Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

Inclusion body hepatitis (IBH) has been occurring as an economically important, emerging disease of broiler chickens in several countries. Historically, IBH has been identified as a secondary disease, often associated with common immunosuppressive diseases. However, few studies have identified IBH as a primary disease with no apparent association with immunosuppressive diseases. The objectives of this study were to develop an animal model of IBH in commercial broilers, to demonstrate vertical transmission of fowl adenoviruses (FAdVs) in broiler breeders and to control IBH in broilers by vaccinating their parents with an inactivated FAdV vaccine. In order to develop an animal model of IBH in commercial broilers, fourteen-day old broilers were inoculated intramuscularly with 1x104 1x107 CCID50 of either FAdV x11a-like virus, two strains of FAdV-8a (FAdV-8a strain TR-59 and FAdV-8a strain T8-A) or FAdV-11strain 1047. Four days following FAdV inoculation, 5% - 15% mortality was observed and dead birds showed histologic lesions of hemorrhagic necrotizing hepatitis. This animal model reproduced the clinical disease, and pathological lesions of IBH that have been described in commercial broilers. In order to demonstrate vertical transmission of the FAdV, 35-week-old broiler breeders were inoculated with 1x106 CCID50 of either FAdV x11a-like virus, FAdV-8a strain TR-59, FAdV-8a strain T8-A or FAdV-11 strain 1047. Eggs from infected breeders were collected and hatched seven days post-inoculation. Clinical signs or mortality were not observed in parents; however broiler progeny derived from broiler breeders inoculated with FAdV-8a strain T8-A had 30% IBH mortality by seven days of age. The hexon gene loop 1 sequence of the virus isolated from affected broiler progeny showed 100% identity to FAdV-8a strain T8-A. In order to demonstrate protection of broilers against IBH by vaccination of their parents, four groups of broiler breeders were vaccinated with either FAdV-8a strain T8-A (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion, or FAdV x11a-like virus (2x107 or 2x104 CCID50) formulated with 20% oil-in-water emulsion at the age of 12 and 15 weeks. The control group was inoculated with 20% oil-in-water emulsion. Broiler progeny were challenged with FAdV-8a strain T8-A to study the immunoprotective effect of the vaccine. Although, survival of broilers following FAdV-8a strain T8-A challenge was not significantly different among vaccinated and non-vaccinated groups (P>0.05), immunoprotective effect was enhanced by the increase dose of FAdV antigens (P>0.05). Further studies are necessary to improve the vaccine efficacy to protect broilers against IBH.<p> In conclusion, the results of this study support the hypothesis that IBH in broilers in Canada is a vertically-transmitted primary disease with no known immunosuppressive involvement. The results also demonstrated that inactivated antigens of FAdV are able to partially protect broilers against IBH by vaccinating their parents. Further studies with different formulations, and priming the immune system of broiler breeders with live FAdV prior to vaccination with inactivated FAdV vaccines are necessary to improve the efficacy of inactivated IBH vaccine.

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Native fowl populations in South Africa were characterized genetically and phenotypically. Four South African native populations, two dual-purpose breeds, and two populations from Mozambique and Botswana were included for genetic analysis. For phenotypic characterization, two commercial lines were also included as a benchmark. Twenty-three micro satellite markers were selected and tested to obtain genetic data for estimation of genetic variability and distance. Growth (weight gain) and egg production were included for phenotypic characterization. A relatively high (53% ¬64%) genetic variation was found among the populations, which suggests conservation as a genetic resource for future use. The lowest genetic variation (53%) was found for the Koekoek and Australorp populations, which are the two populations that were subjected to formal selection, while the highest variation was observed in the Naked Neck population (64%). The New Hampshire has often been included in upgrading programs and this is evident from the close relationship with both the Lebowa- Venda and Naked Neck fowls. Phenotypic trials indicated significant differences among the populations included for growth, carcass and egg production traits. The Koekoek and New Hampshire populations had the best performance for egg production and growth (weight gain) in the study. Genetic and phenotypic differences indicate that the populations can be distinguished as different breeds or groups of fowl. The results of this study may contribute to selection for improved performance for household food production, as well as conservation of the populations as a genetic resource. / Thesis (PhD)--University of Pretoria, 2001. / Animal and Wildlife Sciences / unrestricted

<p> </p><p>The regulation of egg temperature requires the transfer of heat from the brood patch. Thus, the brood patch needs the presence of thermo receptors as well as an appropriate vasomotor response. During the incubation an exact detection of the egg’s temperature is essential. So, in this study we attempted to detect the presence and regulation of the expressionof  thermoTRP channels (thermo Transient Receptor Potential channels) (TRPV1, TRPV3, TRPV4, TRPM8 and TRPA1) during egg incubation. Six incubating Jungle fowl hens, and five non incubating jungle fowl hens and one jungle fowl cock were used as main samples and controls. Total RNA was extracted from liver, kidney, heart, blood, White Blood Cell, Dorsal Root Ganglion and skin. The samples from the skin were taken from the brood patch and inter scapular region. PCR investigation showed that different thermo TRP channels were expressed in different tissues. TRPV1, V3, V4 and M8 mRNA were detected in the skin of brood patch. However, V1 and V3 expression in the brood patch skin did not differ between broody and non broody hens. In conclusion, although considerable morphological changes in the skin of brood patch could be seen, the expression of TRPV1 and V3 channels did not change significantly, but this cannot exclude the alteration in the expression of TRP channels in different stages of broodiness or specific parts of skin like AVAs (Arteriovenous anastomosis) which will be the subject for more studies.</p>

