Shrimp nursery could be more cost-effective in autotrophic systems
Background: Seven-week trial, stocking density 900PLs/ 120L water
- Autotrpphic system: Provided with wheat bran and plastic mesh for the formation of bioflocs and biofilms. Agricultural fertilizer was supplied to maintain a nitrogen:phosphorus (N:P) ratio around 8:1. The tanks were put outdoors and exposed continuously to sunlight. From day 5 until the end of the trial, shrimp received a formulated feed at a rate of 8 percent of their total biomass.
- Heterotrophic system: The water column was additionally fertilized with molasses, maintained N:P ratio over 20:1. The tanks were covered with plastic shades to minimize the penetration of sunlight. From day 5 until the end of the trial, shrimp received a formulated feed at a rate of 8 percent of their total biomass.
- Control group: used formulated feed in whole process.
- The best final weights: the control(1819 mg) and the heterotrophic system(1214 mg).
- The best survival: the autotrophic system(84.6%).