Litopenaeus vannamei) cultured in biosecurity system. Three groups of experimental shrimp (initial weigh 20.1 + or - 1.9 g/male and 21.4 + or - 2.2 g/female) were stocked at density of 10, 20 and 30 heads/m3 in 4m3 indoor tank system. Each treatment was run in triplicate and fed with about 4 percent shrimp weight daily with pellet diets of CP 7704S and 7704P (38 percent crude protein), feeding four times a day. The water temperature ranged from 20.0 - 28.5°C and salinity ranged from 20-28 thounsandths. Water was renewed 80 percent volume weekly. The highest growth rate in weight was recorded in broodstock candidates cultured at 10 heads/m3 (1.03 g/week/male; 1.11 g/week/female), followed by 20 heads/m3 (0.89 g/week/male; 0.98 g/week/female) and the least for 30 heads/m3 (0.53 g/week/male; 0.62 g/week/female). Similarly, survival rate of shrimp at 10 heads/m3 (71.7 + or - 2.7 percent) ranked highest and the lowest rate for the 30 heads/m3 (60.1 + or - 2.8 percent; P0.05). Nevertheless, there is no significant difference in the survival rate between shrimp cultured at 10 heads/m3 (71.7 percent + or - 2.7 percent) and 20 heads/m3 (71.5 + or - 3.0 percent; P0.05). Size variation (CV percent) and FCR recorded on 10 heads/m3 (CV percent: 6.34 + or - 1.12 percent; FCR: 2.78 + or - 0.5) and 20 heads/m3 (CV percent: 6.68 + or - 1.20 percent; FCR: 2.86 + or - 0.3) were found remarkably lower than that for 30 heads/m3 (CV percent: 10.56 + or - 2,24 percent; FCR: 3.42 + or - 0.8; P0.05). The percentage of shrimp harvested that met the criteria of broodstock was 67.1 + or - 2.6 percent and 66.7 + or - 3.2 percent for the 10 and 20 heads/m3, respectively, whereas only 23.1 + or - 5.4 percent for the 30 heads/m3. All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBV and IHHNV.
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