Light- and electron-microscopic studies on the secretory cytology of the adenohypophysis of the Japanese quail,Coturnix coturnix japonica

The effects of thyroidectomy, adrenalectomy, and castration on the pars distalis of male Japanese quail, and of injection of LH-RH on sexually inactive females, were investigated by light and electron microscopy. Correlation between light and electron microscopy was attained by use of alternate thin and thick sections. Six types of secretory cells were identified and the ultrastructural characteristics described. Putative endocrine functions have been designated on the basis of responses to experimental interventions and on other criteria. The putative STH cells are characterized by the presence of large dense secretory granules (250-300 nm) that are stained with orange-G by the trichrome method. They occur only in the caudal lobe and appear to be unchanged by castration, thyroidectomy, adrenalectomy and LH-RH injection. The putative prolactin cells are characterized by large (400-600 nm), spherical or polmorphic, dense secretory granules stainable with acid fuchsin and aniline blue; prominent Golgi apparatus and well developed endoplasmic reticulum with densely packed, regularly parallel lamellae. They are found mainly in the cephalic lobe. The prolactin cells develop some vacuolization after adrenalectomy and undergo some degeneration after castration. The ACTH cells, which are restricted to the cephalic lobe, are identified by the dense, spherical granules (250-300 nm) that are stained with acid fuchsin. After adrenalectomy, they lose their secretory granules and are transformed into large, chromophobic adrenalectomy cells. TSH cells are so designated by their response to thyroidectomy including loss of their fine secretory granules and transformation to large, vacuolated thyroidectomy cells. We have found TSH cells and thyroidectomy cells only in the cephalic lobe. Basophilic cells, considered to be gonadotropes, occur in both the cephalic and caudal lobes. The gonadotropes of the cephalic lobe appear to have slightly larger (120-200 nm) granules than the caudal lobe (120-150 nm). However, after castration, the gonadotropes in both lobes become hypertrophied and vacuolated and are transformed into mutually indistinguishable castration cells. Twenty minutes after injection with LH-RH, the gonadotropes of both lobes increase in size and number, degranulate, develop vacuoles in the cytoplasm, and appear very similar to castration cells.     

The epididymal region of the Japanese quail (Coturnix coturnix japonica).

The epididymal region of the Japanese quail was studied histologically. The organ consists of the extratesticular portion of the rete testis, the ductuli efferentes proximales and distales, the ducti conjugentes and ductus epididymidis. Distinct tubuli recti link the seminiferous tubules with the rete testis. The non-ciliated cells of the ductuli efferentes proximales and distales show, between them, certain internal structural differences which were highlighted. In 40% of the birds, the ductus deferens showed dark-grey pigments, regarded as melanin. The epididymal region was generally similar in structure to that of the domestic fowl, turkey and duck.     

Blood sampling and intravenous injections in Japanese quail (Coturnix coturnix japonica).

The suitability of five different sites (brachial, jugular, caudal tibial vein, external dorsal thoracic vein and the heart) were examined for blood sampling and intravenous injections in Japanese quail. In terms of safety, ease of collection, repeated collections or injections, the jugular vein was found to be the most suitable.     

Regulation of hydroxyindole-O-methyltransferase gene expression in Japanese quail (Coturnix coturnix japonica).

Hydroxyindole-O-methyltrasferase (HIOMT) plays an important role as the final enzyme in the synthesis of melatonin. In this study, the expression of the HIOMT gene in Japanese quail was investigated with respect to tissue distribution and the effects of light and vitamin A deficiency. HIOMT mRNA in the pineal gland and eye had a clear daily rhythm with peak values in daytime. The testis also contained a detectable amount of HIOMT mRNA, which did not display a rhythmic change over a 24-h period. When birds were rendered vitamin A deficient through feeding with a vitamin A-free diet, the daily rhythm of the HIOMT gene almost disappeared in both the pineal gland and eye due to increases in the nighttime values. Our previous observations and these results suggest that vitamin A and a photo-signal are required to maintain the rhythmic expression of the HIOMT gene as well as the arylalkylamine N-acetyltransferase gene.     

Cultivation of Eimeria tenella in Japanese quail embryos (Coturnix coturnix japonica).

