Agricultural grasslands have replaced native Midwestern prairies in the form of pasture, idle cropland and conservation fields. The condition of these cover types directly and indirectly influences the distribution, variety and productivity of avian populations within these landscapes. CP33 habitat buffers are an incentive-based conservation practice specifically designed to increase upland bird habitat and productivity. Landowners are encouraged to remove row crops from production and return them to early successional grassland habitat along the margin of agricultural fields. However, buffers exhibit a high perimeter-to-area ratio, which may increase negative edge effects, thereby creating sink populations. During the 2013 and 2014 breeding seasons, I assessed grassland bird response to CP33 habitat buffers in southern Illinois. Focal species included the northern bobwhite (Colinus virginianus), dickcissel (Spiza americana), eastern meadowlark (Sturnella magna), field sparrow (Spizella pusilla), indigo bunting (Passerina cyanea), and red-winged blackbird (Agelaius phoeniceus). I used a hierarchical multiscale framework to examine the influence of habitat variables at multiple scales on avian abundance, species richness, and occupancy. I also used this same framework, and logistic exposure modeling, to examine daily survival rates of nests found within CP33 habitat buffers. Multiscale occupancy and logistic exposure models consistently performed better than single-scale models for focal bird species; however, relative importance of local variables and landscape variables differed considerably among focal species. Nest survival rate was not strongly affected by edge effects or edge type. Microhabitat variables were much more influential in predicting nest survival. In my study area, CP33 habitat buffers are unlikely to support source populations for most of the focal grassland bird species I studied. To increase nest survival rates within established CP33 habitat buffers, managers should focus on microhabitat vegetation characteristics. To increase bird occupancy of CP33 habitat buffers in southern Illinois, managers should increase the size of CP33 habitat buffers within a landscape having adequate grassland cover. However, managers should not consider CP33 habitat buffers a panacea for most grassland avian species.

Master of Science / Department of Biology / David A. Haukos / Playa wetlands are unique ecological systems crucial to the ecology of the western Great Plains of North America. Playas offer a variety of ecological goods and services: flood water retention; water quality improvement; habitat for a distinctive assemblage of resident and migratory biota; and primary recharge points for the Ogallala Aquifer. The major threat to the function of playas is caused by watershed disturbance and habitat loss, primarily through sediment accumulation that decreases playa hydroperiod, density, and size. Previous research focused on playas in the Southern High Plains in Texas and the Rainwater Basin of Nebraska, with little playa studies located in the Central Great Plains. My objectives were to (1) identify the number and level of functionality of existing playas in the Smoky Hill River watershed, (2) determine the relative contribution of playas to the biodiversity of the landscape and influences from watershed disturbance levels, and (3) assess relationships among avian community composition and environmental variables through a canonical correlation analysis (CCA). To assess playa functionality, I randomly selected 20% of the 3,310 historical playas in the watershed and confirmed playa presence and anthropogenic modifications through imagery analysis (n = 608). To achieve the last two objectives, I conducted breeding bird surveys using point counts in >25 playas with paired, nonplaya sites. I recorded avian relative abundance and species richness. Plant species occurrence was detected using step-point methods along transects. Species diversity was derived using Simpson’s index. Approximately 22% of playas have been lost from the landscape. Of the remaining playas, only 3.15% were not affected by anthropogenic influences. Playas contribute greater than 40% and 16% greater avian species richness and diversity to the surrounding landscape, respectively. Playas located in grassland watersheds had a 63% and 35% greater avian species richness and diversity, as well as 57% and 66% greater floral species richness and diversity than playas located in croplands, respectively. CCA results identify playa soil moisture and watershed disturbance as significant influences to the playa avian community. It is important to reduce watershed disturbance and anthropogenic influence on playas to maintain biodiversity at local, regional, and continental scales.

The hyperpallium densocellulare (HD) is an avian cerebral structure, the origin of which remains unclear and considered to be critical to the understanding of the non-mammalian forebrain evolution. The main goal of this investigation was to clarify the anatomical characteristics and behavioral implications of HD, which had been assumed to be a homogeneous unitary entity. This project had three specific aims: 1) To identify possible subdivisions of HD in terms of cytoarchitecture, Substance P distribution, and connections based on unpublished (Aim 1a) as well as published data (Aim 1b); 2) To identify the unknown connections of these subdivisions by using anatomical tract-tracing methods; and 3) To identify the behavioral implications of these subdivisions by examining the expression of an immediate early gene EGR-1 (early growth response protein 1) using immunohistochemical methods. Based on the present study, four subdivisions of HD (rdHD, cdHD, rvHD, and cvHD) were identified in terms of cytoarchitecture, hodology, and EGR-1 immunoreactivity. In general, the results showed that the dorsal regions of HD (rdHD and cdHD) are closely connected to each other and involved in networks linking sensory and limbic functions. The ventral regions of HD (rvHD and cvHD) also have close connections between them, but also have direct associations with many limbic forebrain structures. In terms of behavioral implications, the EGR-1 study showed that only one subdivision, rvHD, had significant changes in EGR-1 immunoreactivity when animals were exposed to live conspecifics. These findings suggest that this area is uniquely involved in reactions to external stimuli. These results further provide an important insight on the organization and evolution of the avian forebrain, the cerebrum in particular.

