CARBON TO NITROGEN RATIO AND NITROGENOUS WASTE ACCUMULATION IN THE INTENSIVE CATFISH (Clarias gariepinus) CULTURE
ABSTRACT: This experiment was
carried out to determine the optimum C/N ratio for heterotrophic bacteria
(biofloc) growth in order to control nitrogenous waste accumulation in thecatfish
(Clarias gariepinus) culture. Twenty fish with an initial individual size of
about50 g were stocked in fiberglass tanks which were filled with 200 L of
water. Fish werefed with commercial floating fish feed with a protein level of
31%-33% (manufacturerlabel). The daily feeding rate was 2.5% of the fish
biomass. The inoculation ofcommercial Bacillus sp. isolates was applied in the
first day of the experiment afterfish stocking in order to obtain a bacterial
density in water of 106 cfu/L. Molases wassuplemented daily to the tanks to
adjust C/N ratio in water. Four C/N ratios, i.e. 0, 7,14, and 21, were applied
as treatments in this experiment. The results showed that molasses
suplementation up to C/N ratio 14 to 21 were able to support the growth ofheterotrophic
bacteria and to inhibit the accumulation of total ammonia nitrogen (TAN) and
nitrite in water therefore increase water quality for better growth of cultured
catfish.
KEYWORDS: C/N ratio,
nitrogenous waste, heterotrophic bacteria, biofloc
Author: Bambang Gunadi
Journal Code: jpperikanangg110007
