• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 26
  • 9
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 54
  • 54
  • 12
  • 9
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 4
  • 4
  • 4
  • 4
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

CHARACTERIZING THE ROLE OF GLUCOCORTICOIDS IN THE SIGN TRACKING BEHAVIOR OF MALE JAPANESE QUAIL (<em>COTURNIX JAPONICA</em>)

Rice, Beth A. 01 January 2018 (has links)
A devastating feature of drug-dependence is the susceptibility of relapse (40-60%) after stretches of abstinence. One theory that may account for relapse suggests that drug cues (e.g., paraphernalia) may increase stress hormones, and this may prompt relapse. Repeatedly pairing a neutral cue with a reward is commonly utilized to measure what subjects learn about a cue that is predictive of reward. Research has shown that animals that attend to a cue more than to the reward (sign trackers) may be more vulnerable to drug addiction. Additionally, research has shown that sign tracking is associated with an increase in corticosterone (CORT), a primary stress hormone. PT 150 is a novel glucocorticoid receptor antagonist that attenuates the effects of CORT. Experiment 1 hypothesized that subjects given repeated oral administration of 40 mg/kg PT 150 would reduce sign tracking compared to subjects given placebo. Results of Experiment 1 showed that repeated oral consumption of 40 mg/kg PT 150 decreased sign tracking behavior compared to placebo. In Experiment 2, it was hypothesized that PT 150 (20/40/60 mg/kg) given by subcutaneous (SC) injection would reduce sign tracking dose-dependently, and that sign tracking behavior would correlate with CORT levels. Results of Experiment 2 showed that SC injection of 20 mg/kg PT 150 reduced sign tracking but not 40 or 60 mg/kg. Additionally, the correlation between CORT and the sign tracking for the 20 mg/kg approached significance. Although tentative, the correlation may suggest that elevated plasma CORT concentrations correlate with elevated sign tracking. The current findings extend the current literature by suggesting that the glucocorticoid receptor may be a potential pharmacological target for reducing relapse-like behaviors.
42

THE EFFECT OF EARLY LIFE PHOTOPERIOD MANIPULATION ON COCAINE-INDUCED BEHAVIORAL SENSITIZATION IN MALE AND FEMALE JAPANESE QUAIL

Eaton, Shannon Elizabeth 01 January 2018 (has links)
Estrogens seem to play a role in the locomotor activating effects of cocaine. Japanese quail provide a good model for hormonal manipulation as alterations of their photoperiod controls hormone levels. The current study aims to examine the role of early life photoperiod manipulation in cocaine-induced behavioral sensitization in quail. It was expected that if quail were raised on a short photoperiod, they would have a reduction in gonadal hormones and this reduction in hormones would affect the acquisition of cocaine-induced behavioral sensitization. Quail were raised on an 8L:16D or a 16L:8D light cycle. Following 2 days of habituation, quail were administered saline, 5 mg/kg, or 10 mg/kg cocaine for 10 days. Restricted photoperiods in early life were correlated to lower gonadal hormone levels in females and males. Male quail raised on the short-light cycle developed a sensitized response to 10 mg/kg cocaine. Female quail raised on the short- or long-photoperiod developed behavioral sensitization to 5 mg/kg cocaine. Furthermore, early life reduction in estradiol in females modulated the amount of activity on day 10 of cocaine treatment. The current research extends previous research by finding a possible early life gonadal hormone control of behavioral sensitization in the quail.
43

Roles of ERα and ERβ in Normal and Disrupted Sex Differentiation in Japanese Quail

