White Leghorn (WL) breed is homozygous for an allele on the α2C-AR gene while the Red Junglefowl (RJF) is mostly heterozygous for that. The gene is also hypermethylated in WL. The gene codes for the α2C -adrenergic receptor, which plays various roles including regulation of neurotransmitter release from adrenergic neurons in the central nervous system and sympathetic nerves The aim of this study was to investigate the effects of the variation of α2C-AR gene on the chickens’ behaviour. Various behavioural tests mostly associated with fear and stress was conducted in progeny of an F9 generation of the advanced intercross line (AIL) between RJF and WL, selected for homozygosity of the alternative alleles on the α2C-AR gene. In the emergence test, the stress effect on both poking and total exit latency was significantly higher in WL genotype females in comparison to RJF genotype females (effect on head poking time: WL -70.62 ± 18.603 versus RJF 15.63 ± 29.069; effect on total exit time WL -72.14 ± 20.582 RJF 5.64 ± 30.140). In the aerial predator test RJF genotype birds showed significantly more agitated behaviours after the predator exposure in comparison to WL genotype birds (RJF 27.65 ± 0.700 versus WL 25.09 ± 0.915) Although we found differences in behaviour of individuals with WL genotype, more research is needed to find out how the variation on the ADRA2C gene has played a role in domestication of layer chicken.

The purpose of this work was to examine the effectiveness of several replacements for antibiotics in broiler chickens using bacterial challenge models. For this work, pathogen challenge models were developed using three model pathogens; two human pathogens (<i>Salmonella enteritidis</i> and <i>Campylobacter jejuni</i>), and one poultry pathogen (<i>Clostridium perfringens</i>). The first set of experiments involved the selection and use of 2 model probiotics; <i>Bifidobacterium animalis</i> and <i>Lactobacillus fermentum</i>. Oral administration of either probiotic did not significantly reduce (P < 0.05) the level of intestinal colonization by either <i>S. enteritidis</i> or <i>C. jejuni</i> in experimentally infected broiler chickens. The next set of experiments examined the effectiveness of orally administered, pathogen-specific antibodies obtained from hyperimmunizing laying hens in controlling bacterial infections with <i>S. enteritidis</i>, <i>C. jejuni</i> or <i>Clostridium perfringens</i> in broiler chickens. Regardless of the concentration, or mode of administration, anti-<i>S. enteritidis</i> hen-egg antibodies or anti-<i>C. jejuni</i> hen-egg antibodies were unable to significantly reduce (P < 0.05) the intestinal colonization by either pathogen in experimentally infected broiler chickens. Likewise, administration of anti-<i>C. perfringens</i> hen-egg antibodies did not reduce intestinal colonization by <i>C. perfringens</i>, and actually exacerbated the clinical outcome of this important poultry pathogen by significantly increasing (P < 0.05) intestinal lesions scores compared to negative control birds. Lastly, the effect of dietary protein source on intestinal <i>C. perfringens</i> populations was investigated. In broiler chickens experimentally infected with <i>C. perfringens</i> and fed diets which varied in the source of dietary protein, it was shown that birds fed fish meal, meat/bone meal, feather meal and potato protein concentrate had significantly higher intestinal <i>C. perfringens</i> counts than the birds fed corn gluten meal, soy or pea protein concentrates or the control diet (P < 0.05). Further, it was shown that the glycine content of the diets and ileal contents was significantly, positively correlated with <i>C. perfringens</i> numbers in ileum and cecum. It is concluded that although the intervention strategies employed in these studies show promise, diet composition clearly had the largest effect on intestinal bacterial populations. Further studies are required to examine both the impact that diet and these intervention strategies have on the factors which control intestinal colonization by pathogens on a case by case basis.