<p>Early life stress is something that animals used in production often have to experience. What we do not know is if there are any consequences of this treatment later on in life. Zebra finches postnatal treated with the stress hormone corticosterone showed an exaggerated and prolonged stress response later on. To examine the effects of early life stress 77 White Leghorn chicks were used, half of them was stressed from postnatal day 1-14 and then tested between 47-63 days of age. The tonic immobility (TI) test is a commonly used test to evaluate the fearfulness and stress reaction in fowl. The chicks were placed on their back in a V-shaped wooden cradle and TI was induced by applying light pressure on the breast and neck. The number of inductions required to induce TI was recorded as well as the time until the first alert head movement and the total duration of the TI. The birds were tested in a calm environment but also after a stressful situation. There were no differences in the total duration of the TI reactions. However, stressed animals tended to need more induction attempts than the control animals. While looking at the time elapsed until the first head movement stressed chicks had a significantly lower duration. This indicates a dullness or shift in the stress response of the treated birds and there seem to be a more exaggerated response in the males.</p>

Early life stress is something that animals used in production often have to experience. What we do not know is if there are any consequences of this treatment later on in life. Zebra finches postnatal treated with the stress hormone corticosterone showed an exaggerated and prolonged stress response later on. To examine the effects of early life stress 77 White Leghorn chicks were used, half of them was stressed from postnatal day 1-14 and then tested between 47-63 days of age. The tonic immobility (TI) test is a commonly used test to evaluate the fearfulness and stress reaction in fowl. The chicks were placed on their back in a V-shaped wooden cradle and TI was induced by applying light pressure on the breast and neck. The number of inductions required to induce TI was recorded as well as the time until the first alert head movement and the total duration of the TI. The birds were tested in a calm environment but also after a stressful situation. There were no differences in the total duration of the TI reactions. However, stressed animals tended to need more induction attempts than the control animals. While looking at the time elapsed until the first head movement stressed chicks had a significantly lower duration. This indicates a dullness or shift in the stress response of the treated birds and there seem to be a more exaggerated response in the males.

The aim of this study was to examine how food deprivation effects food-related and other behavioural systems of red junglefowl (Gallus gallus) and the domesticated White Leghorn layers. If an animal is denied to perform their natural behaviours, like eating, sleeping or preening, the motivation for the behaviour can increase. Behavioural systems may interact and motivation to perform behaviours may be influenced. After being deprived of a certain need the reaction can become exaggerated or abnormal. Food deprivation is often used in ethology research to motivate animals. The hypothesis in this study was that the chickens would become affected by the food deprivation and reallocate their behaviours. They would get more stressed and frustrated. Domestication effects and sex differences were explored. The birds were tested in four standardized behavioural tests; food consumption test, general behavioural test, open field test and novel object test. The results showed that they foraged and explored more, had less comfort behaviours, and less perching the longer they had been without food. They did not show a higher degree of frustration, stress or aggressive behaviours. There were domestication effects, where the Leghorns seem to have lost some of their ability to respond adaptively to food shortage. Differences between the sexes were found, where the females foraged more and the males were more stressed. The conclusion was that the birds do not get more stressed when food deprived, but they forage and explore more which is a desirable effect of food deprivation used in ethology research.

The regulation of egg temperature requires the transfer of heat from the brood patch. Thus, the brood patch needs the presence of thermo receptors as well as an appropriate vasomotor response. During the incubation an exact detection of the egg’s temperature is essential. So, in this study we attempted to detect the presence and regulation of the expressionof  thermoTRP channels (thermo Transient Receptor Potential channels) (TRPV1, TRPV3, TRPV4, TRPM8 and TRPA1) during egg incubation. Six incubating Jungle fowl hens, and five non incubating jungle fowl hens and one jungle fowl cock were used as main samples and controls. Total RNA was extracted from liver, kidney, heart, blood, White Blood Cell, Dorsal Root Ganglion and skin. The samples from the skin were taken from the brood patch and inter scapular region. PCR investigation showed that different thermo TRP channels were expressed in different tissues. TRPV1, V3, V4 and M8 mRNA were detected in the skin of brood patch. However, V1 and V3 expression in the brood patch skin did not differ between broody and non broody hens. In conclusion, although considerable morphological changes in the skin of brood patch could be seen, the expression of TRPV1 and V3 channels did not change significantly, but this cannot exclude the alteration in the expression of TRP channels in different stages of broodiness or specific parts of skin like AVAs (Arteriovenous anastomosis) which will be the subject for more studies.

Domestication has taken place over thousands of years and during that time we have bred animals on different traits. The red jungle fowl is the ancestor to all domesticated chicks, including the white leghorn which is used in egg production. The domestication of the red jungle fowl has resulted in behavioral changes between itself and domesticated breeds, such as white leghorn. In this study we examine how these two breeds handle stress and whether or not they use social support when coping and recovering from a stress experience. The study took place in a built arena with two stimuli animals on each side. There the animal was studied for 5 minutes, stressed for 3 minutes and studied again for 5 minutes. We found that the red jungle fowl males spent more time in the unfamiliar zone before stress than males of the white leghorn. Our results also showed that the females of white leghorn and red jungle fowl spent more time in the familiar zone than males after being stressed. This is an indication that they are more dependent on social support from familiar animals after stress than the males are. Aggressive behavior was also observed among the males. Red jungle fowl males acted aggressively towards the unfamiliar stimuli animals and the white leghorn towards the familiar stimuli animals. In conclusion, we found that the females where in greater need of social support than the males. / Biologi