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Aggression and social discrimination in small flocks of laying hens, Gallus gallus domesticusGregory, Robin Alexander January 2000 (has links)
No description available.
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A comparison of white Plymouth rocks and New Hampshires for broiler productionWilliams, Isaac Terrell. January 1950 (has links)
Call number: LD2668 .T4 1950 W55 / Master of Science
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Detailed spatiotemporal expression of Prmd1/Blimp1 binding partners during chick embryonic developmentZwane, Thembekile Buhle Christina 26 January 2015 (has links)
A Dissertation submitted to the Faculty of Science, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. 2015. / Prdm1/Blimp1 is a transcription factor whose mechanism of action is mainly repression; however it has been identified as an activator in some cases. As a transcriptional repressor, it plays multiple roles during embryonic development, including neural crest specification. Prdm1 acts by repressing large sets of genes via sequence specific recruitment of co-repressors, many of which are epigenetic modifiers. Neural crest is a transient, migrating cell population that gives rise to a number of diverse cell lineages that form important structures in the vertebrate embryo. Examples of these include peripheral nervous system, melanocytes and cranial cartilage. Prdm1 is expressed during neural crest specification in Xenopus, zebrafish and lamprey. The expression of Prdm1 had not yet been investigated in the neural crest during chick embryonic development. The mechanism of Prdm1 action or the nature of possible binding partners that mediate its effects in the neural crest had not yet been addressed. Prdm1 binding partners are known to play important roles during embryonic development, yet in many cases no spatiotemporal expression analysis during early vertebrate development has been performed. Single and double in situ hybridization for Prdm1 and all the binding partners was performed to determine localization of mRNA during early stages of chick embryonic development. We report the expression patterns of Prdm1 and seven of its known or putative binding partners (Hdac1, Hdac2, Tle1, Tle3, G9a, Prmt5 and Lsd1) during early stages (HH4-HH10) of chicken embryogenesis. Prdm1 expression was observed in the neural plate border and pre-migratory neural crest during chick development. Six Prdm1 binding partners (except Tle1) are co- expressed with Prdm1 in the prospective neural plate border at HH4-HH6, and all seven show strong and specific expression in the neural plate border at HH7-HH8, suggesting all of them co-operate with Prdm1 during neural crest development in chick embryos. Future work will focus on protein interaction studies in order to directly demonstrate the association between Prdm1 and the binding partners it co-localizes with.
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Effects of dietary energy level and tanniniferous Acacia Karroo leaf meal level of supplementation at finisher stage on performance and carcass characteristics of ross 308 broiler chickens.Nakalebe, Papali Mary 01 October 2010 (has links)
Thesis (M.Sc) (Agriculture) --University of Limpopo,2009. / The study was conducted to determine the effect of dietary energy level and tanniniferous Acacia karroo leaf meal level of supplementation at finisher stage on performance and carcass characteristics of male and female Ross 308 broiler chickens. Three hundred and sixty, 21-day old male and female broiler chickens were assigned to twelve treatments with three replications of ten birds in a 2 (sex) x 3 (dietary energy level) x 3 (tanniniferous Acacia karroo leaf meal level) factorial, complete randomized design. Supplementation with Acacia karroo leaf meal had no effect on diet intake, digestibility and live weight of broiler chickens. However, supplementation with 9 and 12 g of Acacia karroo leaf meal per kg DM feed reduced fat pad weights in male broiler chickens by 26 and 29 percentage points, respectively. Similarly, supplementation with 9 and 12 g of Acacia karroo leaf meal per kg DM feed reduced fat pad weights in female chickens by 26 percentage points. These reductions were achieved without any significant reduction in feed intake and digestibility. However, the physiological explanation for this effect is not clear and it, thus, merits further investigation. / National Research Foundation.
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The effect of diluent, storage time, temperature and dilution ratio on fertility of semen from two breeds of fowl.Lopez Lorenzo, Ricardo. January 1978 (has links)
No description available.
