The expression of photorefractoriness, a feature of seasonal breeding in birds, is important in production species, where egg production and fertility are affected by the photoperiod. Years of selection in meat-type birds have reduced the potential reproductive function, and the environmental manipulation of such genotypes is essential to maximise productivity. While it is known that egg-type pullets no longer exhibit photorefractoriness, and that female broiler breeders do, there is not much information about the response of male broiler breeders to photoperiod. Such information is important when designing lighting programmes for breeding stock, and this study aimed to gain more insight into the male response to photoperiod. A series of experiments was designed in order to achieve this. In the first the response of male broiler breeders to rearing on constant photoperiods was measured, and in the second the effects of age at photostimulation on age at sexual maturity were assessed. The response to an increase in photoperiod during the production cycle was investigated in the third trial. Evidence of photorefractoriness in males was observed, but this was not the case in all birds, possibly due to high variation in some of the fertility traits measured. It seems possible that males do not respond to photoperiod to the same extent as females. Unexpected observations of a response in some birds to early photostimulation, and the high variation observed prompted another experiment in which the heritability of the response to early photostimulation was measured as a potentially revolutionary method of selection, whilst checking that this response is not negatively linked to broiler growth rates. Left and right testis weight data, collected in the above experiments, were analysed for asymmetry. There was no consistent response in testes asymmetry to photoperiod, or evidence that asymmetry in testis weights is as a result of the imposition of genetic or environmental stress. The strong correlation found between testes dimensions and weight suggests that predictions of testis weights could be made through ultrasonics or laparoscopy. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

No abstract available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Includes bibliographical references (leaves 166-195) / xxi, 195 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Addresses the nature of the central mechanisms involved in the regulation of the circadian pattern of secretion of the pineal hormone melatonin in the highly seasonal Suffolk breed of sheep. Provides new information on the behaviour of the onset and offset of melatonin secretion under different photoperiodic conditions. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1991?

Typescript. Includes vita and abstract. Bibliography: Includes bibliographical references (leaves 83-90). Description: xii, 90 leaves : ill. ; 29 cm.

