On day 5 of incubation, 0.64mg of estradiol benzoate (EB) was administered to fertilized eggs to investigate its effects on the differentiation and development of the oviduct in female chickens.
The increases of body and ovary weights of treated females in 0 to 366 days old were similar to those of females not treated with EB(control). However, thirty one % of the mature treated females did not produce any eggs. The egg production rate of the treated females that produced eggs was low, and the first egg production was delayed, although there were large individual variations among the treated females. A right oviduct at various developmental stages was seen in every treated female; there was a significant negative correlation between egg production rate and the weight of the right oviduct(p<0.01), and a significant positive correlation between egg production rate and the weight of the left oviduct(p<0.01). The number of yellow follicles in the ovary of the treated females was similar to those of the control, but intraperitoneal ovulations were observed in most of the treated females.
These findings suggest that suppression of anti-Müllerian hormone by estrogen in embryogenesis allows the development of the right Müllerian duct, which differentiates and develops into an oviduct. One of the causes of the reduced egg production in the mature treated females could be inhibition of the normal differentiation and development of the left Müllerian duct by exogenous estrogen, thus resulting in a functionally immature left oviduct.

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The thickness and weight of the shell portion (shell with shell membrane) of eggs at various times during the stay in the uterus and at oviposition were found to be greater in the guineafowl than those in the chicken (White Leghorn). A greater increase in the thickness and weight of the shell portion was found in the guineafowl during the stay in the uterus. The weight of the whole egg at 2 hours of stay in the uterus did not differ between the guineafowl and the chicken. In both the guineafowl and the chicken, the weight of the whole egg showed an increase at 8 hours of stay and almost no change thereafter. The amount of the increase in the weight of the whole egg was less in the guineafowl than that in the chicken. The size of the egg, as estimated by the length of the long and short axes, showed a minor enlargement at 8 hours of stay in the uterus in the guineafowl, whereas marked enlargement was observed in the chicken at the same time point. These results suggest that (1) the greater thickness and weight of the shell portion in the guineafowl egg is due to a larger amount of minerals deposited on a thicker shell membrane, (2) the size of egg in both the guineafowl and the chicken is determined by 8 hours of stay in the uterus, and (3) the smaller egg size and the smaller amount of albumen in the guineafowl egg is due to less extensive of plumping during the first 8 hours after entering the uterus.

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In the chicken ovary, one small yellow follicle (SYF) is selected daily to enter the hierarchy and ovulates a few days later. Cellular changes that occur in these follicles may provide an understanding of the mechanism of follicular selection. It was reported that granulosa cells isolated from SYF undergo apoptosis within 6 h in suspension culture. In this study, a culture method in which granulosa cells from SYF remain viable in vitro for 24 h is reported. Granulosa layers were isolated from SYF (Gr-SYF) and from the largest preovulatory follicle (Gr-F1) and dispersed in collagenase (1.5 mg/ml) for 15 min. Cells (1×10⁶/500μl for Gr-SYF and 2×10⁵/500μl for Gr-F1) were cultured either in 24 well plates in an incubator with 5% CO₂/95% O₂ at 39°C or in suspension in falcon tubes and incubated in water bath at 37C, for 0, 6, 12 and 24 h. Theca cell explants (8 mm diameter) were cultured in 1 ml of the same medium for 6 and 12 h. Cell proliferation (n=6) at 6, 12 and 24 h, DNA integrity and membrane permeability (n=4) were determined by a colorimetric assay, gel electrophoresis and flow cytometry, respectively. Proliferation increased in Gr-SYF cultured in a plate at 12 and 24 h whereas it did not change in Gr-F1 cells at any time of culture. DNA fragmentation was observed in Gr-SYF cultured in suspension at 12 h and theca cells at 6 and 12 h but not in Gr-SYF cultured in the plate. Cell permeability and DNA stainability (indicative of apoptosis) were only increased in Gr-SYF cultured in suspension. In conclusion, we have identified culture conditions that will allow the culture of granulosa cells obtained from SYF, the stage prior to selection.

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The goal of this study was to determine whether lysosomal hydrolase activity changes during induced molting in the hen pituitary. White Leghorn aged laying hens were subjected to induced molting by feed withdrawal. Gradual feeding was started on 4th d of egg-laying cessation. The anterior pituitaries were collected from hens of pretreatment, 3 d and 5 d after starvation, 3 d and 10 d after cessation of egg-laying (6 d after resumption of feeding), on day of and 7 d after resumption of egg-laying. They were processed for the detection of acid phosphatase (AcPase) activity by enzyme histochemistry. Sections were then examined under a light microscope with an image analysis computer system. The AcPase activity was observed in the cellular cytoplasm in both cephalic and caudal lobes of the anterior pituitary in all groups of hens. In the both lobes the positive area increased significantly in the group of 3 d after cessation of egg-laying when compared with pretreatment group. These results suggest that lysosomal enzyme activity in the anterior pituitary of chicken was enhanced a few days after cessation of laying, which may be responsible for the digestion of unusable hormonal granules at this phase.