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Embryonic chick edema : inheritance and an explanation for incomplete penetrancePhillips, Wenona Anne 21 November 2003 (has links)
The concept of genetic penetrance, "the frequency of manifestation of a
genetic factor," was introduced by Timofeef-Ressovsky (Naturwissenschaften
19:493,1931). Incomplete penetrance has been used to explain the absence
of phenotypic expression when otherwise anticipated. Studies of Embryonic
Chick Edema, ECE (Poultry Sci. 77(suppl. 1):69, 1998) have been conducted
in order to determine the origins for incomplete penetrance of this disorder.
ECE was originally reported as the expression of two autosomal recessive loci
with incomplete penetrance. Pedigreed inter se mating of ECE individuals
have resulted in familial incidences ranging for 0 to 100% with a mean of
48.2% in the most recent generation selected. With consideration of a third
contributing locus, current data and 2 sets of previous data were evaluated.
Heterogeneity and pooled chi square tests when applied to the data sets
support the hypothesis that ECE was the result of two completely dominant
loci and one homozygous recessive locus. / Graduation date: 2004
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Identification of a mechanism underlying heritable subfertility in roosters homozygous for the rose comb alleleMcLean, Derek J. 08 May 1997 (has links)
The overall objective of this research was to define the cellular basis underlying
heritable subfertility in roosters homozygous for the rose comb allele (R/R). Fertilization
in the hen is preceded by the ascension of motile sperm through the vagina and sperm
sequestration within sperm storage tubules (SST). The objective of the first set of
experiments was to determine if reduced sperm sequestration could account for subfertility.
Sperm sequestration differed between genotypes following intravaginal insemination (p<0.0001). However, sperm sequestration did not differ between genotypes when sperm
were incubated with SST in vitro (p>0.05). Therefore, subfertility was attributed to
reduced sperm transport within the vagina. To test this hypothesis, an assay was developed
to evaluate fowl sperm motility in vitro. Based upon this assay, ejaculates from subfertile
males contained smaller subpopulations of highly motile sperm than the ejaculates from
controls (p<0.001).
The objective of the next set of experiments was to characterize the motility of
individual sperm and to identify a mechanism that could account for the genotypic
difference in sperm cell motility. Computer-assisted sperm motion analysis evaluation
revealed that ejaculates from controls contained 91% motile sperm whereas ejaculates from
subfertile males contained 62% motile sperm (p<0.001). The ATP concentration in sperm
from subfertile males was 63% less than that of sperm from controls (p<0.001). A link
between sperm ATP concentration and immotility was investigated. First, sperm
metabolism was evaluated using motility as an endpoint. The genotypic difference in sperm
motility persisted when ATP synthesis was limited to glycolysis (p<0.001). Consequently,
mitochondrial respiration could not account for the genotypic difference in sperm motility.
In contrast, sperm uptake of [1,2-��H] 2-deoxy-D-glucose did differ between genotypes (p<0.001). The activity of key glycolytic enzymes, creatine kinase, and dynein ATPase did
not differ between genotypes (p>0.05). Therefore reduced sperm motility did not appear
to be due to ATP synthesis, allocation of high energy phosphate bonds along the axoneme,
or ATP consumption (p>0.05). In conclusion, subfertility of roosters homozygous for the
rose comb allele was attributed to decreased spermatozoal glucose transport. / Graduation date: 1997
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Studies of managerial variables on broiler performance and abdominal fat levelsHakimi, Ali Y. 14 September 1992 (has links)
Today's consumers have shown a greater concern in the relationship between dietary fat and human health. The demand for leaner meat is continuously on the rise. The reduction of fat deposits in the abdominal area of ready-to-cook fryers, considered a waste product in the poultry industry, has become a major opportunity for the researcher.
Experiments were conducted to evaluate the merit of managerial practices affecting abdominal fat (AF) levels in broiler chickens. Factors studied included seasons of the year, source of the commercial broiler strain crosses, stocking densities, lighting systems, types of housing, dietary salt (NaCl) 1eve1s and feed restriction.
