The potential use of natural enemies and semiochemicals for the integrated management of the poultry red mite, Dermanyssus gallinae were examined. The seasonal population dynamics of the pest and two of its potential predators, Alphitobius diaperinus (Coleoptera: Tenebrionidae) and Carcinops pumilio (Coleoptera: Histeridae) were studied on two commercial egg-producing poultry farms. Only a weak negative relationship was found between the number of adult A. diaperinus and those of D. gallinae, but subsequent laboratory-based feeding studies demonstrated that both adults and late instar larvae of this species fed readily on the eggs and larvae of D. gallinae. Early instar larvae were unable to feed on mite eggs and larvae. The effects on D. gallinae of the entomopathogenic fungus Beauveria bassiana (Hyphomycetes: Moniliales) strain IMI 386367 and its compatibility with A. diaperinus were studied in laboratory bioassays. Confining mites on filter paper treated with aqueous suspensions of B. bassiana resulted in 100 % mortality of engorged adult females of D. gallinae within 10 days, an 80 % reduction in egg hatch within 5 days and the death of all newly emerged larvae within 24 hours of emergence. The fungus was less effective when applied to plywood surfaces. A. diaperinus adults were less susceptible than larvae; exposure of adults resulted in 36 % mortality within 31 days compared to 100 % mortality of larvae within 9 days. Studies on the mating behaviour of D. gallinae demonstrated that while males showed precopulatory "mate guarding" behaviour towards engorged female deutonymphs, the response did not appear to be elicited by short-range volatile or contact semiochemicals produced by female mites. Behavioural responses of females were not essential in eliciting mating behaviour in males, since males responded to freshly-killed females. There was no evidence of a female specific compound. The hydrocarbons tricosane and pentacosane found in adult females were also present in male mites but at much lower levels

The aim of this study was to identify policy approaches to promote sustainable broiler production in Malaysia and this was addressed by three specific objectives namely to: i) estimate the environmental impact of different broiler production systems; ii) estimate consumers’ willingness to pay (WTP) for chicken meat produced with a higher regard for the environment (chicken-HRE); iii) investigate potential policy changes which could be brought in to livestock production in Malaysia and assess their impact on the poultry industry from the perspective of various stakeholders including broiler producers, integrated broiler companies and the Government. Evaluation of environmental impact was carried out using the Life Cycle Assessment method, with a functional unit of 1 tonne live weight of broiler chickens and a cradle to point of slaughter criterion as the system boundary. The environmental impact analysis used various sources to obtain foreground data on two broiler production systems, namely intensive closed house (CH) and open house (OH) systems. The CH system produced 6 to 7% lower environmental burdens but marginally greater use of energy than the OH system. Feed-related inputs (mainly raw materials and transportation) accounted for the greatest proportion of environmental burdens with, on average, 89.8% of energy use, 94.1% of greenhouse gas emissions, 76.8% of acidifying emissions and 86.8% of eutrophying emissions. A Contingent Valuation Method was used in a survey of over 200 selected consumers across Peninsular Malaysia to ascertain the maximum WTP for chicken-HRE. Some 50% of respondents were willing to pay an increment of 10% above the existing market price. Using a mixed method approach, quantitative findings from the environmental assessment and the socio demographic and economic survey were integrated with qualitative results to explore the impact of potential policy approaches to promote sustainable broiler production in Malaysia. Even though the economic aspects explored in this study give only an indication of the likely societal attitudes to broiler chicken production, they nevertheless provide an indication of the growing stakeholder interest in methods of food production and implications for the level of environmental quality to be experienced by future generations.

