Showing papers on "Coturnix published in 2008"

Thyrotrophin in the pars tuberalis triggers photoperiodic response

Abstract: Molecular mechanisms regulating animal seasonal breeding in response to changing photoperiod are not well understood. Rapid induction of gene expression of thyroid-hormone-activating enzyme (type 2 deiodinase, DIO2) in the mediobasal hypothalamus (MBH) of the Japanese quail (Coturnix japonica) is the earliest event yet recorded in the photoperiodic signal transduction pathway. Here we show cascades of gene expression in the quail MBH associated with the initiation of photoinduced secretion of luteinizing hormone. We identified two waves of gene expression. The first was initiated about 14 h after dawn of the first long day and included increased thyrotrophin (TSH) beta-subunit expression in the pars tuberalis; the second occurred approximately 4 h later and included increased expression of DIO2. Intracerebroventricular (ICV) administration of TSH to short-day quail stimulated gonadal growth and expression of DIO2 which was shown to be mediated through a TSH receptor-cyclic AMP (cAMP) signalling pathway. Increased TSH in the pars tuberalis therefore seems to trigger long-day photoinduced seasonal breeding.

Characterization of Japanese Quail yellow as a Genomic Deletion Upstream of the Avian Homolog of the Mammalian ASIP (agouti) Gene

Abstract: ASIP is an important pigmentation gene responsible for dorsoventral and hair-cycle-specific melanin-based color patterning in mammals We report some of the first evidence that the avian ASIP gene has a role in pigmentation We have characterized the genetic basis of the homozygous lethal Japanese quail yellow mutation as a >90-kb deletion upstream of ASIP This deletion encompasses almost the entire coding sequence of two upstream loci, RALY and EIF2B, and places ASIP expression under control of the RALY promoter, leading to the presence of a novel transcript ASIP mRNA expression was upregulated in many tissues in yellow compared to wild type but was not universal, and consistent differences were not observed among skins of yellow and wild-type quail In a microarray analysis on developing feather buds, the locus with the largest downregulation in yellow quail was SLC24A5, implying that it is regulated by ASIP Finally, we document the presence of ventral skin-specific isoforms of ASIP mRNA in both wild-type quails and chickens Overall, there are remarkable similarities between yellow in quail and lethal yellow in mouse, which involve a deletion in a similar genomic position The presence of ventral-specific ASIP expression in birds shows that this feature is conserved across vertebrates

Toxicological effects of diclofenac in four avian species.

Abstract: The objective of the present study was to investigate the toxico-pathological effects of diclofenac in different avian species including broiler chicks (Gallus gallus, 15 days old), pigeons (Columba livia, 3 months old), Japanese quail (Coturnix japonica, 4 weeks old) and mynah (Acridotheres tristis, independent young). For each species, five groups each containing 10 birds were maintained and administered diclofenac sodium orally at dose rates of 0, 0.25, 2.5, 10 and 20 mg/kg body weight, respectively, for seven consecutive days. Clinical signs in all species included depression, somnolence, decreased body weight and mortality. Severity of clinical disease increased in a dose-related manner and was most severe in broiler chicks, followed by pigeons, Japanese quail, and was least severe in mynah. Serum creatinine levels were elevated in all species. Serum urea levels varied non-significantly in broiler birds, significantly decreased in pigeons and significantly elevated in Japanese quail and mynah. Broiler chicks and pigeons administered 10 and 20 mg diclofenac/kg had visceral gout; however, this was not observed in Japanese quail and mynah. The kidneys and liver were enlarged in all species. Histologically, the kidneys of all species showed acute renal necrosis and the livers had fatty change and necrosis of hepatocytes. The kidneys and liver of broiler chicks and pigeons given 10 and 20 mg/kg diclofenac also exhibited uric acid crystal aggregates (tophi) and associated lesions in the parenchyma.

Selective estrogen receptor alpha activation disrupts sex organ differentiation and induces expression of vitellogenin II and very low-density apolipoprotein II in Japanese quail embryos.

Abstract: The Japanese quail (Coturnix japonica) is a widely used model species for studying the roles of steroid hormones in avian sex differentiation. The aim of the present study was to elucidate the significance of estrogen receptors alpha and beta (ERalpha and ERbeta) in normal sex differentiation of the reproductive organs in the Japanese quail and in xenoestrogen-induced disruption of reproductive organ differentiation. Real-time PCR indicated that ERalpha (ESR1) mRNA is expressed in both right and left gonads and Mullerian ducts (MDs) in both sexes during early morphological differentiation. ERbeta (ESR2) transcripts were also detected in gonads and MDs, but at very low levels. Both receptor subtypes were expressed in the liver and may therefore mediate the expression of estrogen-regulated egg-yolk proteins. Aromatase mRNA was expressed at much higher levels in female than male gonads as early as embryonic day 5, indicating early sex differences in estrogen synthesis. Treatment with the ERalpha-selective agonist propyl pyrazole triol showed that frequently reported xenoestrogen effects, such as ovotestis formation, abnormal MD development, and hepatic expression of egg-yolk proteins, were induced by selective activation of ERalpha. Taken together, our results suggest that activation of ERalpha is crucial for estrogen-dependent sex differentiation of the reproductive organs and that ERalpha mediates xenoestrogen-induced toxicity during reproductive development in birds.

