Description

Abstract: An experiment was conducted to test the effect of chicken manure, 16-20-0, feeds with 20% crude protein (CP) and their combinations on pond productivity and water quality and on the growth and production of Nile tilapia (Oreochromis niloticus) in brackishwater ponds. Results showed low average daily weight increments of Nile tilapia of 0.52 to 1.25 g/day and 0.56 to 1.04 g/day for the first and second runs, respectively. Fish from treatments that received feed (either alone or in combination with chicken manure and/or 16-20-0) were significantly bigger (P<0.01) than fish from treatments without feed. The combination of chicken manure and 16-20-0 did not contribute significantly to the production of tilapia. Higher temperatures were obtained in the treatments with inputs. Dissolved oxygen Content was lowest in the feed-chicken manure-16-20-0 combination. Nitrate and nitrite levels were significantly higher in the treatments that received chicken manure (P<0.05); available phosphorus was significantly highest (P<0.01) in the chicken manure-feed combination. There are indications that the phosphorus Content of chicken manure increased that in the soil although total phosphorus in the soil contributed only about 0.8% of that in water. The organic matter Content of the pond soil was influenced by the various inputs resulting in significantly higher (P<0.01) organic matter Content of the sediments in the treatments that received chicken manure, feeds and their combination. There were no significant differences (P>0.05) among the treatments in terms of primary productivity, zoo- and phytoplankton populations and algal biomass. A highly significant difference (P<0.01) among the treatments was observed in terms of chlorophyll a concentration.