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The present study was undertaken to evaluating the effects of diethylstilbestrol (DES) on sperm motility and reproductive function in male Japanese quail. To do so, we have identified the method that ensures maximal quail sperm motility, i.e. the semen from the ductus deferens was diluted with Lake’s solution supplemented with 0.005% (w/v) caffeine and 10% (v/v) quail cloaca fluid. Sperm motility was analyzed by the computer-assisted sperm motility analysis system (CASA). Compared with control birds, administration of DES (0.1 or 1 mg DES on a daily basis for a week) caused a significant reduction in testicular weight, a marked disintegration of the seminiferous epithelium and a significant decrease in the sperm population of the seminiferous lumen. Sperm recovery and motility also showed a significant decrease in treated individuals. These results suggested that enhanced estrogenic effect caused by DES injection could cause a disruption in reproductive function by affecting spermatogenesis and influencing sperm motility.

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Tea saponin is known to depress growth rates of chicks by decreasing feed intake. Since tea saponin has bitter taste, gustatory sensation was proposed to be responsible for the decreased feed intake. However, inconsistent observations are also reported. The present experiment was conducted with chicks to evaluate the involvement of factors other than taste in the decreased feed intake due to saponin. Chicks freely fed diets containing tea saponin or quinine sulfate at 0.5 and 1% levels for 12 h decreased feed intake within 4 h. Chicks given a choice between the basal diet and the diet containing 0.5 or 1% quinine sulfate for 12 h showed strong aversion to quinine-added diets within 4 h. Chicks preferred the basal diet to the diet containing 0.5 or 1% saponin in a similar two-choice preference test, but there were no statistical differences in feed intake of the first 4 h between the basal diet and the diet containing 0.5% saponin. When chicks were given a free access to the basal diet for 6 h a day in a 12-d feeding experiment, daily feed intake during 0-2 h was kept constant, whereas feed intake during 2-6 h gradually increased as the experiment progressed. On the other hand, feed intake during 0-2 and 2-6 h in chicks fed the diet containing 0.5% saponin was always suppressed to the same extent throughout the experiment. Force-feeding this saponin-added diet delayed the crop emptying, which was reversed by the concomitant addition of cholesterol. These results suggest that the decreased feed intake due to tea saponin is related to the crop distention by the ingesta remained in this organ rather than taste.

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We investigated which of the following substances is most effective for inducing improved growth performance and activated intestinal villus function: a wood vinegar compound solution (WVC), a charcoal powder, or a mixed powder of amorphous charcoal powder and WVC (CWVC). Cockerels (Julia strain) were fed ad libitum the following treatment diets for 28 d : 1) a commercial basal diet (CP, 16% ; ME, 2,800 kcal/kg), 2) 0.1% WVC in water, 3) 1% dietary charcoal powder diet, and 4) 1% dietary CWVC (CP, 2.5%) diet. After the end of feeding experiment, each intestinal segment was examined by light and scanning electron microscopy for morphological changes in the villi.
Although feed intake and body weight gain were not significantly different among feeding experimental groups, they tended to be increased in all experimental groups than those of control after feeding each experimental substance. In the feed conversion ratio, CWVC group showed the lowest value.
Although intestinal villus height, epithelial cell area and cell mitosis number did not show a significant difference among feeding experimental groups, these parameters tended to be more increased in all experimental groups than those of control. In CWVC group, cell area of the jejunum and ileum were significantly elevated (P<0.05).
On the duodenal villus surface of WVC and charcoal groups, some cells devoid of microvilli were observed. In the CWVC group, such damaged cells were not found, and more remarkable cell protuberances than those of the control group appeared, suggesting that duodenal villus function might be activated. Such an activated morphology on the villus tip surface was found in all experimental groups in the jejunum, but in the charcoal and CWVC groups in the ileum.
The present villus morphological findings demonstrate that among WVC, charcoal and CWVC, the dietary supplement of CWVC might be most effective substance for activating the intestinal absorptive function, and that the functional activation of whole intestine including the ileum may induce a slight elevation of chicken growth performance.

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Inhibitory effects of prostaglandin F_2α, arachidonic acid and phosphate solution on the eggshell formation were investigated in Japanese quail. All injections were performed intrauterinely 8h before the predicted oviposition. Prematurely oviposited eggs distinctly presented significantly lower values of eggshell weight (64-70%) and eggshell thickness (65-70%) than those of control (p<0.01). Spontaneously oviposited eggs, of which averaged oviposition intervals were approximately 24h, also showed significantly lower values (p<0.01) than control in eggshell weight and thickness (71-79% in both). When indomethacin was pretreated, oviposition-inducing effect and inhibiting effect on eggshell formation were disappeared in injection with arachidonic acid, whereas not inhibiting effect on eggshell formation but oviposition-inducing effect only disappeared in injection with phosphate solution. These results indicated that prostaglandin and phosphate solution had the inhibitory effect on the eggshell formation.

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