Mattsson, Anna January 2008 (has links)
Exposure to xenoestrogens during development has been shown to impair sexual differentiation in various species. The major aim of this thesis was to elucidate the respective roles of the two estrogen receptors ERα and ERβ in normal and disrupted differentiation of sex organs and copulatory behavior in the Japanese quail (Coturnix japonica). The expression of ERα mRNA was much stronger than that of ERβ mRNA in the gonads and Müllerian ducts (embryonic oviducts) in early embryos. By contrast, ERβ seemed to be predominantly expressed in regions of the embryonic brain that are associated with male sexual behavior. Embryos were exposed to the selective ERα agonists propyl-pyrazole-triol (PPT) and 16α-lactone-estradiol (16α-LE2). The estrogens 17β-estradiol (E2) and 17α-ethynylestradiol (EE2), which activate both ERα and ERβ, were used as positive controls. All substances impaired reproductive organ differentiation. The effects observed included oviductal malformations in females and partial development of oviducts in males. All substances also induced testis feminization (ovotestis) in male embryos. The male copulatory behavior was severely impaired by the positive controls but was unaffected by PPT and 16α-LE2 at doses that disrupted sex organ differentiation. A higher dose of 16α-LE2 significantly suppressed the behavior. However, it is possible that this effect was caused by cross-activation of ERβ. The substances also induced hepatic expression of mRNA encoding the egg-yolk proteins vitellogenin II and very low-density apolipoprotein II, which are commonly used as indicators of estrogen exposure. In conclusion, the results suggest that ERα is important for female reproductive organ differentiation. Excess activation of ERα by xenoestrogens impairs differentiation in both females and males and induces hepatic expression of egg-yolk proteins. The results also indicate that ERα alone cannot mediate demasculinization of male copulatory behavior in quail, although further studies are needed to test this hypothesis.
44

Adaptive significance of Pavlovian conditioning on reproductive behavior and fertility in Japanese quail (Coturnix japonica)

Mahometa, Michael Jason 28 April 2015 (has links)
The adaptive significance of Pavlovian conditioning has been an established idea within the learning literature. Pavlov himself indicated the potential for associative learning's role as an adaptive mechanism. As investigations into Pavlovian conditioning moved into the laboratory, the idea of adaptive significance was lost. The current body of work seeks to re-establish the adaptive importance of Pavlovian conditioning by investigating changes in the reproductive behavior of Japanese quail. Experiment 1 was a preliminary exploration of the relationship between the reproductive behaviors of the male and female Japanese quail, and fertility rates. Fertility rates were highly correlated with female immobility and male copulatory efficiency--a measure of copulatory behavior quality for males. Also, female immobility was highly correlated with male copulatory efficiency. In Experiment 2, changes in reproductive behavior and fertility due to Pavlovian conditioning were examined. The results indicated that Pavlovian conditioning altered the fertility rates for subjects if both partners of the copulatory pair were signaled. The Pavlovian conditioning procedure was refined for Experiment 3, which also showed changes in fertility rates as well as male copulatory efficiency. These experiments served to establish that Pavlovian conditioning can increase copulatory behavior and fertility when both partners of the copulatory pair are signaled. Experiments 4 - 6 investigated how factors related to the Conditioned Stimulus impact reproductive behavior and fertility rates. Experiment 4 showed that altering the CS-US interval for females did not produce significant differences in behavior or fertility. Experiment 5 demonstrated that context could be a viable CS in the Pavlovian conditioning of behavior and fertility. Experiment 6 showed that a naturalistic cue did not significantly alter either behavior or fertility over an arbitrary cue. In Experiment 7, visual access as an Unconditioned Stimulus in the Pavlovian conditioning of reproductive behavior was examined. Visual access to a female increased behavior and fertility over a control procedure, but not as much as full copulatory access. The present experiments provide definitive evidence of the adaptive significance of Pavlovian conditioning through changes in reproductive behavior and fertility. The relevance of the findings to Pavlovian conditioning in other behavior systems is discussed. / text
45

Métodos de muda forçada para codornas japonesas (Coturnix japonica)