Magister Public Health - MPH / Avian Influenza (AI) is a contagious viral zoonotic disease with great public health implications and negative socioeconomic impact (WHO, 2006a). The highly pathogenic avian influenza (HPAI) infection is transmitted from birds to man mostly through contact with contaminated poultry and objects (INFOSAN, 2005), hence people who come in contact with birds such as live bird sellers (LBS) are the more vulnerable population (WHO, 2006a). Inadequate knowledge of AI health risks and poor practice of AI preventive measures amongst LBS increases the risk of spread of the infection in both humans and animals.The aim of this study was to describe and quantify the knowledge and practice of LBS with regards to avian influenza health risks and preventive activities in Agege, an urban area in Lagos State, Nigeria. / South Africa

Avian influenza H5N1 causes occasional but serious infections in humans and efforts to produce vaccines against this strain continue. Current influenza vaccines are prophylactic and utilize the two major antigens, hemagglutinin and neuraminidase. NP is an attractive alternative antigen because it is highly conserved across all influenza strains, has been shown to increase the rate of viral clearance, and potential therapeutic vaccines would elicit cytotoxic T lymophcyte responses in an infected person. The NP antigen from H5N1 was characterized using a variety of physiochemical methods to gain insights into both the biological and physical properties of the antigen which are important from a regulatory viewpoint when considering therapeutic vaccines. Results obtained to date show that NP is relatively unstable and indicate that the conformation of the H5N1 NP antigen is highly dependent upon purification procedure, buffer conditions, pH and the presence or absence of RNA. These factors will need to be clearly defined and taken into consideration when manufacturing and regulating NP vaccine preparations.

Highly pathogenic notifiable avian influenza (HPNAI) is a disease caused by influenza A virus. It is frequently fatal in poultry. Since late 2003, disease outbreaks caused by the Asian strains of HPAI H5N1 virus have ravaged the poultry industry with the death of over 200 million birds. The epidemic has spread from Asia to Europe and more recently to Africa. To date, more than 200 human fatalities have occurred. A clear understanding of the full epidemiology of the disease at the genetic and spatial/temporal level is critical for the management, control and eventual eradication of the virus. In this study, modern tools of molecular epidemiology (Reverse-transcriptase polymerase chain reaction (RT-PCR), molecular characterization and phylogenetic analyses), Geographical Information Systems (GIS) and remote sensing, and other epidemiological tools were used to explore the outbreak of HPNAI in Nigeria. The molecular and spatial analyses both concluded that Nigeria was infected with multiple infections. The spread of primary outbreaks, which affected mainly sectors 2 and 3 of the poultry industry as described by Food and Agricultural Organisation of the United Nations, were strongly linked to trades, live bird markets, inappropriate disposal of carcasses and poorly implemented control measures. This work did not find a strong correlation between wild birds and HPNAI H5N1 in Nigeria. Some of the analyzed viruses showed genetic drift, and the implications of these for future epidemiology and ecology of avian influenza in Africa will need further evaluation. The option of vaccination and its implications were adjudged good, and its shortcomings were highlighted. Community initiative at fighting emergency diseases like HPNAI H5N1 was similarly advocated. The financial losses to the Nigerian poultry industry were estimated at around $680 million. The risk of the spread of infection was assessed using ecological niche modeling and the whole of West Africa is at risk of infection, should no concrete action be taken to halt the spread. In conclusion, useful suggestions were proffered to affected countries like Nigeria, and unaffected countries that are at risk of infection, so that Africa can be safe from the scourge of HPNAI H5N1. / Dissertation (MSc)--University of Pretoria, 2008. / Production Animal Studies / unrestricted

