Expression of arginine vasotocin and estrogen receptor alpha (ERα) in the shell gland altered by the specific phase relations of neural oscillations affects the reproductive physiology of Japanese quail.

In order to study the effect of specific phase relation of neural oscillations on reproductive regulation and the response of AVT (the avian homologue of mammalian AVP) the expression of AVT in the shell gland was monitored in sexually immature quail. In this study 3-week-old female Japanese quail were administered with serotonin precursor, 5-hydroxytryptophan followed by the dopamine precursor, l-dihydroxyphenylalanine at interval of 8h and 12h daily over a period of 13days. At thirty two days post treatment, a significant decrease in gonadal activity was seen in 8h quail although 12h quail exhibited an increase as compared to controls. A significant decrease in plasma estradiol level was noted in 8h quail while 12h exhibited no significant difference compared to controls. To address the relative roles of estrogen mediated action we also investigated estrogen receptor alpha (ER-α) expression and localization in the shell gland by visualizing it through confocal immuno-fluorescence microscopy. Results indicate increased expression of immunoreactive (ir)-AVT (myometrium), ir-ER-α (epithelial cells of endometrial region), along with significant increase in hypothalamic, plasma and shell gland AVT and a rapid increase in egg laying thus maintaining full breeding condition in 12h while low expression of ir-AVT and ir-ER-α was observed in 8h quail along with a significant decrease in hypothalamic, plasma and shell gland AVT with the suppression of gonads thereby stopping the egg-laying behaviour was noted. These findings not only suggest the modulation of gonadal development by changing the specific phase relation of neural oscillations but also demonstrate a parallel relation of AVT and gonadal activity in both conditions. It is concluded that the egg laying performance in response to AVT is regulated by the temporal phase relationship of neurotransmitters, and in part, this effect appears to be estrogen dependent.

Integrated 3D view of postmating responses by the Drosophila melanogaster female reproductive tract, obtained by micro-computed tomography scanning.

Physiological changes in females during and after mating are triggered by seminal fluid components in conjunction with female-derived molecules. In insects, these changes include increased egg production, storage of sperm, and changes in muscle contraction within the reproductive tract (RT). Such postmating changes have been studied in dissected RT tissues, but understanding their coordination in vivo requires a holistic view of the tissues and their interrelationships. Here, we used high-resolution, multiscale micro-computed tomography (CT) scans to visualize and measure postmating changes in situ in the Drosophila female RT before, during, and after mating. These studies reveal previously unidentified dynamic changes in the conformation of the female RT that occur after mating. Our results also reveal how the reproductive organs temporally shift in concert within the confines of the abdomen. For example, we observed chiral loops in the uterus and in the upper common oviduct that relax and constrict throughout sperm storage and egg movement. We found that specific seminal fluid proteins or female secretions mediate some of the postmating changes in morphology. The morphological movements, in turn, can cause further changes due to the connections among organs. In addition, we observed apparent copulatory damage to the female intima, suggesting a mechanism for entry of seminal proteins, or other exogenous components, into the female's circulatory system. The 3D reconstructions provided by high-resolution micro-CT scans reveal how male and female molecules and anatomy interface to carry out and coordinate mating-dependent changes in the female's reproductive physiology.

Distal oviduct and genital chamber of eriophyoids (Acariformes, Eriophyoidea): refined terminology and remarks on CLSM technique for studying musculature of mites.

The general morphology of cuticle-lined internal genitalia and oviduct is analyzed in intact females of the phytophagous mites, Loboquintus subsquamatus and Trisetacus cf bagdasariani (Acari: Eriophyoidea) using tetramethylrhodamine B isothiocyanate-phalloidin, three anaesthetics (magnesium sulphate, lidocaine and CO2-enriched water) and confocal laser scanning microscopy (CLSM). This is the first protocol adopted for CLSM studying musculature of mites. Revision of the previous terminology of eriophyoid internal genitalia from Nuzzaci and Alberti (Eriophyoid mites: their biology, natural enemies and control. World crop pests 6. Elsevier, Amsterdam, pp 101-150, 1996) resulted in the refinement of the terms "distal oviduct", "genital chamber" and "spermatheca". Relative position of the elements of cuticle-lined internal genitalia is discussed and a generalized 3D model and animation (available on-line as supplementary material) of eriophyoid genital apparatus are provided. The wall of eriophyoid oviduct contains strong longitudinal muscles attached to the cuticle genital chamber with folded walls. When the egg is being extruded by contraction of the oviduct muscles, it forms lobes corresponding to the internal topography of the oviduct and genital chamber; these lobes invaginate inward from the gonopore, resulting in the "flower-shaped" figures rarely observed in slide-mounted mites. Gnathosomal muscles (cheliceral muscles and extrinsic muscles of palps) and opisthosomal muscles D1 of Loboquintus mites are attached to the three posterior depressions near the rear prodorsal shield margin. Prospects of CLSM approach for studying different aspects of mite morphology are briefly discussed.

