THE EFFECT OF HUMAN CHORIONIC GONADOTROPHIN (HCG) INJECTION ON SOME REPRODUCTIVE PERFORMANCE OF FAYOUMI CHICKENS

A.A. Abd El-Hakeam , A.k.I. Abd El- moty ; A.H. Bogdady ; A.M.M. Hamdy and

H.M. Hassanein

 Animal Production Department, Faculty of Agriculture , Minia University

ABSTRACT  

        This study has been carried out in poultry research farm, Faculty of Agriculture, Minia University .This experiment was designed to study the effect of Human Chorionic Gonadotrophin (HCG) injection on some reproductive performance of Fayoumi chickens . A total of 240 (192 females, 48 males) of birds at age of 16 weeks were used in the present study. Birds were divided randomly into four treatments, each treatment contained 48 females & 12 males . Birds of each treatment were subdivided into four replicates, each of 12 females & 3 males. The first group was injected subcutaneously with 1 m1 normal saline solution at 18 , 26 , 53 weeks of age and served as control . Birds in second, third and fourth groups were injected at 18,26,and 53 weeks of age , respectively .Daily injected with 50 1 U (HCG) in saline solution for successive  days were carried out in groups 2,3 and 4 . The experiment was continued for 52 weeks ( age of birds 68 weeks ) .

      HCG injection at 18 weeks hastened ( p < 0.05 ) age of sexual maturity compared with the control group . Semen pH was not significantly affected by HCG injection, while HCG injection group had higher ( p < 0.05) ejaculate volume than the control . Sperm cell concentration / ml or / ejaculate x10⁹ and number of motile spermatozoa / ejaculate were positively (p < 0.05) affected by HCG injection . Serum testosterone concentration was higher (p < 0.05) in HCG injected groups at 18, 26, and 53 weeks of age compared to the non injection group (control ) . Fertility and hatchability percentages revealed better value but not significant, in injected groups at 18, 26, and 53 weeks of age compared with the control group.

Keywords : HCG , reproductive performance , Fayoumi 

Introduction

     The Egyptian consumer still prefer eggs from of local strains. Therefore, improvement of Fayoumi egg production is very important. Studying the physiological traits of production and reproduction characteristics could be used as indicators for improving egg production .

          The functions of the ovary and testis, which are controlled by the hypothalamic and hypophysical hormones , have been studied in Fowls by several investigators. Tamab et al., (1983) showed that the reproductive stage and productivity of hen are largely depended on different hormonal levels. Etches and Cunningham (1976) and Saleh et al.,  (1977) revealed that the initial period of the ovulatory cycle of hens is accompanied with increase in gonadotrophin hormones by the hypothalamus which affect Follicle – Stimulating Hormones (FSH) and luteinizing Hormone (LH) release from adenohypophysis. Furthermore, Saleh et al.,  (1977) reported that the pituitary contents of gonadotrophin increased follicular maturation and ovulation. A positive connection between plasma LH concentration and rates of egg production was   noted (Sturkie, 1986) . Recently Wakabayashi et al.,  (1996) found that  injection of gonadotrophin in immature female Japanese quail, immediately after hypophysectomy led to induce ovulation at sexual maturity. The role of LH and FSH in controlling testicular functions in the male bird is now being established. LH acts primarily to stimulate the leydig cells to differentiate and produce testosterone, while FSH promotes spermatogenesis (Brown et al., 1975 a,b ). They also reported that the administration of chicks LH to hypophysectomized Japanese quall greatly increased the number of mature leydig cells .HCG has both LH and FSH like action, but has predominately LH like biological action. The LH like action of HCG has made it the first hormone available for treatment of cystic ovaries in mammals  (Hafez , 1985). There is little information about the injection effect of hormonal compound as HCG on ovarian and testicular activity in hens . Singal   and Gupla (1984) reported that percentage of active leydig cells in turkey toms was increased by HCG treatment. Shneider and Scheller (1992) reported that the treated ganders (7-9 months) one or  twice weekly with different doses of testosterone HCG or PMSG or a combination of them lead to a significant increase in blood testosterone. They also concluded that spermatogenesis of birds treated with testosterone and or HCG began earlier than controls. Ismail (1994) reported that the daily injection (7days ) with 50 or 75 i.u HCG led to increase growth and number of follicles and egg production from force molted  hens treated with hormone during or after fast period . In addition, Hassona (1998) observed that the cockerels injected with HCG recorded significantly higher serum testosterone values and at the same time better semen characteristics than the control groups (non injected). The objective of this work was to study the possibility to improve some reproductive performance, such as age at sexual maturity, semen characteristic , fertility  and hatchability , of Fayoumi chickens by HCG injection at various age .