Toxicity testing is moving from animal-based studies to faster, more ethical in vitro approaches that focus on mechanistic toxicology. The use of bisphenol A (BPA) replacement compounds is increasing and there is limited toxicity data available for these compounds in avian species. The overall goals of this thesis were to: a) determine if avian cell lines are suitable alternatives to primary hepatocytes for chemical screening; b) generate toxicity data for five BPA replacement compounds: bis(4-hydroxyphenyl)methane (BPF), bis(3-allyl-4-hydroxyphenyl)sulfone (TGSH), 7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane (DD-70), 2,2-bis(4-hydroxyphenyl)hexafluoropropane (BPAF) and 4-hydroxyphenyl 4-isoprooxyphenylsulfone (BPSIP) in three in vitro models: primary chicken embryonic hepatocytes (CEH), double-crested cormorant (DCCO) embryonic hepatocytes (DCEH) and chicken LMH cell line; and 3) prioritize two replacements for early-life stage testing (ELS). LMH cells cultured as 3D spheroids, as opposed to 2D monolayer, had enhanced mRNA expression and CYP1A activity and were therefore used for screening. Additionally, an immortalized DCCO hepatic cell line, DCH22, was established, which may be useful for future avian toxicity testing. DD-70 and BPAF were the most cytotoxic across the three in vitro models. TGSH and DD-70 altered expression of genes associated with multiple toxicity pathways, but not estrogen response, and are potential non-estrogenic replacements. BPAF, BPF and BPSIP are potential estrogenic replacements. In general, the replacements were more cytotoxic and/or transcriptionally active than BPA. There was species-specific variability in toxicity; the replacements were more transcriptionally active in CEH compared to DCEH. LMH spheroids were more sensitive to estrogenic endpoints than CEH. DD-70 and BPAF were prioritized for ELS studies based on in vitro results. All of the replacements modulated the expression of genes related to bile acid regulation in vitro and an increase in gallbladder mass was observed in chicken embryos after exposure to DD-70 or BPAF. Overall, this thesis evaluated the utility of LMH cells cultured as spheroids as an animal free alternative for chemical screening, established a DCCO cell line, and generated novel cytotoxicity and gene expression data for five BPA replacement compounds in three in vitro avian models and determined ELS toxicity of two replacement compounds.

We are the first lab to report the occurrence of a diet-induced transsulfuration (TS) blockade associating with elevated S-adenosylmethionine (i.e. SAM) synthesis, enhanced lifespan and enhanced reproductive capacity, in a vertebrate animal model. In this paradoxical study, we used LC-MS/MS-derived metabolomics data to report the effects of flaxseed (Linum Usitatissimum) on one-carbon metabolism in White Leghorn laying hens (Gallus gallus). Flaxseed contains a vitamin B6-antagonizing molecule called ‘linatine’ that is particularly effective at reducing vitamin B6 levels in small rodents and poultry. Linatine reduces TS flux through its inhibition of the vitamin B6-dependent enzymes cystathionine beta synthase (CBS) and cystathionine gamma lyase (CSE). In this study, our flaxseed-fed hens displayed decreased 4-pyridoxic acid and decreased pyridoxamine, concomitant with 15-fold elevated cystathionine. Homocysteine levels were stable in flaxseed-fed hens despite such highly elevated cystathionine. This is an astonishing finding, because mammalian models would predict the induction of hyperhomocysteinemia (i.e. elevated homocysteine) when cystathionine is so highly elevated (1). We are therefore reporting a phenomenon that might be unique to birds. Our metabolomics data indicate increased consumption of one-carbon donor molecules (e.g. choline, betaine, dimethylglycine, serine, etc) in flaxseed-fed hens, probably as a means of fueling the betaine homocysteine methyltransferase (BHMT) and methionine synthase-B12 (MS-B12) reactions. This modeling approach provides a rationale that flaxseed-fed hens increase their rate of homocysteine remethylation via BHMT and MS-B12, and in turn this would maintain stable homocysteine levels in the animal. We observed that the culminating outcome is elevated synthesis of SAM and an elevated SAM:SAH ratio. The associated biological outcomes are extended lifespan and increased reproductive capacity (i.e. increased daily egg laying) in flaxseed-fed hens. Our data further indicate that flaxseed tremendously stimulates a glucagon-like phenotype in hens. Specifically, flaxseed-fed hens exhibit 3-fold elevated glycated hemoglobin (HbA1c), 2-fold elevated serum free fatty acids (FFAs), 10 to 14% reduced body weight, and slightly reduced plasma pyruvate. These phenotypic markers suggest that glucagon might also play a large role in extending lifespan and enhancing reproductive capacity in flaxseed-fed hens. We predict that the anti-vitamin B6 effects of flaxseed are responsible for stimulating this glucagon-like phenotype in hens. Therefore, we conclude that the vitamin B6-antagonizing effects of linatine (via flaxseed dieting) improve liver function, body leanness, egg laying and survival, in a manner associated with increased SAM synthesis, increased blood FFA levels and increased blood glucose levels, in laying hens. The second part of this dissertation is used to test the hypothesis that polyunsaturated fatty acids (PUFAs) regulate lipid metabolism, increase mitochondrial respiration and decrease E-cadherin expression, in laying hen ovarian tumors. Researchers are unaware of the mitochondrial effects of PUFAs within laying hen ovarian tumors, and only a few publications exist regarding the analysis of E-cadherin in laying hen ovarian cancer. The results of this present work suggest that dietary PUFAs accumulate within laying hen ovarian tumors, and these same tumors exhibit decreased gene transcripts that govern de novo lipogenesis (i.e. FASN). Simultaneously, these tumors exhibit elevated transcripts for oxidative phosphorylation (OXPHOS) and decreased transcripts for phase 2 antioxidant enzymes. These patterns associated with decreased transcript levels of CDH1 (the gene for E-cadherin) in ovarian tumors, but no effect on full length 120kDa protein was observed by PUFAs versus our control diet. Interestingly, the effect of PUFAs on E-cadherin occurred at the level of the cleaved 37kDa and 80kDa E-cadherin fragments, such that PUFAs reduced their levels in hen ovarian tumors. We therefore developed a system for depleting the 80kDa E-cadherin fragment from hen ascites fluid (i.e. fluid from a hen that had ovarian cancer), so that we could test our hypothesis that the 80kDa E-cadherin fragment is important for supporting mitochondrial respiration in normal ovarian surface epithelial cells (IOSE80s). Mitochondrial membrane potential was decreased in IOSE80s when the 80kDa fragment was removed from the ascites; however, there was no effect on basal oxygen consumption in subsequent tests using extracellular flux analysis with Seahorse XFp. During our analysis of microRNA-200a-3p (miR-200a) we did not observe any effect of diet on miR-200a within hen ovarian tumors; however, we did observe that miR-200a levels increased within the tumor when going from stage 2 to stage 4 disease. Overall, we observed reduced risk of ovarian cancer, stage 4 ovarian cancer, multiple peritoneal tumor involvement and cancer-associated mortality, in laying hens that consumed a diet that was supplemented with PUFAs.

