Effect of method and rates of feeding on the growth performance and feed utilization of monosex tilapia nilotica (oreochromis niloticus L.) In semi-intensive culture system [electronic resource].

Includes references.

This study was carried out to Investigate the effect of method and rates of feeding on growth performance, feed utilization and econmic evaluation for Oreochromis niloticus L. reared in aerated earthen ponds. Nine rectangular earthen ponds, each of a total area of one feddan, representing nine treatments,i.e. three different methods of feeding ( hand feeding, automatic feeder and demand feeder) within each of three feeding rates ( 3, 4 and 5 %of total biomass of fish )were tested . Experimental fish were fed on a commercial diet ( 25% CP and 4100 Kcal/ kg diet) and ponds were fertilized with 100 kg organic fertilizer ( chicken manure , devided Into two portions) monthly. One paddle wheel aerator ( 1 horse power) per pond was used to increase the rate of oxygenation of pond water . The pond water was completly changed every 3Odays. The experiment expanded 16 weeks after start . Results obtained can be summarized as follows: The water quality measurements were found to be within the normal range of tolerance and for the well being of monosex Nile tilapia. Results obtained at the end of the experiment for the growth performance' of monosex Nile tilapia represented in body weight ( BW), weight gain (WG), accumulative growth rate(AGR), total yield ( TV) ,feed intake ( FI), and feed conversion ratio ( FCR) showed that fish fed by automatic feeder at 5% feeding rate of liIapia biomass I day exhibited superior growth performance rather than those reared on demand feeder and hand feeding at 3% and 4% of tilapia biomass! day. Statistical evalation of the results showed that the differences among the experimental groups were significant ( p < 0.05 ) . Based On the results obtained, it could be recommended that using the automatic feeder method with 5% of biomass! day as a feeding rate for monosex Nile tilapia cultured in earthen ponds at stocking density of 50 fish/m³ with using a paddle wheel aerator per pond must be used to Increase the rate of oxygenation of pond water to obtain higher yield and economic net profit.

Summary in Arabic.

1