The precise combination of environmental factors required for maturation, ovulation and spawning. However, quite often, under farm conditions, the requisite environmental factors are either not available or do not persist for sufficient length of time for spontaneous maturation to occur. The pioneering discovery of B.A. Houssay (1931) and Von Ihering (1935, 1937, Argentina) that fishes can be induced to spawn by injecting pituitary homogenates has somewhat mitigated the problem. The principal advantage of this technique, referred to in aquaculture parlance as “Hypophysation.”

2. INTRODUCTION
 The precise combination of environmental factors required
for maturation, ovulation and spawning.
 However, quite often, under farm conditions, the requisite
environmental factors are either not available or do not persist
for sufficient length of time for spontaneous maturation to
occur.
 The pioneering discovery of B.A. Houssay (1931) and Von
Ihering (1935, 1937, Argentina) that fishes can be induced to
spawn by injecting pituitary homogenates has somewhat
mitigated the problem.
 The principal advantage of this technique, referred to in
aquaculture parlance as “Hypophysation.”

3. HYPOPHYSATION TECHNIQUE
 The technique of induction of breeding by
administration of any chemical or biological agent is
known as Hypophysation technique.
 In India the first attempt to induce C. mrigala o spawn
by the injection of mammalian pituitary extracts was
done by Khan.H(1937).
 Later Chaudhury,H. (1955)succeed in inducing L.
rohita, C. mrigala, C. reba, P. sarana to spawn with carp
pituitary.

4. ADVANTAGES OF HYPOPHYSATION
TECHNIQUE
 The technique, therefore, permits a rather accurate
prediction of the time of spawning and the aqua culturist can
plan his work well in advance.
The nurseries can be stocked with seed of uniform age, size
and quality.
This technique can increase the breeding period of the fishes.
We can collect the fish seed of any size at any time from the
farms without depending on the nature and season.

5. INDUCING AGENTS OF
HYPOPHYSATION
 The agents which are to be used for induced breeding of
fish in hypophysation technique are known as Inducing
agents.
There are mainly two types of inducing agents :
A.Natural inducing agents (e.g. pituitary extracts)
B. Synthetic inducing agents (e.g. mamalian gonadotrophin,
steroids, other drugs etc.)

7. NATURAL INDUCING AGENT
 Natural inducing agent is mainly pituitary extracts used
in hypophysation technique. The different steps involved
in hypophysation technique are:
A. Collection of pituitary gland
B. Preservation of pituitary glands
C. Preparation of pituitary gland extracts and
D. Administration of pituitary extracts to the brood fish.

8. COLLECTION OF PITUITARY GLANDS
 The pituitary gland is usually collected
from a freshly killed or ice preserved
mature fish.
The donor fish for pituitary can be carp
of either sex.
The brain is dissected out by cutting
open the dorsal side of skull and then the
pituitary is picked up and kept on the
watch glass for preservation.
Pituitary can also be obtained from
freshwater catfish such as B. bagarius, P.
pungasius, M. singhala at a slightly higher
dose.

9. PRESERVATION OF PITUITARY GLANDS:
Alcohol preservation:
The freshly collected pituitary are preserved in absolute alcohol in
amber color file. Two or three changes of alcohol at two to four hours
intervals help in defattening be gland and keep the gland in better
condition. This can be kept in refrigerator or in a cool place.
Refrigerator increase the self life of the gland up to two years.
Acetone preservation:
The fresh gland put in fresh acetone or a in dry ice chilled acetone
and kept in a refrigerator for 36-48 hours. During this period acetone
is changed 2-3 times at 8-12 hours interval. Then glands are taken out
from the acetone , put on a filter paper and allowed to dry at room
temperature. Then the gland are transferred to the separate phials
and stored in refrigerator.

10. PREPARATION OF PITUITARY GLAND
EXTRACT
The extracts of the gland is usually prepared just before the
injection.
Weighed the gland
Homogenized in distilled water or 0.3% saline
Add the distilled water such way that the final volume will be
0.2ml/kg breeder.
Usually the volume may not exceed over 1-1.5ml for one fish.

11. PREPARATION OF PITUITARY GLAND EXTRACT

12. ADMINISTRATION OF PITUITARY
EXTRACTS TO THE BROOD FISH
 Usually the female is given two doses of
pituitary gland injection.
 The first one is called as initial dose or booster
dose and the second one is called as final dose or
decisive dose or resolving dose.
 The male usually given only one dose at the
time of the second dose given to female.
 Dosage required for successfully spawning
varies from species to species or from fish to fish
even the same species.
 The dosage depends on the readiness of the
brood fish, their size age and sensitivity.

13. DOSE OF PITUITARY EXTRACTS
The first dose of injection is given to advance the final maturation of
oocytes.
 The interval between initial dose and final dose varies from species
to spices or from place to place depending on the temperature.
For females of Indian Major Carps one initial (preparatory) dose
and after 5-6 hours another final is administrated.
 But in sub-tropical or temperate climates sometimes one
preparatory dose followed after 18-22hours by to decisive dose.
The degree hours depends on the species of fish, size and age of the
female, type of treatment etc.

