1. FERTILIZATION PROCESS IN MAMMALS
UNIVERSITY OF DUHOK
COLLEGE OF AGRICULTURE
DEP. ANIMAL PRODUCTION
SEMINAR ABOUT
FERTILIZATION PROCESS
PREPERED BY\
MOHAMMAD J. QASM
SUPERVISED BY\
M. ARAZ JAFFAR
FERTILIZATION PROCESS IN MAMMALS
For more information visit
Copyright©2008
Student: Mohammad Jalel Qasm
Supervision: M. Araz Jaffar

2. Introduction:
Fertilization is the process of union of mature male gamete (sperm) with mature female gamete (ovum) to produce new cell of life which is called (zygote) through chain of events in the oviduct (fallopian tubes). Indeed, interruption of any event will cause fertilization failure.

3. Folliculogenesis and ovulation:
Folliculogenesis is the maturation of the ovarian follicle, describes the progression of a number of small primordial follicles into large mature follicles under the influence of FSH prior to puberty.
Ovulation By the end of the follicular phase the mature follicle will develop and rupture, excrete the oocyte with some granulosa cells into oviduct. The oocyte is now competent to undergo fertilization.
Ruptured follicle will transformed into the corpus luteum, that produce large amount of progesterone that helps to prepare the uterus for implantation of fertilized egg
In absence of fertilization corpus luteum degenerates.

4. Image showing phases of follicle development and ovulation:
Mohamad J. (according to Gougeon A (1986). "Dynamics of follicular growth in the human.)

5. 3d animation about folliculogenesis and ovulation:

6. Hormonal control of folliculogenesis and ovulation:
Mohamad J. (according to H. J. Bearrden and J. W. Fuquay,2000 Applied Animal Reproduction.)

7. Ovum structure:
Mohamad J. (according to McRorie and Williams,1974 Ann. Rev. Biochem.)

8. Mechanisms of ovum transport:
Fimbria on terminal oviduct--acts as funnel to receive ovum
Fluids (abdominal cavity and that escaping from follicle during ovulation) serve as medium for free-floating ovum
Cilia lining oviduct and muscular contractions assists in moving ovum to site of fertilization
The site of fertilization on most farm animals is (ampullary-isthmic junction) while in human is (ampulla) region.
Image show goat reproductive system

9. 3d animation about ovum transport:

10. Species Fertile life 8-12 hours 16-24 hours
Fertile life of ovum:
Estimate fertile life of ovum in different mammals is shown in table(1):
Species
Fertile life
Cow
8-12 hours
Sheep
hours
Swine
hours
Human
hours
H. J. Bearrden and J. W. Fuquay,2000 Applied Animal Reproduction.
Adapted from [Hamner, McLaren, Dukelow and Riegle

11. Mating process :
Is the period when female receptive and will stand for mating with males during estrous phase of estrous cycle, the main purpose of mating is deposition of fertile semen into female genital tract after ejaculation, characteristics of ejaculate in different mammals is shown in table(2):
species
Site of semen deposition
Volume of ejaculate (ml)
Sperm concentration (billion/ml)
No. of sperm reaching site of fertilization
Cow
Vagina 4 1
Sheep 2
Swine
Cervix and uterus
125
0.200
Few
Human
3.5
0.120
Adapted from [Blandau, R. J., in “Handbook of Physiology” (R. O. Greep, ed.)Vol. II, sect. 7, p Williams & Wilkins, Baltimore, Maryland , (1974)]
Arthur C. Guyton, 2006

12. Time of ovulation in different mammals shown in table(3):
Deposition of semen into female tract must be closely synchronized with ovulation to ensure the incidence of fertilization
Time of ovulation in different mammals shown in table(3):
species
Time of ovulation
Cow
10-12 hours after end of estrous phase
Sheep
Late of estrous phase
Goat
Few hours after end of estrous phase
Swine
Mid-estrous phase
Human
Day(14) after initiation of menstrual cycle
H. J. Bearrden and J. W. Fuquay,2000 Applied Animal Reproduction.

