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Abstract
The study was conducted at Wet Lab, Faculty of Fisheries, Hue University of Agriculture and Forestry to determine the performance of growth and digestive enzyme of whiteleg shrimp postlarvae (PL) in biofloc environment at a high stocking density of 5.000 PL10/m3. The 30-day experiment consisted of two treatments under the different rearing conditions including (i) non-biofloc (ii) biofloc in indoor nursery tanks of 1 m3 with the salinity at 15‰. Molasses, as a source of carbohydrate, was employed to facilitate biofloc formation and maintain the C/N ratio at 15. The results showed that digestive enzymes including amylase and cellulase of shrimp were affected by biofloc in the way of enhancement. Shrimp of biofloc treatment achieved significantly higher values (p<0,05) of length (47,20 ± 1,52 mm), weight (0,71 ± 0,08 g), total hemocyte count (7,29 ± 0,15 x 106 cells/mL) and survival (73,54 ± 0,65%) than those of shrimp in non-biofloc treatment, (40,64 ± 2,62 mm, 0,52 ± 0,05 g, 6,12 ± 0,51 x 106 cells/mL, 85,61 ± 0,61%, respectively). It was reported that rearing whiteleg shrimp postlarvae under the biofloc condition resulted in a greater ability of environmental stress tolerance concerning pH, temperature and salinity. Our findings shed a light on feasibility in nursing whiteleg shrimp postlarvae with high stocking density in biofloc environment, answering to the demand for the development of this shrimp industry at present.