EFFECT OF DIFFERENT CARBON SOURCES ON MICROBIAL ACTIVITY, WATER QUALITY AND GROWTH PERFORMANCE OF OREOCHROMIS NILOTICUS CULTURED

EFFECT OF DIFFERENT CARBON SOURCES ON MICROBIAL ACTIVITY, WATER QUALITY AND GROWTH PERFORMANCE OF OREOCHROMIS NILOTICUS CULTURED

IN BIOFLOC INDOOR TANKS

H.S. Shalaby¹; A.A. El Gamal¹; M.A. Amer¹;

T.A. Aboelmakarem¹and T.S. Eltayeb²

¹Animal Production Department, Faculty of Agriculture, Ain Shams University, 68 HadaekShoubra, 11241, Cairo, Egypt.

² Department of Agriculture Microbiology, Faculty of Agriculture, Ain Shams University, 68 HadaekShoubra, 11241, Cairo, Egypt.

Abstract

Application of bioflocs technology (BFT) in aquaculture offers a solution to water scarcity problems. Where BFT is the development and control of dense heterotrophic microbial flocs in the water column by adding carbon sources to fish culture pond. Hence, the objective of the present study is to evaluate the effects of two different carbon sources: molasses (T1), and cornstarch (T2); on microbial activity, water quality parameters and growth performance of Orechromis niloticus in indoor biofloc tanks compared with that reared in a clear water with no carbon sources (T3). The present study was maintained for 112 day; the experimental tanks stoked with 64 fish / m⁻³ with average initial weight of 31.5 ± 0.431g and carbon sources were added at C/N ratio20: 1 in molasses and corn starch.

The results demonstrated that the addition of molasses and cornstarch had a significant reduction in concentrations of the total ammonium nitrogen, nitrite nitrogen and increased the total heterotrophic bacterial densities (P<0.05), respectively compared to control. The biofloc development in terms of Floc volume index (FVI) and total heterotrophic bacteria count were in favor of molasses tanks than corn starch tanks. parameters of growth performance of tilapia including net yield, specific growth rate (SGR), weight gain percentage, growth rate and feed conversion ratio demonstrated that, carbohydrate addition into zero-water exchange systems for O. niloticus intensive culture can effectively improve water quality, bacterial activities and fish growth. which, eventually lead to a higher growth performance compared to that cultured under traditional systems.

Keywords: Biofloc technology, Zero water exchange, Heterotrophic bacteria, Carbohydrate addition, Total suspended solids, Floc volume index, C/N ratio, Orechromis niloticus.