Received: 11-07-2013 / Accepted: 08-11-2013
Experiments on the effects of broodstock size at 35-39g; 40-44g; 45-49g; 50-55g and 60g (experiment 1) and age ranging from 7; 8; 9; 10 and 11 months old (experiment 2) to reproductive performance of white leg shrimp (Litopenaeus vannamei) broodstocks free of pathogen were conducted in in-door composite tanks of 14m2(for broodstock intensive rearing) and 1m3(for spawning and larval rearing) under biosecurity conditionattemperature of 28-30oC, and salinity of 28-30‰. Shrimpswere fed 4 times per day with blood worm (50%) and fresh squid (50%).Water was renewed 100% daily. For breedinginduction, eye-stalk ablation was applied to the female shrimpsafter 30 days intensive rearing. Female shrimps of 45g or bigger showed significantly better reproductive performance than smaller ones (P<0.05), reaching mature rate of 89.0%, mating and spawning rate of 86.0%, fecundityof 175,200 eggs/dam/spawn, and nauplii production per spawn of 88,700 nauplii. On the other hand, shrimpsat age of 8 -12 months have considerably higher spawning performancecompared to age group of 7 months (P<0.05) with mature rate of 86.7%, mating and spawning rate of 84.1%, fecundity of 207,400 eggs/dam/spawn, production of nauplii per spawn of 127,500 nauplii.