Material and Methods

This experiment was carried out in the poultry research farm, Faculty of Agriculture, Minina University  

·   Experimental design

     A total number of 240 (192 females and 148 males) of Fayoumi birds, aged 16 weeks at the start of the experiment were used in the present study . Birds were divided randomly into four treatment groups (48 females and 12 males / each). Birds in each treatment were subdivided into four replicates (12 females and 3 males / each) .Pregnyl HCG (Nile Co. Cairo, Egypt) was used for individually subcutaneous injection of males and females. Birds in-group 1 were injected with 1 ml normal physiological saline solution (Sham) at 18,26 and 53 weeks of age and were served as control. Birds in groups 2,3 and 4 were injected with 50 I.U/ml saline solution for successive 7 days at age of 18 weeks (before sexual maturity) , at age of 26 weeks (before peek of egg production) and at age of 53 weeks ( after decreasing of egg production ) , respectively . The experiment was continued for 52 weeks (age of birds at the end of the experiment was 68 weeks ) .

·   Feeding and management:

     Birds were fed ad-libitum on laying ration during the experimental period and tap water was available all time. The ration contained 16.53% crude protein, 2750 kcal ME/kg , 3.41%calcium and 0.70% total phosphorous . All birds were kept under the same managerial and environmental conditions regime. Birds were exposed to natural day light regime during experimental period. Birds of each replicate were housed in floor pen provided with wood sharing as a litter.

·    Date collection:

      Daily egg production / replicate was recorded. Age at sexual maturity (days) was calculated at the first egg produced from 30% of the total number of female birds in each treatment (Soltan and Ahmed,1990).

   To study semen quality, semen was collected from all cockerels using the abdominal massage method as described by Burrows and Guinn (1937). Semen collection was continued every two weeks during two periods from 24 to 40 weeks and from 55-65 weeks of age. Ejaculate volume was recorded to the nearest 0.1ml using 3 ml graduated centrifuge tube. The hydrogen ion concentration (PH) of the freshly collected semen was determined immediately after collection using whatman PH indicator paper.Motility of spermatozoa was assessed by microscopic examination. Examination was made under the high magnification (x400) for several fields of the microscope. Evaluation of progressive motility for each ejaculate was recorded as percentage of motile spermatozoa.

     Sperm concentration (per/mlx10⁹) was determined using heamocytometer , under x400 magnification. Multiplication of  sperm concentration /ml by the ejacultate volume gave total number of sperm / ejaculate . Multiplication of  motility by the sperm  concentration /ml and by the sperm concentration / ejaculate  gave the number of motile sperm / ml and the number of motile  sperm / ejaculate , respectively.  At 42 and 58 weeks of age 100 egg / treatment were collected and incubated under standard condition.Fertility and hatchability percentages were obtained as follows: Fertility % = ( no of fertile egg / total no. of egg set ) x100. Hatchability percentage was obtained as follows: Hatchability % = ( no. of hatched chicks / total no. of fertile eggs ) x100.

·            Blood Sampling:

    Blood samples were collected from wing vein starting at 18 weeks of age every 3 weeks . Samples were taken from 5 males chosen randomly from each group . Serum were obtained by centrifuging the whole blood samples at 3000 rpm for 20 min. to obtain the serum , which was stored at – 20 ^oC until analysis . Serum testosterone concentration was determined according to Jaff and Behrmen (1974) .Hormone determination was done by using Coat–A-Count I¹²⁵ radioamminoassy (RIA) Kits were purchased from Diagnostic products  , Los Angeles , California , 90045 , USA .

·            Statistical analysis:

   Data were analyzed statistically by the analysis of Variance method (ANOVA) , SAS (1994) . Duncan’s (1955) test was used to detect differences among means. All percentages were transformed to arcsine before statistical analysis was made .

