes to egg size. By analyzing isotopes in coot tissues, I confirmed that coots use endogenous lipid reserves for egg formation but not endogenous protein reserves, and the size of eggs is more dependent on exogenous sources of nutrients. My data demonstrate that carotenoids are not causal in egg size, but are components of natural, high quality diets.</p> <p>Carotenoids are obtained through the diet and deposited into egg yolk. It has been hypothesized that concentrations and percentages of individual carotenoids can be labile and dependent on diets or maintained in an optimal balance to meet requirements of embryos. In chapter 3, I investigate deposition of carotenoids in egg yolk among nesting locales, among hens within a site and among treatments in a diet manipulation experiment. My data show maintenance in the percent composition of a suite of 3 important carotenoids, lutein, zeaxanthin and âcarotene, independent of scale of investigation and in contrast to other individual carotenoids that appear to vary in proportions based on diet. These results suggest that birds can maintain nutritional balances in their eggs despite variation in diets.</p><p>In chapter 4, I tested 3 hypotheses regarding the apportionment of carotenoids into egg yolk over the laying sequence. Without exception, concentrations of these nutrients have previously been shown to decline with egg sequence. In contrast to these findings, coots actually increased the carotenoid concentration in yolks over the laying sequence. My experimental evidence supports the explanation that this pattern of deposition depends on carotenoid availability to the laying female.

Production, egg quality, behaviour, and physical condition were compared from Wk 20 to Wk 50 among three beak- trimmed commercial laying strains, Lohmann White (LW), H & N White (HN), Lohmann Brown (LB), and a non-commercial Cross between Rhode Island Red (male) and Barred Plymouth Rock (female) in conventional cages and in floor pens. All chicks were reared in their respective environments, and 450 and 432 pullets were housed at 18 and 7 weeks of age in cages and floor pens respectively. Hens in cages were provided with 688 cm2/bird and those in pens with over 6,000 cm2/bird, both of which are more than provided by commercial standards. Body weights and eggshell weights were higher for birds in floor pens than those in cages, and although they increased with age, body weight of hens in cages decreased at Wk 50. White-egg layers (LW, HN) used perches and nest boxes more than Brown-egg layers (LB, Cross). During the laying period, mortality was higher for all strains in cages and during the rearing period mortality was higher in floor pens for LB hens but not other strains. No aggressive behaviours were found, but the frequency of gentle feather pecking and pecking at the enclosure was higher in cages than in floor pens. Feather condition deteriorated over time in cages mainly because of contact with the cage wires whereas in floor pens, feather condition of birds at Wk 20 was not different from that at Wk 50. The frequency of keel bone deformities was higher for White-egg layers than for Brown-egg layers in cages and was higher for Cross hens than other strains in floor pens. Claws were longer in cages than in the floor pens. Foot condition was worse in floor pens than in cages. The welfare indicators used in this study showed that cages restricted the hens' behaviour compared to floor pens and resulted in higher laying period mortality, reduced body weight and deteriorated feather condition than floor pens. Both systems had advantages and disadvantages in regard to the hens’ health and welfare. The use of environmental complexities was strain specific in floor pens. The environment by genotype interactions suggests that the strain should be considered when considering alternative housing systems.

Metal mines release treated effluents that contain a variety of metals, metalloids, and organics into the aquatic environment. A number of metal mine effluents (MMEs) have been found to contribute to adverse effects in fish and benthic invertebrates, such as decreased diversity and density, however the specific causal factors of toxic responses during chronic exposures to the MMEs are often unknown. Therefore, the overall objective of this dissertation was to explore causative and modifying factors of MME toxicity to a resident fish species, the fathead minnow (Pimephales promelas), during chronic, multi-trophic exposures. The representative MME used in this study was the process water effluent (PWE) of a Canadian metal mine, which is released into Junction Creek in Sudbury, Ontario, Canada. Chronic exposure to the MME has been a source of decreased reproductive output in fathead minnows in several previous studies, however, these same studies were not able to determine the potential causal factors of the reproductive impairment. In order to address the overall objective, several laboratory mesocosm studies were conducted, which consisted of three separate components. The first component included exploring several metals (Cu, Ni, and Se; alone and in mixture) that are consistently present in the MME and are known to cause toxicity at fairly low concentrations as potential causes for decreased egg production in fathead minnows. The second component included evaluating the role of decreased food availability (a possible indirect effect of MME in the receiving environment) as a potential cause of decreased egg production in fathead minnows. The third and final component included examining the role of water chemistry [(increased alkalinity and dissolved organic carbon (DOC)] as potential modifying factors of chronic MME toxicity to fathead minnows. In general, my results suggest that the metals present in the MME likely do not contribute directly to decreased reproductive performance in fathead minnows during chronic exposures, under the conditions examined. Instead, the MME appears to decrease food availability, therefore indirectly influence fathead minnow egg production. Furthermore, water chemistry modifications tested in this thesis were not able to entirely mitigate the reproductive effects in fish induced by the MME, although they did improve egg production relative to unmodified MME. Metal concentrations in fish tissues were not influenced by increases to alkalinity or DOC level in the exposure water, suggesting that bioavailability of metals during chronic exposure to metal-mixtures cannot be fully explained based on our understanding of metal complexation with abiotic ligands (inorganic and organic) during single metal or acute exposures. From a regulatory perspective, water chemistry modifications may somewhat improve fathead minnow reproductive performance during chronic exposure to the MME, however the MME would still not be entirely free of effects relative to the uncontaminated water. Future studies should focus on understanding the factors responsible for decreased food availability in MME-impacted aquatic ecosystems, and further explore potential approaches for ameliorating effluent quality.

