AN ASSESSMENT STUDY OF TILAPIA POLYCULTURE IN FLOATING NET CAGES | ||||
| Journal of Animal and Poultry Production | ||||
| Article 2, Volume 2, Issue 5, May 2011, Page 75-92 PDF (543.56 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2011.83344 | ||||
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| Authors | ||||
| F. F. Khalil1; A. I. Mehrim1; A. A. El-Shebly2; M. E.A. Abdelaal1 | ||||
| 1Animal Production Dept., Fac. Agric., Mans. Univ., Mans., Egypt. | ||||
| 2Fish culture Lab., National Inst. of Oceanography and Fisheries, Egypt. | ||||
| Abstract | ||||
| The present study was carried out from 15th May 2005 to 15th September 2005, in order to evaluate the polyculture of three tilapia species namely, Oreochromis niloticus, Sarotherodon galilaeus and Tilapia zillii in cages. This study was carried out at three sites in the project of fish cage culture of young farmers in El-Manzala Lake, El-Dakahlia Governorate, Egypt, under different three management conditions of tilapia polyculture as following: the 1st management site depending on the natural feeds only under low stocking density conditions (34.7 fish/ m3, approximately) and initial weight of 36.7g; the 2nd management site depending on the natural feeds and the supplementary feeding (19.9% crude protein) under high stocking density conditions (49.2 fish /m3) and initial weight of 25.9g and the 3rd management experimental site depending on a commercial fish pelleted diet (26.7% crude protein) and initial weight of 26.6g under high stocking density conditions (42.8 fish/ m3). The tested parameters included the water quality, growth performance, carcass composition of fish, feed and nutrients utilization and the economic efficiency. The obtained results showed that: 1- Water quality criteria were suitable for fish rearing such as water temperature ranged between 21 and 33oC, pH values 7.2 – 8.3 and dissolved oxygen 6.7 – 8.4 mg/l. other water biochemical parameters (ppm) of the three experimental cage's sites are also suitable for fish rearing except salinity, total hardness and bicarbonates were slightly differences. 2- Fish growth performance in 3rd cage's site one is better than other cage's sites (1st and 2nd). 3- There were superiority of O. niloticus in growth performance and carcass composition comparing with other tilapia species (S. galilaeus and T. zillii). 4- The 3rd cage's site was better than 2nd cage's site not only fish growth, but also in all feed and nutrients utilization parameters. There by the 3rd cage's site realized the best economic efficiency and relative economic efficiency comparing with other cage's sites, while the 2nd management site came second. So, it could be concluded that it must be using the commercial complete diets for feeding fish especially under intensive fish culture such as cages in 3rd management site for higher fish production with economically efficiency. Yet, the obtained results in the present management study confirmed the superiority of Nile tilapia (O. niloticus) comparing with other tilapia species (S. galilaeus and T. zillii), in growth performance parameters and carcass composition in all experimental cage's sites and management. Also, from environmentally point of view, it could be concluded that the overcoming of different sources of water pollution in LakeEl-Manzala are very important to get high quality and safety fish production | ||||
| Keywords | ||||
| Fish polyculture; Tilapia spp. - Cages - Water quality - Growth - Economic efficiency | ||||
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