Domestication And Early Experiences In Chickens
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Domestication And Early Experiences In Chickens
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Author : Pia Katrine Løtvedt
language : en
Publisher: Linköping University Electronic Press
Release Date : 2017-11-17
Domestication And Early Experiences In Chickens written by Pia Katrine Løtvedt and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-11-17 with categories.
A number of animal species have undergone domestication, the process of becoming adapted to living in captivity and in proximity to humans. Common for these species is that they have all developed certain traits, including changes to coat color, body size and level of fearfulness. This has been termed the domestic phenotype. Among these traits is also an attenuation of the response to stress, both behaviorally and physiologically. Thus, release of glucocorticoids such as cortisol or corticosterone is lower in domesticated species. However, the underlying mechanism for this is not yet well understood. In this thesis, we have investigated genetic mechanisms for the attenuation of the physiological stress response in ancestral chickens, the Red Junglefowl, and domesticated chickens, the White Leghorn. We found a number of genes that differed in expression between the two breeds in several tissues involved in the stress response. Among the most interesting findings were lower expression of genes involved in production and secretion of ACTH in the pituitary, and in the production of glucocorticoids in the adrenal glands, in the domesticated White Leghorns. We also found higher expression of the glucocorticoid receptor in White Leghorns, indicating that they may have a more efficient negative feedback of the physiological stress response. We then investigated the transcriptome of the chicken pituitary more closely, and we discovered that a number of genes highly involved in several important physiological axes showed differential expression between the ancestral and the domesticated breed. Among these were genes involved in the stress response, the reproductive system, and in metabolism and growth. As these traits are modified in domesticated species, our results suggest that changes to gene expression in the pituitary may be an important underlying factor of the domestic phenotype. A separate aim of this thesis was to investigate effects of hatching time in chickens on their subsequent phenotype. Time of hatching constitutes an early experience that may differ between individuals, and we therefore hypothesized that differences in hatching time would affect chickens later in life. While a number of studies have been performed on hatching time and post-hatch growth, very little work has been done on effects on behavior. We found that the time of hatching had sex-specific effects. Hatching times in females were negatively correlated with body weight, whereas in males, behaviors such as reaction to novelty and spatial learning were affected. As time of hatching is governed by various hormones, including thyroid hormone and corticosterone, we suggest that changes to the levels of these hormones could affect both hatching time and post-hatch phenotypes. Understanding these mechanisms better would be beneficial in terms of production, where batch homogeneity is important, in research on early experiences and the potential for maternal programming, and in evolutionary questions on trade-off between different life strategies.
Dog Behaviour
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Author : Ann-Sofie Sundman
language : en
Publisher: Linköping University Electronic Press
Release Date : 2019-04-17
Dog Behaviour written by Ann-Sofie Sundman and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-04-17 with categories.
Dogs, Canis familiaris, share the lives of humans all over the world. That dogs, and the behavior of dogs, are of interest to many is therefore no surprise. In this thesis, the main aim has been to identify factors that affect dogs’ behaviours. The dog, Canis familiaris, is our first domesticated animal. Since domestication, various types of dogs have developed through adaptation to an environment shared with humans and through our selective breeding, resulting in a unique variation in morphology and behaviour. Although there is an individual variation in the behaviour of dogs, there is also a difference between breeds. Moreover, selection during the last decades has split some breeds into divergent types. Labrador and golden retrievers are divided into a common type, for show and companionship, and a field type, for hunting. By comparing the breed types, we can study the effects of recent selection. In Paper I, we investigate differences in general behavioural traits between Labrador and golden retriever and between common and field type within the two breeds by using results from the standardized behaviour test Dog Mentality Assessment. There were differences between breeds and types for all behavioural traits. However, there was also an interaction between breed and type. Thus, a common/field-type Labrador does not behave like a common/field-type golden retriever. Even though they have been selected for similar traits, the selection has affected the general behavioural traits differently in the two breeds. In paper II, we were interested in dogs’ human-directed social skills. Dogs have a high social competence when it comes to humans. Two experiments commonly used to study these skills are the problem-solving test, where dogs’ human-directed behaviours when faced with a problem are measured, and the pointing test, where dogs are tested on how well they understand human gestures. We compared the social skills of German shepherds and Labrador retrievers, and of common- and field-type Labradors. Labradors were more successful in the pointing test and German shepherds stayed closer to their owners during the problem solving. Among Labrador types, the field type had more human eye contact than the common type. Importantly, when comparing the two experiments, we found no positive correlations between the problem-solving test and the pointing test, suggesting that the two