Made available in DSpace on 2015-03-26T13:55:25Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2542048 bytes, checksum: 3cd501c8888bc3e0615e6d266c9926f1 (MD5) Previous issue date: 2014-07-16 / Studies on the grazing of forage in full sun enabled management to set goals for input and output of animals in rotational stocking, but there is no information available in the literature for interruption of regrowth in silvopastoral systems. In the face of no related to the management of grazing forage in silvopastoral systems studies, we proposed this experiment in order to determine goals of pre-grazing based on the interception of photosynthetically active radiation in Brachiaria decumbens in a silvopastoral system and monoculture for define strategies for grazing management in rotational stocking method. The experiment was conducted at the Federal University of Viçosa in an area belonging to the Department of Animal Science, Viçosa, Minas Gerais, during the period October 2013 to March 2014. The treatments consisted of four combinations of grazing frequencies based on the interception of photosynthetically active radiation (85, 90, 95 and 100%) and two production systems (monoculture and silvopastoral) in a factorial arrangement 4x2. Experimental design used was randomized complete block design with two blocks and two replicates per block. The variables height, number of cycles and range grazing, light interception by the canopy, leaf area index, mass removal and accumulation of forage and morphological components in the pre and post- grazing tiller density were evaluated provided pre-grazing. The pre-grazing heights were higher in all the targets studied in a silvopastoral system. Treatments of 90% IL showed greater number of grazing cycles and lower range of grazing compared to 95% of IL and 100% in monoculture and silvopastoral system treatments. The greater accumulation of total dry matter (16.698,8 kg ha-1 DM) was observed in 95% target of IL monoculture, as observed for the accumulation of leaf blades. Silvopastoral system in the greater accumulation of total dry matter was observed in 95% target IL (12.482,6 kg ha-1 DM). The monoculture showed higher accumulation of leaf blades in relation to silvopastoral system. The accumulation of leaf blades was lower in the 100% IL in both systems due to the increased participation of stems of forage mass treatments. In treating 100% greater increase in IL senescent forage on targets of 90% and 95% IL occurred. The monoculture showed more senescent forage that the silvopastoral system. The goals of 90 and 95% IL enabled greater tiller density than the target of 100% of IL. However, the management goals did not influence tiller density in a silvopastoral system. Monoculture provided higher tiller density than the silvopastoral system. Due to the high accumulation of total dry matter, leaf blades and greater efficiency attributed to greater removal of grazing forage pastures of Brachiaria grass should be grazed at 95% of IL in a silvopastoral system (height 40 cm) and monoculture (height 20 cm) in pre-grazing on the method of blending intermittently during the growth of the grass. / Estudos sobre manejo do pastejo das forrageiras em pleno sol possibilitaram definir metas para entrada e saída dos animais, em lotação intermitente, mas ainda não há informações disponíveis na literatura para interrupção da rebrotação em sistemas silvipastoris. Em face de não haver estudos relacionados ao manejo de forrageiras sob pastejo em sistemas silvipastoris, foi proposto este experimento com objetivo de determinar metas de pré-pastejo com base na interceptação da radiação fotossinteticamente ativa em pastos de Brachiaria decumbens em sistema silvipastoril e monocultivo, para definir estratégias de manejo do pastejo no método de lotação intermitente. O experimento foi conduzido na Universidade Federal de Viçosa em uma área pertencente ao Departamento de Zootecnia, Viçosa, Minas Gerais, durante o período de outubro de 2013 a março de 2014. Os tratamentos foram constituídos combinações entre quatro frequências de pastejos com base na interceptação da radiação fotossinteticamente ativa (85, 90, 95 e 100%) e dois sistemas de produção (monocultivo e silvipastoril), constituindo um arranjo fatorial 4x2. Foi utilizado delineamento experimental em blocos completos ao acaso, com dois blocos e duas repetições por bloco. Foram avaliadas as variáveis altura, número de ciclos e intervalo de pastejos, interceptação de luz pelo dossel forrageiro, índice de área da folhagem, massa, remoção e acúmulo de forragem e componentes morfológicos nas condições de pré e pós-pastejo, densidade populacional de perfilhos na condição de pré-pastejo. As alturas pré- pastejo foram maiores em todas as metas estudadas em sistema silvipastoril. Os tratamentos de 90% de IL apresentaram maior número de ciclos de pastejo e menor intervalo de pastejos em relação aos tratamentos de 95% de IL e 100% em monocultivo e sistema silvipastoril. O maior acúmulo de matéria seca total (16.698,8 kg ha-1 MS) foi observado na meta de 95% de IL em monocultivo, assim como observado para o acúmulo de lâminas foliares. No sistema silvipastoril o maior acúmulo de matéria seca total foi observado na meta de 95% de IL (12.482,6 kg ha-1 MS). O monocultivo apresentou maior acúmulo de lâminas foliares em relação ao sistema silvipastoril. O acúmulo de lâminas foliares foi menor nos tratamentos de 100% de IL em ambos sistemas em virtude da maior participação de colmos na massa de forragem. No tratamento de 100% de IL ocorreu maior incremento de forragem senescente em relação às metas de 90% e 95% de IL. O monocultivo apresentou maior quantidade de forragem senescente que o sistema silvipastoril. As metas de 90 e 95% de IL possibilitaram maior densidade populacional de perfilhos que na meta de 100% de IL. Contudo, as metas de manejo não influenciaram a densidade populacional de perfilhos no sistema silvipastoril. O monocultivo proporcionou maior densidade populacional de perfilhos que o sistema silvipastoril. Em função dos elevados acúmulos de matéria seca total, lâminas foliares e maior eficiência de pastejo atribuída a maior remoção de forragem, os pastos de capim-braquiária devem ser manejados com 95% de IL em sistema silvipastoril (altura de 40 cm) e em monocultivo (altura de 20 cm) em pré- pastejo no método de lotação intermitente durante o período de crescimento da forrageira.