The lesser prairie chicken (Tympanuchus pallidicinctus; LPC) has declined in numbers since the late 1800s. Reasons for this decline have been attributed to habitat degradation (decreased forb and grass cover and increased woody cover) and fragmentation caused by overgrazing and conversion of native rangelands to croplands. The herbicide, Tebuthiuron, has been used extensively throughout the LPC’s range to reduce dominance of woody shrubs and allow growth of forbs and grasses. Tebuthiuron treatment of shinnery oak (Quercus havardii) rangelands has been reported as being both beneficial and detrimental to LPC populations. My study evaluated the effects of Tebuthiuran treatment of shinney oak on LPC survival, movement, and reproduction. I trapped (48), radio-tagged (38), and monitored LPC survival, movements, reproduction, and habitat use during spring and summer 2006 and 2007. I also determined potential LPC nest predators using dummy nests (domestic chicken eggs) and motion-sensitive infrared cameras. No differences were found in survival between ages, sexes, or years. Range size did not differ by age, sex, or year. Female LPC moved greater distances from lek of capture than did males. Females nested almost exclusively in non-grazed rangeland and under sand sagebrush (Artemisia filifolia). Nest-sites had higher obstruction of vision (OV), higher (%) woody cover, and lower (%) bare ground than surrounding areas. All LPC were found to use non-grazed rangeland areas more than all other vegetation types, and to use tebuthiuron-treated, grazed areas slightly more than non-treated, grazed areas. Non-grazed rangeland had higher OV than all other vegetation types. Tebuthiuron treatment lowered woody plant dominance and increased forbs and grasses. Fire reduced vegetation height and OV and increased growth of grasses and forbs, but did not kill woody vegetation as did tebuthiuron-treatment. The most common dummy nest predator found was the Chihuahuan raven (Corvus cryptoleucus).

Lesser prairie-chickens (Tympanuchus pallidicinctus) have declined throughout their range because of overgrazing and loss or fragmentation of habitat from conversion of native prairie to agricultural cropland. Lesser prairie-chickens were radio-marked (n = 225) as part of 2 separate field studies in the Texas Panhandle (2001–2003, 2003– 2007). These data were used to evaluate whether differences in demographic parameters existed between populations occurring in 2 areas dominated by different vegetation types (sand sagebrush [Artemisia filifolia] versus shinnery oak [Quercus havardii]) in the Texas Panhandle from 2001–2007. A model-selection approach was used to test hypotheses explaining differences in survival and reproductive success of lesser prairiechickens. Additionally, a population viability analysis was constructed using the above demographic parameters to evaluate effects of harvest and no harvest scenarios on viability and population persistence of lesser prairie-chickens in Texas. Overall, survival, reproduction, and population viability were lower in the shinnery oak compared to the sand sagebrush vegetation type. Lesser prairie-chicken survival differed between breeding and non-breeding periods. I estimated annual survival of lesser prairiechickens at 31% in the shinnery oak and 52% in the sand sagebrush vegetation type. Nest success was (41%, 95% CI = 25–56%) in the shinnery oak population compared to the sand sagebrush population (75%, 95% CI = 54–94%). Population viability analysis predicted continued declines in lesser prairie-chicken populations in Texas. Estimates of local occupancy indicated lesser prairie-chicken populations would go extinct in the southwestern shinnery oak vegetation type more quickly compared to the northeastern sand sagebrush vegetation type (approximately 10 years compared to 30 years, respectively) without changes in population vital rates. Harvest at all levels increased risk of extinction. Results suggest that differences in survival and reproduction of lesser prairie-chickens within sand sagebrush and shinnery oak vegetation types throughout the Texas Panhandle should be evaluated, especially during the breeding season. Improvements to vegetation conducive for successful nesting are important to the viability of lesser prairie-chickens. Conservation and recovery strategies for lesser prairie-chicken populations should address variables that increase survival and nest success and consideration of no harvest.