Effect of rooibos tea (Aspalathus linearis) on Japanese quail growth, egg production and plasma metabolites

Abstract: 1. Birds have been proposed as a suitable model for studies on ageing because of their long life in comparison with similar-sized mammals. However, some weak fliers, such as Galliformes, are the exception to this rule. The aim of the present study was to determine the effects of the treatment with rooibos tea (Aspalathus linearis), a natural source of flavonoid antioxidants and compounds with phyto-oestrogenic activity, on postnatal development and egg production of aged Japanese quail (Coturnix coturnix japonica). 2. Substitution of drinking water with traditional rooibos tea or diet supplementation with ground rooibos tea affected body weight of Japanese quail up to 100 d of age. The body weight of males drinking rooibos tea or eating rooibos-supplemented food decreased significantly. There was a trend toward increased body weight of tea drinking females and a significant increase in the body weight of hens fed the rooibos-supplemented diet. Although rooibos treatment did not significantly increase egg ...

Plumage development and moult in the European Quail Coturnix c. coturnix: criteria for age determination

Abstract: Sequence, rate and duration of moult were studied in captive bred European Quail Coturnix coturnix coturnix. The founder population originated from southwest France. The study was conducted between 1986 and 1989 on birds aged from 1 day to 2 years, exposed to a seasonal photoperiod corresponding to latitude 16°N during autumn and winter and latitude 48°N during the remainder of the year. Under these conditions, adult quail showed two annual moults with only the post-breeding one being complete. The pre-breeding moult essentially involved the throat feathers. Large interindividual variation was observed in the duration, timing and development of the post-breeding moult: 60% of the studied birds suspended moult when they developed migratory restlessness and then finished renewing their feathers during the winter. The post-juvenile moult was also suspended when 7–9 weeks old (3–6 primaries and 1–10 secondaries renewed). After this suspension, the length of which was related to the hatching date, the moult continued up to p7. The three outer primaries were kept for the first year and were replaced only during the post-breeding moult. Based on the examination of wing patterns, our study provides reliable criteria for discriminating between age classes. The numbers of primaries and secondaries simultaneously in growth or renewed were different between the age classes. The secondaries of adults were renewed later in the moult stage than were the secondaries of juveniles. These criteria provide field researchers with a guide that enables them to age quail with reasonable accuracy.

Expression and localization of Ca2+-ATPase in the uterus during the reproductive cycle of king quail (Coturnix chinensis) and zebra finch (Poephila guttata).

Abstract: Calcium ATPase (Ca2+-ATPase) is a key enzyme that participates in the translocation of calcium in the uterus of oviparous amniotes during eggshell formation. We used Western blot and indirect immunofluorescence microscopy to determine expression and localisation of uterine Ca2+-ATPase during the reproductive cycle of king quail and zebra finch. The pattern of Ca2+-ATPase expression and localisation during the reproductive cycle was similar for both species. Immunoblots of uterine extracts from quail and finch indicated that Ca2+-ATPase expression is reduced in non-reproductive compared to reproductive females. Similarly, in non-reproductive females, weak apical immunofluorescent staining of Ca2+-ATPase is localised to epithelial cells in a small number of uterine tubular glands. A large increase in apical immunofluorescent staining of tubular gland epithelia occurs in both vitellogenic and reproductive females. The presence of Ca2+-ATPase on the apical surface of tubular gland epithelial cells suggests that the enzyme is involved in the translocation of calcium out of the tubular gland epithelia and into the concentrated fluid of the uterine lumen. Presence of Ca2+-ATPase in vitellogenic females indicates that the enzyme is expressed prior to the time of ovulation and eggshell calcification.

Functional disorder of the retina in manganese-deficient Japanese quail revealed by electroretinography using a contact lens electrode with built-in light source.

