The use of S-GnRHa (salmon gonadotropin releasing hormone analogue) in induced breeding and early embryonic development of Gulsha, Mystus cavasius

The current study was carried out to optimize the dose of synthetic hormone for induction, and observe embryonic larval developmental in Gulsha, Mystus cavasius. Induced breeding conducted by using Ovupin (S-GnRHa) (each 1.5 ml vial contain 0.2 mg an analogue S-GnRHa) at four different doses i.e., 0.25, 0.5, 1.0- 1.50-ml kg-1 body weight (BW) females, half these were applied males. Among doses, 0.5 BW female 0.25 male provided maximum fertilization (83.66%) hatching (80.0%) rates. eggs M. cavasius strongly adhesive, with covering on egg surface. average diameter fertilized just after spawning 85.58±5.87 µm. After fertilization, first, second, third cleavage stages occurred within 20-25, 35-40 60-65 min, respectively. identity blastomeres gradually lost appeared 64-cell stage 128-cell onwards. 150-160 min morula 3:00-3:20 h (blastomeres completely lost), gastrula 5:0-5:30 which blastoderm spread both sides about 60-70% area, together a thread-like germinal ring. Afterward, twisting locomotion recorded 23:30 h. larvae started 24:00 25:00 barbells partially visible when 10-12 age. Finally, yolk sac fully absorbed end Day 3.