Finfish Breeding and Hatchery Management

Unit 3 - Breeding of major carps

3.3.1. Collection of pituitary gland

Fish pituitary gland can be collected by dissecting and removing a portion of the scalp or through the Foramen magnum.

(1) Dissecting and removing a portion of the scalp

• In this method, the brain case (cranium) is obliquely cut using a butcher’s knife/hand saw/bone cutter and the scalp removed.
• The brain is then exposed by removing grey matter and fatty substance with forceps and cotton.
• The anterior end (optic and olfactory nerves) of the brain is cut and the entire brain is lifted up and laid back, thus exposing the pituitary under a membrane.
• After removing the membrane and the fluid, the pituitary is lifted up by inserting the blunt end of the forceps and carefully transferred to a vial containing a preservative.
  

Making an oblique cut in the cranium Fatty tissue and grey matter exposed

The brain being exposed The pituitary seen as a small whitish body

The pituitary mounted on to a wrist

(2) Through the Foramen magnum

• Foramen magnum is a large posterior aperture of the skull through which the spinal cord passes.
• The grey matter and fatty substance are first removed with the help of forceps and cotton (they are pulled out posteriorly).
• The brain is then exposed.
• After this, the anterior end (optic and olfactory nerves) of the brain is cut and the entire brain is lifted up and laid back, thus exposing the pituitary.
• After removing the fluid the membrane, the pituitary is lifted up by inserting the blunt end of the forceps and carefully transferred to a vial containing a preservative.

The first method is commonly practiced even though the second method is less time consuming and a large number of glands can be collected within a short time, with a good resale value of the fish.