Showing papers by "University of Veterinary Science published in 1981"

A light and electron microscopic study of the agent of carp mucophilosis.

Abstract: . The authors failed to detect algae or fungi in the gills of carp showing the typical clinical signs of mucophilosis. Electron microscopic examination showed the presence of rickettsia- or chlamydia-like organisms, inside the characteristic mucophilus cysts. These organisms are believed to be the causative agents of mucophilosis. The organisms develop intracellularly in the gill epithelium and after several divisions give rise to mucophilus cysts 70–80 μm in diameter. The morphological and ultrastructural changes observed in the course of mucophilosis bear a striking resemblance to the cysts and cyst-inducing causative agents responsible for epitheliocystis disease.

The influence of thyroid hormones and sex steroids on the peripheral metabolism of corticosterone in the male and female japanese quail

Abstract: Publisher Summary This chapter describes the influence of thyroid hormones and sex steroids on the peripheral metabolism of corticosterone in the male and female Japanese quail. In the experiments described in the chapter, eight-week-old male and female Japanese quails exposed to short and long photoperiodes were applied. The surgical procedures performed on the quails include castration, ovariectomy, thyroidectomy and castration plus thyriodectromy. Thyroxine treatments were carried out by intramuscular injection, while sex steroids were applied in silastic tubes places subcutan. Thyroxine treatment increases the metabolic clearance rate (MCR) of corticosterone in sexually immaturated male and female birds, but thyroidectomy is ineffective. Hypo-, and hyperthyroxinaemie in sexually mature birds, inhibiting the sex steroid level, which stimulates the corticosterone metabolism, will result indirectly a decrease of MCR of corticosterone. The sex steroids increase the MCR both in male and female animals. The opposing effect of gonadectomy at the same time is less manifested, probably because of the increase of the thyroid function. The change in testosterone level does not affect the secretion rate of corticosterone in sexually immatured birds. In photogonadostimulated animals, both the plasma level of corticosterone and its secretion rate increase in spite of high testosterone and low thyroxine level.

Interconnection between plasma levels of sex steroids, thyroid hormones and corticosterone during the ovulatory-oviposition cycle in the domestic hen

Abstract: Publisher Summary This chapter discusses the interconnection among plasma levels of sex steroids, thyroid hormones, and corticosterone during the ovulatory-oviposition cycle in the domestic hen. In the experiment described in the chapter, 11 adult New Hampshire laying hens fed by laying hen concentrate and water ad libitum were used. Progesterone peak 4–6 hours prior to ovulation was definitely detectable in hens from which blood sample could be drawn 6–10 hours before the ovulation. In most of the cases, oestron and 17-oestradiol reach their maximum parallel with the progesterone. The plasma concentration of oestrogen shows not so definite synchronization as that of progesterone. In some cases, elevated testosterone level 10–12 hours before the oviposition has been found this phenomenon was however not regular. The chapter describes most characteristic changes of the sexual steroids. It is established that the progesterone plays an important and decisive role in the regulation of the ovulatory-oviposition cycle exhibiting a peak that precedes the ovulation by 4–6 hours. Testosterone, estrone, and estradiol do not take part directly in the regulation of ovulation, however, in separate cases, high testosterone levels could be detected 10–12 hours before oviposition.

Effect of sex steroids and thyroid hormones on free and total cholesterol level of male and female japanese quail

Abstract: Publisher Summary This chapter discusses the effect of sex steroids and thyroid hormones on free and total cholesterol level of male and female Japanese quail. Mature and immature male and female Japanese quails were fed with commercial poultry laying diet. Peed and water was given ad libitum. In the case of sexually immature birds, the maturation was inhibited by short day photoperiod, while the mature animals were exposed to long day photoperiod. The quantity of free cholesterol in the plasma of mature females was much higher than in the immature or in the male birds. Thus, the ratio of free to total cholesterol is about twofold in the mature females, in comparison to the immatures. Thyroidectomy results an increase only in the case of immature animals. In both cases, the total cholesterol level shows a significant difference compared to the control group. Thyroidectomy has not changed the ratio of free/total cholesterol in any case which is in conformity with the experimental results of the investigations conducted on humans in the matter of correlation between thyroid function and lipid metabolism.

Effect of ovariectomy on the plasma levels of thyroid hormones during the ontogenesis in the domestic hen

Abstract: Publisher Summary This chapter describes the effect of ovariectomy on the plasma levels of thyroid hormones during the ontogenesis in the domestic hen. The chapter discusses the changes in the plasma concentration of thyroid hormones and the diurnal rhythm during ontogeny dealing with chicken from 1 day to 22 weeks old. The T3 plasma level of the controls in both 1 day and 3 weeks of age show a morning minimum and an afternoon peak. In the other ages, this rhythm ceases to exist and a lower almost continuous hormone level can be seen. It should be noticed that in 3-week-old animals the production is always significantly higher than in other ages. In the age of 3 weeks ovariectomized animals one can see that levels have more than doubled becoming as high as those of the otherwise high control levels the diurnal rhythm of which tends to shift 4 h to the left. In ovariectomized one-day-old animals the 24 h average plasma levels move toward the peak level of controls, resulting the disappearance of the diurnal rhythm. The elevating effect of ovariectomy to the T3 plasma level is observable in the other ages as well.