SUMMARY AND CONCLUSION
The present study was carried out at the Laboratory of Fish Nutrition Faculty of Agriculture at Moshtohor‚ Benha University. The aim of this study was to investigate the effect of different regimes of over-wintering on growth performance and survival rate of O. niloticus.
The experiment was conducted during the winter period from the 1st of January 2013 till the 1st of April of the same year (12 weeks). Twelve plastic indoor tanks (500 liter for each) were used in the study and each tank was filled by 400 liter freshwater to represent different four experimental treatments (3 replicates for each treatment) and each tank was stocked with 40 fish with an initial weight ranged from 6.31 to 6.39±0.003 g.
Fish were given the basal diets at a daily rate of 1% of total biomass 6 day/week during the experimental period. Also Starch was added in BFT tanks at a daily rate of 48% of pelleted feed to developing the bio-flocs. The tanks were cleaned and water was replaced at a daily rate of 20% of total water in three treatments (control & L-carnitine and covering with plastic sheets) while it was replaced at a daily rate of 2% of total water in treatment one (bio-flocs Technology).
Results obtained can be summarized as follows:
- The initial body weight for fish received the different treatments ranged between 6.31 and 6.39 g and the differences in BW among different treatments were insignificant. At experiment termination (after 12 weeks from the experiment start) results showed that, fish in treatment one (bioflocs technique, BFT) showed the highest BW (10.79 g) and control group showed the lowest (9.11 g) one and the differences between different treatments were significant (P |