Results and Discussion

1.  Age at sexual maturity:

    Mean values for age at sexual maturity under the effect of HCG injection showed that  hens injected with HCG at 18 weeks of age significantly (p<0.05) reached sexual maturity earlier than control group. Hastening of sexual as a result of HCG injection may be due to its contents of both LH and  FSH . Mainly FSH causes follicular growth and maturation, while LH induces ovulation (Abd El Razik , 1977 and Etches , 1979) .In the present study average value of age at first egg (Sexual maturity) was 152 ± 2.67 day for the control group , while it was 145 ± 0.57 day for the injected group. There was a great variation in age at sexual maturity of Fayoumi hen’s in the literature. Many studies observed that the age at sexual maturity was ranged between 140-181 days (Afify 1984, Soltan and Ahmed ,1990 ) .However, El Hammady et al, (1992 ) reported that the average age at sexual maturity of Fayoumi hens was 189 days . Also, Ahmed et al,  (1997) found that age at first egg of Fayoumi hens was 187 days . The differences among researchers for age at first egg (sexual maturity) may be due differences in managerial , climatic conditions and differences in the genetic make up of the different flocks of Fayoumi .

2.  Semen parameters :

          Data of semen pH, ejaculate volume, semen motility, sperm concentration / ml or ejaculate x10⁹ are presented in Tables (1) and (2).

          Data of semen pH and volume are presented in Table (1). Date indicated that HCG injection at 18 or at 26 weeks of age did not significantly affect semen pH. However, control cockerels had lower  semen pH value than the HCG injected groups at 18 or at 26 weeks of age during 24- 40 weeks of age . Also, the results showed that semen pH values during 55-65 weeks of age was not significantly affected by the injection with HCG, but the value of pH for semen collected from cockerels injected at 53 weeks was higher than those  injected with HCG at 18 or 26 weeks and the control group ( Table ,1) .

          Generally, the overall mean values of semen pH for HCG injected cockerels at 18,26,53 and control groups ranged between 7.34 to 7.42 (Table, 1) . Sturkie (1986) stated that the pH of cocks semen ranged from 7 to 7.6 depending on the amount of transparent fluid in present semen . Kamar et al, (1979) reported that the overall mean of PH in Fayoumi was 7.42 , while it was 7.60 as  reported by Khalife et al (1983) . The present results are in agreement with these finding .

          Data in Table (1) show that injection of HCG at 26 weeks increased ejaculate volume (ml) during the period from 24 to 40 weeks of age than  injection  at 18 or the control . In addition, the obtained date during the period from 55-65 weeks of age revealed that , cockerels injected at 53 weeks had  a higher (p<0.01) ejaculate volume than  those of the other groups . Meanwhile , HCG injection resulted in higher values of ejaculate volume during the experimental period than control . Hassona (1998) reported that HCG injection resulted in significantly higher ejaculate volume of semen produced by cockerels compared with non-injected group.From the present result it can be observed that the overall means of ejaculate volume of Fayoumi cockerels ranged between 0.17-0.22 ml. .These values are in agreement with the other results reported by Kamer et al, (1979) and Sarhan (1983) .

        The results in Table (1) illustrated that the overall mean values of percentage motility of spermatozoa were significantly (p<0.01) different between HCG injected groups and non injected one (control) . Meanwhile , HCG injection at 18, 26 or at 53 weeks of age had a positive effect (p<0.01) on sperm cell motility during experimental period (24-40 and 55-65 weeks of age ) . The present finding is in agreement with that reported by Hassona (1998) . Who found that  HCG injection resulted in significant increase in sperm motility .This positive effect of HCG injection on motility of spermatozoa is related to its direct positive effect on testosterone concentration (Table,3),which is considered essential for testicular development and maturation of spermatozoa (Sturike , 1986) .

          Data of sperm cell concentration /ml or/ejaculate x10⁹ during the experimental periods as affected by HCG injection are present in Table (2). During the period between 24-40 weeks of age , it was observed that Fayoumi cockerels which were injected with HCG either at 18or at 26 weeks of age yielded higher value of sperm cell concentration /m/or/ejaculate in comparison  with the control group .A highly significant differences (p<0.01) were found in sperm cell concentration / ml due to injection of Fayoumi cockerels at 18, 26 or 53 weeks of age compared to control group. The same trend was observed in sperm cell concentration / ejaculate but the difference was not significant during 24-40 weeks of age, while the difference was highly significant (p<0.01) during 55-65 weeks of age (Table 2).