Membrane chromatography was investigated as an alternative method to packed-bed chromatography for protein recovery. The purification of lysozyme from egg white with Natrix adseptTM weak cation-exchange membranes was investigated under two different binding configurations: (1) a non-flow, static set-up with variable pH and sodium chloride (NaCl) concentrations during the binding and elution steps, and (2) a dynamic, cross-flow set-up with recycle at pH 7.5 and no NaCl addition during binding. The weak cation-exchange membrane consisted of a carboxylic acid-based, environmentally-responsive hydrogel layer bonded to a polymer matrix. Lysozyme was chosen to illustrate protein-membrane binding interactions due to its well-characterized nature and positive surface charge over a large pH range. For the static binding set-up, two sources of lysozyme were studied: pure lysozyme and egg whites treated with 60 % (v/v) ethanol (ESEW). Elution of bound protein was performed with 1 M NaCl under two pH strategies: binding and elution at a constant pH, and binding at pH 4.5 and variable elution pH. The highest maximum total protein binding capacity for pure lysozyme and ESEW was observed at pH 4.5 with no NaCl addition; however, poor total protein and lysozyme activity recovery were achieved during separation. As well, other egg white proteins, such as ovomucoid, were observed to bind to the membrane surface at pH 4.5, despite possessing similar charge polarity to the anionic membrane surface, indicating a non-electrostatic binding mechanism during operation below the membrane’s pKa (4.7). Based on the conditions tested, the highest total protein and lysozyme activity recovery was demonstrated for the separation of lysozyme from ESEW at pH 7.5 binding and elution and no NaCl addition. In the dynamic binding study, very high pure lysozyme dynamic binding capacity was achieved at 10 % breakthrough (167.3 mg/ml membrane for a 0.35 mg/ml lysozyme solution). The lysozyme dynamic binding capacity was 2.2 times greater than the static binding capacity under similar conditions, significantly higher than published results for other cation-exchange membranes. The separation of lysozyme from four lysozyme sources was tested: pure lysozyme, ESEW, and aqueous egg whites with (ASEW) and without (AEW) 100 mM NaCl. The highest lysozyme activity recovery during separation and lysozyme purity was achieved from the ESEW feed. Lysozyme separation from aqueous egg whites was not as effective, likely due to a high concentration of negatively-charged protein impurities fouling the surface of the membrane. Competitive binding to the membrane limited lysozyme binding and reduced the purity of the recovery elution stream. The application of feed-side pressure during the separation of ESEW produced a high purity, high recovery lysozyme elution stream with a significant reduction in processing time; however, protein aggregates were observed to form on the membrane surface, limiting the applicability of high-pressure operation and reducing protein functionality in the elution stream. The weak cation-exchange membrane system was shown to successfully separate out a target protein from a low concentration protein mixture through electrostatic interactions, and may be further applied to other protein systems.

I studied carotenoids in the eggs of American coots (<i>Fulica americana</i>) from 3 study sites in Saskatchewan, Canada. I supplemented two diet types designed to reduce carotenoids in the diet of laying coots to investigate the relationship of carotenoids and the size of eggs and to examine the allocation of carotenoids into eggs.</p><p>In chapter 2, I examined influences of local environment, food quantity and food quality on egg size. Carotenoid content and stable nitrogen and carbon isotopes in yolk were measured and used to elucidate whether variation in type of food eaten contributes to egg size. By analyzing isotopes in coot tissues, I confirmed that coots use endogenous lipid reserves for egg formation but not endogenous protein reserves, and the size of eggs is more dependent on exogenous sources of nutrients. My data demonstrate that carotenoids are not causal in egg size, but are components of natural, high quality diets.</p> <p>Carotenoids are obtained through the diet and deposited into egg yolk. It has been hypothesized that concentrations and percentages of individual carotenoids can be labile and dependent on diets or maintained in an optimal balance to meet requirements of embryos. In chapter 3, I investigate deposition of carotenoids in egg yolk among nesting locales, among hens within a site and among treatments in a diet manipulation experiment. My data show maintenance in the percent composition of a suite of 3 important carotenoids, lutein, zeaxanthin and âcarotene, independent of scale of investigation and in contrast to other individual carotenoids that appear to vary in proportions based on diet. These results suggest that birds can maintain nutritional balances in their eggs despite variation in diets.</p><p>In chapter 4, I tested 3 hypotheses regarding the apportionment of carotenoids into egg yolk over the laying sequence. Without exception, concentrations of these nutrients have previously been shown to decline with egg sequence. In contrast to these findings, coots actually increased the carotenoid concentration in yolks over the laying sequence. My experimental evidence supports the explanation that this pattern of deposition depends on carotenoid availability to the laying female.