Abstract: Manganese deficiency results in neurological and skeletal defects, together with ultrastructural disarrangement of the retina in rats. Wild birds show a range of Mn concentrations in their tissues, including the liver, raising the possibility of Mn-related disorders in the wild. Electroretinography (ERG) provides a useful noninvasive approach to evaluate visual function. This method is especially useful in birds, as objective analysis of them is very difficult, while they have well-developed vision. In this study, we carried out a convenient and reliable ERG recording using a contact lens electrode with a built-in light source (LED electrode) of Japanese quail (Coturnix coturnix japonica) fed a Mn-deficient diet. After 10 min light adaptation, single-flash and flicker cone responses were reproducibly recorded to cause an intensity-dependent increase in amplitude of both a-wave and b-wave in single-flash ERG. Mn-deficient feeding markedly decreased the Mn concentration in the liver by almost half in 3 to 6 weeks, followed by body weight loss in 13 to 15 weeks. Implicit time of a-wave and b-wave cone response by single-flash stimulation was significantly delayed in quail with a Mn depletion from 3 to 6 weeks. Every cone response of the Mn-deprived quail had a tendency to decrease amplitude. The ultrastructure of cone photoreceptor cells was disorganized by Mn deficiency, including changes in outer segment discs of photoreceptor cells. These results suggest the essential role of Mn in the integrity of the retinal function of birds.

Pterylography, plumage development and moult of japanese quail coturnix c. japonica in captivity

Abstract: Summary Japanese Quail were kept in small cages under controlled conditions of temperature and light, and their pterylography and moult are described There are 10 primaries, 14 secondaries and corresponding numbers of greater upper and lower wing coverts The alula has four feathers and the tail from five to six pairs of feathers There is an apterium in the dorso-pelvic tract similar to that in other quail genera The arrangement of feathers in the ventral and cervical tracts appears to differ from that described for some North American quail The chicks hatch with a covering of natal down Pre-juvenile moult can be seen when the chicks are three days old Juvenile body plumage is complete in about 30 days; the sides of the face, around the eyes, are the last places to acquire feathers The tenth and last juvenile primary to grow is mature when the chicks are 41 days old The moult in which the juvenile plumage is replaced overlaps the post-natal moult and in part of the ventral tract natal down is replaced by the first adult feathers This makes it possible to sex the quail at 14 days old The first adult moult is complete, in the body tracts, by the time the birds are five to six weeks old The dropping of juvenile primaries commences at about three weeks old and ceases when about eight weeks old Only from three to six primaries are replaced; most birds studied replaced five The significance of this difference from other Galliformes is discussed; it is thought to be associated with the species' migratory behaviour Quail which remained in the controlled laboratory environment did not undergo any further moult All birds moulted when both temperature and light period were reduced and most birds moulted when the light period alone was reduced Adult birds housed in small cages in an unheated, unlit shed underwent a complete moult between August and December in which all primaries were replaced This moult took 8–14 weeks to complete

Effect of egg turning and incubation time on carbonic anhydrase gene expression in the blastoderm of the Japanese quail (Coturnix c. japonica).

Abstract: 1. The gene expression of carbonic anhydrase, a key enzyme for the production of sub-embryonic fluid (SEF), was assessed in turned and unturned eggs of the Japanese quail. The plasma membrane-associated isoforms CA IV, CA IX, CA XII, CA XIV, and the cytoplasmic isoform CA II, were investigated in the extra-embryonic tissue of the blastoderm and in embryonic blood. 2. Eggs were incubated at 37·6°C, c.60% RH, and turned hourly (90°) or left unturned. From 48 to 96 h of incubation mRNA was extracted from blastoderm tissue, reverse-transcribed to cDNA and quantified by real-time qPCR using gene-specific primers. Blood collected at 96 h was processed identically. 3. Blastoderm CA IV gene expression increased with the period of incubation only in turned eggs, with maxima at 84 and 96 h of incubation. Only very low levels were found in blood. 4. Blastoderm CA II gene expression was greatest at 48 and 54 h of incubation, subsequently declining to much lower levels and unaffected by turning. Blood CA II gene expre...

Thermoregulatory and metabolic responses of Japanese quail to hypoxia.

Abstract: Common responses to hypoxia include decreased body temperature ( T b ) and decreased energy metabolism. In this study, the effects of hypoxia and hypercapnia on T b and metabolic oxygen consumption (V.O 2 ) were investigated in Japanese quail ( Coturnix japonica ). When exposed to hypoxia (15, 13, 11 and 9% O 2 ), T b decreased only at 11% and 9% O 2 compared to normoxia; quail were better able to maintain T b during acute hypoxia after a one-week acclimation to 10% O 2 . V.O 2 also decreased during hypoxia, but at 9% O 2 this was partially offset by increased anaerobic metabolism. T b and V.O 2 responses to 9% O 2 were exaggerated at lower ambient temperature ( T a ), reflecting a decreased lower critical temperature during hypoxia. Conversely, hypoxia had little effect on T b or V.O 2 at higher T a (36 °C). We conclude that Japanese quail respond to hypoxia in much the same way as mammals, by reducing both T b and V.O 2 . No relationship was found between the magnitudes of decreases in T b and V.O 2 during 9% O 2 , however. Since metabolism is the source of heat generation, this suggests that Japanese quail increase thermolysis to reduce T b . During hypercapnia (3, 6 and 9% CO 2 ), T b was reduced only at 9% CO 2 while V.O 2 was unchanged.