Two housing types (open-sided and windowless) and different seasons were utilized to evaluate the influence on broiler performance and AF levels. Raising broilers from the same strain cross in an open-sided building did not affect performance and AF levels. Mean body weight (BW) were highest
in fall season (1929 g ) and lowest in summer (1735 g) (p<.05) while highest and lowest % AF revels were observed in spring and winter (2.34, and 1.42 respectively).
The comparative effect of feeding regime, (full feed, FF), 95 and 90% FF), dietary salt 1evels (0, 0.25, and 0.5% of the finisher diet), stocking densities (0.06, 0.07, and 0.09 m�� of floor space per bird) and type of housing (battery cages and litter pens) were examined on broiler performance and AF lever. Ninety % FF resulted in significantly lower body weights and AF levers compared to ad libitum feeding. At 49 days of age, mean BW of broilers fed 0.5% salt were higher (P<.05) than the group not provided with salt. Altering stocking densities and rearing in battery cages failed to show any significant improvements performance and % AF.
Lighting regime 12 h light (L): 12 h dark (D), recycled during the rearing period resulted in lower (p<.05) mean BW than continuous lighting regime (CL) when applied from 5 days of age. Broilers raised on 16L:8D after 21 days had comparable performance to CL. Lighting regime of 12L:12D, recycled in combination with increasing stocking densities from 0. 06 to 0.8 m�� floor space/broiler and intermittent righting of lL:3D in combination with the addition of 0.5% salt to the diet resulted in improved (P<.05) BW with no corresponding increases in AF levels.
Factors such as season of the year, feeding of salt, and manipulation of light (up to 8 h dark) can be used as tools in reducing % AF and overall production costs. / Graduation date: 1993
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An examination of price transmission in the United States beef, pork, and broiler industriesSirolli, Ryan T. January 2006 (has links)
Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: John Bernard, Dept. of Food & Resource Economics. Includes bibliographical references.
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The effects of an experimental chlorate product on the microbial ecology in Gallus gallus var. domesticus.McReynolds, Jackson Lee 30 September 2004 (has links)
Previous reports have shown that some bacteria utilize a dissimilatory nitrate reductase enzyme (NR) in anaerobic environments. This enzyme reduces nitrate to nitrite and also has been shown to co-metabolize chlorate to cytotoxic chlorite. A commercially available competitive exclusion (CE) product was evaluated for its nitrate reductase activity and therefore its experimental chlorate product (ECP) sensitivity. Of the 29 constituent bacteria of the CE culture, 11 had slight utilization of NR, 3 had moderate utilization of NR; the remaining were NR negative (with slight and moderate utilization: >0.1 to < 1.0 mM and > 1.0 mM nitrate utilized within 6 h, respectively). In vivo studies utilizing CE and ECP showed significant reductions in Salmonella. Although some of the bacteria were affected by ECP, the combined effect of the CE culture and ECP were effective in reducing Salmonella. Clostridium perfringens (CP) is a pathogen in the commercial poultry industry, which is the etiologic agent of necrotic enteritis (NE). Day-of-hatch broilers were fed a wheat diet and assigned to the following groups: control, commercial coccidia vaccine, commercial bursal disease vaccine, or the combination of the two, and challenged with CP in order to develop a disease model. Broilers in each treatment group had significant increases (P≤ 0.05) in lesion scores, mortality, and CP incidence. As pressure mounts for discontinuing the use of antibiotics in the agriculture industry, it is important to develop new strategies to combat these costly enteric pathogens. In vitro investigations evaluated a mixed gut culture with CP and the ECP at 5 mM or a 10 mM concentrations, over time. By 3 h there was a reduction (P≤ 0.05) in the 5 mM ECP and 10 mM ECP treatment groups. In vivo studies showed significant reductions in the incidence of CP and populations of intrinsic E. coli in all of the chickens provided ECP in the drinking water. Birds administered ECP in the feed showed significant reductions in lesion scores, incidence of CP and also had reduced E. coli log10 values. These results show that an ECP could provide the industry with a new management tool for controlling NE.
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