Faitarone, Ana Beatriz Garcia [UNESP] 27 February 2007 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-27Bitstream added on 2014-06-13T19:35:46Z : No. of bitstreams: 1 faitarone_abg_me_botfmvz.pdf: 105803 bytes, checksum: 71794ea74b3d114021f28c46763de4aa (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O experimento foi realizado na Unidade de Pesquisa e Desenvolvimento de Brotas da Agência Paulista de Tecnologia dos Agronegócios do Centro-Oeste, SP. Objetivouse avaliar o desempenho e a qualidade dos ovos de codornas japonesas submetidas à muda forçada com o intuito de otimizar o plantel para mais um ciclo de produção. Foram utilizadas 400 codornas, em produção, com 65 semanas de idade, distribuídas em um delineamento inteiramente ao acaso em esquema fatorial 5 x 4 (cinco tratamentos e quatro períodos), sendo os tratamentos: (T1= não sofreu muda forçada; T2= 3 dias de jejum, e após ração à vontade; T3= 1 dia de jejum + 13 dias 15g/ave; T4= 2 dias de jejum + 12 dias 15g/ave; T5= 3 dias de jejum + 11 dias 15g/ave), com quatro repetições de 20 aves por parcela. As rações utilizadas nos tratamentos foram todas isonutritivas e balanceadas, seguindo as recomendações de NRC (1994). Foram observadas diferenças significativas entre os tratamentos e períodos estudados. Embora, ao se utilizarem 3 dias de jejum seguidos de alimentação à vontade, o peso dos ovos tenha sido menor, este tratamento apresentou melhores percentagens de postura, massa de ovos e conversões alimentares (CA/dz e CA/kg). Por outro lado, o mesmo período de jejum seguido de alimentação restrita apresentou maior consumo de ração e piores conversões alimentares (CA/dz e CA/kg). Constatou-se também que a não realização da muda forçada resulta em menor percentagem de postura e menor massa de ovos. / The experiment was carried through in the Unidade de Pesquisa e Desenvolvimento de Brotas of the Agência Paulista de Tecnologia dos Agronegócios do Centro-Oeste Paulista, SP. It was objectified to search optimum method to reduce stress it of forced moulting in Japanese quails with intention to optimize the breeding in performance terms and quality of eggs for plus a production cycle. 400 had been used quails, in production, with 65 weeks of age, distributed in a delineation entirely to perhaps in factorial project 5 x 4 (five treatments and four periods), being the treatments: (T1= did not suffer forced moulting; T2= 3 fasting day , and after ration ad libitum; T3= 1 fasting day + 13 days 15g/ave; T4= 2 fasting day + 12 days 15g/ave; T5= 3 fasting day + 11 days 15g/ave), with four repetitions of 20 birds for parcel. The rations used in the treatments had been all balanced isonutritive and following the NRC recommendations (1994). The treatments and studied periods had been observed significant differences between. Although to if using 3 fasting day followed of feeding to the will the weight of eggs it has been lesser, this presented better percentages of position, alimentary egg mass and conversions (CA/dz and CA/kg). On the other hand, the same period of fasting followed of restricted feeding presented greater consumption of ration and worse alimentary conversions (CA/dz and CA/kg). One also evidenced that not the forced accomplishment of the moulting one, results in lesser percentage of position and minor egg mass.
46

Energetics of laying and incubation in birds : studies of swallows Hirundo rustica, dippers Cinclus cinclus and Japanese quail Coturnix coturnix

