Effects of reproductive state on molt in the Japanese quail

Hall, Michael R.; Laouar, L.; Ivings, W. E.

doi:10.1002/jez.1402650306

Cited by 5 publications

(2 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We assumed that the low ambient temperature during those days initiated molt, however, the role of the shorter photoperiod could not be ruled out. Molting as a result of lower temperature (Thompson and Boag, 1976) and shorter photoperiod (Hall et al ., 1993) have been reported. The intensity of molt was assessed by the number of shed feathers found on the floor of the cages.…”

Section: Discussionmentioning

confidence: 99%

Deleterious Effects of Molting on the Morpho-physiology of Japanese Quail Layers (Coturnix japonica)

Arora

Vatsalya

2011

International J. of Poultry Science

View full text Add to dashboard Cite

Molting is a natural physiological phenomenon involving the periodic replacement of old feathers with new ones in the avian species. During mid-November an extensive loss of feathers in Japanese quail was observed in our breeding colony. The cause of molting could not be established, however, lower ambient temperatures may have played a major role and the decrease in day length could not be ruled out as a contributing factor. This study was conducted to correlate some aspects of the molting process using various physiological and morphometric parameters. Forty healthy 125-days old layers, hatch-mates, of approximately similar body weights (130.0±3.9 g) and in peak production were used for cohort evaluation of the molting process. Most of the birds lost feathers extensively from the cervical, thorax and dorsum areas, while some did not molt and continued laying eggs as usual, serving as a premolting control group. The molting birds drastically lost body weight weighing on average 117.5 g compared to 130.0 g in the control group and ceased egg production completely. There was a significant increase in blood glucose (293.03 mg/dL vs. 222.11 mg/dL), an increase in PCV values (47.14% vs. 41.43%) and a decrease in total plasma proteins (3.5 g/dl vs. 5.56 g/dl) and oviducts (1.55 g vs. 5.78 g, a decrease of 73.2%). Ovarian follicles underwent atresia and resorption. Birds that recovered from the molt resumed egg production and regained their body weights showing similar morpho-physiological measures of the control values, which changed during the molting phase. Scientists working with Japanese quail should be fully aware of the physiology of the molting process and its impact on on-going studies involving growth, physiology, endocrinology, nutrition, reproduction and toxicology.

show abstract

Section: Discussionmentioning

confidence: 99%

Deleterious Effects of Molting on the Morpho-physiology of Japanese Quail Layers (Coturnix japonica)

Arora

Vatsalya

2011

International J. of Poultry Science

View full text Add to dashboard Cite

show abstract

“…A indução da muda forçada em codornas poedeiras através da redução do fotoperíodo de 18 para 8 horas de luz por dia foi também conseguida por Hall et al (1993). A utilização de jejum alimentar para a indução de muda forçada em codornas poedeiras foi pesquisada por Zamprônio et al (1996) que submeteram um grupo de aves após um ano de produção a um jejum alimentar de três dias, sendo um dia também de jejum hídrico; um segundo grupo recebeu jejum alimentar por seis dias, sendo um dia também de jejum hídrico.…”

Section: Introductionunclassified

Alimentação de Codornas com Milho Moído e Ração de Postura no Período Pós-jejum Durante a Muda Forçada e Seus Efeitos Sobre o Desempenho

Garcia

Mendes

Pizzolante³

et al. 2002

Rev. Bras. Cienc. Avic.

View full text Add to dashboard Cite

O experimento foi realizado com o objetivo de avaliar o desempenho de codornas poedeiras alimentadas por diferentes períodos com milho moído ou ração de postura durante sete dias após três dias de jejum, método de muda utilizado. Após esse período, as aves foram alimentadas com ração de postura durante as 20 semanas do período experimental. Utilizou-se um delineamento inteiramente ao acaso com três tratamentos (ração de postura por sete dias, ração de postura por três dias e milho moído por quatro dias e milho moído por sete dias), e quatro repetições de 24 aves por parcela. Os resultados mostraram que aves alimentadas apenas com ração de postura nos sete primeiros dias após o jejum apresentaram maior produção de ovos nas seis primeiras semanas do período de produção pós-muda. Porém, não foi constatado efeito de tratamento sobre a produção de ovos, peso dos ovos, consumo de ração e conversão alimentar durante as 20 semanas do período experimental.

show abstract

The thyroid and photoperiodic control of seasonal reproduction in American tree sparrows (Spizella arborea)

Wilson

Reinert

1993

J Comp Physiol B

View full text Add to dashboard Cite

To explore the role of the thyroid gland in the control of seasonal reproduction in obligately photoperiodic American tree sparrows (Spizella arborea), the effects of (1) thyroxine administered in drinking water to thyroid-intact photosensitive or photorefractory birds, and (2) radiothyroidectomy before and after photostimulation and during photorefractoriness were examined. Chronic administration of pharmacological doses of thyroxine induced testicular growth and usually regression in initially photosensitive birds held on short or intermediate daylengths. Some thyroxine-treated birds with regressed testes were absolutely photorefractory, but most remained photosensitive. Exogenous thyroxine never induced testicular growth in photorefractory birds moved to short days, though it often impeded, and sometimes even blocked, the recovery of photosensitivity. Although circumstantial, these effects of exogenous thyroxine are consistent with an hypothesis that assigns to thyroid hormones two roles--one stimulatory and the other inhibitory--in the control of seasonal reproduction. Radiothyroidectomy before photostimulation inhibited (but did not prevent) photoinduced testicular growth, blocked spontaneous testicular regression, suppressed molt, and prevented photorefractoriness. Moreover, as demonstrated by testicular growth after thyroxine replacement therapy, radiothyroidectomy during photorefractoriness later restored photosensitivity despite continued photostimulation. Thus, euthyroidism is an essential condition for maximizing (but not for initiating) photoinduced testicular growth and for triggering and maintaining photorefractoriness in photostimulated tree sparrows. However, when performed early during photostimulation, radiothyroidectomy neither immediately induced nor later blocked spontaneous testicular regression. Thus, endogenous thyroid hormones and long days may interact during a critical period to program a sequence of physiological events that plays out as photorefractoriness in chronically photostimulated birds. Such an organizational event cannot be permanent, for seasonal reproduction is episodic and its control mechanism necessarily cyclic. Because thyroidectomy simulated the well-known restorative effect of short days (and exogenous thyroxine impeded it), short days may dissipate photorefractoriness by creating a milieu wherein thyroid hormones are deficient or inactive.

show abstract

Effects of reproductive state on molt in the Japanese quail

Cited by 5 publications

References 21 publications

Deleterious Effects of Molting on the Morpho-physiology of Japanese Quail Layers (Coturnix japonica)

Deleterious Effects of Molting on the Morpho-physiology of Japanese Quail Layers (Coturnix japonica)

Alimentação de Codornas com Milho Moído e Ração de Postura no Período Pós-jejum Durante a Muda Forçada e Seus Efeitos Sobre o Desempenho

The thyroid and photoperiodic control of seasonal reproduction in American tree sparrows (Spizella arborea)

Contact Info

Product

Resources

About