      Regardless to the time of injection and the period  of semen collection, injection of HCG had highly  (p<0.01) positive effect on  sperm cell concentration / ml or ejaculate x10^9. The positive effect of HCG injection may be due to its contents of LH and FSH. HCG has both LH like biologic action. Singal and Gupla (1984) reported that the percentage of leydig cells was increased by HCG treatment. They concluded that administration of HCG increased sexual efficiency of turkey. Furthermore, Hassona (1998) found that the injected cockerels with HCG had a significant increase in sperm concentration when compared with the control group (non – injected)

Data in Table(2) showed that there was highly significant differences in motile spermatozoa/ml or/ ejaculate x 10⁹ due to HCG injection. During the period from 24-40 week of age, HCG injection at 26 weeks of age gave the best results compared with the other groups. During the period from 55-65 weeks of age, HCG injection at 53 weeks of age resulted in  the highest value compared with the other two injected groups and the control one. Generally, regardless to the time of injection and the period of semen collection, there was a highly significant (P<0.01) differences in overall mean values of motile sperm concentration/ ml or/ ejaculate x 10⁹ between HCG injected groups at 18,26 or53 weeks of age and the control group (Table,2).

Finally, both semen traits (motile sperm concentration/ ml and per ejaculate) are mainly dependant on the percent of motility, sperm cell concentration per ml or per ejaculate. These two semen parameters are positively affected by HCG injection as it is shown in the present study. Therefor, both parameters led to positive effect on number of motile spermatozoa/ ml or ejaculate.

3-  Serum testosterone Concentration

          Data in Table (3) show  mean values  of testosterone concentration in blood of Fayoumi cockerels as affected by HCG injection. It can be observed that cockerels injected with HCG at 18,26 and 53 weeks of age had  significantly (P<0.01) higher values of serum testosterone concentration  than the control. There was no significant difference in testosterone concentration at 18 weeks of age. After three weeks from the first injection, the difference in testosterone became highly significant and this difference continued throughout the experimental period (from 21 weeks till 58 weeks of age) in comparison with the control group (Table,3). Generally, the role of LH and FSH in controlling  the  testicular functions in the male bird is well established (Sturkie, 1986). LH acts primerily to stimulate the leydig cells to differentiate and produce testosterone, while FSH promotes spermatogensis. El Far et al (1994)   reported that testosterone was increased significantly when cockerel was stimulated with HCG. Also, Hassona (1998) observed that the cockerels which were injected with HCG recorded significantly higher serum testosterone values  than the control groups .

4-   Fertility and hatchability

          It was observed that both fertility and hatchability percentages were not affected by HCG injection (Table,4). However, the fertility percentage of the control group was about 8% lower than that of the injected group. Similar  trend of effect due to HCG injection at 53 weeks was observed at 58 weeks of age. The improvement of fertility in the HCG injected groups may  be due to its positive effect  on the semen characteristics.

          Generally, from the present results, it can be observed that fertility percentage ranged between 91 to 99%, while the hatchability percentage ranged between 89 and 93% in different groups at different ages (Table,4). Values of fertility and hatchability percentage reported recently by Nawar and Abdou (1999) were in agreement with those  obtained in the present study. They reported that values of fertility and hatchability percentage in new selected Fayoumi strain were 90+ 0.69 and 84.20+ 0.70, respectively.

          From the present results it can be concluded that injection of HCG led to positive effect on reproductive performance by hastening of age at sexual maturity and improvement of semen quality.

REFERENCES

Abd El-Razik, M.A. (1977): Some effects of light on plasma luteinizing hormone concentration in the domestic hen Ph. D. Thesis, Univ. of Reading, England.

Afifiy, U.S. (1984): Comparative studies on some productive traits of different genotypes of chickens. M. Sc. Thesis Fac. of Agric. Assuit Univ.

Ahmed N; A. Maghraby and M.A.M; Kicka (1997): Duodenal calcium absorption, egg shell quality and bone ash as affected by vegetable oil concentration in the diet of laying hens. J. Agric. Sci. Mansoura Univ., 20:1111.

Brown, N.L; Bayle, H.D.; Scanes, C.G. and B.K. Follett (1975a): Chicken gonadotrophins their effects on the testes of immature and hypophysectomized japans quail. Cell Tissue Res. 156, 499.

Brown, N.L; Bayle, J.D.; Scanes, C.G. and B.K. Follett (1975b): The actions of avian LH and FSH on the testes of hypophysectomized quail. Cell Tissue Res., 156:499.