Morphology of the oviduct of commercial egg-laying hens supplemented with organic minerals.

OBJECTIVE: To analyze the morphology of the oviduct of commercial egg-laying hens supplemented with organic minerals. STUDY DESIGN: A total of 2,400 Dekalb hens at 42 weeks of age were included in the study. Throughout the period of the experiment (10 months, divided into 4 periods of 10 weeks each) a supplement was administered. The animals were divided at random into 2 groups, each consisting of 1,200 hens: Group I, the control group of hens that did not receive the supplement, and Group II, the group of hens that were administered the supplement. The morphology of the oviduct was evaluated; all tests were performed from 52 to 82 weeks. After the hens were sacrificed by cervical dislocation, fragments of the oviduct were collected, 10 hens per group, which were fixed in Bouin liquid for 6 hours. Then they were processed and analyzed for light microscopy. RESULTS: Analyzing the hens' oviduct, there was no change in weight of organs, but microscopy revealed that the hens' oviduct epithelium in Group II was preserved, with uniform cilia. CONCLUSION: Based on our results we can conclude that the organic mineral supplementation causes an improvement in hens' oviduct morphology.

High doses of dietary zinc induce cytokines, chemokines, and apoptosis in reproductive tissues during regression.

In chickens, high levels of dietary zinc cause molting, and the reproductive system undergoes complete remodeling concomitant to feather replacement. In the present study, the expression profiles of cytokines and chemokines were investigated in the ovary and oviduct of control hens and of hens induced to molt by zinc feeding. The zinc-induced feed-intake suppression, the changes in corticosterone levels, the immune cell populations in the reproductive tract, and the apoptosis of reproductive tissues were analyzed. The expression of mRNAs for interleukin-6 (IL-6), interferon-gamma (IFN-gamma), the avian ortholog of mammalian IL-8 (chCXCLi2), and a chicken MIP-1beta-like chemokine (chCCLi2) in the ovary and of mRNAs for IL-1beta, IL-6, IFN-gamma, transforming growth factor-beta2, chCXCLi2, and chCCLi2 in the oviduct were upregulated significantly during zinc-induced molting. A simultaneous feed-intake reduction was observed with higher expression of cytokines and chemokines. The results of the present investigation also suggested that the upregulation of corticosterone was closely associated with the increased expression of cytokines and chemokines. An increase in apoptosis within reproductive tissue during tissue regression was also noted. We had previously observed the upregulation of these cytokines expression in an earlier study (molting by feed withdrawal). However, the pattern and the level of expression were different among these two methods. These findings indicate that cytokines might be a common mediator of tissue regression during molting induced by diverse methods, although the pattern of induction is different. Thus, a high dose of dietary zinc seems to induce reproductive regression via the upregulation of cytokines and chemokines, the suppression of feed intake, and the increase in serum corticosterone, resulting finally in the apoptosis of reproductive tissues.

Effect of dietary daidzein on egg production, shell quality, and gene expression of ER-alpha, GH-R, and IGF-IR in shell glands of laying hens.