Complete development of Eimeria tenella in Japanese quail embryos was observed. Sporozoites were inoculated into the allantoic cavity of 7-day-old Japanese quail embryos (Coturnix coturnix japonica), after which the infected embryos were incubated at 41 C. In the chorioallantoic membrane mature first generation schizonts, mature second generation schizonts, and gametes were detected at 48 hr postinoculation of sporozoites (PI), 84 hr PI, and 126 hr PI, respectively. Mature gametes and zygotes were found at 132 hr PI, and oocysts were detected at 138 hr PI. Mortality of embryos increased with increment of inoculum size of sporozoites. LD50 was 1.7 x 10(2) sporozoites. Oocyst production was also dependent on inoculum size. Oocysts harvested from embryos sporulated. The oocysts were inoculated into 13-day-old chickens, and oocysts, capable of sporulating normally, were recovered from ceca 7 days after inoculation.     

Stumpy limb--an embryonic lethal mutation in Japanese quail (Coturnix coturnix japonica).

An embryonic lethal mutant was found in Japanese quail and named "stumpy limb (SL)". All SL embryos died at pre-hatching stages, showing brachycephaly, a thickened neck, short upper and lower beaks, and short and thick extremities, while their body length was similar to that of the normal embryos. Observations on the skeleton revealed a globular skull, unusual curvature of the Processus palatinus maxillaris of the upper beak, and shortening and thickening of the appendicular bones. Some embryos showed a bending of the humerus, femur and/or tibiotarsus. Abnormality was more conspicuous in the leg bones than in the wing bones. No conspicuous differences were observed in the vertebrae between the SL and normal embryos. A genetic analysis suggested that the mutation is controlled by an autosomal recessive gene, for which the gene symbol sl was proposed.     

Lipogenesis depending on sexual maturity in female Japanese quail (Coturnix coturnix japonica).

1. Lipid biosynthesis in the liver as well as transport into the follicles in Japanese quail were investigated depending on sexual maturity at 5, 7, 9 and 11 weeks of age. Lipogenesis of the liver and incorporation of lipid into the follicles were determined by administering [1-14C]sodium acetate. 2. Body weight increased up to 9 weeks of age, whereas the weight of the liver and follicle did not alter after 7 weeks of age. 3. Fatty acid synthesis in the liver was at its highest at 7 weeks of age. Incorporation of 14C into non-saponifiable lipid and glyceride-glycerol fractions in the liver was not influenced by aging. 4. The labelled fatty acids in the follicle increased linearly as the birds became sexually mature.     

Cutaneous candidiasis in Japanese quail (Coturnix coturnix japonica)

Cutaneous candidiasis involving the foot pads of 5–30 weeks old Japanese quails was recorded in a large quail breeding unit. Histopathological lesions comprising granulomatous reaction in the dermis and hyperkeratosis resembled with those of candida granuloma of human beings. The causative fungus, isolated from the foot pad lesions on Sabouraud agar, was identified as Candida albicans on morphological and biochemical characteristics. Predisposing factors such as overcrowding and un-sanitary conditions were found to be apparently responsible for candidiasis in quails. These factors when taken care of resulted in a marked decrease in the disease incidence. This appears to be the first report of cutaneous candidiasis in avian species.     

The acute phase response in Japanese quail (Coturnix coturnix japonica)

Experiments were conducted to determine the effect of injection of lipopolysaccharide (LPS, from S. typhimurium) or muramyl dipeptide (MDP, N-acetylmuramyl-L-ala-isoglutamine) in Japanese quail. Doses of MDP between 0.3 and 10 mg/kg body wt. had no effect on body temperature. In contrast, doses of 1.0-22.5 mg LPS/kg body wt. caused significant increases in body temperature. None of the doses of LPS or MDP resulted in mortality. The febrile response to LPS was diminished following a second injection 48 h after the first, and was absent following a third injection. Plasma zinc, an indicator of the acute phase response, was significantly reduced by either LPS or MDP after the first injection (P<0.001), but not after the second or third injection. Splenic interleukin 1-beta (IL-1beta) mRNA expression was increased after the first and last injection of LPS (P<0.001), but only after the first injection of MDP (P<0.005). Hepatic IL-1beta mRNA expression was increased after the first, but not the third injection of LPS (P<0.001), while MDP had no effect. These data indicate that Japanese quail are less sensitive to MDP than LPS, and that quail demonstrate tolerance to LPS following repeated injections.     

Evidence for genetic etiology of heteroploidy in embryos of the Japanese quail (Coturnix coturnix japonica).

