Browsing by Subject "Avian"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Establishment, identification, quantification of methanogenic archaea in chicken ceca and methanogenesis inhibition in in vitro chicken ceca by using nitrocompounds(Texas A&M University, 2006-08-16) Saengkerdsub, SuwatIn the first phase of this study, the diversity of methanogenic bacteria in avian ceca was found to be minimal. Based on 16S rDNA clone libraries, a common phylotype, designated CH101, ranged between 92.86 to 100 % of the total clones whereas less than 1% of the other phylotypes were found. On the basis of the sequence identity, all of the sequences, except sequence CH1270, are related from 98.97 to 99.45% to 16S rDNA Methanobrevibacter woesei GS. Sequence CH1270 is 97.62% homologous to the sequence identified to uncultured archaeon clone ConP1-11F. Clearly, the predominant methanogen found to reside in the chicken ceca was M. woesei. By using a MPN enumeration method, methanogen counts were found to be in the range of 6.38 to 8.23 log10 organisms per gram wet weight. The 16S rDNA copy number per gram wet weight in the samples was between log10 5.50 and 7.19. The second phase of the study was conducted to observe the effects of selected nitrocompounds and two different feedstuffs on in vitro methane production in chicken cecal contents and rumen fluid. Initially, one of the three nitrocompounds was added to incubations containing cecal contents from laying hens supplemented with either alfalfa or layer feed. Both feed materials influenced volatile fatty acids (VFA) production and also fostered methane production in the incubations although methane was lower (P < 0.05) in incubations with added nitrocompound, particularly nitroethane. Secondly, nitroethane was examined in incubations of bovine or ovine rumen fluid or cecal contents containing either alfalfa or layer feed. Unlike cecal contents, layer feed significantly (P < 0.05) supported in vitro methane production in incubations of both rumen fluids. The results show that nitroethane impedes methane production, especially in incubations of chicken cecal contents. The final phase of this study was carried out to determine the methanogenic establishment in the chicken ceca by the cultural method with the quantitative PCR. The results suggested that methanogens colonized in chicken ceca at a few days after birth. Litter and house flies could be potential sources for methanogenic colonization in broiler chicks.Item Investigation of Circadian Clock in Peripheral Tissues and Immune-Circadian Interaction in the Domestic Fowl, Gallus Domesticus(2012-12-07) Kallur, SailajaThe circadian system provides living organisms a means to adapt their internal physiology to constantly changing environmental conditions that exists on our rotating planet, Earth. Clocks in peripheral tissues are referred to as peripheral which may participate in tissue-specific functions. The first step to investigating the circadian regulation in the peripheral tissues of avians was to examine for the presence of avian orthologs of core components of the molecular clock using Quantitative real time (qRTPCR) assays. We investigated the avian spleen for daily and circadian control of core clock genes and regulation of the inflammatory response by the spleen clock. The core clock genes, bmal1, bmal2, per2, per3 and clock displayed both daily and circadian rhythms. Proinflammatory cytokines TNF?, IL-1?, IL-6 and IL-18 exhibited daily and circadian rhythmic oscillations. A differential expression of proinflammatory cytokine induction was observed in the spleen undergoing lipopolysaccharide (LPS)-induced acute inflammation. Exogenous melatonin administration during inflammation seems to enhance some and repress a few inflammatory cytokines, implying that melatonin is pleiotropic molecule. To compare and contrast the role of peripheral clocks in regulating energy balance and reproduction in layer vs. broiler chicken, the visceral adipose tissue (VAT), ovary and hypothalamus were examined for the presence of core clock genes were investigated in these two lines of poultry birds. Quantitative RT-PCR was employed to examine daily control of core clock genes in these three peripheral tissues over a 24hr period. The layer hens exhibit rhythmic oscillations in the mRNA abundance of the core clock genes in the VAT, ovary and the hypothalamus. The hypothalamus and VAT of the broiler hens exhibit rhythmic mRNA abundance of the core clock genes. However, the clock genes in the ovary of the broiler pullets exhibit marked reduction in their amplitude and rhythms over a 24hr period. The broiler hens are prone to poor energy balance, obesity and reproductive capacity. In summary, these data provide evidence for a functional link between the circadian clock and the ovary by determining clock gene regulation under conditions of disrupted or eliminated reproductive function vs. normal reproductive output.Item Pre-wind energy development assessment of the avian community in the Central Texas Panhandle(2010-12) Wulff, Sarah J.; Ballard, Warren B.; Butler, Matthew J.; Boal, Clint W.; Boydston, Kathy; Linehan, AndrewWind energy development is a fast growing renewable energy source. It has the potential to reduce some of our dependence on fossil-fuels. Despite the many benefits of wind power, there are some concerns regarding the environmental impact of wind turbines, such as habitat loss, habitat disturbance, soil disturbance and possible erosion, vegetation loss, promotion of invasive species, noise pollution, and collision-related avian