Science Target Conference Systems, Ajman 4th International Environment Conference 2016

Font Size: 
Effect of ozone and stocking fish density rates on growth performance, blood components and water quality of Nile tilapia (Oreochromis niloticus)
Mohamed Salah Ayyat, Hany Ibrahim El-Marakby, Safaa Mahmoud Sharaf

Last modified: 2015-10-04


The experiment was based on a 2 x 2 factorial design with two stocking density; low level (10 fish/aquarium – 135 fish/m3) and high level (20 fish/aquarium – 270 fish/m3) and two levels of ozone treatment at the levels 0 or 0.5 mg/l, each replicated three time. Increasing fish density to 270 fish/m3 reduced final body weight, daily gain, daily feed offered and survival rate by 3.19, 3.88, 3.66 and 0.83%, respectively, while feed conversion impaired by 1.54% when compared with fish groups stocked at 135 fish/m3. Fish group stocked at the lower density recorded higher gain% (348.45%) when compared with those stocked at the high level. The concentrations of ammonia, nitrite and nitrate in aquarium water increased with increasing fish density in units, on the other hand the concentration of dissolved oxygen decreased.

Fish groups reared in water treatment with ozone increased survival rate and gain percent. Treatment aquarium water with ozone increased final body weight, daily gain and daily feed offered by 10.83, 13.62 and 8.83%, respectively, when compared with those reared in untreated water with ozone. The concentrations of ammonia, nitrite and nitrate decreased in water when treated with ozone, while dissolved oxygen increased. Fish group reared at the low density and treated with ozone recorded higher feed cost, return from body gain and final margin than fish group reared at the high density and treated with ozone, when compared with the other experimental groups.