Burrows, W.H. and Guinn, J.P. (1937): Collection of spermatozoa from domestic fowl and turkey. Poultry Sci. 16:19-24.

Duncan, D.B. (1955): Multiple range and multiple F test. Biometrics, 11:1-42.

El-Far, A.A.: M.M., Mashaly and GA Kamar, (1994): Bursectomy and in vitro response of adrenal gland to adenocorticotropic hormone and testis to human chorionic gonadotropin in mature male chickens. Poultry Sci. 73 (1):113-117.

El-Hammady,. Y., Sarara, H.H. and T.M., El-Sheikh (1992): Effect of feeding regimes and lighting programs on egg production performance of laying hens. Egypt Poultry Sci. 12:791-817.

Etches, R.J. (1979): The temporal relationship between ovulation and an injection of progesterone or corticosterone in the hen. Biol. Reprod. 16:255-257.

Etches, R.J. and F.J., Cunningham (1976): The interrelationship between progesterone and luteinizing hormone during the ovulation cycle of the hen. J. Endocrind., 71:51-58.

Hafez, E.S.E. (1985): Endocrinology of reproduction. In reproduction in Farm animals edited by E.S.E. Hafez, 5^Th edition PP. 57-113. Philadelphia.

Hassona, M.A. (1998): Reproductive performance of Hubbard parent cockerels as affected by force molting after the first year of production. M. Sc. Thesis. Fac. Agric. Minia Univ., Egypt..

Ismail, H.T.M. (1994): Studies on follicle lstimulating hormone during molting laying fowls. M. Sc. Thesis Fac. of Agric. Zagazig, Univ. Egypt.

Jaffe, B.M. and Behrmen, N.A.B. (1964): Methods of hormone radioimmunoassay (Academic Press).

Kamar, G.A.R.; A., Obiedah; N.E., Gohar and M.A., Khalifa (1979): Genetical studies on semen characteristics of cocks. Egypt J.Anim. Prod. 19 (1): 101-113.

Khalifa, M.A.; M.K. Shebaita; G.A.R. Kamar and A.A., Sarhan (1983): Studies on some economical traits in Fayoumi and its crosses along with semen evaluation. Dept. of Ainm. Sci., College of Agric. At El-Fayoum and Anim. Prod. Dept., fac. of Agric., Cairo Univ. Egypt.

Nawar, M.E. and F. H., Abdou (1999): Analysis of heterotic gene action and maternal effects in crossbred Fayoumi chickens. Egypt Poult. Sci. 19 (11) Sept. (671-689).

Saleh, S.Y.: El-Mougy, S.; Sokkar, S.; Ali, Z.M. and F.A. Soliman (1977): Hypothalamic and pituitary control of ovulatory cycle of the hens. Assuit. Vet. Med. J.4:27-36.

Sarhan, A.A. (1983): Studies on some economical traits in Fayoumi and its crosses along with semen evaluation. M. Sc. Thesis, Fac. of Agric., Cairo University.

SAS (1994): S.A.S user's Guide: Statistics. SAS lnstitute lnc, Cary NC., USA.

Schneider, K.H. and W.  Scheller, (1992): Effect of exogenous testosterone and gonatotrophic hormones on the ejaculate production by ganders. Proceeding 19^th world Poultry congers. Amsterdam, Netherlands, 20-24 September, 1992. Vol3. 307.

Singal, Sp. and Sc., Gupla (1984): Sudies on the response of reproductive tract of turkey Toms of different ages to human chorionic gonadotropin. 10^th international congress on Animal reproduction and artificial insemination. Juni 10-14.

Soltan, M.E. and B.M., Ahmed (1990): Performance of selected Sanai fowl in comparison with Fayuomi and Baladi fowl as standard Egyptian local breeds. 1. Egg production. World Per Anim. Prod. 25(2):17-26.

Sturkie, P.D. (1986): Avain physiology. Spriner-verlag New Yourk, Berlin Heidelberg Tokyo.

Tamabe, Y.; K., Hirose; T., Nakamura; K., Walanabe and S., Ebisawa (1983): Relationship between the egg production rate and plasma estradiol, progestrone and testosterone concentration in White Leghjorn, Rhode lsland Red and their hybrid pullets at various ages. Processing of the 5^th World Conference of Animal Production, Tokyo 2:99.

