EFFECTS OF BIOFLOC TECHNOLOGY ON GROWTH PERFORMANCE OF NILE TILAPIA (Oreochromis Niloticus)FINGERLINGS AND MICROBIAL COLONIZATION IN THE SYSTEM.

Abstract

Aquaculture intensification is characterized by high stocking density and need of high quality and quantity of artificial feed. Increased fish biomass and feed input brings about rapid deterioration of water quality hence a water quality management system need to be put in place in such systems. Biofloc technology has been developed as a viable option to recycle nutrient by maintaining a high carbon/nitrogen (C/N) ratio in the water in order to stimulate heterotrophic bacterial growth which converts ammonia into useful microbial biomass. This study investigated the effect of carbon source supplement in biofloc system on growth performance, water quality and microbial community in the system. The experimental research was conducted at the University of Eldoret from June -September 2017. A complete randomized design was used in triplicate treatments. The supplementation carbon source constituted molasses, wheat flour, potatoes flour and control respectively. At molasses carbon added treatments Nile tilapia indicated the highest significant growth at (p < 0.05) than other treatments with final mean weights (8.774±0.394g) and total length (7.956±0.123cm). The least growth of Nile tilapia fingerlings wasat control treatments with final mean (3.784±0215g, 5.827±0.114cm) weights and length respectively. Molasses added bioflocexhibited highest protozoan (520.13±1.02), rotifers (200.6±1.08), cyanobacteria (143.1±1.22) and diatoms (60.033±0.083) and improved water quality as compared to other treatments. The results revealed that molasses added in biofloc system improves Nile tilapia growth, microorganism colonization and water quality in the system than other carbon added treatment tested. The study recommends molasses carbon source for Nile tilapia fingerlings growth as it pertaining to the improved results of microorganism levels and water quality obtained in the system.