Broiler breeders experience a natural decline in fertility levels as a flock ages. A male management practice such as double interspiking could be applied to counteract this decline. Our objective was to investigate the effects of double interspiking on flock fertility, testosterone concentrations, stress responses, and behavioral responses of broiler breeders in heat stressed environments. Two hundred and eighty-eight broiler breeder pullets and thirty-six broiler breeder roosters (Ross 708) were assigned to three groups at 21 weeks of age (WOA). All three groups were housed in slatted floor pens in which room temperature cycled from 23.8 to 30 C to mimic heat stressed environments. Double interspiking was carried out between two pens at 42 and 52 WOA. Beginning at 32 WOA, eggs were set every two weeks, candled at day 12, and percent fertility calculated. Concentrations of the hormones testosterone and corticosterone (CS) were measured by radioimmunoassays at specific time points in the experiment. Lymphocytes and heterophils were counted in order to calculate heterophil:lymphocyte (H:L) ratios. Behavior was monitored with Panasonic video cameras which recorded video footage using the Noldus MPEG Recorder from 1900 hr to 2100 hr at specific time points. Recordings were analyzed, and frequency of specific behavioral responses of individual (preening, feather ruffling, wing flapping), male-to-male (fighting, pecking, retreating), and male-to-female (attempted and completed mating) behaviors were assessed. The introduction of unfamiliar roosters resulted in a fertility increase (P<0.01) between control and spiked birds after the first interspike and a sustainment of fertility levels after the second interspike. Testosterone concentrations declined (P<0.0001) from 1.95ng/mL to 0.11ng/mL as the birds aged. Corticosterone concentrations differed among bird groups and was elevated (P=.0333) for both groups that were interspiked. H:L ratios were also different among bird groups with all birds housed in the interspiked rooms showing higher ratios. Double interspiking increased the occurrence of male-to-male interactions, but there were no significant differences in male-to-female or individual behaviors. Regardless of treatment, there was a decrease in male-to-female behaviors as the birds aged. Double interspiking does show promise as a tool to increase fertility levels in a broiler breeder flock.

Thesis (M.A.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 146-158). Also available via the World Wide Web.

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

published_or_final_version / Microbiology / Doctoral / Doctor of Philosophy

published_or_final_version / Community Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / Politics and Public Administration / Master / Master of Public Administration