Our previous studies demonstrated that dietary daidzein improves egg production in ducks during the late period of the laying cycle. The present study was aimed to investigate the effect of daidzein in laying hens, with more focus on eggshell quality. The expression of ER-alpha, GH-R, and IGF-IR mRNA in shell glands was determined to identify the target genes of daidzein action and to reveal the relationship between shell quality and profiles of gene expression in shell glands of laying hens. 1000 ISA hens, at 445 days of age, were allotted at random to two groups and given the basal diet with or without 10 mg of daidzein per kg diet for 9 weeks. Daidzein supplement significantly increased the egg laying rate and the feed conversion ratio. The eggshell thickness increased, while the percentage of cracked eggs decreased in daidzein-treated hens. Serum E2 and phosphate concentrations were not altered, but the level of serum Ca2+ and the tibia bone mineral density were significantly increased in the daidzein-treated group compared with their control counterparts. In parallel with the significant increase of oviduct weight, significant down-regulation of GH-R and IGF-IR mRNA and a trend of decrease in ERalpha mRNA expression in shell glands were observed in daidzein-treated hens. The results indicate that dietary daidzein improves egg laying performance and eggshell quality during the late (postpeak) laying stage of hens, which is associated with modulations in gene expression in the shell gland.

Antioxidant status of the lower oviduct in the chicken varies with age and dietary vitamin E supplementation.

Protection of sperm membranes against lipid peroxidation is a pre-requisite to prolonged sperm storage, both in vivo and in vitro. As females from avian species can store spermatozoa in the utero-vaginal junction (UVJ) for prolonged periods, we investigated the mechanisms involved in antioxidative protection of the plasma membrane of chicken sperm in this region. Comparisons of concentrations in nonenzymatic (alpha-tocopherol, ascorbic acid, and GSH) and enzymatic (GSH-Px, SOD) antioxidants among the vagina, UVJ and uterus of sexually mature chicken hens revealed tissue-specific profiles, with higher ascorbic acid content and increased GSH-Px and SOD activity in the UVJ compared to other regions of the lower oviduct (vagina, uterus). Deterioration of the antioxidant profile in the UVJ was observed in aging hens, but it was partially compensated by dietary supplementation with vitamin E (130 ppm). It is concluded that the chicken UVJ provides a complex defense barrier against lipid peroxidation of the sperm membrane during in vivo storage, which can be partially improved by dietary supplementation with vitamin E. The protective effects of this barrier decline over time during the reproductive season.

Roles of antioxidants on prolonged storage of avian spermatozoa in vivo and in vitro.

This review focuses on natural and assisted prevention against lipid peroxidation in avian spermatozoa. The presence of high levels of n-6 polyunsaturated fatty acids (PUFAs) in the plasma membrane creates favorable conditions for the formation of peroxidative products, a major cause of membrane damage which may ultimately impair male fertility. However, a complex antioxidant system involving vitamin C, vitamin E and GSH is naturally present in avian semen. Coupled with a battery of enzymatic defenses (e.g., SOD, GSH-Px either Se- or non-Se-dependent), this system acts to prevent or restrict the formation and propagation of peroxides. The presence of specialized sites dedicated to prolonged sperm storage in avian females raises the question of durable protection of sperm membranes against peroxidation. Preliminary observations have revealed the presence of a specific antioxidant system at these sites in which vitamin C could exert a major role. From a practical standpoint, the extensive use of artificial insemination in poultry, along with the emergence in some species of workable techniques to cryopreserve spermatozoa, demand better control of peroxidation occurring in the plasma membrane of spermatozoa before or during storage. Dietary supplementation with vitamin E is effective in limiting lipid peroxidation of sperm plasma membranes, both in chickens and turkeys. In addition, organic Se with or without vitamin E stimulates Se-GSH-Px activity in seminal plasma. Preliminary observations in female chickens have also revealed the effectiveness of dietary supplementation with vitamin E, organic selenium or both to sustain fertility in aging flocks.

An attempt to distinguish between the direct and indirect effects, in the laying domestic fowl, of added dietary copper sulphate.

1. An experiment is reported in which the effects of giving copper sulphate-supplemented diets and control unsupplemented pair-fed diets to laying hens were compared. 2. The level of food intake significantly adversely affected mean body-weight, egg number, egg weight, liver, kidney, oviduct and ovary weights. Gizzard weight/kg body-weight was significantly increased both with decreasing levels of food intake and increased CuSO4 supplementation. 3. There was evidence of a depressing effect of CuSO4 per se on egg production and possibly on oviduct and ovary weight. 4. Liver lipid concentration was significantly decreased with decreasing levels of food intake and the results also suggest a depressing effect of CuSO4. 5. The Cu concentrations and total contents in liver and kidneys were significantly increased by dietary added CuSO4. Liver and kidney Zn and Fe concentrations were increased with decreasing levels of food intake rather than by CuSO4 addition.