Wakabayashi, S.; Kikuchi, m and S.  lshii, (1996): Hormonal induction of ovulation and ovipostion in japanese quail kept under a short day regimen. Poultry and Avian Biology Reviews: 7(4): 183-192.

Table (3)  Means (+ SE) of testosterone concentrations (ng/100ml) as  affected by HCG injection at different ages.

a-   b Means within each row with different letters are significantly different.

        **  P< 0.01    NS  =  not significant

Table (4)  Fertility and hatchability percentages of Fayoumi eggs as affected by HCG injection at different ages

                                                     13

Data in Table(2) showed that there was highly significance differences in motile spermatozoa/ml or/ ejaculate x 10⁹ due to HCG injection. During the period from 24-40 week of age, HCG injection at 26 weeks of age gave the best results compared with the other groups. During the period from 55-65 weeks of age, HCG injection at 53 weeks of age recorded the highest value compared with the other two injected groups and the control group. Generally, regardless to the period of semen collection, there was a highly significant (P<0.01) differences in overall mean values of motile sperm concentration/ ml or/ ejaculate x 10⁹ between HCG injection groups at 18,26 or53 weeks of age and the control group (Table,2).

Finally, both semen traits (motile sperm concentration/ ml and per ejaculate) are mainly depended on the percent of motility, sperm cell concentration per ml or per ejaculate. These two semen parameters are positively affected by HCG injection at is shown in the present study. Therefor, both parameters led to positively effect on number of motile spermatozoa/ ml or ejaculate.

3-  Serum testosterone Concentration

          Data in Table (3) show that means of testosterone concentration in blood of Fayoumi cockerels as affected by HCG injection. It can be observed that cockerels injected with HCG at 18,26 and 53 weeks of age recorded significantly (P<0.01) higher values of serum testosterone concentration values than the control. There was no significant difference in testosterone concentration at 18 weeks of age. After three weeks from the first injection, the difference in testosterone was highly significant and this difference continued throughout the experimental period (from 21 weeks till 58 weeks of age) in comparison with the control group (Table,3). Generally, the role of LH and FSH in controlling  the  testicular functions in the male bird is well established (Sturki, 1986). LH acts primerily to stimulate the leydig cells to differentiate and produce testosterone, while FSH promotes spermatogensis. El Far et al (1994)   reported that testosterone was increased significantly when cockerel was stimulated with HCG. Also, Hassona (1998) observed that the cockerels injected with HCG recorded significantly higher serum testosterone value than the control groups .

Table (3)  Means (+ SE) of testosterone concentrations (ng/100ml) as  affected by HCG injection at different ages.

b-    b Means within each row with different letters are significantly different.

        **  P< 0.01    NS  =  not significant

4-   Fertility and hatachability

          It was observed that both fertility and hatchability percentage were not affected by HCG injection (Table,4). However, the fertility percentage of the control group was about 8% lower than that of the injected group. Similar same trend of effect due to HCG injection at 53 weeks was observed at 58 weeks of age. The improvement of fertility in the HCG injected group due to the positive effect of HCG injection on the semen characteristics.

          Generally, from the present results, it can be observed that firtility percentag ranged between 91 to 99%, while the hatchability percentage ranged between 89 and 93% of different groups at different age (Table,4) Recently, values of fertility and hatchability percentage reported by Nawar and Abdou (1999) were in agreement with the values obtained in the present study. They reported that values of fertility and hatachability percentage in new selected Fayoumi strain were 90+ 0.69 and 84.20+ 0.70, respectively.

          From the present results it can be concluded that injection HCG led to positive effect on reproductive performance by hasten of age at sexual maturity and improvement of semen quality.

Table (4)  Fertility and hatachability percentages of Fayoumi eggs as affected by HCG injection at different ages

REFERENCES

Abd El-Razik, M.A. (1977): Some effects of light on plasma luteinizing hormone concentration in the domestic hen Ph. D. Thesis, Univ. of Reading, England.

Afifiy, U.S. (1984): Comparative studies on some productive traits of different genotypes of chickens. M. Sc. Thesis Fac. of Agric. Assuit Univ.

Ahmed N; A. Maghraby and M.A.M; Kicka (1997): Duodenal calcium absorption, egg shell quality and bone ash as affected by vegetable oil concentration in the diet of laying hens. J. Agric. Sci. Mansoura Univ., 20:1111.

