Induced breeding in fishes

inducded breeding in feshes

1. By: Khansa M . Phil zoology

2. OUTLINE: INTRODUCTION HISTORY TECHNIQUES FACTORS PROBLEMS ADVANTAGES AND DISADVANTAGES

3. Induced breeding Induced breeding is a technique by which the economically important fish (which generally do not breed in captive condition) are bred through artificial stimulation. Induced breeding is a technique whereby ripe fish breeders are stimulated by pituitary hormone or any other synthetic hormone introduction to breed in captive condition.

4. WHY INDUCED BREEDING?? Induced breeding is a technique where organism is stimulated by particular hormone or other synthetic hormone or by providing condition, introduced to breed in captive condition. The stimulation promotes timely release of sperms and eggs from ripe gonads.

5. NEED OF INDUCED BREEDING Because of environmental condition like photoperiod, rain , Temperature, currents of water. Insufficient release of hormones in captive condition. Insufficient of natural foods.

6.  INDUCED BREEDING IN FISHES The Artificial Process By Means Of Which The Extract Of The Pituitary Is Introduced Inside The Body Of Both The Matured Male And Female Fishes, Then After Being Excited, They Lay Eggs In The Pond Water And Subsequently Fertilization Takes Place And The Process Is Called Induced Breeding Of Fishes. This Process Of Breeding Is Also Known As Hypophysation .

7. HISTORY OF INDUCED BREEDING The technique of induced breeding was first evolved in Argentina after producing pituitary extract by B. A. Hussay in 1930. Brazilian was the first country to develop a technique for hypophysation in 1934 . In India, first attempt to induce breeding was made by Hamid khan in 1937 on Cirrhinus mrigala . Dr. Hiralal Chaudhary applied this technique in minor carps in 1955 .

8. WHY DOES FISH NOT BREED IN CAPTIVITY?? Many cultural farm fishes like IMC do not breed in captivity. The reason may be. Environmental and consequently hormonal . Certain environmental parameters like photoperiods, rain, temperature, current of water influence the hormonal activity from pituitary and gonads. Disturbances arise in environment may cause the insufficient release of hormones in captive conditions and thus, the fish does not breed in captivity. Other factors like poor foods or insufficient natural foods, exposure to biocides and other pollutants badly affect the maturation of ovary.

9. WHY INDUCED BREEDING IS NECESSARY FOR FISH CULTURE: It gives pure spawn of certain species of fishes under cultivation. Spawn collected from natural water is not pure as because some undesirable wild species may come with them. In culture pond, Sorting of pure seed is quite impossible in those stages. In later stages it is possible, but time consuming. It assures timely available of pure seed, where as in nature the availability of seed is quite uncertain. It can fulfil any quantity of demand in any time

10. Cont..….. The technique is very simple and does not need too much technical assistance or knowledge. It can be easily learnt by a layman without much training. The cost of expenditure is very low than the natural collections of spawns.

11. TECHNIQUES FOR INDUCED BREEDING

12. Method of Induced Breeding

13. Fish Pituitary Gland—Collection and Preservation 1-Location of pituitary gland :- Pituitary gland is also known as Hypophysis . This gland in fishes is located at Sella turcica of sphenoid bone It is situated on the ventral side of the brain just behind the optic chiasma and below the Hypothalamus.

14. REMOVAL OF GLAND REMOVAL THROUGH FORAMEN MAGNUM: The foramen magnum was first exposed by removing vertebral parts adhering to skull. Fat is removed first by means of forceps and then cotton piece. A pair of forceps then inserted into foramen magnum dorsally to the brain and anterior part of the brain now detached and remaining is carefully lifted out through the foramen magnum. The gland is then located and removed.

15. material used for pituitary extract preparation and injection. (A) homogenizer (B) Head centrifuge (c) syringe Different Forceps that used in removing the gland

16. Removal of gland by dissecting head:- This technique is not used commercially as because the heads are damaged by this process. At first the head is dissected using sharp butcher’s knife, a portion of scalp is chopped off in a clean cut with one stroke. Fat surrounding the brain is removed with the help of cotton. Olfactory and optic nerves are now severed, and then brain is lifted up and removed. Locate the gland. Dissecting the head of fish

17. Cont..……. The gland may come up along with the brain or may remain behind on the floor of brain cavity often covered with a membrane. In any case the gland is carefully removed after separating it from membrane or the brain proper . The gland must not be damaged or torn. The first method of removal is less time consuming and economical as the heads are used for human consumptions later

18. Collecting pituitary gland

19. C). PRESERVATION OF GLAND : I-ALCOHOL PRESERVATION: After collection of glands immediately put in absolute alcohol for defatting and dehydration. After 24 hour’s glands washed with absolute alcohol and kept again in fresh abs. Alcohol store in refrigerator up to 2-3 years or at room temperature up to 1 year. II-ACETONE PRESERVATION: Glands kept in fresh acetone or in dry ice-chilled acetone inside a refrigerator at -20 0C for 36-48 hours. 2-3 changes of acetone at about 8-12 hours intervals glands are taken out of acetone, put on filter paper and dried at room temperature for one hour. largely practiced in USSR and USA.