Ward, Sally January 1992 (has links)
The doubly labelled water technique was validated for captive-bred, laying Japanese quail (Coturnix coturnix), and used to measure the energy expenditure of free-living laying swallows (Hirundo rustica). Swallows had a slightly higher energy expenditure during laying than during incubation or nestling-rearing. Energy expenditure and the net cost of incubation increased sharply for female dippers (Cinclus cinclus) when clutches were enlarged to 6 eggs. Lipophilic dyes were used to determine the rate of ovarian follicular growth and the volume of yolk deposjted in a 24 h period by captive quail and free-living swallows. Rates of yolk deposition were related to daily energy expenditure in quail, but not in swallows. Balances placed under swallow nests recorded an increase in female mass from 5 d before the first egg was laid. Female mass peaked on the evening before the first egg and declined as eggs were laid. Mass changes during laying were equal to the mass of the oviduct and developing ova. However, body composition also changed, as a lipid reserve was built up in the final 4 d before the first egg was laid, whilst body water content declined. This substantially increased the peak energy requirement for biosynthesis in a laying swallow. The lipid reserve was catabolized during the remainder of the laying period. The lipid reserve was likely to serve as an insurance against a drop in food intake during laying. Shortage of food on the day before the first egg was laid led to a reduction in clutch size for some swallows. There was no evidence for use of a protein reserve by laying swallows. A model was developed from which it was predicted that egg production by swallows, and probably all other insectivorous birds, would be constrained by energy rather than crude lipid or protein requirements. It was concluded that laying patterns and clutch sizes were sometimes constrained by food availability during egg-laying, and that an upper limit to clutch size could be set by the capacity of an incubating bird to cover the eggs.
47

Density of sperm-producing tissue is positively linked to male reproductive success, but not to testes size in the Japanese quail (Coturnix japonica)

Graf, Martine January 2020 (has links)
If sexual selection acts in a sex-limited way on a trait that has a shared genetic basis between males and females, the resulting intralocus sexual conflict can have a considerable impact on the opposite sex. A prime example of sexual conflict affecting a shared characteristic would be the reproductive organs in males and females. This study investigates how artificial selection on the female-specific trait egg size influences male reproductive success, particularly male testes morphology, by analysing the density and number of seminiferous tubules within the testes. It was found that selection on female reproductive investment has a concordant effect on male reproductive success, by demonstrating increased density of seminiferous tissue in the testes of males originating from high investment selection lines. Interestingly, a non-significant trend suggested that the density of seminiferous tissue influences testes size in a negative way. This study therefore provides evidence that female-specific selection on reproductive investment influences testes morphology in males, and that testes size depends on more than sperm-producing tissue.
48

Development of the Stress Response in Fast (Coturnix Japonica) Versus Slow (Callipepla Gambelii) Growing Species

Gastecki, Michelle Lynn January 2012 (has links)
In this study, we evaluated the development of stress response in (1) two different species of quail, one species that is relatively fast-growing (Japanese quail, Coturnix japonica) and one that is relatively slow-growing (Gambel’s quail, Callipepla gambelii) and (2) two strains of a single species, the Japanese quail (wild-type and domesticated), that differ considerably in final size. Our data indicate that wild-type Japanese quail and Gambel’s quail have experienced trade-offs between growth and the stress response (e.g. Gambel’s quail have slower growth rates, but greater levels of CORT). However, the domesticated strain of Japanese quail used in this study seem to violate some predictions based on the life history theory (e.g. the domestic strain has faster growth rates and greater levels of CORT). The data in this study contribute to the understanding of differences in the stress response between species that exhibit different life history strategies.
49

Effects of ammonium perchlorate exposure on the thyroid function and the expression of thyroid-responsive genes in Japanese quail embryos and post hatch chicks

