Question

Which hormone is commonly used for induced breeding of Indian major carps?

• A. Insulin
• B. Gonadotropin-releasing hormone analogues (GnRH)
• C. Thyroxine
• D. Melatonin

Hint:

IMC breeding → GnRH analogues like Ovaprim.

Answer 1

The Correct Option is B

Step 1: Induced breeding is done to obtain seed outside natural season.
Step 2: Synthetic GnRH analogues like Ovaprim or Ovatide are commonly used as they stimulate pituitary gonadotropins to induce spawning.
Step 3: Insulin and thyroxine have no role. Melatonin influences seasonal cycles but not directly used for induction.

Answer 2

Mechanism-Based Recall: Induced breeding needs a hormone that can trigger the pituitary to release its OWN spawning hormones — narrow down by that mechanism.

GnRH analogues (like Ovaprim/Ovatide) stimulate the fish's pituitary gland to release gonadotropins, directly inducing spawning outside the natural season.

Insulin and thyroxine have no link to the reproductive-hormone pathway, and melatonin only influences seasonal rhythm cues, not direct spawning induction.