Broilers can be faced with a several stressful conditions during their production cycle which can have implications for both growth performance and animal welfare. Animal welfare encompasses the physical and mental well-being of animals, assessed from the biological functioning and subjective experience. The aims of this thesis were i) to develop and validate non-invasive means of assessing the welfare of broilers under physiological and episodic heat stress conditions, ii) to investigate the impact of episodic heat stress, physiological stress and light wavelength on the growth performance, physiology and welfare of broiler chickens and, finally, iii) to investigate a novel means of alleviating heat stress in broilers. Endogenous corticosterone measured in the urate sphere was suppressed by dexamethasone administration. In a cognitive bias task, birds offered mealworms injected with corticosterone to mimic chronic stress were pessimistic in their judgement about ambiguous positions. A positive correlation was established between physiological indicators of stress and cognitive bias. Although light wavelength was confounded with light intensity in our study, there was no difference in growth performance and cognitive ability of birds reared in the blue and red light, except for increased activity of birds in red light. Under simulated episodic heat stress, the change in CBT measured from a temperature-ID chip (ΔCBT-chip) and a data logger (ΔCBT-logger) was positively correlated. Significant positive correlations were found between the change in surface body temperature (SBT) under wing (ΔWT) and ΔCBT-chip, and between ΔWT and ΔCBT-logger. Significant positive regression equations relating change in CBT and RR with apparent equivalent temperature (a factor which combines environmental temperature and RH) were also developed. High temperature coupled with high RH aggravated the respiratory rate (RR) of broilers and this was accompanied by suppression of peening behaviour. High heat stress for 3 hours had a greater impact on birds than moderate heat stress for 6 hours. For broilers exposed to moderate heat stress, the provision of additional cup drinkers reduced the rise in CBT and the proportion of time spent in wing drooping behaviour, but enhanced SBTs suggesting increased heat dissipation.

Campylobacter jejune is the leading cause of gastroenteric bacterial infectious disease in the EU with the majority of human cases being identified as from a poultry source. If the number of cases is to be reduced, more needs to be understood about the behaviour of C. jejuni in the poultry host and its wider epidemiology. Multiple genotypes can be found within anyone C. jejuni population, potentially allowing for quick genotypic and therefore phenotypic adaptation to changes in environment. It was hypothesised that the relatively high level of genetic instability observed in C. jejuni may allow it to change its surface epitopes over the course of colonisation. A five week chicken colonisation study observed changes inflaA that conesponded to decreased reactivity with chicken antibodies at five weeks compared to two weeks. A Multi-Locus Sequence Typing system developed for the characterisation of C. jejuni strains groups sequence types into clonal complexes (CCs). It has become apparent that whilst some CCs contain strains isolated from a range of sources (host genera lists), others contain a majority of strains isolated from only one host group (host specialists). The link between these epidemiological observations and in vivo phenotypes is unknown. The results of bird colonisation work suggest it is not as simple as chicken specialists being better adapted to colonising chickens than generalists or other host specialists. It is not known whether this is because the apparent host association reflects pressures other than colonisation ability in the host, or because the multiple genotypes that are present in any C. jejuni population mean there are still variants within a non-chicken specialist population that are fit for colonising chickens to high levels. In conclusion, these results show that genetic (and therefore antigenic) instability in C. jejuni contributes to its ability to colonise poultry.

EU legislation has led to an almost ten-fold increase in bioethanol production between 2003 and 2011. The current distillery co-product, distiller’s dried grains with solubles (DDGS), is fed primarily to cattle due to the high fibre content but differentiation of the co-product stream would allow penetration of the large monogastric feed sector. The aim of this project was to evaluate a novel separation process producing a high protein yeast protein concentrate (YPC) from DDGS, and assess the potential of this product as a feed ingredient for poultry. A pilot plant study modelling the process confirmed the variability of the stillage, but highlighted the viability of the process for ameliorating some of these differences. Inter-batch variability was reduced from 10% to 1.2% in terms of protein content but dry matter content still varied by more than 8%, due to fibre contamination. The batches of yeast cream with increased fibre content had significantly reduced drying rates, from 37.3mg/min to 23.6mg/min, due to the larger particle sizes included. Additionally, the increased range of particle size introduced by fibre contamination would lead to product separation with detrimental implications for transport and handling of the dried product. It is vital to have measurements of amino acid content and digestibility for any new feed ingredient to ensure accurate feed formulation. Amino acid digestibility was measured in vivo in broiler chicks for five YPCs from potable and bioethanol sources produced using three drying technologies. Amino acid digestibility coefficients (COD) were significantly better for bioethanol produced YPC than potable (bioethanol 0.73 and 0.63 compared with 0.58 and 0.52 for potable). This is likely to be due to the addition of exogenous enzymes during the bioethanol process resulting in reduction of some of the detrimental effects of non-starch polysaccharides. Drying methodology affected both total amino acid content and digestible amino acid content, with spray drying being the least damaging method (COD 0.73 and 0.58) and ring drying the most damaging (COD 0.39). Lysine was particularly damaged