Gonadal Maturation and Spawning in Penaeus semisulcatus de Hann, 1844 by Hormone Injection


Abstract: The effects of 3 hormones, HCG, LH-RH and serotonin (5-HT), on maturation and spawning of Penaeus semisulcatus de Hann, 1844 were investigated in 2 experiments in this study. The experiments were carried out in round (4 m diameter) fiberglass tanks for 50 days. In experiment 1, the effects of 3 dosages (1, 2 and 3 IU g^{-1} body weight (BW)) of HCG were compared against a sterile vehicle solution (0.85% NaCl) injected group (control group) and an eyestalk ablated group. In experiment 2, 3 dosages of both LH-RH (0.01, 0.1 and 0.2 mg g^{-1} BW) and serotonin (20, 50 and 100 µg g^{-1} BW) were tested against the control (0.85% NaCl) and eyestalk ablated groups. In experiment 1, the molting interval did not vary significantly among the treatments (P > 0.05). The highest number of spawns was obtained from the ablated group and this was followed by the groups injected with 3 IU g^{-1} (2 spawns), 2 IU g^{-1} and 1 IU g^{-1} of HCG (1 spawn) respectively. The control group (injected with vehicle solution) did not spawn during the course of the experiment. In experiment 2, no significant difference was established in the molting cycle among the groups (P > 0.05). A total of 28 spawns were obtained from the eyestalk ablated group during the experiment and repeated spawns occurred within the same molting cycle. Four females injected with 50-100 µg g^{-1} of serotonin matured and spawned. Again, 3 females from the group injected with 20 µg g^{-1} of serotonin matured yielding a total of 5 spawns. Three females spawned in the groups that received 0.01 mg g^{-1} and 0.1 mg g^{-1} of LH-RH. Only one female injected with 0.2 mg g^{-1} of LH-RH matured and spawned during the study. It appears that maturation and spawning of P. semisulcatus can be successfully induced by injection of these hormones in captivity, though eyestalk ablation remains the most reliable technique.

Keywords: Penaeus semisulcatus, maturation, spawning, hormone injection, eggs

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