14. DOSES OF PITUITARY GLAND
ADMINISTRATION IN FISHES
Fish
Female(mg/kg weight)
Male(mg/kg
weight)
Ist dose IInd dose
Catla 2-3 6-9 2-3
Rohu 2-3 6-9 2-3
Mrigal 2-3 6-9 2-3
Silver carp 3-4 9-12 3-4
Grass carp 3-4 9-12 3-4

15. DISADVANTAGES OF USING NATURAL
INDUCING AGENTS (PITUITARY EXTRACTS)
•At present pituitary forms a major inducing agent for hypophysation
technique and induced breeding.
•But pisciculturist faced various problems such as:
a)good quality pituitary glands were not available sufficient quality in time.
b)The procedure of preparation of crude pituitary gland extract (CPGE) and
administration to the fish in field conditions particularly during monsoon
season involves cumbersome procedure.
c)crude pituitary extract being a mixture of hormones may have adverse side
effects on gametogenesis and other functions.
d)difficulties involves in collection and storage and non-availability in
adequate quantity and quality were encountered.
e) CPGE has less percentage of successful spawning, less no. of eggs per kg
body weight and less fertilization rate and hatching rate.

16. This led to a search for alternative
synthetic hormone preparation that could
be preserved and used when required by
pisciculturist.
CONT……………….

18. SYNTHETIC INDUCING AGENTS:
Different synthetic compounds used for induced
breeding of fishes under captive condition are of
different categories:
A)Gonadotrophin ,
B) Gonadotrophin realizing hormone
C) Steroids
D) Ovatide
E) Ovaprim
G) Other drugs.

19. GONADOTROPHIN
 Gonadotrophins are hormones secreted by the gonadotrophs
of pituitary gland. Though three distinct gonadotrophins such
as :
1.LH(Luteinizing Hormone),
2. HCG(Human Chronic Gonadotriphin)
3.PMSG(Pregnant mare serum) are reported in higher animals,
have various reproductive function on teleost.
 Gonadotrophins are mainly glycoproteins. Partially purified
from of pituitary have been prepared from pituitary glands of
teleost such as Common carp, Pink salmon, Rainbow trout,
tilapias, Winter flounder, Pike eel etc trough extraction and
chromate graphic procedure.

20. LH(Luteinizing Hormone)
Ovine LH has a molecular weight of 28500 and
has 15.5% carbohydrate b subunit has 119 amino
acids.
Though they are effective in inducing
spawning is not cost effective and hence not
practiced in fish culture.

21. HUMAN CHRONIC
GONADOTROPHIN(HCG):
HCG is a protein hormone secreted by the Langerhans cells of
the chronic villi of human
HCG is also called as salio protein or glycoprotein because the
carbohydrate molecules are attached with the protein molecule.
 Its molecular weight ranging from 30000-40000 and
carbohydrate containing is 30-35%.
HCG contains carbohydrates such as Mannose, Galctose,
Gocosamine, Galactosamine, Fructose and N- acetyl nutraminic
acid.
The effective dose is 100-2000 IU/kg fish for carps.

22. PREGNANT MARE SERUM
GONADOTROPHINS
This is another type of gonadotrophins like molecules
secreted by the endometrial cups of the uterus of a
pregnant mare.
It appears in the blood on the 40th
day of pregnancy.
As molecular configuration it is similar as LH if injected
to the other animal.
Hence administration of PMGC has found useful in
inducing ovulation and spawning in fish.

23. GONADOTROPHIN REALIZING
HORMONE
Gonadotrophin realizing hormone or (GnRH) was first
isolated from porcine hypothalamus by Scally and
Cowrkers in 1971.
Later in 1972 Guillmin and associates isolated it from
ovine hypothalamus.
 The neuro hormones secreted by the GnRH neuros of
hypophysiotrophic area of hypothalamus is regulating
the secretion of gonadotrophins from the pituitary gland.

24. STEROIDS
 Both cortico steroids such as II-deoxycortico sterone
acetate(DOCA) and progestins such as 17@-hydroxy-20b-
dyhydro progresterone have been used by some workers to induce
spawning in fish.
Corticosteroids:
•High dose of corticosteroids have been shown to induce oocyte
maturation and ovulation in several species in fish.
• The first successful use of corticosteroids in induce spawning
teleost was in Misgurnus fossilis with single dose of 1mg DOCA
per fish (Kirshenblatt, 1952).
•Sunderraj and Goswami (1996,1972) induced ovulation in
Heteroneustus fossilis with 5mg DOCA per fish.
• These authors found other steroids such as Cortisol and
Cortisone also effective at a dose of 25 mg pre fish.