during the heating process; reducing in total content from approximately 5% of protein to 2.3% of protein for ring dried material. Freeze dried YPC samples (COD 0.63 and 0.52) may have been negatively affected by the presence of fibre in the YPC due to processing inconsistencies. In terms of bird performance, bioethanol freeze dried YPC inclusion improved weight gain (p=0.003) and feed intake (p=0.006) compared with potable, again likely due to the enzyme addition during the bioethanol process. This was confirmed by the measured digesta viscosity increase in birds fed diets with increasing potable YPC inclusion (p=0.073). Spray dried YPC did not significantly affect FCR up to 20% inclusion, but both intake and bodyweight gain reduced with rate of inclusion. This may be attributed to spray drying producing a small particle size which increases feeding time and can increase viscosity, as was shown in this project (viscosity of spray dried YPC increased with RoI p=0.031). Ring dried YPC was incorporated into pelleted diets and therefore gave the best performance results. FCR for bioethanol YPC was improved from 1.68 for freeze dried material included at 9% of total diet to 1.4 for ring dried material at a higher rate of 12.5% of total diet. Finally the potential of YPC as a source of available phosphorus was considered, by assessing foot ash content of birds fed diets containing varying YPC levels. Increasing rate of YPC inclusion increased foot ash from 17.3% to 18.5% at 20% inclusion (p=0.031). YPC replaced 35% of supplemental phosphorus in chick diets with no significant effects on bone mineralization. The novel YPC from bioethanol distilleries appears to be a viable protein source for chicks at low inclusion levels (less than 6%). In pelleted diets the inclusion level could rise to 17.5% with no detrimental effects on bird performance. Additionally, YPC provides a source of available phosphorus, reducing the need for supplemental phosphorus in chick diets. The most appropriate drying method appears to be ring drying if care is taken to reduce residence time and heat damage. However there is substantial scope for further improvement of both the process and product as a feed ingredient for poultry.

This thesis is concerned with development of improved management practices in indigenous chicken production systems in a research process that includes participatory approaches with smallholder farmers and other stakeholders in Kenya. The research process involved a wide range of activities that included on-station experiments, field surveys, stakeholder consultations in workshops, seminars and visits, and on-farm farmer participatory research to evaluate the effect of some improved management interventions on production performance of indigenous chickens. The participatory research was greatly informed from collective experiences and lessons of the previous activities. The on-station studies focused on hatching, growth and nutritional characteristics of the indigenous chickens. Four research publications from these studies are included in this thesis. Quantitative statistical analyses were applied and they involved use of growth models estimated with non-linear regressions for the growth characteristics, chi-square determinations to investigate differences among different reciprocal crosses of indigenous chickens and general linear models and covariance determination for the nutrition study. The on-station studies brought greater understanding of performance and production characteristics of indigenous chickens and the influence of management practices on these characteristics. The field surveys and stakeholder consultations helped in understanding the overarching issues affecting the productivity of the indigenous chickens systems and their place in the livelihoods of smallholder farmers. These activities created strong networking opportunities with stakeholders from a wide spectrum. The on-farm farmer participatory research involved selection of 200 farmers in five regions followed by training and introduction of interventions on improved management practices which included housing, vaccination, deworming and feed supplementation. Implementation and monitoring was mainly done by individual farmers continuously for close to one and half years. Six quarterly visits to the farms were made by the research team to monitor and provide support for on-going project activities. The data collected has been analysed for 5 consecutive 3-monthly periods. Descriptive and inferential statistics were applied to analyse the data collected involving treatment applications, production characteristics and flock demography characteristics. Out of the 200 farmers initially selected, 173 had records on treatment applications and flock demography characteristics while 127 farmers had records on production characteristics. The demographic analysis with a dissimilarity index of flock size produced 7 distinct farm groups from among the 173 farms. Two of these farm groups were represented in similar numbers in each of the five regions. The research process also involved a number of dissemination and communication strategies that have brought the process and project outcomes into the domain of accessibility by wider readership locally and globally. These include workshops, seminars, field visits and consultations, local and international conferences, electronic conferencing, publications and personal communication via emailing and conventional posting. A number of research and development proposals were also developed based on the knowledge and experiences gained from the research process. The thesis captures the research process activities and outcomes in 8 chapters which include in ascending order – introduction, theoretical concepts underpinning FPR, research methodology and process, on-station research output, FPR descriptive statistical analysis, FPR inferential statistical analysis on production characteristics, FPR demographic analysis and conclusions. Various research approaches both quantitative and qualitative have been applied in the research process indicating the possibilities and importance of combining both systems for greater understanding of issues being studied. In our case, participatory studies of the improved management of indigenous chickens indicates their potential importance as livelihood assets for poor people.