The objective of this study was to field-test the "microenvironment concept" of avian botulism epizootiology. The "microenvironment concept" hypothesizes that aquatic invertebrate carcasses may serve both as a substrate for toxin production by Clostridium botulinum type C in nature and as a vehicle for toxin transmission to waterbirds. This concept has become the generally accepted, but inadequately tested, working hypothesis of type C botulism epizootiology. This study attempted to experimentally induce type C botulism in sentinel flocks of mallard ducks (Anas platyrhynchos) and American coots (Fulica americana) on sewage oxidation ponds in northern Utah. The three experimental oxidation ponds were inoculated with Cl. botulinum type C (strain X220B2) endospores in June,l974. Aquatic invertebrate populations were monitored throughout the summer. Rotenone was used in August in two of the experimental ponds (one pond served as a control) to kill aquatic invertebrates and thereby provide a large amount of substrate for clostridial growth and toxin production. No botulism was detected among the sentinel birds even though they routinely ingested invertebrate carcasses. None of the samples of dead invertebrates collected from the experimental ponds contained detectable (in white mice) botulinum toxin. It was concluded that the "microenvironment concept," as it now stands, cannot always be a sufficient explanation of how type C botulism epizootics are initiated in nature. Microbiological experiments designed to determine why the invertebrate carcasses collected from the study ponds contained no botulinum toxin were started and are now ongoing. Early results indicate that Cl. botulinum (X220B2) cells may not normally be able to effectively compete (at least in terms of toxin production) with other microorganisms present in the sewage ponds. It is suggested that the initiation of a type C botulism epizootic in nature may require the alleviation of the inhibitory effects of other putrefactive microorganisms upon clostridial metabolism and/ or toxin. This hypothesis is highly speculative and requires much further experimentation.

Riparian corridors in California are known to be an important but reduced and degraded resource for landbirds. In spite of previous research, the habitat characteristics that correlate with high landbird abundance remain poorly understood. In particular, the scale at which predictive models are useful (fine scale, watershed, sub-region or region) is ill defined. Herein, point count-based abundance indices for 8 riparian associated/obligate species with uniform and high detection probabilities are correlated with biotic and abiotic habitat variables: a sums of squares procedure is used to select the top 5 predictive variables for each species, best fit linear models are selected in an information theoretic framework, and the relative importance of individual variables assessed. These analyses identified site and vegetation characteristics that could serve as targets for restoration and conservation efforts within this coastal central California region. The specific characteristics vary somewhat across the 8 species I surveyed. In addition, the characteristics that I have found important as predictors are distinct from analyses that others have conducted. Therefore, just as we should probably accept regional variation in the composition of riparian avifaunas, we should also probably expect regional variation in the relationship between habitat variables and avian abundance. It appears that important habitat characteristics vary at the fine, watershed, sub-region and regional scales thus reducing the generality of all of the currently available models.