Highly pathogenic avian influenza H5N1, which is panzootic in poultry, continues to spread and becomes endemic in Asia, Africa, and Europe. It causes human disease with high fatality (about 60%) and continues to pose a pandemic threat. The pathological lesions associated with human H5N1 disease is Acute Respiratory Distress Syndrome (ARDS). The biological basis underlying the development of ARDS in human H5N1 disease remains controversial. Clinical, animal and in vitro studies suggested that the differences between H5N1 influenza viruss and low pathogenic influenza viruses in regard to viral replication, tissue tropism and cytokine dysregulation may contribute to disease pathogenesis. We previously found delayed onset of apoptosis in influenza H5N1 virus infected human peripheral blood monocyte-derived macrophages. This may allow a longer survival time for the virus in target cells for prolonged viral replication, which may contribute to the pathogenesis of H5N1 disease. As human bronchial and alveolar epithelial cells are target cells of influenza virus, I explored if influenza H5N1 and H1N1 virus infected human respiratory epithelial cells displayed differential apoptotic response and dissected the apoptotic pathways triggered by influenza virus infection. In this study, the apoptotic response in highly pathogenic influenza H5N1 viruses, A/HK/483/97 and A/Vietnam/1203/04, their precursor avian influenza H9N2 virus, A/Quail/HK/G1/97, and seasonal H1N1 virus, A/HK/54/98 infected primary human alveolar and bronchial epithelial cells was compared by TUNEL. A delayed onset of apoptosis in influenza H5N1 viruses and avian H9N2 virus infected alveolar epithelial cells was observed; the pattern was similar in bronchial epithelial cells. Concomitantly, by Western blotting, a delay in caspase 3 activation in H5N1 virus (A/HK/483/97) infected alveolar epithelial cells compared to H1N1 virus (A/HK/54/98) infected cells was shown. Also, influenza H5N1 and H1N1 virus induced apoptosis through both intrinsic and extrinsic pathways in human alveolar epithelial cells. Chemokine IP-10 was differentially up-regulated in influenza H5N1 virus infected alveolar epithelial cells, but its relationship to the delayed onset of apoptosis requires further studies. TRAIL, an upstream signaling molecule of extrinsic apoptotic pathway, mRNA was up-regulated in influenza H5N1 infected alveolar epithelial cells but not in influenza H1N1 infected cells. Using recombinant viruses, I showed that the 627 amino acid residue on PB2 of H5N1 virus and mutation of amino acids on 253 and 591 residues on PB2 of H9N2 virus contribute to the TRAIL upregulation. Immunohistochemical staining of physiologically relevant ex vivo model of human bronchus showed that influenza H5N1 (A/Vietnam/3046/04) and H9N2 (A/Quail/HK/G1/97) virus did not infect human bronchi as well as human H1N1 (A/HK/54/98) virus. Profiling of apoptosis related genes showed that TRAIL tends to be up-regulated in H5N1 virus infected bronchi ex vivo. This study demonstrated the delayed onset of apoptosis by H5N1 virus infected respiratory epithelial cells may be a mean for influenza virus to have prolonged replication within the human respiratory tract and contribute to disease severity. The results generated provide a robust research agenda, yielding critical information that elucidate molecular mechanisms, such as TRAIL up-regulation, that may contribute to the virulence and pathogenesis in human H5N1 disease. / HKU 3 Minute Thesis Award, 2rd Runner-up (2011) / published_or_final_version / Pathology / Master / Master of Philosophy

Haemoglobin concentration is becoming a widely popular parameter to use to assess physiological condition within a broad range of species. Assessments of large populations would preferable be done in field to receive quick results and avoid confounding factors associated with transport of blood. A validation study is here performed to see how well the point-of-care device HemoCue Hb 201 + can assess haemoglobin concentration on avian blood. Nucleated erythrocytes have previously been pointed out as something that makes it problematic to apply HemoCue Hb 201 +, designed for human blood, on avian blood. Here it is shown that HemoCue Hb 201 + accurately can estimate haemoglobin concentration for chicken-, tinamou-, and ostrich blood. However, manipulation of ostrich cells, to yield a larger mean corspuscular volume, results in HemoCue Hb 201 + overestimating haemoglobin concentration. A large mean corpuscular volume could therefore be something that impair accuracy in values retrieved with HemoCue Hb 201 +. This study shows that HemoCue Hb 201 + seems possible to apply on avian blood to some extent, but highlights the importance of validation studies when applying this device on new species.

published_or_final_version / Zoology / Master / Master of Philosophy

Each year thousands of western waterfowl succumb to disease, predators, mechanical injury and other decimating factors. Based on a review of records it is conservatively estimated that an average of 25,000 ducks have succumbed to botulism on western marsh areas annually. In a recent study, the United States Fish and Wildlife Services valued each duck and goose at $8.00 (McLeod, 1950). Applying this value to the estimated annual numerical loss, a total of $200,000 has been lost each season in mortality of western waterfowl from botulism. Control of this malady would reduce annual waterfowl and monetary losses. Prevention and cure are the only means of controlling botulism in wild ducks. At present, no economical preventative measure exists and control is based on curing stricken birds. The purpose of this study was to evaluate the cost of treatment and rate of recovery of birds stricken with botulism when treated by selected methods. The 4 treatments selected for evaluation were: (1) hospital inoculation, (2) fresh water, (3) field inoculation, and (4) no treatment or control. Research included a comprehensive evaluation of factors such as age, sex, species, body condition, degrees of affliction, reaction to various amounts of antitoxin, and reaction to selected treatment methods, thought to be pertinent in botulism control. This study was conducted during botulism outbreaks of 1953 and 1954, and was confined to state-owned marshlands of Utah.