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This thesis describes field and experimental investigations on various aspects of the immunopathogenesis, diagnosis and vaccination of infectious bronchitis virus (IBV) and avian metapneumovirus (aMPV) in the chicken. The immunopathogenesis of an economically important variant IBV (IS/885/00 like) seen in the Middle East and North Africa was examined in one day old specific pathogen free (SPF) and commercial broiler chicks (Chapter 3). The virus caused respiratory distress, depression and diarrhoea in both SPF and broiler chicks but the severity was milder in the latter. Mild head swelling was observed in one infected broiler chick at 15 days post infection (dpi) and virus with 100% nucleotide level similarity to the inoculum was detected by reverse transcription polymerase chain reaction (RT-PCR) and virus isolation (VI). In the IS/885/00-like infected SPF chicks, cystic oviducts were found in two female chicks. IBV with 99% part S1 sequence similarity to the initial inoculum was isolated from the cystic fluid. The protection provided by current commercial vaccines against variant IBV IS/885/00 like and IS/1494/00 like was investigated in day old commercial broiler chicks (Chapter 4). Protection was evaluated based on the clinical signs, gross lesions, tracheal ciliary scores and virus detection by RT PCR. It was found that administering combined live H120 and CR88 vaccines simultaneously at day old, followed by CR88 vaccine at 14 days old gave more than 80% ciliary protection against both of the Middle East isolates. Cellular and local immune responses in the trachea following vaccination of day old broiler chicks with different live IBV vaccines were evaluated (Chapter 5). In addition, protection conferred against virulent IBV was also examined. All vaccination programmes were able to induce measurable levels of CD4+, CD8+ and IgA bearing B cells in the trachea following vaccination when compared to unvaccinated birds. Expression levels of CD4+ and CD8+ cells varied between the vaccinated groups. Vaccines containing Mass2 combined with 793B2 produced good protection against challenge with virulent IBV QX compared to vaccines containing Mass (Mass1 or Mass2) alone or Mass1 with D274 or CR88. All vaccination programmes produced more than 80% protection against homologous (M41 and 793B) challenge. In Chapter 6, IBVs with high nucleotide level similarity to IS/885/00 like and IS/1494/06 like strains were detected by RT PCR in a broiler flock exhibiting high mortality and respiratory distress in Libya. For the first time, these findings have highlighted the circulation of variant IBVs in the Eastern part of Libya. Humoral and cellular immune responses and protection studies in SPF chicks that received live Newcastle disease virus (NDV), aMPV and IBV vaccines in single, dual or triple combinations were examined (Chapter 7). Protection against virulent IBV or aMPV was not affected when the vaccines were given either singly or in combination. There were no significant differences in the mean antibody titres of the NDV-vaccinated groups and they remained above the protective titre. The mean titres of antibodies against aMPV were suppressed when aMPV vaccine was given with other live vaccines but the aMPV-vaccinated groups were fully protected when challenged with virulent aMPV. The mean titres of antibodies were similar in the IBV-vaccinated groups and all IBV-vaccinated groups gave almost 100% protection against M41 challenge. Between the vaccinated groups, there were no significant differences in the mean numbers of CD4+, CD8+ and IgA-bearing B cells, reflecting similar levels of tracheal cellular and IgA responses irrespective of single, dual or triple vaccine applications. Despite the aMPV humoral antibody suppression, the efficacy of the live vaccines was not compromised when they were given simultaneously to young SPF chicks. Comparative studies in day old SPF chicks using both aMPV subtype A or B, separately or in combination, were evaluated (Chapter 8). There were significant differences in the degree of the clinical signs induced by the single subtypes A, B or A+B given together, with most severe signs observed in the latter two groups. By RT-PCR or VI, subtype B virus persisted longer than subtype A. Even though similar titres of the viruses were used, birds given subtype B alone or in combination showed a greater increase in antibody titres than those given A. These findings demonstrate that for the two strains used, subtype B was more pathogenic than subtype A and was excreted and persisted in the tissues for longer. The use of Flinders Technology Associates (FTA) cards for detection of several avian pathogens has been previously reported. To date, no information has been published on the use of FTA cards for detection of aMPV. In Chapter 9, the feasibility of using FTA cards for the molecular detection of aMPV subtype A and B by RT-PCR was investigated. Findings showed that FTA cards are suitable for collecting and transporting aMPV-positive samples, providing a reliable and hazard-free source of RNA for molecular characterization.