Two application rates, equivalent to 25 mg L−1and 100 mg L−1ofTSS, were used for organic fertilization, which was distributed on D-1, −4, and −7 during the 7-day period.
C:N ratio of locally purchased rice bran was 20:1.
Therefore, to make sure that the same C:N ratio was provided for all treatments, the tanks fertilized with molasses received ground pelleted feed for shrimp (35% crude protein) to attain the same nitrogen level as that in rice bran tanks.
In all treatments, carbon sources were preweighed and mixed individually in a beaker with pond water, followed by uniform and direct application over the surface of the tanks.
Fertilization rates were calculated using proximate composition of the ingredients (Table 1).