tests measure different aspects of human-directed social behaviour in dogs. A previous study has identified two suggestive genetic regions for human-directed social behaviours during the problem-solving test in beagles. In paper III, we show that these SNPs are also associated to social behaviours in Labrador and golden retrievers. Moreover, the Labrador breed types differed significantly in allele frequencies. This indicates that the two SNPs have been affected by recent selection and may have a part in the differences in sociability between common and field type. The behaviour of dogs cannot simply be explained by genetics, there is also an environmental component. In paper IV, we study which factors that affect long-term stress in dogs. Long-term cortisol can be measured by hair samples. We found a clear synchronization in hair cortisol concentrations between dogs and their owners. Neither dogs’ activity levels nor their behavioural traits affected the cortisol, however, the personality of the owners did. Therefore, we suggest that dogs mirror the stress level of their owners. The mediator between genes and the environment is epigenetics, and one epigenetic factor is DNA methylation. In paper V, we compared methylation patterns of wolves and dogs as well as dog breeds. Between both wolves and dogs and among dogs there were substantial differences in methylated DNA regions, suggesting that DNA methylation is likely to contribute to the vast variation among canines. We hypothesize that epigenetic factors have been important during domestication and in breed formation. In this thesis, I cover several aspects on how dogs’ behaviours can be affected, and paint an intricate picture on how genetics, epigenetics, and human-dog relations forms dog behaviour.
Exploring Fennoscandian Agricultural History Through Genetic Analysis Of Aged Crop Materials
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Author : Maria Lundström
language : en
Publisher: Linköping University Electronic Press
Release Date : 2018-11-07
Exploring Fennoscandian Agricultural History Through Genetic Analysis Of Aged Crop Materials written by Maria Lundström and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-11-07 with categories.
Crop plants have undergone a multitude of genetic changes during and following their domestication. The spread of agriculture brought the crops to new geographic regions exposing them to new environments and selection pressures along the way. This gave rise to many local variants with traits favoured both by agricultural practices and the environment. Agriculture was introduced in Fennoscandia (Norway, Sweden, Finland and Denmark) around 4000 BC. The composition of the archaeobotanical record gives some clues as to which species were cultivated, but macroscale analyses rarely reach beyond that. Therefore, methods like genetic analysis are necessary to expand our knowledge about the history of crop cultivation. Under optimal conditions, DNA can survive in biological samples for several hundred thousand years. The preservation of plant specimens in the Fennoscandian climate has, however, rarely been explored. This thesis therefore attempts to dive deeper into the Fennoscandian cultivation history through genetic analyses of aged plant materials from both museum collections and archaeological sources. Cereal grains from a range of preservation conditions were evaluated to find which ones might be of interest for genetic investigations. Desiccated materials gave the highest success rates, in agreement with previous studies. Waterlogged materials appeared to contain small amounts of endogenous DNA, whereas genetic analysis of charred cereals failed completely in all samples. Population structure was investigated in 17-19th century materials of both barley and rye from Sweden and Finland. Northern and southern populations of Finnish six-row barley were distinct from one another. In southern Sweden, genetic analysis suggested conserved population structure extending over 200 years. The genetic composition of rye also seemed mostly conserved, but rye did not show geographic population structure across the investigated region in Sweden and Finland. A long-standing question in Fennoscandian crop history has been the interpretation of historical written records mentioning Brassica (cole crops, turnips and mustards), as well as the species identity of archaeobotanical finds of Brassica seeds. Thus, Next Generation Sequencing (NGS) was applied to identify which Brassica types that were cultivated in 17th century Kalmar, Sweden. The analysis corroborated morphological species classification in two of the investigated subfossil seeds, whereas no conclusions could be drawn from the remaining samples. The genome coverages were too low to allow subspecies identification. Wheat has been cultivated in Fennoscandia since the introduction of agriculture but has increased dramatically in importance over the last century. The functional allele of the wheat nutrition gene NAM-B1 was found to be particularly prominent in Fennoscandian wheats, likely associated with its effect on grain maturation time. Here the evolutionary history of NAM-B1 was investigated to see if it could truly be considered a domestication gene as suggested in a previous study. By studying extant landrace materials of Mediterranean tetraploid wheat, it was found that the non-functional allele showed signs indicative of a selective sweep. This selection did not, however, appear to have occurred during domestication. In conclusion, aged plant specimens from both museum and archaeological contexts could contribute greatly to our knowledge about historical cultivation, extending the investigated period into the mid 17th century. Subfossil and waterlogged archaeobotanical materials do contain endogenous DNA, suggesting that they are better suited for genetic analysis than charred ones, at least as far as cereals are concerned. There is potential for classifying archaeological Brassica remains using NGS, even though further optimisation of sample and library preparation may be necessary. And finally, despite NAM-B1 showing signs of selection it should not be considered a domestication gene in tetraploid wheat.
