An assessment of water re-use and feed on the growth performance of tilapia and pond water quality
This study was conducted to evaluate the effect of the quality of water (re-use and fresh) and feed (formulated and farm-made) on the growth performance of tilapia (Oreochromis niloticus). It was conducted between March and October, 2011, at Oseibros farms, Kubease in Ashanti Region and Sefwi Asawinso in the Western Region. Complete randomized block design was used with four treatments (New water and farm-made feed; (NWL), new water and formulated feed: (NWR), re-use water and farm-made feed: (OWL), and re-use water and formulated feed: (OWR) in two blocks, each block containing four plots. Two of these plots (OWR and OWL) contained re- use water and the other two plots (NWR and NWL) contained fresh water. All-male tilapia fingerlings (5g) were stocked at 3 fish m-2 and sampled every two weeks using seine net. pH, DO, temperature and TDS were monitored with a Hanna 9828 multi-parameter probe. Water samples were collected at 30cm above the surface and 30cm from the bottom of the pond and was analysed for phosphorus and total dissolved nitrogen. Data was analysed using analysis of variance (ANOVA) with Graph-pad prism 5 package. Results indicated that, ponds that received farm-made feed and filled with re-used water (OWL: 150.7g) although not significant, had higher growth than fresh water (NWL: 143.7g). With regard to formulated feed, fish cultured in fresh water (197.5g) were larger than those grown in re-use water (164.2g). At Asawinso, the specific growth rate (1.25% day−1) and daily weight gain (1.11g/day) were better than those at Kubease, specific growth rate (0.81% day−1) and daily weight gain ( 0.84g/day). There were no differences in pH and temperature among treatments, however, differences in DO, phosphorus, total dissolved nitrogen and TDS were observed (p<0.05). At the end of the study, it was realized that fish in ponds that contained re-use water appear to exhibit better growth if fed with farm-made feed than with formulated feed while the growth of fish in ponds that contained fresh or renewed water appear to be promoted if fed with formulated feed.
A Thesis submitted to the Department of Freshwater Fisheries and Watershed Management, Kwame Nkrumah University of Science and Technology in partial fulfilment of the requirements for the degree of Master of philosophy in Aquaculture, October-2012