Chen, Yu 05 August 2008 (has links)
Perchlorate ion interferes with thyroid function by competitively inhibiting the sodium-iodide symporter, thus blocking iodide uptake into the thyroid gland. In this study, the effect of perchlorate exposure on thyroid function and thyroid-responsive gene expression were examined in (1) embryos from eggs laid by perchlorate-treated Japanese quail hens and (2) perchlorate-treated young Japanese quail. I hypothesized that perchlorate exposure would decrease thyroid function and that the consequent hypothyroidism would alter the expression of thyroid sensitive genes. Laying Japanese quail hens were treated with 2000 mg/l and 4000 mg/l ammonium perchlorate in drinking water. Eggs from these hens were incubated. Embryos, exposed to perchlorate in the egg, were sacrificed at day 14 of the 16.5 day incubation period. Japanese quail chicks, 4-5 days old, were treated with 2000 mg/l ammonium perchlorate in drinking water for 2 and 7.5 weeks. Thyroid status was evaluated by measuring plasma thyroid hormone concentrations, thyroid gland weight and thyroidal thyroid hormone storage. Expression of thyroid-responsive genes was evaluated by measuring the mRNA levels of Type 2 deiodinase (D2) in the brain and liver, RC3/neurogranin mRNA level in the brain and Spot 14 mRNA level in the liver. Maternal perchlorate exposure led to embryonic hypothyroidism, demonstrated by thyroid hypertrophy and very low embryonic thyroidal TH storage. Embryonic hypothyroidism decreased body growth and increased D2 mRNA level in the liver (a presumed compensatory response to hypothyroidism) but did not affect the mRNA levels of D2 and RC3 in the brain. Spot 14 mRNA was not detected in embryonic liver. In the second part of the study, quail chicks showed early signs of hypothyroidism after two weeks of 2000 mg/l ammonium perchlorate exposure; plasma concentration and thyroid gland stores of both T4 and T3 were significantly decreased. After 7.5 weeks of perchlorate exposure, all thyroid variables measured indicated that the chicks had become overtly hypothyroid. D2 mRNA level was increased, a compensatory response to hypothyroidism, and spot 14 mRNA level was decreased, a substrate-driven response in the liver of quail chicks after two weeks of perchlorate exposure. However, no difference was observed in the mRNA levels of D2 and spot 14 in the liver after 7.5 weeks of perchlorate exposure, suggesting there was some adaptation to the hypothyroid condition. The mRNA level of D2 and RC3 in the brain was not affected by perchlorate-induced hypothyroidism in quail chicks after either 2 or 7.5 weeks of perchlorate exposure. As in the embryos, this suggests the brain of chicks was "protected" from the hypothyroid body conditions. / Ph. D.
50

Uridinediphosphate-glucuronosyltransferase (UDP-GT) Ontogeny and PCB Effects in Galliform Birds

McCleary, Ryan J. R. 06 December 2001 (has links)
Hepatic UDP-GTs are partly responsible for metabolism of the thyroid hormone, thyroxine (T4), in mammals, but little is known of UDP-GT activity in birds. To determine the ontogenic pattern of UDP-GT activity in precocial birds, we measured activity in Japanese quail (Coturnix japonica) liver at days 12 and 14 of the 16.5-day incubation, 3 perihatch stages and <1, 1, 4, 6, 7, 20 and 42 days posthatch. We used an enzymatic reaction with para-nitrophenol (pNP) as substrate that was validated for quail tissue. The pattern of UDP-GT development included low embryonic activity, increased activity beginning in the perihatch period, a peak in activity at day 4 posthatch and a return to lower activity levels from day 6 to adults. The profile of UDP-GT activity, in relation to the ontogeny of circulating T4 and triiodothyronine (T3) in quail, is consistent with UDP-GT playing a role in regulating circulating T4 and with the perihatch peak in T3 stimulating the posthatch peak in UDP-GT activity. To examine the effects of polychlorinated biphenyls (PCBs) on UDP-GT in developing precocial birds, we dosed chicken (Gallus domesticus) eggs with concentrations of PCB 126 from 0 to 0.80 ng/g egg (in sunflower oil) prior to incubation. Tissues were sampled at day 20 of the 21-day incubation and assayed for plasma hormones and UDP-GT activity. Eggs also were dosed with 0 or 0.25 ng PCB 126/g egg or with 0 or 0.64 ng/g egg of the coplanar PCB 77, allowed to hatch, and sampled at 42 days posthatch. There was no consistent pattern of altered thyroid hormones or UDP-GT activity in developing chickens exposed to either of these coplanar PCBs although previous studies indicated developmental alterations from exposure to the higher doses. / Master of Science

Page generated in 0.0384 seconds