The Japanese quail was used as an experimental system to detect the effects of genes that affect chromosome behavior and distribution. From a random-bred population, three inbred generations were produced by full-sib matings in 36 families. The expectation from such a breeding scheme was that embryos bearing aberrations induced by recessive mutant genes would cluster within families and recur in particular lineages. Chromosomal aberrations caused by errors during fertilization, cleavage mitosis, and gametogenesis were scored in 2,037 16- to 18-h embryos from 107 families. Comparisons of the observed frequencies among families and lineages and pedigree analysis indicated that four types of chromosome aberrations had a genetic basis: (1) triploidy and triploid chimerism; (2) haploidy and haploid chimerism; (3) diploid/tetraploid mosaicism; and (4) a new aberration, referred to as "atypical mitotic metaphase." Analysis of the sex-chromosome complements of the embryos indicated that triploidy resulted predominantly from diploid ova, haploid cell lines originated from supernumerary sperm nuclei, and tetraploid cell lines resulted from endoreduplication or failure of cytokinesis. Clustering of triploidy in particular lineages was due to dispermy or recurrent suppression of one or both meiotic divisions during oogenesis.     

Polymorphism of serum esterases of Japanese quail (Coturnix coturnix japonica)]

Polymorphism of plasma esterases in quail is very important. Phenotypic frequences of genetic variants of three esterases are examined and they show a high proportion of heterozygotes. The maintenance of this polymorphism is supposed to be due to the organophosphorus pesticides.     

The anterior pituitary of the Japanese quail,Coturnix coturnix japonica

Summary The cytology of the adenohypophysis of the male Japanese quail (Coturnix coturnix japonica) has been studied under a variety of experimental conditions: (1) treatment with long daily photoperiods for variable lengths of time; (2) the change from a long to a short daily photoperiod which induces gonadal regression; (3) castration followed by exposure to either short or long daily photoperiods, and (4) treatment with thyroxine, thiourea and metapirone. In parallel with the Cytological investigations, information on the level of hypophysial gonadotropins has been obtained by bioassay.The cytological investigations permit the recognition of seven types of cells in the adenohypophysis and the identification of gonadotropic cells, thyrotropic cells, and corticotropic cells. The significance of the orangeophilic alpha (STH ?) cells, and the erythrosinophilic eta (prolactin ?) cells remains hypothetical. A seventh cell type kappa is hypercyanophilic and positive with lead hematoxylin; it has been identified in other species of birds and may be a melanophorotropic cell.In castrates, an increase in pituitary gonadotropin appears only with photostimulation. It appears that photostimulation increases thyrotropic activity, an effect that is enhanced by castration.This investigation was supported by Grant No. 5 ROI NB 06,187 from the National Institute of Neurological Diseases and Blindness and by an allocation from the Graduate School Research Fund to Professor Farner.Part of the study was aided by an A. R. C. grant (AG. 24/36) to Dr. B. K. Follett.We are grateful to Doctor August Epple for his histologie analysis of some of the target glands.We wish to thank Miss Maryvonne Lefalchier, biologiste-adjointe du C. N. R. S. for excellent technical assistance in the cytological preparation of the pituitaries.     

Short latency vestibular evoked potentials in the Japanese quail (Coturnix coturnix japonica)

Short-latency vestibular-evoked potentials to pulsed linear acceleration were characterized in the quail. Responses occurred within 8 ms following the onset of stimuli and were composed of a series of positive and negative peaks. The latencies and amplitudes of the first four peaks were quantitatively characterized. Mean latencies at 1.0 g ms⁻¹ ranged from 1265 ± 208 μs (P1, N = 18) to 4802 ± 441 μs (N4, N = 13). Amplitudes ranged from 3.72 ± 1.51 μV (P1/N1, N = 18) to 1.49 ± 0.77 μV (P3/N3, N = 16). Latency-intensity (LI) slopes ranged from −38.7 ± 7.3 μs dB⁻¹ (P1, N = 18) to −71.6 ± 21.9 μs dB⁻¹ (N3, N = 15) and amplitude-intensity (AI) slopes ranged from 0.20 ± 0.08 μV dB⁻¹ (P1/N1, N = 18) to 0.07 ± 0.04 μV dB⁻¹ (P3/N3, N = 11). The mean response threshold across all animals was −21.83 ± 3.34 dB re: 1.0 g ms⁻¹ (N = 18). Responses remained after cochlear extirpation showing that they could not depend critically on cochlear activity. Responses were eliminated by destruction of the vestibular end organs, thus showing that responses depended critically and specifically on the vestibular system. The results demonstrate that the responses are vestibular and the findings provide a scientific basis for using vestibular responses to evaluate vestibular function through ontogeny and senescence in the quail. Accepted: 18 January 1997     

Dynamics of crowing development in the domestic Japanese quail (Coturnix coturnix japonica)

