Walailak Journal of Science and Technology (Apr 2013)
Reproductive Aspects of SPF Penaeus monodon Grown in Closed Culture Captivity
Abstract
Reproductive performance of P. monodon in terms of viable spermatophore, ovarian development and spawning characteristics was examined. The specific pathogen free (SPF) larvae were obtained from the SPF wild caught broodstock spawned in captivity. The SPF post-larvae were reared to mature entirely in the disinfected medium in circulation system. It was found that male shrimp matured far earlier than female shrimp. Maturation of male shrimp was determined by appearing of the ampoules observed between the fifth pereiopod and the first pleopod. The first maturation of male was observed within 6 months at an average body weight of 11 ± 2 g (n = 6). Sperm quantity and quality were examined in shrimp of 12 months old with an average body weight of 48 ± 3 g (n = 5). The average sperm count per spermatophore was 29.7 ± 16.5×106 with viability of 79.0 ± 11.1 %. Maturation of female shrimp was determined by appearing of the gravid ovaries of stage 3 - 4 observed on dorsal part of abdominal segments. The first maturation of female was found within 16 months with an average body weight of 78 ± 4 g (n = 2). The other group of 12 month-old female shrimp was manipulated to mature using eyestalk ablation and artificial insemination techniques. Spawning characteristics of the ablated shrimp found to vary among individuals. A number of ablated female exhibited multiple spawning up to 3 consecutive times with a single insemination. Numbers of egg and percentages of hatch apparently decreased in the later spawning in the group of shrimp spawned 3 consecutive times with single insemination (p > 0.05). Egg counts in each spawning varied from 79,000 to 260,000 showed no particular pattern of relationship with body weight. Hatching feasibility varied from nil to 85 %. This study demonstrated the promising potential in producing specific pathogen free broodstock in tropical climate environment. However, further research is needed to enhance growth performance and survival rate. The quality of spawn in terms of viable spermatophore and ovarian development is yet to be improved.
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