La lumière influence fortement la physiologie et le comportement en exerçant des effets non-visuels de deux types : i) indirects, via la resynchronisation de l’horloge centrale qui est située dans les noyaux suprachiasmatiques (NSC), ii) directs, indépendants du processus circadien, via des mécanismes encore mal compris. Nos travaux chez la souris ont montré que l’influence directe de la lumière constitue un mécanisme majeur de régulation du sommeil, de l’éveil et de l’humeur, au même titre que le processus circadien. Ces effets sont majoritairement médiés par la mélanopsine, un photopigment exprimé dans la rétine, et relayés au niveau cérébral par différentes structures comme les NSCs et le VLPO. Ainsi, le rôle des NSCs ne doit pas être interprété qu’au travers de leur fonction d’horloge. Ensuite, dans une perspective de recherche translationnelle de l’animal à l’homme, nous avons validé Arvicanthis ansorgei, comme modèle d’étude du sommeil afin de pouvoir interpréter nos résultats chez un rongeur diurne. Enfin, de nombreuses données suggérant que les effets directs de la lumière modulent l’activité du système dopaminergique, nous avons évalué l’intérêt de la luminothérapie dans des pathologies dopaminergiques (maladie de Parkinson, syndrome des jambes sans repos, troubles de l’humeur). Ces avancées ouvrent de nombreuses perspectives pour une meilleure utilisation de la lumière dans notre société ainsi qu’en pathologie. / Light influences physiology and behavior through both types of non-image-forming effects: i) indirect, synchronizing the circadian master clock located in the suprachiasmatic nucleus (SCN), ii) direct effects, independent from the circadian process though mechanisms poorly understood. Our studies in mice demonstrate that the direct influence of light constitutes a key mechanism of regulation for sleep, alertness and mood and is as important as the circadian process. The direct effects of light are mainly mediated through melanopsin, a retinal photopigment that projects to the different structures of the brain such as the SCN and the VLPO. The SCN, beyond their role as circadian clock are also a relay system for the direct effects of light. Further, we validated Arvicanthis ansorgei as a diurnal model for the study of sleep regulatory mechanisms. This is an important step in the translational approach from animal research to applications in humans. Various data suggest that the direct effects of light interact with the dopaminergic system. In the last part of this thesis, we evaluated the indication of bright light therapy in dopaminergic pathologies (Parkinson disease, restless legs syndrome, mood disorders). These advances open up new perspectives for possible applications of light therapy and may help improving societal lightening conditions.

Indiana University-Purdue University Indianapolis (IUPUI) / The phototropin photoreceptors are important regulators of plant growth and development and can therefore affect the photosynthetic activity of plants. Phototropin1 and Phototropin2 are versatile protein kinases that become activated when exposed to blue light. Their photobiological actions are best understood in the model plant Arabidopsis thaliana, where they are known to trigger several responses to blue light, one of which is phototropism, the bending of plant organs towards light. Additionally, phot1 and phot2 drive stomatal opening, chloroplast arrangement in leaf cells, leaf expansion, and leaf orientation. The phot1-specific response is rapid inhibition of hypocotyl growth, leaf positioning and mRNA stability whereas phot2 mediates the chloroplast avoidance response to high light. These responses impact a plant’s ability to capture light for photosynthesis, therefore the phototropins play important roles in optimizing a plant’s photosynthetic activity. Soybean (Glycine max) is a very important crop plant in Indiana known for its nutritional versatility and is also utilized for biodiesel production.In spite of soybean being a key crop, there is currently no information about the functionality of soybean phototropins. Also, being a legume, soybean has many structural and functional features that are not present in Arabidopsis. Interestingly, PsPHOT1A (a photoreceptor from garden pea) was found to be a functional phototropin as it was able to complement the phot1 mutation in Arabidopsis. The roles of these proteins in soybean will be elucidated based on the hypothesis that soybean phototropins play essential roles in regulating photosynthetic activity as do the Arabidopsis phototropins. To date, five soybean phototropins, 3 PHOT1s and 2 PHOT2s, are believed to exist. These GmPHOT protein coding regions were amplified by RT-PCR and cloned into pCR8/TOPO or pENTR-D/TOPO vectors via TOPO cloning to utilize Gateway cloning technology to create plant transformation constructs subsequently. The cloned GmPHOT cDNAs from each of the 5 GmPHOTs were sequenced and compared to the GmPHOT sequences from the Phytozome database to assess the accuracy of the gene models. The gene models of all the GmPHOTs were found to be accurate except that of GmPHOT1B-2. The high level of sequence identity between the GmPHOTs and AtPHOTs and the conservation of LOV domains and catalytic domains indicate structural resemblance between them. This suggests that soybean phototropins should encode active photoreceptors. The cloned protein coding regions from soybean were then recombined into a plant expression vector via Gateway technology,which were then used for transformation of Agrobacterium tumefaciens. These plant expression constructs will be utilized in the future to determine the functionality of soybean phototropins in Arabidopsis.