20. ( D). PREPARATION OF GLAND EXTRACT:  Gland weighed and homogenized in distilled water or 0.3% saline  Final volume should be 0.2ml/kg BW of the fish  Centrifuged the suspension  Supernatant used for injection  Extract of the gland prepared just before injection PRESERVATION OF GLAND EXTRACT Preserved extract in glycerin and kept in refrigerator for 24 hours and preserved in propylene glycol and kept in refrigerator for 30 days with Immersed in 1.5% TCA for 12 hours and kept in refrigerator for 10 days

21. (E). BROODER SELECTION:  The brooders must be healthy enough and ripe  2 – 4 years of age is generally selected  1 – 5 kg body weight is preferable

22. Morphology and behavioral To observe the sex of a fish, you’ll have to observe the fish’s size, shape, appearance, and behavior Compare the size of the fish during spawning season. With many fish, like koi, females tend to be larger than the males. This is especially true during spawning time, when females have large abdomens. . This is often caused by the fact that the female carries the eggs in her abdomen . Once the eggs are laid during spawning season, the females and males can return to the same size .

23. Cont.…. Difference Between male and Female Character Look for a bump on the forehead of the fish to identify a male.  Look carefully at the face of the fish just between the eyes and above the mouth. If it has a large, protruding bump, there’s a good chance that the fish is a male. This bump is called a “nuchal hump,” and it’s present on many types of fish, like the tilapia, angelfish, and parrot fish etc . Some species of fish don’t have a nuchal hump, but the presence of one is normally a great indicator that you have a male fish.

24. F).INJECTION TO THE BROODERS:  The pituitary extract is administered into the body of breeders by means of hypodermic syringe either intra muscular or intra peritoneal.  Determination of correct dosage of pituitary extract to be given to the breeders is very important and depends upon the size and state of maturity of the recipient (breeders) as well as upon the state of maturity of the donor for the glands . Intra-cranial injections preferred in USSR and intraperitoneal in USA and japan . Intra-muscular injection is most common practice in India.  Intra-muscular injection given at the caudal peduncle or shoulder regions near the base of the dorsal fin.  Intra-peritoneal injections given at the base of the pelvic fin or pectoral fin.

25. DOSAGE OF PITUITARY EXTRACT Female given 2 doses 1 . Initial dose: 2-3mg/kg body weight. 2 . Resolving dose / final dose: 6-8mg/ body weight. Male given only 1 dose at the time of the 2nd dose given to female (2-3 mg/kg body weight ). For females of Indian major carps one initial and after 5-6 hours final dose given.

26. Dose of fish Synthetic Hormone of Ova tide Species Female(ml/kg) Male(ml/kg) Labeo rohita 0.20-0.40 010-0.20 Cirrhinus mrigala 0.20-0.40 0.10-0.20 Sliver carp 0.40-0.50 0.20-0.25 Grass carp 0.40-0.50 0.20-0.25 A text book of fish and fisheries – Pandey and Shukla .

27. SPAWNING After injection to the brooders, a set of brooders are released into breeding hapa . T he hapa is the fine netting, rectangular in shape and is held by four bamboo poles one at each corner. Closed meshed mosquito netting is preferred for that purpose, as its meshes will allow a good circulation of water and will also not let the laid eggs and milt escape through the meshes .

28. Spawning hapas

29. Spawning pools

30. Stripping :- In stripping method, the ‘eggs’ and ‘milt’ are forcibly extruded out by applying pressure on the belly of breeders when they are ready to breed . Two methods of stripping are generally practiced — dry method and wet method : Dry Stripping Dry Stripping:

31. Dry Stripping: The dry method of stripping has been found to be more convenient and effective and is widely practiced in India. In this method after 3-4 hours of the second infection, the female fishes are examined, whether they have become fit for stripping. The female breeders become fit for stripping when the abdomen becomes very soft and eggs oozes out freely on applying slight pressure on the abdomen

32. Fig: dry stripping__(a) Eggs are collected in an enamel tray. (b) milt is exuded over the eggs

33. Wet striping: In some countries wet method of stripping is also practiced. In wet stripping 0.3% saline solution is used. The salt solution is taken in an enamel tray and the males are made first to exude milt. Then the female breeder is taken and the eggs are stripped into the tray. Generally, the sperms of Chinese carp remain active up to 2-3 minutes in 0.3% saline, while they die much earlier in ordinary water.

34. Wet stripping:

35. FACTORS INFLUENCING THE SPAWNING OF FISH:  Climate - 24°C to 31°C with cloudy days and rainy periods. Light drizzling following heavy rains is ideal. In absence of rain artificial showers are used.  Water – flowing water is preferred .  Turbidity – 100ppm 1000ppm .  Light – it is known to bring that light may help in early maturation and spawning of fish.

36. PROBLEMS OF HYPOPHYSATION TECHNIQUE  Farmer cannot measure the potency of the available gland  Serious difficulties in large scale collection and storage of pituitary  Large gap between the supply and demand of pituitary  Basic equipment’s like chemical balance, centrifuge and refrigerator normally not available in several farms  Pituitary gland very costly in market .

37. advantages of induced breeding: Desired species of carps can be cultured through the induced breeding. Large number of eggs are available from a fish through induced breeding. In same season, a carp can be breed more than once . Transport cost becomes very low as the caps can breed in any desired pond.

38. References :- Fish and Fisheries of India – V. G. Jhingran General and applied Ichthyology – S. K. Gupta and P. C. Gupta A text book of fish and fisheries – Pandey and Shukla.