Sexual selection was defined by Darwin in 1871 as selection acting solely on reproduction success. It is known to act on males resulting in extravagant ornamentations or other attributes, but in recent years more studies have shown that sexual selection also act on females. There is empirical evidence in several taxa that the secondary sexual ornament also acts as a measurement on the females’ reproductive quality, it is an honest trait. In Gallus gallus the comb has been found to be an honest ornament. Quantitative Trait Loci have been found on chromosome 1 and 3 for comb- and egg size. The honesty of the comb is hypothesized to be caused by either a pleiotropic effect gene linkage. In this study an 8th generation Advanced Interline Cross was used to guarantee maximum recombination of alleles to observe phenotypic effects. 177 females were detained during 4 weeks to measure fecundity. Egg number, mean egg weight and total egg size were correlated to comb size: length, area and weight. Correlation between comb size and total egg weight were found to be negative, suggesting the comb to be a dishonest signal. The phenotypic measurements observed in this study suggest that the genes for egg production and comb size are linked, and this linkage has been broken in the F8 analysed in this study.

As part of a state-funded Gopher Tortoise (Gopherus polyphemus Daudin) translocation project, I monitored actively grazed improved pastures to determine if they could serve as suitable recipient sites for the threatened Gopher Tortoise displaced by human development. For cattle ranches to be considered suitable recipient sites females must be able to acquire sufficient energy to produce a clutch of viable eggs, and sufficiently high quality vegetation must be available to support juvenile recruitment into the population. Vegetation surveys were conducted to determine the composition and percent cover of plant species, especially those containing high amounts of nutrients, specifically nitrogen. Resident and relocated females were radiographed during the 2010 and 2011 nesting seasons for the presence of shelled eggs. I was able to determine clutch size and egg diameter for both relocated and resident gravid females. Mean clutch sizes were not significantly different between years. Resident females had larger mean clutch sizes than relocated females in both years, significantly so in 2011, suggesting a period of stress and adjustment for relocated females. Egg diameters were significantly larger by 2.5 to 4.5 mm in 2010 for relocated and resident females, respectively, compared to 2011. Three females were recaptured in both years and exhibited the same trend of similar clutch sizes between years but significantly smaller eggs in 2011. A total of 68 unique taxa from 31 families were found, grasses (Poaceae) were the most dominant and covered a mean of 57% of the total sampled area. Four forb species occurred at much greater percent covers than all others. However, only two species (Richardia and Desmodium) were found to have adequate nutritional content and occur at percent covers greater than five percent, indicating that forage availability may be high, but forage quality may be inadequate to support growing juveniles. Burrow surveys indicate that at least some hatchlings are able to successfully leave the nest by the presence of hatchling size burrows scattered throughout the fields, but the ratio of juveniles to eggs laid is especially low. Survivorship of eggs, hatchlings and juveniles may be too low to support a sustainable Gopher Tortoise population in improved pasture possibly because of lack of adequate forage, burrow compaction by cows, lack of available natural shelter material for protection from desiccation, and the reduced ability of movement in thick pasture grasses, especially by hatchling and yearling tortoises.

Post-weaning diarrhea is a major health challenge in the swine industry and is routinely managed by fortifying pig starter diets with antimicrobials. But there are concerns about antibiotic resistance, hence the need for identifying effective alternatives. The use of spray-dried whole egg powder containing anti-F4 antibodies (SDWE) against recombinant F4 antigens and chitosan oligosaccharide and Enterococcus fecalis probiotic combination (CPRO) was investigated in two trials using enterotoxigenic Escherichia coli K88+ (ETEC) oral challenge model in 21-d-old piglets. Pre-challenge, SDWE supported higher (P < 0.05) piglet performance whereas during the post-challenge period, SDWE and CPRO had no effect on growth performance but diarrhea incidences and severity were reduced (P > 0.05) in SDWE-fed piglets compared to the control. The results show that SDWE supported greater piglet performance pre-ETEC challenge although there was no benefit of SDWE or CPRO supplementation evident during the post-challenge period in early-weaned pigs. / October 2015