The Behavioural Biology Of Chickens
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Author : Christine J Nicol
language : en
Publisher: CABI
Release Date : 2015-05-28
The Behavioural Biology Of Chickens written by Christine J Nicol and has been published by CABI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015-05-28 with Science categories.
Chickens are by far the world’s most widely farmed animal, kept for both meat and egg production. They are at the centre of many debates regarding housing and production systems, causing significant interest in what lies behind chicken behaviour. This accessible book covers sensory biology, behavioural development, preferences and aversions, social behaviour, learning and cognition, behavioural issues in different systems and solutions for behavioural problems. Authored by an authority on chicken ethology, it brings together the fields of animal behaviour, neuroscience, psychology and epidemiology to provide a comprehensive understanding of chicken behaviour and help improve the lives of farmed chickens around the world.
Behavioural Biology Abstracts
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Author :
language : en
Publisher:
Release Date : 1992
Behavioural Biology Abstracts written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1992 with Animal behavior categories.
Chickens And Their Diseases In Hawaii
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Author : Thomas Farrington Sedgwick
language : en
Publisher:
Release Date : 1901
Chickens And Their Diseases In Hawaii written by Thomas Farrington Sedgwick and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1901 with Chickens categories.
Principles And Applications Of Domestic Animal Behavior
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Author : Edward O. Price
language : en
Publisher: CABI
Release Date : 2008
Principles And Applications Of Domestic Animal Behavior written by Edward O. Price and has been published by CABI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Medical categories.
In order to understand and manage animals in their natural or captive environments we must first understand why animals do what they do and recognize limitations in their ability to adapt to different environments. Drawing on the author's considerable experience in both teaching and research, this introductory-level textbook describes the basic principles underlying animal behavior and how those concepts can be used in managing the care of domestic and captive wild animals, covering four key themes: development of behavior, biological rhythms, social behavior and behavioral aspects of animal management. Extensively illustrated with many practical examples and over 150 photos and figures, the book will be essential reading for animal science and veterinary students.
Insectivora
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Author : Heinz Stephan
language : en
Publisher: Springer Science & Business Media
Release Date : 2012-12-06
Insectivora written by Heinz Stephan and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012-12-06 with Medical categories.
This first volume in the series on "Comparative Brain Research in Mammals" deals with the brains of Insectivora. The importance of Insectivora lies above all in the fact that, (1) insectivore-like ancestors are regarded as the initial group for the evolution of higher mammals, and (2) the insectivore brains retained many conservative traits, though the animals have adapted to different living environments. Therefore, the study of Insectivora brains enables an insight into the size and composition of the brain structure of earlier ancestors of the higher mammals including primates and humans; in addition, it illumi nates the various evolutionary trends which made the successful adaptation to different biotopes possible. The alterations which the brain has experienced in the course of the phylo geny and the related adaptive radiation will be examined in the succeeding volumes on the brains of other Eutheria, e.g., bats (Volume 2) and primates (Volume 4). In Volume 3 the brains of marsupials will be compared with those of conservative and evolved Eutheria.
Biology Of Breeding Poultry
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Author : Paul M. Hocking
language : en
Publisher: CABI
Release Date : 2009
Biology Of Breeding Poultry written by Paul M. Hocking and has been published by CABI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with Technology & Engineering categories.
This book reviews the biological science and background to breeding meat poultry, specifically broiler, turkey and duck. These commercial birds have been changed by genetic selection to such an extent that they are substantially different from traditional breeds and laying hens. Covering science, management and husbandry systems, this book is an essential reference for researchers and students in animal science, as well as technical staff of breeding companies and poultry meat producers. Part of the Poultry Science Symposium Series.
Poultry World
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Author :
language : en
Publisher:
Release Date : 1882
Poultry World written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1882 with Poultry categories.