Hypophysation
- 1. Submitted to, Prof .H.V.Parmar College of fisheries veraval Submitted by , Ketul Patel Roll no:-26 Reg.no:-j3-00326-2014
- 2. The technique of induction of breeding by administration of pituitary extract is called hypophysation technique. Brazil was the first country to develop hypophysation technique on commercial scale. In India the first attempt to induce C.mrigla to spawn by injection of mammalian pituitry extract was done by khan in 1937.
- 3. Removal of Pituitary Gland from Donor Fish . Storage of Pituitary Glands. Preparing and Injecting the Pituitary Extract. Release of Induced Donor Fish.
- 4. Select sexually mature and unspent donor fish (male or female) as pituitary donors. Anaesthetise the donor fish using a suitable anesthetic until deeply sedated and sacrifice.
- 5. Wash and remove the fatty tissue away, hold the hind margin of the brain with a pair of fine tweezers, gently lift and fold the brain back on to itself (posterior to anterior direction) to expose the pituitary gland lying directly under the brain
- 7. Wash the surrounding tissue debris by rinsing with clean water before carefully removing the pituitary gland.
- 8. Pituitary glands that are not required for injection immediately can be stored for as long as 6 months using reagent grade acetone. For long-term storage first place the pituitary glands in airtight vials containing acetone for 24 hours and then replace the acetone with a fresh aliquot. These vials can be stored at room temperature or refrigerated until required (up to 6 months).
- 9. Just prior to induction of donor fish, take out the stored pituitary glands from their respective vials and place on tissue paper to air dry. If working with fresh glands use them directly for extraction. Weigh the required amount of pituitary gland (based on the weight of the recipient fish: 4-6 or 10-16mg/kg body weight for male or female recipient respectively)
- 10. Carefully transfer the weighed glands to a microfung tube. Add sterile double distilled water to each vial and grind the tissue finely using a micro-pestle.
- 12. grinding more distilled water was added to achieve a concentration of approximately 40 mg/ml of pituitary extract and mixed thoroughly. The pituitary extract was then centrifuged at approximately 1-2K RPM for about a minute to separate the tissue debris from the extract.
- 14. Suitable sites with water plumes flowing through the holding pen and traps were selected for the trial. Holding pens were placed directly behind fish traps, such that pheromone (attractant) released by the donor fish would be carried through the traps and into the lake. Suitable barriers were installed to avoid inadvertent access of attracted fish to the donor fish.
- 15. Fish seed is guaranteed all year round. Increase the survival rate of fry Improve quality by crossing two different species.
- 16. Loss the donor Whole process is laboratory and highly technical. Very expensive.