Brown, N.L; Bayle, H.D.; Scanes, C.G. and B.K. Follett (1975a): Chicken gonadotrophins their effects on the testes of immature and hypophysectomized japans quail. Cell Tissue Res. 156, 499.

Brown, N.L; Bayle, J.D.; Scanes, C.G. and B.K. Follett (1975b): The actions of avian LH and FSH on the testes of hypophysectomized quail. Cell Tissue Res., 156:499.

Burrows, W.H. and Guinn, J.P. (1937): Collection of spermatozoa from domestic fowl and turkey. Poultry Sci. 16:19-24.

Duncan, D.B. (1955): Multiple range and multiple F test. Biometrics, 11:1-42.

El-Far, A.A.: M.M., Mashaly and GA Kamar, (1994): Bursectomy and in vitro response of adrenal gland to adenocorticotropic hormone and testis to human chorionic gonadotropin in mature male chickens. Poultry Sci. 73 (1):113-117.

El-Hammady,. Y., Sarara, H.H. and T.M., El-Sheikh (1992): Effect of feeding regimes and lighting programs on egg production performance of laying hens. Egypt Poultry Sci. 12:791-817.

Etches, R.J. (1979): The temporal relationship between ovulation and an injection of progesterone or corticosterone in the hen. Biol. Reprod. 16:255-257.

Etches, R.J. and F.J., Cunningham (1976): The interrelationship between progesterone and luteinizing hormone during the ovulation cycle of the hen. J. Endocrind., 71:51-58.

Hafez, E.S.E. (1985): Endocrinology of reproduction. In reproduction in Farm animals edited by E.S.E. Hafez, 5^Th edition PP. 57-113. Philadelphia.

Hassona, M.A. (1998): Reproductive performance of Hubbard parent cockerels as affected by force molting after the first year of production. M. Sc. Thesis. Fac. Agric. Minia Univ., Egypt..

Ismail, H.T.M. (1994): Studies on follicle lstimulating hormone during molting laying fowls. M. Sc. Thesis Fac. of Agric. Zagazig, Univ. Egypt.

Jaffe, B.M. and Behrmen, N.A.B. (1964): Methods of hormone radioimmunoassay (Academic Press).

Kamar, G.A.R.; A., Obiedah; N.E., Gohar and M.A., Khalifa (1979): Genetical studies on semen characteristics of cocks. Egypt J.Anim. Prod. 19 (1): 101-113.

Khalifa, M.A.; M.K. Shebaita; G.A.R. Kamar and A.A., Sarhan (1983): Studies on some economical traits in Fayoumi and its crosses along with semen evaluation. Dept. of Ainm. Sci., College of Agric. At El-Fayoum and Anim. Prod. Dept., fac. of Agric., Cairo Univ. Egypt.

Nawar, M.E. and F. H., Abdou (1999): Analysis of heterotic gene action and maternal effects in crossbred Fayoumi chickens. Egypt Poult. Sci. 19 (11) Sept. (671-689).

Saleh, S.Y.: El-Mougy, S.; Sokkar, S.; Ali, Z.M. and F.A. Soliman (1977): Hypothalamic and pituitary control of ovulatory cycle of the hens. Assuit. Vet. Med. J.4:27-36.

Sarhan, A.A. (1983): Studies on some economical traits in Fayoumi and its crosses along with semen evaluation. M. Sc. Thesis, Fac. of Agric., Cairo University.

SAS (1994): S.A.S user's Guide: Statistics. SAS lnstitute lnc, Cary NC., USA.

Schneider, K.H. and W.  Scheller, (1992): Effect of exogenous testosterone and gonatotrophic hormones on the ejaculate production by ganders. Proceeding 19^th world Poultry congers. Amsterdam, Netherlands, 20-24 September, 1992. Vol3. 307.

Singal, Sp. and Sc., Gupla (1984): Sudies on the response of reproductive tract of turkey Toms of different ages to human chorionic gonadotropin. 10^th international congress on Animal reproduction and artificial insemination. Juni 10-14.

Stino, F.K.R.; N.E., Goher; G.A.R., Kamar and N.A., Hanash (1983): Effect of breed and housing type on egg production of White Baladi and Fayoumi hens in the subtropics. Egypt. J. Anim. Prod. 23:143.

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