EFFECT OF DIFFERENT TEMPERATURES ON GROWTH AND SEX RATIO OF NILE TILAPIA (Oreochromis niloticus) FRY | ||||
| Journal of Animal and Poultry Production | ||||
| Article 5, Volume 34, Issue 11, November 2009, Page 10497-10505 PDF (635.74 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2009.119387 | ||||
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| Author | ||||
| Mervat A. M. Ali* | ||||
| Animal Production and Fish Res. Dept., Faculty of Agric., Sues Canal Univ., 41522 Ismailia, Egypt | ||||
| Abstract | ||||
| The present study was carried out at Fish Research Center (FRC), Suez CanalUniversity, Ismailia, Egypt, in two consecutive experiments. First experiment, was conducted to determine the effect of different water temperatures on growth performance of Nile tilapia (Oreochromis niloticus) fry. Second experiment, was carried out to study the effect of different water temperatures on sex ratio of progenies of Nile tilapia (Oreochromis niloticus), during their early life stages. In experimental 1, twenty-day-old Nile tilapia fry, weighing 0.30±0.03g, were distributed at a density of 30 fry per 45-L fiberglass aquarium for 60 days on four thermal regimes (20, 25, 30, and 35oC) three replicate for each. The physico-chemical parameters of water in all aquaria were recorded. Fish were fed three times daily using a commercial diet containing 46% protein at a rate of 12% of body weight/day. Growth performance was estimated throughout the experiment. Results showed that the final mean weight was significantly higher at 25 and 30oC than at 20 and 35oC. Daily weight gain (DWG) and feed conversion ration (FCR) were better at 25 and 30oC. At all temperatures, survival rates were not affected.. In experiment 2, Nile tilapia fry (first 20 days after yolk sac resorption) were distributed at a density of 100 fry per 45-L fiberglass aquarium for 28 days in four different temperature regimes (22, 27, 32, and 37oC), three replicate for each. Results showed that the high temperature (37oC) treatment produced a significantly higher proportion of males (89%) with low survival rates (79%). Whereas the sex ratio of progenies reared at temperature below 37oC never deviated significantly from the balanced sex ratio. The study suggested that the best growth and feed utilization of O. niloticus juveniles may be higher at 25 and 30oC and it is possible for producing higher males (sex ratio) population of Nile tilapia by thermal sex reversal. | ||||
| Keywords | ||||
| : Nile tilapia (O. niloticus); growth; temperature; six ratio; survival rate | ||||
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