Species-specific behaviours gradually emerge, via incomplete patterns, to the final complete adult form. A classical example is birdsong, a learned behaviour ideally suited for studying the neural and molecular substrates of vocal learning. Young songbirds gradually transform primitive unstructured vocalizations (subsong, akin to human babbling) into complex, stereotyped sequences of syllables that constitute adult song. In comparison with birdsong, territorial and mating calls of vocal non-learner species are thought to exhibit little change during development. We revisited this issue using the crowing behaviour of domestic Japanese quail (Coturnix coturnix japonica). Crowing activity was continuously recorded in young males maintained in social isolation from the age of three weeks to four months. We observed developmental changes in crow structure, both the temporal and the spectral levels. Speed and trajectories of these developmental changes exhibited an unexpected high inter-individual variability. Mechanisms used by quails to transform sounds during ontogeny resemble those described in oscines during the sensorimotor phase of song learning. Studies on vocal non-learners could shed light on the specificity and evolution of vocal learning.     

Urates and allantoic regulation in embryonic Japanese quail, Coturnix coturnix japonica

During embryonic development, allantoic fluid represents the shifting balance between renal excretion and reabsorption by chorioallantoic membranes. Allantoic contents of Na+, K+, Cl-, urate, pH, and water were followed over days 10-15 of the 16 day incubation. Water volume remained near 0.9 ml until day 13, then declined very rapidly. The pH declined more steadily, from 8 to 5.5. Contents of Na+ and Cl- fell regularly to final values 80-88% below day 10. The K+ content changed differently and nearly doubled by day 13 but returned to day 10 values at the end. Urate content rose until day 13, then fell suddenly to low levels. This was due to the abrupt precipitation of most urate into masses not sampled by our method, so that after day 13, urate was underestimated (probably by 90-96%). Ion binding by urates was low (about 3% of Na+ and Cl-, 10% of K+) and appeared to be nonspecific. The underestimate of urate contents means, however, that in late incubation about one third of allantoic Na+ and 65-70% of K+ and Cl- are bound to precipitated urate and do not appear in balance sheets of allantoic ions. These precipitated ions account for the significant amounts of Na+ and K+ that remain in the allantoic remnant, left in the eggshell after hatching, but whose presence is not predicted by analysis of allantoic fluid.     

Formoguanamine-induced blindness and photoperiodic responses in the Japanese quail,Coturnix coturnix japonica

We administered a blindness-inducing substance (formoguanamine hydrochloride) to Japanese quail in order to find whether it is effective to induce retinal degeneration in avian species other than the chicken. We also investigated its effects on the photoperiodic response of various organs including gonads and the entrainment of circadian locomotor activity rhythms. Histological observation revealed conspicuous degeneration of the photo-receptor outer segments and pigment epithelium. Behavioural responses of formoguanamine hydrochloride-treated birds to visual stimuli were completely abolished. These results proved that this chemical substance is effective to induce blindness in avian species other than the chicken. In formoguanamine hydrochloride-treated birds, the locomotor activity rhythm was entrained to light-dark cycles and the photoperiodic gonadal response was almost normal, suggesting that the extraretinal photoreceptors remained intact even after the formoguanamine hydrochloride-treatment.     

Acute reversible cataract due to nitrocompounds in Japanese quail (Coturnix coturnix japonica)

The present study was designed to examine the usefulness of the Japanese quail as an experimental model of cataractogenic activity. Chemicals, 2, 6-dibromo-4-nitro-phenol (2, 6-D), 2, 4-dinitroanisole (2, 4-DA), and 2, 4-dinitrophenol (2, 4-D; for the positive control), were administered singly through an oral route to 2-week old male Japanese quails to investigate the reversibility of cataracts. A single administration of 2, 4-D (36 and 43 mg/kg) produced reversible cataract in 14 of 16 animals (87.5%). This cataract was seen 1 or 2 hours after treatment and continued for 1 to 12 hours. Treatment with 2, 6-D (20 and 25 mg/kg) and 2, 4-DA (120 and 150 mg/kg) caused cataracts in 7 of 11 (63.6%) and 8 of 8 surviving animals (100%), respectively. Cataracts produced by 2, 6-D and 2, 4-DA, which were observed from 1 and 2 to 4 hours after the treatment, continued for 6 to 15 and 1 to 13 hours, respectively. Mortalities in the 25 mg/kg group of 2, 6-D, 120 mg/kg and 150 mg/kg group of 2, 4-DA were found in 2 of 5 animals, 1 of 5 animals and 5 of 9 animals, respectively. These results indicate that the Japanese quail is useful as an animal model to evaluate toxicity to the eye and cataractogenesis.