mortality. The impacts of wind energy development on wildlife can be both direct and indirect. Bird and bat collisions with turbines and other infrastructure are possible direct hazards. Habitat loss, habitat fragmentation, avoidance of structures and other behavioral changes, and increased predation because of increased perching and nesting structures for raptors are some of the potential indirect hazards. Wind farms likely have varying risks and different magnitudes of hazards depending on placement of the facility, topography, weather, wildlife habitat needs, and wildlife migration patterns. Improvements in wind farm placement and new repellant technologies may help reduce mortality at wind facilities. These wildlife impact issues along with the great potential for wind energy development in the Great Plains has increased the need for pre-construction assessments and mitigation to lessen the potential impacts of wind energy development. My intent was to gain a better understanding of grassland bird communities in the Texas Panhandle. I examined avian flight heights to identify possible species at greater risk of collisions with wind turbines and I examined avian diversity and density patterns through the year. Understanding differences in avian diversity between vegetation types will help wildlife managers and wind energy developers identify areas that may be important to avian conservation. I compared the effectiveness of point-counts and line-transects to help researchers plan avian surveys for future pre-construction assessments. During October 2008–August 2009, I recorded flight heights of 65 species at a future wind farm in the Texas High Plains. I observed average flight heights of 29 species were within the potential rotor swept zone (RSZ; 32–124 m). Of those species, 6 were listed as species of concern for the Texas High Plains region by Texas Parks and Wildlife Department. I found that the species (n = 14) with >25% of observed flight heights within the RSZ were composed of 21% raptors/vultures, 50% wetland associated species, and 29% passerine/other species. As indicated by flight heights, I found raptor and waterfowl groups were at greatest risk of collision with wind turbines in the central Texas Panhandle. Turbine placement should be avoided in areas with high concentrations of trees which provide nesting habitat for many raptor species. Turbine placement should also be avoided in areas of high raptor prey densities where raptors may concentrate to feed. For wetland associated species I recommend that turbine placement should be avoided near playa wetlands where these species concentrate to feed, roost, and nest. I stratified our sites into 5 vegetation types (agriculture, breaks, plateau grasslands, playa wetlands, and prairie dog (Cynomys ludovicianus) towns). I calculated Shannon and Simpson’s diversity indices for each site, vegetation type, and season. I found the breaks vegetation type (H’ = 2.96; DS = 0.8907), closest to historic native grassland, had the highest avian diversity and plateau grasslands, primarily non-native, had the lowest avian diversity (H’ = 2.19; DS = 0.7404). I detected the most avian species (n = 95) in agriculture but the lack of nesting habitat in agriculture may reduce its importance to conservation of native grassland birds. I observed moderate avian diversity at playa wetlands and prairie dog towns. Diversity indices, often considered indicative of ecosystem health, are an important component in the assessment of placement of wind facilities. Based on diversity, I recommend wind energy developers avoid construction of wind energy facilities on the breaks, playa wetlands, and prairie dog towns vegetation types. Breaks, playa wetlands, and prairie dog town vegetation types provide habitat to unique segments of the avian community in this region such as declining grassland and shorebird populations. I estimated density using Program Distance 6.0 for 32 of the 163 species observed. While line-transects took more effort they resulted in a greater number of species detected (23 species with point-counts and 29 species with line-transects). This is likely because more area was covered and birds flushed as observers walked along the line. However, differences between survey techniques depended on season and species. For example, non-breeding season sparrows were detected better with line-transects, likely due to flushing of secretive birds. On the other hand, if surveying breeding season sparrows, either survey technique worked well. I recommend line-transect surveys be used when surveying grassland species and non-breeding season surveys. I recommend point-count surveys when survey effort is limited. Potential impacts on wildlife can be reduced during the development phase of a wind facility by relying on pre-construction site assessments. These assessments need to include proper survey techniques for habitats, species, and seasons of studying, along with species occupancy, species density, animal movement through and within a site, and other behaviors of affected avian species. In the Central Panhandle of Texas I recommend placement of wind turbines be avoided near playa wetlands and raptor nesting areas and focused more in agricultural areas. Also, during non-breeding season surveys or when surveying grassland birds the better survey technique is line-transects. More pre-construction research into avain behaviors that may put at greater risk of collision with wind turbines and more specific habitat uses may be helpful in refining the placement of wind turbine placement.