OVARIAN AND TESTICULAR HISTOLOGICAL CHANGES RELATED TO HUMAN CHORIONIC GONADOTROPHIN ADMINISTRATION IN CHICKENS
A.M.M. HAMDY, A.K.I ABD EL MOTY, A.H. EL BOGDADY, A.A. ABD EL HAKEAM AND H.H. M. HASSANEIN
Animal Production Department, Faculty of Agriculture, Minia University, Egypt
ABSTRACT
This study was conducted to examine the effect of Human chorionic gonadotrophin (HCG) on ovarian and testicular histological changes. A total number of 192 of Fayoumi chickens (96 females and 24 males) at 16 weeks of age were used. Birds were divided into two groups; each of 48 females and 12 males. Birds of group 1 were injected by saline solution at 18 weeks of age, while those of group 2 were daily injected subcutaneously by 50 IU of HCG for 7 successive days. The pregnyl trademark was used as a source of the HCG. All birds were reared under the standard managerial conditions. At 18 and 21 weeks of age, 4 females and 4 males from each group were slaughtered. The ovary and testis were removed and processed for obtained tissue sections. From the obtained results, it could be concluded that HCG injection improved the number, the size and the maturation of the ovarian follicles. In cocks, it improves integrity of the seminiferous tubules and precocious spermatogenesis.
INTRODUCTION
Human chorionic gonadotrophin (HCG) is synthesized by the syncytiotrophoplastic cells of the placenta of pregnant primates and is found in the blood and urine. It has been detected in the urine eight days after conception by sensitive radioimmunoassay (Jaffe, 1978). HCG has both LH and FSH-like biologic action. Both avian LH and FSH are glycoprotein hormones with molecular weight of approximately 300,00 (Burke et al., 1979 and Popkoff et al., 1982). Avian LH and FSH like their mammalian homologue, consist of two glycoprotein subunits with molecular weight 15,000 each (Sturkie, 1986). The subunit has 92 amino acids and two carbohydrate chains, while subunit has 145 amino acids and five carbohydrate chains (Hafez, 1985). The function of the ovary and tests, in birds, which are controlled by the hypothalamic and hypophysecal hormones has been studied by several investigators. It is well known that, in the females, FSH mainly causes follicular growth and maturation while LH induces ovulation. While in the males, FSH initiate the growth of seminiferous tubules and LH causes the development of the extratubular leydig cells. Plamar and Bahr (1992) reported that the injection by FSH for old hens (90 wks.) significantly increase the growth of ovarian follicles. Ismail (1994) concluded that daily injection by 50 or 75 IU of HCG led to increased growth and number of follicles and egg production from force molted hens treated during or after fast period. Hamdy et al., (1999) and Hassona, (1998) speculated that HCG injection improved the reproductive performance of Hubbard parent cockerels and prolonged the production period and the semen quality during the second year of production.
The objective of this study was to examine the ovary and testicular histological changes related to HCG administration.
MATERIALS AND METHODS
This work was carried out in the Poultry Research Farm of Animal Production Department, Faculty of Agriculture, Minia University. A total number of 120 (96 females and 24 males) of Fayoumi birds, aged 16 weeks were used. Birds were divided into two groups. Each group contained 48 females and 12 males. Birds in each group were divided into four replicates (12 females and 3 males). All birds were kept under the same managerial and environmental condition regime. Birds were exposed to naturally light regime during the experimental period. Birds of each replicate were housed in floor pen provided with wood sharing as a litter. All birds were fed laying hen ration ad libitum during the entire experimental period and water was available all time. This laying ration contained 16.53% crude protein, 2750 Kcal / kg ME, 3.41% calcium and 0.70% total phosphorus.
Pregnyl HCG (Nile Company, Cairo, Egypt) was used for individually subcutaneously injection of females and males. Birds of the two groups were treated as follows:
Group 1: Injection by 1 ml normal physiological saline solution at 18 weeks.
Group 2: Daily injection by 50 I.U / ml HCG in saline solution for successive of 7 days at 18 weeks (before sexual maturity.
At 18 and 21 weeks of age 4 females and 4 males were chosen randomly from each group at each time. Both ovary and testis were removed after slaughtering and preserved in Bouin’s solution for 24 hrs. then dehydrated in ascending grades of ethyl alcohol, cleaned, embedded, sectioned and stained using Haematoxyline and Eosin stain for microscopically identification of histological structure microscopy. The pictures were taken at magnification power of X100.
RESULTS AND DISCUSSION
1-Females
Plates 1,2 and 3 show the histological sections of the ovary at 18 and at 21 (non-injected and injected), respectively. The sections showed that the injection of HCG clearly increased the number of mature follicles. At the same time the size of both follicles and oocytes increased. The possibility remains that each of FSH and LH has a certain role and strong relationship with the metabolic activity tools especially thyroid hormones. This may led to increased yolk volume deposition. It was observed that age has a positive effect on the development of ovarian follicles as it can be seen from the comparison between plates 1 and 2.The positive effect of HCG injection on the ovarian follicles development may explain the earlier sexual maturity, and the increase in egg production data, which was published elsewhere. The histological effects of HCG injection are in agreement with those stated by Sturkie (1986). Moreover, Plamar and Bahr (1992) and Ismail (1994) concluded similar observations.
2- Males
Plates 4, 5 and 6 show the histological sections of the testes at 18 and 21. It seems logic that the reproductive organs grow by advantage of age, that could be observed clearly when comparing the plates 4 with plate 5. However, HCG injection has an analeptic effect on seminiferous tubules and precocious spermatogenesis. These differences are clear when plate 5 compared with plate 6. Furthermore, HCG injection caused significantly improvement the reproduction characters in males (Hamdy et al., 1999 and Hassona, 1998). Hocking (1991) reported that stimulating the sections of androgen from leydig cells through the hypothalamus-hypophysial gonadal axis could cause the histological differences in testis. Moreover, the physiological effects of HCG on increasing metabolic activity and semen quality were published elsewhere.
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