13. Mechanisms of sperm transport: Pass into cervix by own movement
As the sperm enter the cervix, orient themselves into current of thin mucus during estrus
Myometrium moves them through the uterus
Moved through oviduct by cilia of oviduct and uterine contractions and a thin fluid secreted by glandular cells.
Image show goat reproductive system

14. Species Fertile life 24-48 hours 30-48 hours
Fertile life of sperm:
Estimate fertile life of sperm in different mammals is shown in table(4):
Species
Fertile life
Cow
24-48 hours
Sheep
hours
Swine
Human
28-48 hours
H. J. Bearrden and J. W. Fuquay,2000 Applied Animal Reproduction.
Adapted from [Hamner54a, McLaren, Dukelow and Riegle

15. Fertilization events:
a) Sperm capacitation:
Freshly ejaculated sperm are unable to fertilize an egg. Rather, they must first undergo a series of changes known as capacitation. Capacitation is associated with removal of adherent seminal plasma proteins, reorganization of plasma membrane lipids and proteins.

16. b) Acrosome reaction:
The acrosome reaction involves breakdown and fusion of outer acrosome membrane with the plasma membrane of the sperm. This results in formation of vesicles and release of enzymes needed for sperm to penetrate the cumulus oophorus and corona radiata as well as zona pellucida . during the penetration process the acrosome is lost with only the inner acrosomal membrane remaining around the sperm head.

17. c) Sperm penetration:
Sperm cell penetrate cumulus oophorus by the enzyme (hyaluronidase) released during acrosome reaction
Sperm cell penetrate corona radiata by the enzyme (corona-penetrating enzyme) also released during acrosome reaction.
Sperm cell penetrate zona pellucida by the acrosin (trypsinlike enzyme) also released during acrosome reaction.
Mohamad J. (according to McRorie and Williams,1974 Ann. Rev. Biochem.)

18. Then membrane of sperm fuses with the vitelline membrane of the egg, the egg cytoplasm around the area of contact surrounds the sperm head and incorporating it into the egg
The nucleus of sperm is then release into the egg cytoplasm without the tail

19. Animation show entrance of sperm nucleus into the egg

20. d) Consequences of fertilization:
In most mammals after releasing the sperm nucleus into egg cytoplasm it stimulates the diffusion of cortical granules into the previtelline space, the erection of a barrier to prevent fertilization by more than one sperm will occur, this process is called zona reaction and vitelline block.
Then the male and female pronuclei are formed and unite (syngamy) to establish the diploid one cell zygote.

21. Animation show egg activation

22. Time of formation of zygote (hours)
Time of formation of zygote and time required to entry the fertile ovum into uterus in different mammals is shown in table(5):
Species
Time of formation of zygote (hours)
Entry to uterus (days)
Cow
0-24
3-4
Sheep
0-38
2-4
Goat
0-30 4
Swine
0-15
Human 3
-Adapted from [Brinster, R. L., J. Anim. Sci. 38, 1003 (1973)]
-Times estimated from ovulation

23. Post fertilization events:
The first of many changes following fertilization is to become multicellular, and the one-cell embryo rapidly cleaves into 2, 4, 8 and more cells. It then starts to do some interesting things like develop a discrete inside and an outside. Finally, the embryos of many species start to secrete hormones that ensure their survival - a process called maternal recognition of pregnancy.

24. Main 3d animation about fertilization process:

25. References:
Al-Dahash S. Y. A. and fathallah M. F. (1982) veterinary Gynecology and female genital diseases. Mousel university.
Arthur, G.H: Noakes, D. E: pearson. H.and Parkinson, T. J. (1996). Veterinary reproduction obstetric. 7th ed. W. B. sounders co. , London.
Austin, C. R., in “fertilization” (C. B. Metz and A. Monroy, eds.), p.437. Academic Press, New York, 1969.
Barros, C., and franklin, L. E., J. Cell Biol. 37, C13 (1968).
Biggers, J. D., J. Reprod. Fert. Suppl (1971).
Boling, J. L., in “the mammalian oviduct” (E. S. E. Hafez and R. J. Blandau. Eds.), p. 163 Univ. of Chicago Press, Chicago, Illinois, 1969)
Fortune J, Cushman R, Wahl C, Kito S (2000). "The primordial to primary follicle transition.". Mol Cell Endocrinol 163 (1-2): PMID
Gougeon A (1986). "Dynamics of follicular growth in the human: a model from preliminary results.". Hum Reprod 1 (2): PMID
Hafez, B and Hafez., E. S. E. (2002) reproduction in farm animal. 7th ed. Kiawah island, South Carolina.

26. THANKS FOR ALL UNIVERSITY OF DUHOK COLLEGE OF AGRICULTURE
DEP. ANIMAL PRODUCTION
SEMINAR ABOUT
FERTILIZATION PROCESS
PREPERED BY
MOHAMMAD J. QASM
SUPERVISED BY\
M. ARAZ JAFFAR
THANKS FOR ALL
For more information visit
Copyright©2008