25. Progestogens:
 There is good evidence that progestogen action on oocyte maturation
and associated oocyte hydration may also be under their control.
 Several studies has been conducted to know the efficiency of
progestin's (17@hudroxy progesterone and 17@20B dihydroxy
progesterone) in inducing ovulation of trout's, common carp, and
northern pike.
 These studies have indicated that while progesterone derivatives
induced final maturation, ovulation occur only when the endogenous
gondotrophin is sufficient or when a minimum dose of gonadotrophin is
supplied exogenously.
At present neither corticosteroids nor progestin are utilized
commercially for inducing spawning in fish.

26. OVATIDE
It is a synthetic compound launched by
Hemmopharma ,Bombay.
a)Produces increased number of eggs through
complete spawning with high fertilization and
hatching percentage.
b) Can be easily injected due to low viscosity.
c) Can be administrated in single dose without
causing any adverse effect on brood fish.
d) Is effective even under adverse climatic
conditions.
e) Can be stored at room temperature (20-30)’c.
f) Produced healthy fish seed with high
potential for excellent growth.

27. Species Male(ml/kg body wt) Female(ml/kg body wt)
Catla 0.2-0.3 0.4-0.5
Rahu 0.1-0.2 0.2-0.4
Mrigal 0.1-0.2 0.2-0.4
Silver carp 0.2-0.25 0.4-0.5
Grass Carp 0.2-0.25 0.4-0.5
OVATIDE USED IN DIFFERENT
SPECIES:

28. OVAPRIM
 It is a synthetic compound manufactured
by Syndal laboratories, British Colombia.
 The recommended single dose of Ovaprim
is 0.5mg/kg of fish.
 The Ovaprim has shown highly successful
and advantageous when compared to the
traditional method of CPGE administration.
 Use of Ovaprim has resulted in higher
percentage of spawning success, higher
number of eggs per kg body weight of brood,
higher fertilization rate and higher
percentage of hatchlings.

29. WOVA-FH
 It is a synthetic
gonadotrophin releasing
hormone analogue prepared
and marketed by
WOCKHARDT.
 The recommended dose
is 0.5ml/kg body weight of
fish.

30. OTHER DRUGS
1. Prostaglandins:
Prostaglandins has been shown to be involved in the
follicular rapture during ovulation of the different
species like teleost.
Injection of gonadotrophin that induce ovulation has
been shown to cause increase in the endogenous
prostaglandins in several species.
These studies have indicated that prostaglandis may
be used in future to stimulate natural spawning in
culture condition.
Injection of Indomethcin, an inhibitor of
prostaglandins has inhibited ovulation in Gold fish

31. 2. Antiestrogens:
 Antiestrogens are synthetic compounds that can compete
with estrogen for binding on estrogen receptors.
 There is a decrease in estradiol level during final
maturation and ovulation.
 Estradiol has been shown to have negative feedback
inhibition gonadotrophin release. The lowering of estradiol
is hence found to enhance the gonadotrophin secretion.
 In spite of success in some of the experimental studies
these drugs are not used commercially for inducing
ovulation in fish in large scale breeding works.

32.  Synahorin, trade name for a commercial
preparation, a mixture of HCG and
mammalian hypophysial extracts, has
been used for inducing ovulation and
spawning of in fish. However for IMC 70-
80% of pituitary gland can be replaced by
HCG.

33. DOSES OF DIFFERENT HORMONES USED
FOR INDUCED BREEDING
Fish species Sex Ova-FH Ovatide Ovaprim
Rohu Male 0.1-0.3 0.1-0.3 0.1-0.2
Female 0.3-0.5 0.3-0.5 0.3-0.4
Catla Male 0.1-0.3 0.1-0.3 0.1-0.2
Female 0.3-0.5 0.3-0.5 0.3-0.4
Mrigal
Male 0.1-0.3 0.1-0.3 0.1-0.2
Female 0.3-0.5 0.3-0.5 0.2-0.4
Grass Carp Male 0.1-0.30 0.1-0.3 0.1-0.2
Female 0.40-0.80 0.4-0.7 0.3-0.5
Silver Carp Male 0.1-0.3 0.1-0.3 0.1-0.5
Female 0.4-0.8 0.4-0.7 0.3-0.5
Labeo
dyocheilus
Male 0.2-0.4 0.2-0.4 0.2-0.4
Female 0.8-1.0 0.8-1.0 0.8-0.1
Cat fishes
Male 1.0-1.5 1.0-1.5 1.0-1.5
Female 2.5-3.0 2.5-3.0 2.5-3.0

34. CONCLUSION
Due to uncertainty of fish seed resources from Natural
river system, Most of the farmers depends Upon the
hatcheries for collection of fry and fingerlings. The
optimum no. of fry and fingerlings produced in the
hatchery is highly depends upon the induced breeding of
breeders. So the fish should be very much sensitive to the
agent which is to be induced during hypophysation
technique. On the other hand the famer should use proper
and appropriate inducing agents for induce breeding of
fish. Otherwise the fish may not response to the agents
and there may be results of breeding operation failure.