Salmonella and Escherichia coli O157:H7 (EC) contamination continues to be one of the major concerns for the microbiological safety of raw poultry and beef products. Application of more than one decontamination agent as a multi-hurdle intervention to carcasses in a processing line might produce greater reductions than one treatment alone due to different modes of action of individual antimicrobials. In this study, sequential spray applications of e-polylysine (EPL), lauric arginate and acidic calcium sulfate (ACS) solutions were evaluated against Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) on artificially inoculated broiler carcasses and against ST and EC on beef rounds and ground beef derived from the rounds. All possible 2-way combinations and individual applications of 20 % ACS (ACS20), 300 mg/liter EPL (EPL300) and 200 mg/liter LAE (LAE200) were evaluated using a sterile membrane filter model system. The combinations that provided higher Salmonella reductions were further evaluated on inoculated chicken carcasses using either response surface methodology (RSM) or in various concentrations applied in a sequential manner. Sequential spray applications of EPL300 - ACS 30 % (ACS30) or LAE200-ACS30 produced the highest Salmonella reductions on inoculated chicken carcasses. In a subsequent experiment, treatment of Salmonella inoculated carcasses with EPL300-ACS30 or LAE200-ACS30 combinations were found effective for reducing initial Salmonella counts by 1.5 and 1.8 log CFU/ml, respectively, immediately after treatment and by 1.2 and 1.8 log CFU/ml, respectively, following 6 days of storage at 4.4 °C. Evaluation of the resident microflora including aerobic plate counts (APC), E. coli, coliforms and psychrotrophs on uninoculated chicken carcasses after treatment with EPL300-ACS30 or LAE200-ACS30 and during storage indicated that these treatments have the potential to increase the shelf-life of poultry carcasses. Furthermore, application of warm (55 °C) EPL300-ACS30 or LAE200-ACS30 onto inoculated beef rounds reduced both ST and EC counts over 6 days of storage at 4.4 °C by 4.5 and 4.3 log CFU/cm2, respectively. Ground beef manufactured with EPL300-ACS30 or LAE200- ACS30 treated rounds had lower ST and EC counts initially and stayed lower over 4 days of storage at 4.4 °C when compared to control.

The aim of this study was to identify common messenger molecules used in both the immune and the neuroendocrine systems in birds, and to shed light on a cell type within the bursa of Fabricius that has historically been postulated as a potential neuroendocrine-immune link, the bursal secretory dendritic-like cells (BSDC). An immunocytochemical approach was used to identify neuroendocrine cell populations in the thymus, pituitary and bursa of Fabricius in the chicken. Molecular confirmation of the neuroendocrine cell marker, chromogranin A (CgA) in the thymus tissue of the chicken was reported. Previously the serine protease inhibitor, ovoinhibitor, was localized in bursal follicles, specifically the cortico-medullary border region. The presence of ovoinhibitor was identified and confirmed in the chicken pituitary by this study. Continued focus on the neuroendocrine-immune interactions in chicken immune tissue narrowed the study around the BSDC population. The BSDC are a component of the stromal, non-lymphoid cellular environment of the bursa of Fabricius and are thought to play a role in B-cell maturation and differentiation. They are located mainly along the cortico-medullary border of the bursal follicles in the same area as the majority of the ovoinhibitor-positive cell population. During attempts to isolate the BSDC population by flow cytometry and laser capture microdissection, a cell culture method was developed that enriched the BSDC population by 10-fold. This enriched population was used to evaluate protein product secretion following lipopolysaccharide (LPS) challenge and compared to in vivo challenge with live Salmonella. For the first time, up-regulation of the pro-inflammatory cytokine IL-12 was documented in the chicken following in vivo challenge. In addition, the gene expression of serine protease inhibitors was markedly decreased in the adherent cell population following LPS stimulation. As a result of this research a novel method for the enrichment of an adherent population, including the BSDC, was developed, providing a valuable tool for the analysis of this population during immune stimulation.

Neuroendocrine cell populations were systematically studied and characterized in the thymus, an avian primary immune organ. The expression of the specific mRNAs for both Chromogranin A (CgA) and Carboxypeptidase E (CpE) in the thymus was first verified by RT-PCR. Additional evidence using immunofluorescent dual labeling, has demonstrated for the first time the co-existence of CgA and CpE in identical neuroendocrine cells at the protein level in a vetebrate primary lymphoid organ. These CpE- and CgA-positive cells were primarily found in the transition zone between the cortex and the medulla of the thymic lobules, an area known to contain numerous arterioles and to be heavily innervated by the autonomic nervous system, suggesting that these cell population can potentially receive input from each other, from the autonomous nervous system, from the circulation, or all of the above. (Neuro)endocrine messenger molecules produced by the thymic microenvironment, such as somatostatin (SST), seem to play a potentially important immunomodulatory role with regard to cell proliferation, differentiation, and migration, as well as cytokine production. The results showed that both SST and its receptor, SSTR2, are expressed locally within chicken thymus. The in vitro study showed that SST significantly inhibits IL-2 and concanavalin A (ConA) induced proliferation of thymocytes. In comparison with controls (medium containing IL-2 and ConA but without SST), addition of SST at 10-9 M and 10-6 M resulted in a nearly 20% decrease in proliferation (P < 0.01). The effects of somatostatin (SST) on the immune system, the role of SST on the gene expression of cytokines (IL-1, TGF, INF), chemokine receptors (CXCR4) as well as MHC-I components was assessed by real-time PCR. The question as to exactly which stimuli trigger the release of mediators such as somatostatin remains for future study. In addition, a complete inventory of all substances stored in the thymic LDCV and their effects on the developing T-cells when released in the microenvironment of the thymus are also questions that warrant further investigation.

The mitochondnal genome was screened for genetic variation associated with production traits in White Leghorns. Analysis was done on an unselected randomly mated population of White Leghorn chickens. An AsnI restriction fragment length polymorphism (RFLP) was detected in the control region of the mitochondrial genome, a region responsible for transcription and replication. The RFLP segregated at a frequency of 0.76 for the AsnI (+) allele (presence of an AsnI restriction site). The AsnI RFLP was in linkage disequilibrium with a previously detected MspI RFLP in the NADH sub-unit IV of the mitochondrial genome for the same population of White Leghorns. Genotypes were denoted as follows: The first sign represented individuals that were positive (+) or negative (-) for the MspI restriction site, where as the second denoted whether individuals were positive or negative for the AsnI restriction site. Comparison of the three genotypic classes (+,+), (-,+) and (-,-) revealed that (-,-) individuals had a significantly higher body weight (5.5%) than individuals of the other genotypes. Dot blot analysis revealed no difference in the mitochondrial DNA copy number in peripheral blood cells between AsnI(-) or AsnI(+) individuals.

Today’s poultry is in the need of the finding new ways to increase the bird’s productivity and the production quality. The growth performance, nutrient and energy utilization as well as product quality are mainly the reasons, why animal feed additives are widely used. With the trend towards more “natural” poultry production systems, antibiotics are being banned. All active substances in phytogenic preparations are of plant original, which do not cause antibiotic resistance and do not residues in poultry products. In this job was analyzed facility of the phytogenic preparations (Digestarom Geflügel Premium – 1317 and Aviance) utilization in the Rosso kroso chickens feed. The following phytogenic preparations impact on the chickens growing input of the feed, digest of the nutrient and quality of the meat was tested to motivate in physiology. The test results showed that when we had used the phytogenic preparations the resorption of amino acids, lipids had mended, the stock of nucleic acids, triglycerides, lipids in blood had increased, the biosynthesis of protein had intensified. Chicken broilers mass who was 42 day years old was 7,2 % bigger neither control mass for impact of the phytogenic feed additive Digestarom Geflügel Premium – 1317. And the same chickens mass was 4,5 % bigger neither control mass for impact of the second phytogenic feed additive – Aviance. The chickens who was fed feed with Digestarom Geflügel Premium – 1317 and who was 42 day years old digested feed... [to full text]

In today’s poultry new ways are finding how to increase the bird’s productivity, to improve the quality of production. The feed additives which stimulate the growth, consolidate the immunity, improve the quality of meat are using for better appropriation of nutrient. It is necessary to regard that preparation witch are bringing into feeds would be natural, their garbage wouldn’t stay in the terminal product, wouldn’t raise resistance for antibiotics and wouldn’t do other effect for consumer health. Before antibiotics were used for this purpose, but nowadays more often they are exchanging into natural probiotical preparations. In this job are analyzed practice facilities of the probiotic Bio Plus 2 B in the Ross chicken broilers feeds and was trying to motivate in physiology this probiotic preparation influence to the growth of chickens, to the index of blood and to the quality of meat. Researches of the blood index was showed: the stock of the nucleic acid was increased from 12,69 % (P<0,05) to 22,41 % (P<0,001), total proteins – from 8,50 % (P<0,05) to 17,68 % (P<0,001), lipids – from 8,69 % (P<0,05) to 25,43 % (P<0,001) and triglycerides – from 5,00 (P<0,05) % to 16,38 % (P<0,001). The alive mass was increased from 6,7 % (P<0,05) to 14,51 % (P<0,001). Researches of the meat chemical composition was showed that the stock of dry material in chickens breast muscles was increased for the effect of probiotic preparation from 23,67 % to 24,01 %, from 21,87 % to 22,37 %... [to full text]